diff --git a/apps/bench.py b/apps/bench.py
index 67299db..7bbba77 100644
--- a/apps/bench.py
+++ b/apps/bench.py
@@ -16,6 +16,7 @@
 # Imports
 # -----------------------------------------------------------------------------
 import asyncio
+import dataclasses
 import enum
 import logging
 import os
@@ -97,34 +98,6 @@ DEFAULT_RFCOMM_MTU = 2048
 # -----------------------------------------------------------------------------
 # Utils
 # -----------------------------------------------------------------------------
-def parse_packet(packet):
-    if len(packet) < 1:
-        logging.info(
-            color(f'!!! Packet too short (got {len(packet)} bytes, need >= 1)', 'red')
-        )
-        raise ValueError('packet too short')
-
-    try:
-        packet_type = PacketType(packet[0])
-    except ValueError:
-        logging.info(color(f'!!! Invalid packet type 0x{packet[0]:02X}', 'red'))
-        raise
-
-    return (packet_type, packet[1:])
-
-
-def parse_packet_sequence(packet_data):
-    if len(packet_data) < 5:
-        logging.info(
-            color(
-                f'!!!Packet too short (got {len(packet_data)} bytes, need >= 5)',
-                'red',
-            )
-        )
-        raise ValueError('packet too short')
-    return struct.unpack_from('>bI', packet_data, 0)
-
-
 def le_phy_name(phy_id):
     return {HCI_LE_1M_PHY: '1M', HCI_LE_2M_PHY: '2M', HCI_LE_CODED_PHY: 'CODED'}.get(
         phy_id, HCI_Constant.le_phy_name(phy_id)
@@ -225,13 +198,135 @@ async def switch_roles(connection, role):
             logging.info(f'{color("### Role switch failed:", "red")} {error}')
 
 
-class PacketType(enum.IntEnum):
-    RESET = 0
-    SEQUENCE = 1
-    ACK = 2
+# -----------------------------------------------------------------------------
+# Packet
+# -----------------------------------------------------------------------------
+@dataclasses.dataclass
+class Packet:
+    class PacketType(enum.IntEnum):
+        RESET = 0
+        SEQUENCE = 1
+        ACK = 2
+
+    class PacketFlags(enum.IntFlag):
+        LAST = 1
+
+    packet_type: PacketType
+    flags: PacketFlags = PacketFlags(0)
+    sequence: int = 0
+    timestamp: int = 0
+    payload: bytes = b""
+
+    @classmethod
+    def from_bytes(cls, data: bytes):
+        if len(data) < 1:
+            logging.warning(
+                color(f'!!! Packet too short (got {len(data)} bytes, need >= 1)', 'red')
+            )
+            raise ValueError('packet too short')
+
+        try:
+            packet_type = cls.PacketType(data[0])
+        except ValueError:
+            logging.warning(color(f'!!! Invalid packet type 0x{data[0]:02X}', 'red'))
+            raise
+
+        if packet_type == cls.PacketType.RESET:
+            return cls(packet_type)
+
+        flags = cls.PacketFlags(data[1])
+        (sequence,) = struct.unpack_from("<I", data, 2)
+
+        if packet_type == cls.PacketType.ACK:
+            if len(data) < 6:
+                logging.warning(
+                    color(
+                        f'!!! Packet too short (got {len(data)} bytes, need >= 6)',
+                        'red',
+                    )
+                )
+            return cls(packet_type, flags, sequence)
+
+        if len(data) < 10:
+            logging.warning(
+                color(
+                    f'!!! Packet too short (got {len(data)} bytes, need >= 10)', 'red'
+                )
+            )
+            raise ValueError('packet too short')
+
+        (timestamp,) = struct.unpack_from("<I", data, 6)
+        return cls(packet_type, flags, sequence, timestamp, data[10:])
+
+    def __bytes__(self):
+        if self.packet_type == self.PacketType.RESET:
+            return bytes([self.packet_type])
+
+        if self.packet_type == self.PacketType.ACK:
+            return struct.pack("<BBI", self.packet_type, self.flags, self.sequence)
+
+        return (
+            struct.pack(
+                "<BBII", self.packet_type, self.flags, self.sequence, self.timestamp
+            )
+            + self.payload
+        )
 
 
-PACKET_FLAG_LAST = 1
+# -----------------------------------------------------------------------------
+# Jitter Stats
+# -----------------------------------------------------------------------------
+class JitterStats:
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        self.packets = []
+        self.receive_times = []
+        self.jitter = []
+
+    def on_packet_received(self, packet):
+        now = time.time()
+        self.packets.append(packet)
+        self.receive_times.append(now)
+
+        if packet.timestamp and len(self.packets) > 1:
+            expected_time = (
+                self.receive_times[0]
+                + (packet.timestamp - self.packets[0].timestamp) / 1000000
+            )
+            jitter = now - expected_time
+        else:
+            jitter = 0.0
+
+        self.jitter.append(jitter)
+        return jitter
+
+    def show_stats(self):
+        if len(self.jitter) < 3:
+            return
+        average = sum(self.jitter) / len(self.jitter)
+        adjusted = [jitter - average for jitter in self.jitter]
+
+        log_stats('Jitter (signed)', adjusted, 3)
+        log_stats('Jitter (absolute)', [abs(jitter) for jitter in adjusted], 3)
+
+        # Show a histogram
+        bin_count = 20
+        bins = [0] * bin_count
+        interval_min = min(adjusted)
+        interval_max = max(adjusted)
+        interval_range = interval_max - interval_min
+        bin_thresholds = [
+            interval_min + i * (interval_range / bin_count) for i in range(bin_count)
+        ]
+        for jitter in adjusted:
+            for i in reversed(range(bin_count)):
+                if jitter >= bin_thresholds[i]:
+                    bins[i] += 1
+                    break
+        for i in range(bin_count):
+            logging.info(f'@@@ >= {bin_thresholds[i]:.4f}: {bins[i]}')
 
 
 # -----------------------------------------------------------------------------
@@ -281,19 +376,37 @@ class Sender:
                 await asyncio.sleep(self.tx_start_delay)
 
             logging.info(color('=== Sending RESET', 'magenta'))
-            await self.packet_io.send_packet(bytes([PacketType.RESET]))
+            await self.packet_io.send_packet(
+                bytes(Packet(packet_type=Packet.PacketType.RESET))
+            )
+
             self.start_time = time.time()
             self.bytes_sent = 0
             for tx_i in range(self.tx_packet_count):
-                packet_flags = (
-                    PACKET_FLAG_LAST if tx_i == self.tx_packet_count - 1 else 0
+                if self.pace > 0:
+                    # Wait until it is time to send the next packet
+                    target_time = self.start_time + (tx_i * self.pace / 1000)
+                    now = time.time()
+                    if now < target_time:
+                        await asyncio.sleep(target_time - now)
+                else:
+                    await self.packet_io.drain()
+
+                packet = bytes(
+                    Packet(
+                        packet_type=Packet.PacketType.SEQUENCE,
+                        flags=(
+                            Packet.PacketFlags.LAST
+                            if tx_i == self.tx_packet_count - 1
+                            else 0
+                        ),
+                        sequence=tx_i,
+                        timestamp=int((time.time() - self.start_time) * 1000000),
+                        payload=bytes(
+                            self.tx_packet_size - 10 - self.packet_io.overhead_size
+                        ),
+                    )
                 )
-                packet = struct.pack(
-                    '>bbI',
-                    PacketType.SEQUENCE,
-                    packet_flags,
-                    tx_i,
-                ) + bytes(self.tx_packet_size - 6 - self.packet_io.overhead_size)
                 logging.info(
                     color(
                         f'Sending packet {tx_i}: {self.tx_packet_size} bytes', 'yellow'
@@ -302,14 +415,6 @@ class Sender:
                 self.bytes_sent += len(packet)
                 await self.packet_io.send_packet(packet)
 
-                if self.pace is None:
-                    continue
-
-                if self.pace > 0:
-                    await asyncio.sleep(self.pace / 1000)
-                else:
-                    await self.packet_io.drain()
-
             await self.done.wait()
 
             run_counter = f'[{run + 1} of {self.repeat + 1}]' if self.repeat else ''
@@ -321,13 +426,13 @@ class Sender:
         if self.repeat:
             logging.info(color('--- End of runs', 'blue'))
 
-    def on_packet_received(self, packet):
+    def on_packet_received(self, data):
         try:
-            packet_type, _ = parse_packet(packet)
+            packet = Packet.from_bytes(data)
         except ValueError:
             return
 
-        if packet_type == PacketType.ACK:
+        if packet.packet_type == Packet.PacketType.ACK:
             elapsed = time.time() - self.start_time
             average_tx_speed = self.bytes_sent / elapsed
             self.stats.append(average_tx_speed)
@@ -350,52 +455,53 @@ class Receiver:
     last_timestamp: float
 
     def __init__(self, packet_io, linger):
-        self.reset()
+        self.jitter_stats = JitterStats()
         self.packet_io = packet_io
         self.packet_io.packet_listener = self
         self.linger = linger
         self.done = asyncio.Event()
+        self.reset()
 
     def reset(self):
         self.expected_packet_index = 0
         self.measurements = [(time.time(), 0)]
         self.total_bytes_received = 0
+        self.jitter_stats.reset()
 
-    def on_packet_received(self, packet):
+    def on_packet_received(self, data):
         try:
-            packet_type, packet_data = parse_packet(packet)
+            packet = Packet.from_bytes(data)
         except ValueError:
+            logging.exception("invalid packet")
             return
 
-        if packet_type == PacketType.RESET:
+        if packet.packet_type == Packet.PacketType.RESET:
             logging.info(color('=== Received RESET', 'magenta'))
             self.reset()
             return
 
-        try:
-            packet_flags, packet_index = parse_packet_sequence(packet_data)
-        except ValueError:
-            return
+        jitter = self.jitter_stats.on_packet_received(packet)
         logging.info(
-            f'<<< Received packet {packet_index}: '
-            f'flags=0x{packet_flags:02X}, '
-            f'{len(packet) + self.packet_io.overhead_size} bytes'
+            f'<<< Received packet {packet.sequence}: '
+            f'flags={packet.flags}, '
+            f'jitter={jitter:.4f}, '
+            f'{len(data) + self.packet_io.overhead_size} bytes',
         )
 
-        if packet_index != self.expected_packet_index:
+        if packet.sequence != self.expected_packet_index:
             logging.info(
                 color(
                     f'!!! Unexpected packet, expected {self.expected_packet_index} '
-                    f'but received {packet_index}'
+                    f'but received {packet.sequence}'
                 )
             )
 
         now = time.time()
         elapsed_since_start = now - self.measurements[0][0]
         elapsed_since_last = now - self.measurements[-1][0]
-        self.measurements.append((now, len(packet)))
-        self.total_bytes_received += len(packet)
-        instant_rx_speed = len(packet) / elapsed_since_last
+        self.measurements.append((now, len(data)))
+        self.total_bytes_received += len(data)
+        instant_rx_speed = len(data) / elapsed_since_last
         average_rx_speed = self.total_bytes_received / elapsed_since_start
         window = self.measurements[-64:]
         windowed_rx_speed = sum(measurement[1] for measurement in window[1:]) / (
@@ -411,15 +517,17 @@ class Receiver:
             )
         )
 
-        self.expected_packet_index = packet_index + 1
+        self.expected_packet_index = packet.sequence + 1
 
-        if packet_flags & PACKET_FLAG_LAST:
+        if packet.flags & Packet.PacketFlags.LAST:
             AsyncRunner.spawn(
                 self.packet_io.send_packet(
-                    struct.pack('>bbI', PacketType.ACK, packet_flags, packet_index)
+                    bytes(Packet(Packet.PacketType.ACK, packet.flags, packet.sequence))
                 )
             )
             logging.info(color('@@@ Received last packet', 'green'))
+            self.jitter_stats.show_stats()
+
             if not self.linger:
                 self.done.set()
 
@@ -479,25 +587,32 @@ class Ping:
                 await asyncio.sleep(self.tx_start_delay)
 
             logging.info(color('=== Sending RESET', 'magenta'))
-            await self.packet_io.send_packet(bytes([PacketType.RESET]))
+            await self.packet_io.send_packet(bytes(Packet(Packet.PacketType.RESET)))
 
-            packet_interval = self.pace / 1000
             start_time = time.time()
             self.next_expected_packet_index = 0
             for i in range(self.tx_packet_count):
-                target_time = start_time + (i * packet_interval)
+                target_time = start_time + (i * self.pace / 1000)
                 now = time.time()
                 if now < target_time:
                     await asyncio.sleep(target_time - now)
+                    now = time.time()
 
-                packet = struct.pack(
-                    '>bbI',
-                    PacketType.SEQUENCE,
-                    (PACKET_FLAG_LAST if i == self.tx_packet_count - 1 else 0),
-                    i,
-                ) + bytes(self.tx_packet_size - 6)
+                packet = bytes(
+                    Packet(
+                        packet_type=Packet.PacketType.SEQUENCE,
+                        flags=(
+                            Packet.PacketFlags.LAST
+                            if i == self.tx_packet_count - 1
+                            else 0
+                        ),
+                        sequence=i,
+                        timestamp=int((now - start_time) * 1000000),
+                        payload=bytes(self.tx_packet_size - 10),
+                    )
+                )
                 logging.info(color(f'Sending packet {i}', 'yellow'))
-                self.ping_times.append(time.time())
+                self.ping_times.append(now)
                 await self.packet_io.send_packet(packet)
 
             await self.done.wait()
@@ -531,40 +646,35 @@ class Ping:
         if self.repeat:
             logging.info(color('--- End of runs', 'blue'))
 
-    def on_packet_received(self, packet):
+    def on_packet_received(self, data):
         try:
-            packet_type, packet_data = parse_packet(packet)
+            packet = Packet.from_bytes(data)
         except ValueError:
             return
 
-        try:
-            packet_flags, packet_index = parse_packet_sequence(packet_data)
-        except ValueError:
-            return
-
-        if packet_type == PacketType.ACK:
-            elapsed = time.time() - self.ping_times[packet_index]
+        if packet.packet_type == Packet.PacketType.ACK:
+            elapsed = time.time() - self.ping_times[packet.sequence]
             rtt = elapsed * 1000
             self.rtts.append(rtt)
             logging.info(
                 color(
-                    f'<<< Received ACK [{packet_index}], RTT={rtt:.2f}ms',
+                    f'<<< Received ACK [{packet.sequence}], RTT={rtt:.2f}ms',
                     'green',
                 )
             )
 
-            if packet_index == self.next_expected_packet_index:
+            if packet.sequence == self.next_expected_packet_index:
                 self.next_expected_packet_index += 1
             else:
                 logging.info(
                     color(
                         f'!!! Unexpected packet, '
                         f'expected {self.next_expected_packet_index} '
-                        f'but received {packet_index}'
+                        f'but received {packet.sequence}'
                     )
                 )
 
-        if packet_flags & PACKET_FLAG_LAST:
+        if packet.flags & Packet.PacketFlags.LAST:
             self.done.set()
             return
 
@@ -576,89 +686,56 @@ class Pong:
     expected_packet_index: int
 
     def __init__(self, packet_io, linger):
-        self.reset()
+        self.jitter_stats = JitterStats()
         self.packet_io = packet_io
         self.packet_io.packet_listener = self
         self.linger = linger
         self.done = asyncio.Event()
+        self.reset()
 
     def reset(self):
         self.expected_packet_index = 0
-        self.receive_times = []
-
-    def on_packet_received(self, packet):
-        self.receive_times.append(time.time())
+        self.jitter_stats.reset()
 
+    def on_packet_received(self, data):
         try:
-            packet_type, packet_data = parse_packet(packet)
+            packet = Packet.from_bytes(data)
         except ValueError:
             return
 
-        if packet_type == PacketType.RESET:
+        if packet.packet_type == Packet.PacketType.RESET:
             logging.info(color('=== Received RESET', 'magenta'))
             self.reset()
             return
 
-        try:
-            packet_flags, packet_index = parse_packet_sequence(packet_data)
-        except ValueError:
-            return
-        interval = (
-            self.receive_times[-1] - self.receive_times[-2]
-            if len(self.receive_times) >= 2
-            else 0
-        )
+        jitter = self.jitter_stats.on_packet_received(packet)
         logging.info(
             color(
-                f'<<< Received packet {packet_index}: '
-                f'flags=0x{packet_flags:02X}, {len(packet)} bytes, '
-                f'interval={interval:.4f}',
+                f'<<< Received packet {packet.sequence}: '
+                f'flags={packet.flags}, {len(data)} bytes, '
+                f'jitter={jitter:.4f}',
                 'green',
             )
         )
 
-        if packet_index != self.expected_packet_index:
+        if packet.sequence != self.expected_packet_index:
             logging.info(
                 color(
                     f'!!! Unexpected packet, expected {self.expected_packet_index} '
-                    f'but received {packet_index}'
+                    f'but received {packet.sequence}'
                 )
             )
 
-        self.expected_packet_index = packet_index + 1
+        self.expected_packet_index = packet.sequence + 1
 
         AsyncRunner.spawn(
             self.packet_io.send_packet(
-                struct.pack('>bbI', PacketType.ACK, packet_flags, packet_index)
+                bytes(Packet(Packet.PacketType.ACK, packet.flags, packet.sequence))
             )
         )
 
-        if packet_flags & PACKET_FLAG_LAST:
-            if len(self.receive_times) >= 3:
-                # Show basic stats
-                intervals = [
-                    self.receive_times[i + 1] - self.receive_times[i]
-                    for i in range(len(self.receive_times) - 1)
-                ]
-                log_stats('Packet intervals', intervals, 3)
-
-                # Show a histogram
-                bin_count = 20
-                bins = [0] * bin_count
-                interval_min = min(intervals)
-                interval_max = max(intervals)
-                interval_range = interval_max - interval_min
-                bin_thresholds = [
-                    interval_min + i * (interval_range / bin_count)
-                    for i in range(bin_count)
-                ]
-                for interval in intervals:
-                    for i in reversed(range(bin_count)):
-                        if interval >= bin_thresholds[i]:
-                            bins[i] += 1
-                            break
-                for i in range(bin_count):
-                    logging.info(f'@@@ >= {bin_thresholds[i]:.4f}: {bins[i]}')
+        if packet.flags & Packet.PacketFlags.LAST:
+            self.jitter_stats.show_stats()
 
             if not self.linger:
                 self.done.set()
@@ -1471,7 +1548,7 @@ def create_mode_factory(ctx, default_mode):
 def create_scenario_factory(ctx, default_scenario):
     scenario = ctx.obj['scenario']
     if scenario is None:
-        scenarion = default_scenario
+        scenario = default_scenario
 
     def create_scenario(packet_io):
         if scenario == 'send':
@@ -1530,6 +1607,7 @@ def create_scenario_factory(ctx, default_scenario):
     '--att-mtu',
     metavar='MTU',
     type=click.IntRange(23, 517),
+    default=517,
     help='GATT MTU (gatt-client mode)',
 )
 @click.option(
@@ -1605,7 +1683,7 @@ def create_scenario_factory(ctx, default_scenario):
     '--packet-size',
     '-s',
     metavar='SIZE',
-    type=click.IntRange(8, 8192),
+    type=click.IntRange(10, 8192),
     default=500,
     help='Packet size (send or ping scenario)',
 )
diff --git a/bumble/device.py b/bumble/device.py
index 4ab5c28..14ae6c3 100644
--- a/bumble/device.py
+++ b/bumble/device.py
@@ -2475,7 +2475,7 @@ class Device(CompositeEventEmitter):
             if self.random_address != hci.Address.ANY_RANDOM:
                 logger.debug(
                     color(
-                        f'LE Random hci.Address: {self.random_address}',
+                        f'LE Random Address: {self.random_address}',
                         'yellow',
                     )
                 )
diff --git a/examples/mobly/bench/one_device_bench_test.py b/examples/mobly/bench/one_device_bench_test.py
index 6fbc101..c715885 100644
--- a/examples/mobly/bench/one_device_bench_test.py
+++ b/examples/mobly/bench/one_device_bench_test.py
@@ -28,7 +28,7 @@ class OneDeviceBenchTest(base_test.BaseTestClass):
 
     def test_l2cap_client_ping(self):
         runner = self.dut.bench.runL2capClient(
-            "ping", "4B:2A:67:76:2B:E3", 128, True, 100, 970, 100
+            "ping", "4B:2A:67:76:2B:E3", 128, True, 100, 970, 100, "HIGH"
         )
         print("### Initial status:", runner)
         final_status = self.dut.bench.waitForRunnerCompletion(runner["id"])
@@ -36,12 +36,34 @@ class OneDeviceBenchTest(base_test.BaseTestClass):
 
     def test_l2cap_client_send(self):
         runner = self.dut.bench.runL2capClient(
-            "send", "7E:90:D0:F2:7A:11", 131, True, 100, 970, 0
+            "send",
+            "F1:F1:F1:F1:F1:F1",
+            128,
+            True,
+            100,
+            970,
+            0,
+            "HIGH",
+            10000,
         )
         print("### Initial status:", runner)
         final_status = self.dut.bench.waitForRunnerCompletion(runner["id"])
         print("### Final status:", final_status)
 
+    def test_gatt_client_send(self):
+        runner = self.dut.bench.runGattClient(
+            "send", "F1:F1:F1:F1:F1:F1", 128, True, 100, 970, 100, "HIGH"
+        )
+        print("### Initial status:", runner)
+        final_status = self.dut.bench.waitForRunnerCompletion(runner["id"])
+        print("### Final status:", final_status)
+
+    def test_gatt_server_receive(self):
+        runner = self.dut.bench.runGattServer("receive")
+        print("### Initial status:", runner)
+        final_status = self.dut.bench.waitForRunnerCompletion(runner["id"])
+        print("### Final status:", final_status)
+
 
 if __name__ == "__main__":
     test_runner.main()
diff --git a/examples/mobly/bench/sample_config.yml b/examples/mobly/bench/sample_config.yml
index 7a1a0d4..50823a4 100644
--- a/examples/mobly/bench/sample_config.yml
+++ b/examples/mobly/bench/sample_config.yml
@@ -2,8 +2,8 @@ TestBeds:
   - Name: BenchTestBed
     Controllers:
         AndroidDevice:
-          - serial: 37211FDJG000DJ
+          - serial: emulator-5554
             local_bt_address: 94:45:60:5E:03:B0
 
-          - serial: 23071FDEE001F7
-            local_bt_address: DC:E5:5B:E5:51:2C
+          #- serial: 23071FDEE001F7
+          #  local_bt_address: DC:E5:5B:E5:51:2C
diff --git a/extras/android/BtBench/app/build.gradle.kts b/extras/android/BtBench/app/build.gradle.kts
index 05d36e1..887be16 100644
--- a/extras/android/BtBench/app/build.gradle.kts
+++ b/extras/android/BtBench/app/build.gradle.kts
@@ -10,7 +10,7 @@ android {
 
     defaultConfig {
         applicationId = "com.github.google.bumble.btbench"
-        minSdk = 30
+        minSdk = 33
         targetSdk = 34
         versionCode = 1
         versionName = "1.0"
diff --git a/extras/android/BtBench/app/src/main/AndroidManifest.xml b/extras/android/BtBench/app/src/main/AndroidManifest.xml
index 6be3478..f522fb8 100644
--- a/extras/android/BtBench/app/src/main/AndroidManifest.xml
+++ b/extras/android/BtBench/app/src/main/AndroidManifest.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.github.google.bumble.btbench">
-     <uses-sdk android:minSdkVersion="30" android:targetSdkVersion="34" />
+     <uses-sdk android:minSdkVersion="33" android:targetSdkVersion="34" />
     <!-- Request legacy Bluetooth permissions on older devices. -->
     <uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30" />
     <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" android:maxSdkVersion="30" />
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Advertiser.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Advertiser.kt
new file mode 100644
index 0000000..b7370a8
--- /dev/null
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Advertiser.kt
@@ -0,0 +1,39 @@
+package com.github.google.bumble.btbench
+
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.le.AdvertiseCallback
+import android.bluetooth.le.AdvertiseData
+import android.bluetooth.le.AdvertiseSettings
+import android.bluetooth.le.AdvertiseSettings.ADVERTISE_MODE_LOW_LATENCY
+import android.os.Build
+import java.util.logging.Logger
+
+private val Log = Logger.getLogger("btbench.advertiser")
+
+class Advertiser(private val bluetoothAdapter: BluetoothAdapter) : AdvertiseCallback() {
+    @SuppressLint("MissingPermission")
+    fun start() {
+        val advertiseSettingsBuilder = AdvertiseSettings.Builder()
+            .setAdvertiseMode(ADVERTISE_MODE_LOW_LATENCY)
+            .setConnectable(true)
+        advertiseSettingsBuilder.setDiscoverable(true)
+        val advertiseSettings = advertiseSettingsBuilder.build()
+        val advertiseData = AdvertiseData.Builder().build()
+        val scanData = AdvertiseData.Builder().setIncludeDeviceName(true).build()
+        bluetoothAdapter.bluetoothLeAdvertiser.startAdvertising(advertiseSettings, advertiseData, scanData, this)
+    }
+
+    @SuppressLint("MissingPermission")
+    fun stop() {
+        bluetoothAdapter.bluetoothLeAdvertiser.stopAdvertising(this)
+    }
+
+    override fun onStartFailure(errorCode: Int) {
+        Log.warning("failed to start advertising: $errorCode")
+    }
+
+    override fun onStartSuccess(settingsInEffect: AdvertiseSettings) {
+        Log.info("advertising started: $settingsInEffect")
+    }
+}
\ No newline at end of file
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/AutomationSnippet.java b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/AutomationSnippet.java
index 3a7afa4..ca7d41d 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/AutomationSnippet.java
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/AutomationSnippet.java
@@ -22,11 +22,13 @@ import androidx.test.core.app.ApplicationProvider;
 
 import com.google.android.mobly.snippet.Snippet;
 import com.google.android.mobly.snippet.rpc.Rpc;
+import com.google.android.mobly.snippet.rpc.RpcOptional;
 
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.io.IOException;
 import java.security.InvalidParameterException;
 import java.util.ArrayList;
 import java.util.UUID;
@@ -71,12 +73,15 @@ public class AutomationSnippet implements Snippet {
     private final Context mContext;
     private final ArrayList<Runner> mRunners = new ArrayList<>();
 
-    public AutomationSnippet() {
+    public AutomationSnippet() throws IOException {
         mContext = ApplicationProvider.getApplicationContext();
         BluetoothManager bluetoothManager = mContext.getSystemService(BluetoothManager.class);
         mBluetoothAdapter = bluetoothManager.getAdapter();
         if (mBluetoothAdapter == null) {
-            throw new RuntimeException("bluetooth not supported");
+            throw new IOException("bluetooth not supported");
+        }
+        if (!mBluetoothAdapter.isEnabled()) {
+            throw new IOException("bluetooth not enabled");
         }
     }
 
@@ -85,32 +90,46 @@ public class AutomationSnippet implements Snippet {
         switch (mode) {
             case "rfcomm-client":
                 runnable = new RfcommClient(model, mBluetoothAdapter,
-                                          (PacketIO packetIO) -> createIoClient(model, scenario,
-                                                                                packetIO));
+                                            (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                  packetIO));
                 break;
 
             case "rfcomm-server":
                 runnable = new RfcommServer(model, mBluetoothAdapter,
-                                          (PacketIO packetIO) -> createIoClient(model, scenario,
-                                                                                packetIO));
+                                            (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                  packetIO));
                 break;
 
             case "l2cap-client":
                 runnable = new L2capClient(model, mBluetoothAdapter, mContext,
-                                         (PacketIO packetIO) -> createIoClient(model, scenario,
-                                                                               packetIO));
+                                           (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                 packetIO));
                 break;
 
             case "l2cap-server":
                 runnable = new L2capServer(model, mBluetoothAdapter,
-                                         (PacketIO packetIO) -> createIoClient(model, scenario,
-                                                                               packetIO));
+                                           (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                 packetIO));
+                break;
+
+            case "gatt-client":
+                runnable = new GattClient(model, mBluetoothAdapter, mContext,
+                                          (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                packetIO));
+                break;
+
+            case "gatt-server":
+                runnable = new GattServer(model, mBluetoothAdapter, mContext,
+                                          (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                packetIO));
                 break;
 
             default:
                 return null;
         }
 
+        model.setMode(mode);
+        model.setScenario(scenario);
         runnable.run();
         Runner runner = new Runner(runnable, mode, scenario, model);
         mRunners.add(runner);
@@ -140,7 +159,21 @@ public class AutomationSnippet implements Snippet {
         JSONObject result = new JSONObject();
         result.put("status", model.getStatus());
         result.put("running", model.getRunning());
+        result.put("peer_bluetooth_address", model.getPeerBluetoothAddress());
+        result.put("mode", model.getMode());
+        result.put("scenario", model.getScenario());
+        result.put("sender_packet_size", model.getSenderPacketSize());
+        result.put("sender_packet_count", model.getSenderPacketCount());
+        result.put("sender_packet_interval", model.getSenderPacketInterval());
+        result.put("packets_sent", model.getPacketsSent());
+        result.put("packets_received", model.getPacketsReceived());
         result.put("l2cap_psm", model.getL2capPsm());
+        result.put("use_2m_phy", model.getUse2mPhy());
+        result.put("connection_priority", model.getConnectionPriority());
+        result.put("mtu", model.getMtu());
+        result.put("rx_phy", model.getRxPhy());
+        result.put("tx_phy", model.getTxPhy());
+        result.put("startup_delay", model.getStartupDelay());
         if (model.getStatus().equals("OK")) {
             JSONObject stats = new JSONObject();
             result.put("stats", stats);
@@ -167,12 +200,12 @@ public class AutomationSnippet implements Snippet {
 
     @Rpc(description = "Run a scenario in RFComm Client mode")
     public JSONObject runRfcommClient(String scenario, String peerBluetoothAddress, int packetCount,
-                                      int packetSize, int packetInterval) throws JSONException {
-        assert (mBluetoothAdapter != null);
-
+                                      int packetSize, int packetInterval,
+                                      @RpcOptional Integer startupDelay) throws JSONException {
         // We only support "send" and "ping" for this mode for now
         if (!(scenario.equals("send") || scenario.equals("ping"))) {
-            throw new InvalidParameterException("only 'send' and 'ping' are supported for this mode");
+            throw new InvalidParameterException(
+                    "only 'send' and 'ping' are supported for this mode");
         }
 
         AppViewModel model = new AppViewModel();
@@ -180,6 +213,9 @@ public class AutomationSnippet implements Snippet {
         model.setSenderPacketCount(packetCount);
         model.setSenderPacketSize(packetSize);
         model.setSenderPacketInterval(packetInterval);
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
 
         Runner runner = runScenario(model, "rfcomm-client", scenario);
         assert runner != null;
@@ -187,15 +223,18 @@ public class AutomationSnippet implements Snippet {
     }
 
     @Rpc(description = "Run a scenario in RFComm Server mode")
-    public JSONObject runRfcommServer(String scenario) throws JSONException {
-        assert (mBluetoothAdapter != null);
-
+    public JSONObject runRfcommServer(String scenario,
+                                      @RpcOptional Integer startupDelay) throws JSONException {
         // We only support "receive" and "pong" for this mode for now
         if (!(scenario.equals("receive") || scenario.equals("pong"))) {
-            throw new InvalidParameterException("only 'receive' and 'pong' are supported for this mode");
+            throw new InvalidParameterException(
+                    "only 'receive' and 'pong' are supported for this mode");
         }
 
         AppViewModel model = new AppViewModel();
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
 
         Runner runner = runScenario(model, "rfcomm-server", scenario);
         assert runner != null;
@@ -205,12 +244,12 @@ public class AutomationSnippet implements Snippet {
     @Rpc(description = "Run a scenario in L2CAP Client mode")
     public JSONObject runL2capClient(String scenario, String peerBluetoothAddress, int psm,
                                      boolean use_2m_phy, int packetCount, int packetSize,
-                                     int packetInterval) throws JSONException {
-        assert (mBluetoothAdapter != null);
-
+                                     int packetInterval, @RpcOptional String connectionPriority,
+                                     @RpcOptional Integer startupDelay) throws JSONException {
         // We only support "send" and "ping" for this mode for now
         if (!(scenario.equals("send") || scenario.equals("ping"))) {
-            throw new InvalidParameterException("only 'send' and 'ping' are supported for this mode");
+            throw new InvalidParameterException(
+                    "only 'send' and 'ping' are supported for this mode");
         }
 
         AppViewModel model = new AppViewModel();
@@ -220,28 +259,83 @@ public class AutomationSnippet implements Snippet {
         model.setSenderPacketCount(packetCount);
         model.setSenderPacketSize(packetSize);
         model.setSenderPacketInterval(packetInterval);
-
+        if (connectionPriority != null) {
+            model.setConnectionPriority(connectionPriority);
+        }
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
         Runner runner = runScenario(model, "l2cap-client", scenario);
         assert runner != null;
         return runner.toJson();
     }
 
     @Rpc(description = "Run a scenario in L2CAP Server mode")
-    public JSONObject runL2capServer(String scenario) throws JSONException {
-        assert (mBluetoothAdapter != null);
-
+    public JSONObject runL2capServer(String scenario,
+                                     @RpcOptional Integer startupDelay) throws JSONException {
         // We only support "receive" and "pong" for this mode for now
         if (!(scenario.equals("receive") || scenario.equals("pong"))) {
-            throw new InvalidParameterException("only 'receive' and 'pong' are supported for this mode");
+            throw new InvalidParameterException(
+                    "only 'receive' and 'pong' are supported for this mode");
         }
 
         AppViewModel model = new AppViewModel();
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
 
         Runner runner = runScenario(model, "l2cap-server", scenario);
         assert runner != null;
         return runner.toJson();
     }
 
+    @Rpc(description = "Run a scenario in GATT Client mode")
+    public JSONObject runGattClient(String scenario, String peerBluetoothAddress,
+                                    boolean use_2m_phy, int packetCount, int packetSize,
+                                    int packetInterval, @RpcOptional String connectionPriority,
+                                    @RpcOptional Integer startupDelay) throws JSONException {
+        // We only support "send" and "ping" for this mode for now
+        if (!(scenario.equals("send") || scenario.equals("ping"))) {
+            throw new InvalidParameterException(
+                    "only 'send' and 'ping' are supported for this mode");
+        }
+
+        AppViewModel model = new AppViewModel();
+        model.setPeerBluetoothAddress(peerBluetoothAddress);
+        model.setUse2mPhy(use_2m_phy);
+        model.setSenderPacketCount(packetCount);
+        model.setSenderPacketSize(packetSize);
+        model.setSenderPacketInterval(packetInterval);
+        if (connectionPriority != null) {
+            model.setConnectionPriority(connectionPriority);
+        }
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
+        Runner runner = runScenario(model, "gatt-client", scenario);
+        assert runner != null;
+        return runner.toJson();
+    }
+
+    @Rpc(description = "Run a scenario in GATT Server mode")
+    public JSONObject runGattServer(String scenario,
+                                    @RpcOptional Integer startupDelay) throws JSONException {
+        // We only support "receive" and "pong" for this mode for now
+        if (!(scenario.equals("receive") || scenario.equals("pong"))) {
+            throw new InvalidParameterException(
+                    "only 'receive' and 'pong' are supported for this mode");
+        }
+
+        AppViewModel model = new AppViewModel();
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
+
+        Runner runner = runScenario(model, "gatt-server", scenario);
+        assert runner != null;
+        return runner.toJson();
+    }
+
     @Rpc(description = "Stop a Runner")
     public JSONObject stopRunner(String runnerId) throws JSONException {
         Runner runner = findRunner(runnerId);
@@ -276,7 +370,7 @@ public class AutomationSnippet implements Snippet {
         JSONObject result = new JSONObject();
         JSONArray runners = new JSONArray();
         result.put("runners", runners);
-        for (Runner runner: mRunners) {
+        for (Runner runner : mRunners) {
             runners.put(runner.toJson());
         }
 
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Connection.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Connection.kt
new file mode 100644
index 0000000..df46521
--- /dev/null
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Connection.kt
@@ -0,0 +1,109 @@
+package com.github.google.bumble.btbench
+
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothDevice
+import android.bluetooth.BluetoothGatt
+import android.bluetooth.BluetoothGattCallback
+import android.bluetooth.BluetoothManager
+import android.bluetooth.BluetoothProfile
+import android.content.Context
+import android.os.Build
+import androidx.core.content.ContextCompat
+import java.util.logging.Logger
+
+private val Log = Logger.getLogger("btbench.connection")
+
+open class Connection(
+    private val viewModel: AppViewModel,
+    private val bluetoothAdapter: BluetoothAdapter,
+    private val context: Context
+) : BluetoothGattCallback() {
+    var remoteDevice: BluetoothDevice? = null
+    var gatt: BluetoothGatt? = null
+
+    @SuppressLint("MissingPermission")
+    open fun connect() {
+        val addressIsPublic = viewModel.peerBluetoothAddress.endsWith("/P")
+        val address = viewModel.peerBluetoothAddress.take(17)
+        remoteDevice = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            bluetoothAdapter.getRemoteLeDevice(
+                address,
+                if (addressIsPublic) {
+                    BluetoothDevice.ADDRESS_TYPE_PUBLIC
+                } else {
+                    BluetoothDevice.ADDRESS_TYPE_RANDOM
+                }
+            )
+        } else {
+            bluetoothAdapter.getRemoteDevice(address)
+        }
+
+        gatt = remoteDevice?.connectGatt(
+            context,
+            false,
+            this,
+            BluetoothDevice.TRANSPORT_LE,
+            if (viewModel.use2mPhy) BluetoothDevice.PHY_LE_2M_MASK else BluetoothDevice.PHY_LE_1M_MASK
+        )
+    }
+
+    @SuppressLint("MissingPermission")
+    open fun disconnect() {
+        gatt?.disconnect()
+    }
+
+    override fun onMtuChanged(gatt: BluetoothGatt, mtu: Int, status: Int) {
+        Log.info("MTU update: mtu=$mtu status=$status")
+        viewModel.mtu = mtu
+    }
+
+    override fun onPhyUpdate(gatt: BluetoothGatt, txPhy: Int, rxPhy: Int, status: Int) {
+        Log.info("PHY update: tx=$txPhy, rx=$rxPhy, status=$status")
+        viewModel.txPhy = txPhy
+        viewModel.rxPhy = rxPhy
+    }
+
+    override fun onPhyRead(gatt: BluetoothGatt, txPhy: Int, rxPhy: Int, status: Int) {
+        Log.info("PHY: tx=$txPhy, rx=$rxPhy, status=$status")
+        viewModel.txPhy = txPhy
+        viewModel.rxPhy = rxPhy
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun onConnectionStateChange(
+        gatt: BluetoothGatt?, status: Int, newState: Int
+    ) {
+        if (status != BluetoothGatt.GATT_SUCCESS) {
+            Log.warning("onConnectionStateChange status=$status")
+        }
+
+        if (gatt != null && newState == BluetoothProfile.STATE_CONNECTED) {
+            if (viewModel.use2mPhy) {
+                Log.info("requesting 2M PHY")
+                gatt.setPreferredPhy(
+                    BluetoothDevice.PHY_LE_2M_MASK,
+                    BluetoothDevice.PHY_LE_2M_MASK,
+                    BluetoothDevice.PHY_OPTION_NO_PREFERRED
+                )
+            }
+            gatt.readPhy()
+
+            // Request an MTU update, even though we don't use GATT, because Android
+            // won't request a larger link layer maximum data length otherwise.
+            gatt.requestMtu(517)
+
+            // Request a specific connection priority
+            val connectionPriority = when (viewModel.connectionPriority) {
+                "BALANCED" -> BluetoothGatt.CONNECTION_PRIORITY_BALANCED
+                "LOW_POWER" -> BluetoothGatt.CONNECTION_PRIORITY_LOW_POWER
+                "HIGH" -> BluetoothGatt.CONNECTION_PRIORITY_HIGH
+                "DCK" -> BluetoothGatt.CONNECTION_PRIORITY_DCK
+                else -> 0
+            }
+            if (!gatt.requestConnectionPriority(connectionPriority)) {
+                Log.warning("requestConnectionPriority failed")
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Gatt.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Gatt.kt
new file mode 100644
index 0000000..126c5bc
--- /dev/null
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Gatt.kt
@@ -0,0 +1,23 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.github.google.bumble.btbench
+
+import java.util.UUID
+
+var CCCD_UUID = UUID.fromString("00002902-0000-1000-8000-00805F9B34FB")
+
+val BENCH_SERVICE_UUID = UUID.fromString("50DB505C-8AC4-4738-8448-3B1D9CC09CC5")
+val BENCH_TX_UUID = UUID.fromString("E789C754-41A1-45F4-A948-A0A1A90DBA53")
+val BENCH_RX_UUID = UUID.fromString("016A2CC7-E14B-4819-935F-1F56EAE4098D")
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/GattClient.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/GattClient.kt
new file mode 100644
index 0000000..fe7080e
--- /dev/null
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/GattClient.kt
@@ -0,0 +1,224 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.github.google.bumble.btbench
+
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothGatt
+import android.bluetooth.BluetoothGattCharacteristic
+import android.bluetooth.BluetoothGattDescriptor
+import android.bluetooth.BluetoothProfile
+import android.content.Context
+import java.io.IOException
+import java.util.UUID
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.Semaphore
+import java.util.logging.Logger
+import kotlin.concurrent.thread
+
+private val Log = Logger.getLogger("btbench.gatt-client")
+
+
+class GattClientConnection(
+    viewModel: AppViewModel,
+    bluetoothAdapter: BluetoothAdapter,
+    context: Context
+) : Connection(viewModel, bluetoothAdapter, context), PacketIO {
+    override var packetSink: PacketSink? = null
+    private val discoveryDone: CountDownLatch = CountDownLatch(1)
+    private val writeSemaphore: Semaphore = Semaphore(1)
+    var rxCharacteristic: BluetoothGattCharacteristic? = null
+    var txCharacteristic: BluetoothGattCharacteristic? = null
+
+    override fun connect() {
+        super.connect()
+
+        // Check if we're already connected and have discovered the services
+        if (gatt?.getService(BENCH_SERVICE_UUID) != null) {
+            Log.fine("already connected")
+            onServicesDiscovered(gatt, BluetoothGatt.GATT_SUCCESS)
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun onConnectionStateChange(
+        gatt: BluetoothGatt?, status: Int, newState: Int
+    ) {
+        super.onConnectionStateChange(gatt, status, newState)
+        if (status != BluetoothGatt.GATT_SUCCESS) {
+            Log.warning("onConnectionStateChange status=$status")
+            discoveryDone.countDown()
+            return
+        }
+        if (gatt != null && newState == BluetoothProfile.STATE_CONNECTED) {
+            if (!gatt.discoverServices()) {
+                Log.warning("discoverServices could not start")
+                discoveryDone.countDown()
+            }
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun onServicesDiscovered(gatt: BluetoothGatt?, status: Int) {
+        Log.fine("onServicesDiscovered")
+
+        if (status != BluetoothGatt.GATT_SUCCESS) {
+            Log.warning("failed to discover services: ${status}")
+            discoveryDone.countDown()
+            return
+        }
+
+        // Find the service
+        val service = gatt!!.getService(BENCH_SERVICE_UUID)
+        if (service == null) {
+            Log.warning("GATT Service not found")
+            discoveryDone.countDown()
+            return
+        }
+
+        // Find the RX and TX characteristics
+        rxCharacteristic = service.getCharacteristic(BENCH_RX_UUID)
+        if (rxCharacteristic == null) {
+            Log.warning("GATT RX Characteristics not found")
+            discoveryDone.countDown()
+            return
+        }
+        txCharacteristic = service.getCharacteristic(BENCH_TX_UUID)
+        if (txCharacteristic == null) {
+            Log.warning("GATT TX Characteristics not found")
+            discoveryDone.countDown()
+            return
+        }
+
+        // Subscribe to the RX characteristic
+        Log.fine("subscribing to RX")
+        gatt.setCharacteristicNotification(rxCharacteristic, true)
+        val cccdDescriptor = rxCharacteristic!!.getDescriptor(CCCD_UUID)
+        gatt.writeDescriptor(cccdDescriptor, BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
+
+        Log.info("GATT discovery complete")
+        discoveryDone.countDown()
+    }
+
+    override fun onCharacteristicWrite(
+        gatt: BluetoothGatt?,
+        characteristic: BluetoothGattCharacteristic?,
+        status: Int
+    ) {
+        // Now we can write again
+        writeSemaphore.release()
+
+        if (status != BluetoothGatt.GATT_SUCCESS) {
+            Log.warning("onCharacteristicWrite failed: $status")
+            return
+        }
+    }
+
+    override fun onCharacteristicChanged(
+        gatt: BluetoothGatt,
+        characteristic: BluetoothGattCharacteristic,
+        value: ByteArray
+    ) {
+        if (characteristic.uuid == BENCH_RX_UUID && packetSink != null) {
+            val packet = Packet.from(value)
+            packetSink!!.onPacket(packet)
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun sendPacket(packet: Packet) {
+        if (txCharacteristic == null) {
+            Log.warning("No TX characteristic, dropping")
+            return
+        }
+
+        // Wait until we can write
+        writeSemaphore.acquire()
+
+        // Write the data
+        val data = packet.toBytes()
+        val clampedData = if (data.size > 512) {
+            // Clamp the data to the maximum allowed characteristic data size
+            data.copyOf(512)
+        } else {
+            data
+        }
+        gatt?.writeCharacteristic(
+            txCharacteristic!!,
+            clampedData,
+            BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE
+        )
+    }
+
+    override
+    fun disconnect() {
+        super.disconnect()
+        discoveryDone.countDown()
+    }
+
+    fun waitForDiscoveryCompletion() {
+        discoveryDone.await()
+    }
+}
+
+class GattClient(
+    private val viewModel: AppViewModel,
+    bluetoothAdapter: BluetoothAdapter,
+    context: Context,
+    private val createIoClient: (packetIo: PacketIO) -> IoClient
+) : Mode {
+    private var connection: GattClientConnection =
+        GattClientConnection(viewModel, bluetoothAdapter, context)
+    private var clientThread: Thread? = null
+
+    @SuppressLint("MissingPermission")
+    override fun run() {
+        viewModel.running = true
+
+        clientThread = thread(name = "GattClient") {
+            connection.connect()
+
+            viewModel.aborter = {
+                connection.disconnect()
+            }
+
+            // Discover the rx and tx characteristics
+            connection.waitForDiscoveryCompletion()
+            if (connection.rxCharacteristic == null || connection.txCharacteristic == null) {
+                connection.disconnect()
+                viewModel.running = false
+                return@thread
+            }
+
+            val ioClient = createIoClient(connection)
+
+            try {
+                ioClient.run()
+                viewModel.status = "OK"
+            } catch (error: IOException) {
+                Log.info("run ended abruptly")
+                viewModel.status = "ABORTED"
+                viewModel.lastError = "IO_ERROR"
+            } finally {
+                connection.disconnect()
+                viewModel.running = false
+            }
+        }
+    }
+
+    override fun waitForCompletion() {
+        clientThread?.join()
+    }
+}
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/GattServer.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/GattServer.kt
new file mode 100644
index 0000000..8a36ecc
--- /dev/null
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/GattServer.kt
@@ -0,0 +1,243 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.github.google.bumble.btbench
+
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothDevice
+import android.bluetooth.BluetoothGatt
+import android.bluetooth.BluetoothGattCharacteristic
+import android.bluetooth.BluetoothGattDescriptor
+import android.bluetooth.BluetoothGattServer
+import android.bluetooth.BluetoothGattServerCallback
+import android.bluetooth.BluetoothGattService
+import android.bluetooth.BluetoothManager
+import android.bluetooth.BluetoothStatusCodes
+import android.content.Context
+import androidx.core.content.ContextCompat
+import java.io.IOException
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.LinkedBlockingQueue
+import java.util.concurrent.Semaphore
+import java.util.logging.Logger
+import kotlin.concurrent.thread
+import kotlin.experimental.and
+
+private val Log = Logger.getLogger("btbench.gatt-server")
+
+@SuppressLint("MissingPermission")
+class GattServer(
+    private val viewModel: AppViewModel,
+    private val bluetoothAdapter: BluetoothAdapter,
+    context: Context,
+    private val createIoClient: (packetIo: PacketIO) -> IoClient
+) : Mode, PacketIO, BluetoothGattServerCallback() {
+    override var packetSink: PacketSink? = null
+    private val gattServer: BluetoothGattServer
+    private val rxCharacteristic: BluetoothGattCharacteristic?
+    private val txCharacteristic: BluetoothGattCharacteristic?
+    private val notifySemaphore: Semaphore = Semaphore(1)
+    private val ready: CountDownLatch = CountDownLatch(1)
+    private var peerDevice: BluetoothDevice? = null
+    private var clientThread: Thread? = null
+    private var sinkQueue: LinkedBlockingQueue<Packet>? = null
+
+    init {
+        val bluetoothManager = ContextCompat.getSystemService(context, BluetoothManager::class.java)
+        gattServer = bluetoothManager!!.openGattServer(context, this)
+        val benchService = gattServer.getService(BENCH_SERVICE_UUID)
+        if (benchService == null) {
+            rxCharacteristic = BluetoothGattCharacteristic(
+                BENCH_RX_UUID,
+                BluetoothGattCharacteristic.PROPERTY_NOTIFY,
+                0
+            )
+            txCharacteristic = BluetoothGattCharacteristic(
+                BENCH_TX_UUID,
+                BluetoothGattCharacteristic.PROPERTY_WRITE_NO_RESPONSE,
+                BluetoothGattCharacteristic.PERMISSION_WRITE
+            )
+            val rxCCCD = BluetoothGattDescriptor(
+                CCCD_UUID,
+                BluetoothGattDescriptor.PERMISSION_READ or BluetoothGattDescriptor.PERMISSION_WRITE
+            )
+            rxCharacteristic.addDescriptor(rxCCCD)
+
+            val service =
+                BluetoothGattService(BENCH_SERVICE_UUID, BluetoothGattService.SERVICE_TYPE_PRIMARY)
+            service.addCharacteristic(rxCharacteristic)
+            service.addCharacteristic(txCharacteristic)
+
+            gattServer.addService(service)
+        } else {
+            rxCharacteristic = benchService.getCharacteristic(BENCH_RX_UUID)
+            txCharacteristic = benchService.getCharacteristic(BENCH_TX_UUID)
+        }
+    }
+
+    override fun onCharacteristicWriteRequest(
+        device: BluetoothDevice?,
+        requestId: Int,
+        characteristic: BluetoothGattCharacteristic?,
+        preparedWrite: Boolean,
+        responseNeeded: Boolean,
+        offset: Int,
+        value: ByteArray?
+    ) {
+        Log.info("onCharacteristicWriteRequest")
+        if (characteristic != null && characteristic.uuid == BENCH_TX_UUID) {
+            if (packetSink == null) {
+                Log.warning("no sink, dropping")
+            } else if (offset != 0) {
+                Log.warning("offset != 0")
+            } else if (value == null) {
+                Log.warning("no value")
+            } else {
+                // Deliver the packet in a separate thread so that we don't block this
+                // callback.
+                sinkQueue?.put(Packet.from(value))
+            }
+        }
+
+        if (responseNeeded) {
+            gattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, value)
+        }
+    }
+
+    override fun onNotificationSent(device: BluetoothDevice?, status: Int) {
+        if (status == BluetoothGatt.GATT_SUCCESS) {
+            notifySemaphore.release()
+        }
+    }
+
+    override fun onDescriptorWriteRequest(
+        device: BluetoothDevice?,
+        requestId: Int,
+        descriptor: BluetoothGattDescriptor?,
+        preparedWrite: Boolean,
+        responseNeeded: Boolean,
+        offset: Int,
+        value: ByteArray?
+    ) {
+        if (descriptor?.uuid == CCCD_UUID && descriptor?.characteristic?.uuid == BENCH_RX_UUID) {
+            if (offset == 0 && value?.size == 2) {
+                if (value[0].and(1).toInt() != 0) {
+                    // Subscription
+                    Log.fine("peer subscribed to RX")
+                    peerDevice = device
+                    ready.countDown()
+                }
+            }
+        }
+
+        if (responseNeeded) {
+            gattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, value)
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun sendPacket(packet: Packet) {
+        if (peerDevice == null) {
+            Log.warning("no peer device, cannot send")
+            return
+        }
+        if (rxCharacteristic == null) {
+            Log.warning("no RX characteristic, cannot send")
+            return
+        }
+
+        // Wait until we can notify
+        notifySemaphore.acquire()
+
+        // Send the packet via a notification
+        val result = gattServer.notifyCharacteristicChanged(
+            peerDevice!!,
+            rxCharacteristic,
+            false,
+            packet.toBytes()
+        )
+        if (result != BluetoothStatusCodes.SUCCESS) {
+            Log.warning("notifyCharacteristicChanged failed: $result")
+            notifySemaphore.release()
+        }
+    }
+
+    override fun run() {
+        viewModel.running = true
+
+        // Start advertising
+        Log.fine("starting advertiser")
+        val advertiser = Advertiser(bluetoothAdapter)
+        advertiser.start()
+
+        clientThread = thread(name = "GattServer") {
+            // Wait for a subscriber
+            Log.info("waiting for RX subscriber")
+            viewModel.aborter = {
+                ready.countDown()
+            }
+            ready.await()
+            if (peerDevice == null) {
+                Log.warning("server interrupted")
+                viewModel.running = false
+                gattServer.close()
+                return@thread
+            }
+            Log.info("RX subscriber accepted")
+
+            // Stop advertising
+            Log.info("stopping advertiser")
+            advertiser.stop()
+
+            sinkQueue = LinkedBlockingQueue()
+            val sinkWriterThread = thread(name = "SinkWriter") {
+                while (true) {
+                    try {
+                        val packet = sinkQueue!!.take()
+                        if (packetSink == null) {
+                            Log.warning("no sink, dropping packet")
+                            continue
+                        }
+                        packetSink!!.onPacket(packet)
+                    } catch (error: InterruptedException) {
+                        Log.warning("sink writer interrupted")
+                        break
+                    }
+                }
+            }
+
+            val ioClient = createIoClient(this)
+
+            try {
+                ioClient.run()
+                viewModel.status = "OK"
+            } catch (error: IOException) {
+                Log.info("run ended abruptly")
+                viewModel.status = "ABORTED"
+                viewModel.lastError = "IO_ERROR"
+            } finally {
+                sinkWriterThread.interrupt()
+                sinkWriterThread.join()
+                gattServer.close()
+                viewModel.running = false
+            }
+        }
+    }
+
+    override fun waitForCompletion() {
+        clientThread?.join()
+        Log.info("server thread completed")
+    }
+}
\ No newline at end of file
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capClient.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capClient.kt
index a6567a6..1049411 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capClient.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capClient.kt
@@ -16,89 +16,25 @@ package com.github.google.bumble.btbench
 
 import android.annotation.SuppressLint
 import android.bluetooth.BluetoothAdapter
-import android.bluetooth.BluetoothDevice
-import android.bluetooth.BluetoothGatt
-import android.bluetooth.BluetoothGattCallback
-import android.bluetooth.BluetoothProfile
 import android.content.Context
-import android.os.Build
 import java.util.logging.Logger
 
 private val Log = Logger.getLogger("btbench.l2cap-client")
 
 class L2capClient(
     private val viewModel: AppViewModel,
-    private val bluetoothAdapter: BluetoothAdapter,
-    private val context: Context,
+    bluetoothAdapter: BluetoothAdapter,
+    context: Context,
     private val createIoClient: (packetIo: PacketIO) -> IoClient
 ) : Mode {
+    private var connection: Connection = Connection(viewModel, bluetoothAdapter, context)
     private var socketClient: SocketClient? = null
 
     @SuppressLint("MissingPermission")
     override fun run() {
         viewModel.running = true
-        val addressIsPublic = viewModel.peerBluetoothAddress.endsWith("/P")
-        val address = viewModel.peerBluetoothAddress.take(17)
-        val remoteDevice = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
-            bluetoothAdapter.getRemoteLeDevice(
-                address,
-                if (addressIsPublic) {
-                    BluetoothDevice.ADDRESS_TYPE_PUBLIC
-                } else {
-                    BluetoothDevice.ADDRESS_TYPE_RANDOM
-                }
-            )
-        } else {
-            bluetoothAdapter.getRemoteDevice(address)
-        }
-
-        val gatt = remoteDevice.connectGatt(
-            context,
-            false,
-            object : BluetoothGattCallback() {
-                override fun onMtuChanged(gatt: BluetoothGatt, mtu: Int, status: Int) {
-                    Log.info("MTU update: mtu=$mtu status=$status")
-                    viewModel.mtu = mtu
-                }
-
-                override fun onPhyUpdate(gatt: BluetoothGatt, txPhy: Int, rxPhy: Int, status: Int) {
-                    Log.info("PHY update: tx=$txPhy, rx=$rxPhy, status=$status")
-                    viewModel.txPhy = txPhy
-                    viewModel.rxPhy = rxPhy
-                }
-
-                override fun onPhyRead(gatt: BluetoothGatt, txPhy: Int, rxPhy: Int, status: Int) {
-                    Log.info("PHY: tx=$txPhy, rx=$rxPhy, status=$status")
-                    viewModel.txPhy = txPhy
-                    viewModel.rxPhy = rxPhy
-                }
-
-                override fun onConnectionStateChange(
-                    gatt: BluetoothGatt?, status: Int, newState: Int
-                ) {
-                    if (gatt != null && newState == BluetoothProfile.STATE_CONNECTED) {
-                        if (viewModel.use2mPhy) {
-                            Log.info("requesting 2M PHY")
-                            gatt.setPreferredPhy(
-                                BluetoothDevice.PHY_LE_2M_MASK,
-                                BluetoothDevice.PHY_LE_2M_MASK,
-                                BluetoothDevice.PHY_OPTION_NO_PREFERRED
-                            )
-                        }
-                        gatt.readPhy()
-
-                        // Request an MTU update, even though we don't use GATT, because Android
-                        // won't request a larger link layer maximum data length otherwise.
-                        gatt.requestMtu(517)
-                    }
-                }
-            },
-            BluetoothDevice.TRANSPORT_LE,
-            if (viewModel.use2mPhy) BluetoothDevice.PHY_LE_2M_MASK else BluetoothDevice.PHY_LE_1M_MASK
-        )
-
-        val socket = remoteDevice.createInsecureL2capChannel(viewModel.l2capPsm)
-
+        connection.connect()
+        val socket = connection.remoteDevice!!.createInsecureL2capChannel(viewModel.l2capPsm)
         socketClient = SocketClient(viewModel, socket, createIoClient)
         socketClient!!.run()
     }
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capServer.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capServer.kt
index bb989c6..69b31dc 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capServer.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capServer.kt
@@ -37,34 +37,15 @@ class L2capServer(
     @SuppressLint("MissingPermission")
     override fun run() {
         // Advertise so that the peer can find us and connect.
-        val callback = object : AdvertiseCallback() {
-            override fun onStartFailure(errorCode: Int) {
-                Log.warning("failed to start advertising: $errorCode")
-            }
-
-            override fun onStartSuccess(settingsInEffect: AdvertiseSettings) {
-                Log.info("advertising started: $settingsInEffect")
-            }
-        }
-        val advertiseSettingsBuilder = AdvertiseSettings.Builder()
-            .setAdvertiseMode(ADVERTISE_MODE_LOW_LATENCY)
-            .setConnectable(true)
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
-            advertiseSettingsBuilder.setDiscoverable(true)
-        }
-        val advertiseSettings = advertiseSettingsBuilder.build()
-        val advertiseData = AdvertiseData.Builder().build()
-        val scanData = AdvertiseData.Builder().setIncludeDeviceName(true).build()
-        val advertiser = bluetoothAdapter.bluetoothLeAdvertiser
-
+        val advertiser = Advertiser(bluetoothAdapter)
         val serverSocket = bluetoothAdapter.listenUsingInsecureL2capChannel()
         viewModel.l2capPsm = serverSocket.psm
         Log.info("psm = $serverSocket.psm")
 
         socketServer = SocketServer(viewModel, serverSocket, createIoClient)
         socketServer!!.run(
-            { advertiser.stopAdvertising(callback) },
-            { advertiser.startAdvertising(advertiseSettings, advertiseData, scanData, callback) }
+            { advertiser.stop() },
+            { advertiser.start() }
         )
     }
 
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/MainActivity.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/MainActivity.kt
index 02729eb..bb3e558 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/MainActivity.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/MainActivity.kt
@@ -17,9 +17,12 @@ package com.github.google.bumble.btbench
 import android.Manifest
 import android.annotation.SuppressLint
 import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothDevice
 import android.bluetooth.BluetoothManager
+import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
+import android.content.IntentFilter
 import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
@@ -66,6 +69,7 @@ import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.core.content.ContextCompat
 import com.github.google.bumble.btbench.ui.theme.BTBenchTheme
+import java.io.IOException
 import java.util.logging.Logger
 
 private val Log = Logger.getLogger("bumble.main-activity")
@@ -76,6 +80,7 @@ const val SENDER_PACKET_SIZE_PREF_KEY = "sender_packet_size"
 const val SENDER_PACKET_INTERVAL_PREF_KEY = "sender_packet_interval"
 const val SCENARIO_PREF_KEY = "scenario"
 const val MODE_PREF_KEY = "mode"
+const val CONNECTION_PRIORITY_PREF_KEY = "connection_priority"
 
 class MainActivity : ComponentActivity() {
     private val appViewModel = AppViewModel()
@@ -84,6 +89,47 @@ class MainActivity : ComponentActivity() {
         super.onCreate(savedInstanceState)
         appViewModel.loadPreferences(getPreferences(Context.MODE_PRIVATE))
         checkPermissions()
+        registerReceivers()
+    }
+
+    private fun registerReceivers() {
+        val pairingRequestIntentFilter = IntentFilter(BluetoothDevice.ACTION_PAIRING_REQUEST)
+        registerReceiver(object: BroadcastReceiver() {
+            @SuppressLint("MissingPermission")
+            override fun onReceive(context: Context, intent: Intent) {
+                Log.info("ACTION_PAIRING_REQUEST")
+                val extras = intent.extras
+                if (extras != null) {
+                    for (key in extras.keySet()) {
+                        Log.info("$key: ${extras.get(key)}")
+                    }
+                }
+                val device: BluetoothDevice? = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE)
+                if (device != null) {
+                    if (checkSelfPermission(Manifest.permission.BLUETOOTH_PRIVILEGED) == PackageManager.PERMISSION_GRANTED) {
+                        Log.info("confirming pairing")
+                        device.setPairingConfirmation(true)
+                    } else {
+                        Log.info("we don't have BLUETOOTH_PRIVILEGED, not confirming")
+                    }
+                }
+
+            }
+        }, pairingRequestIntentFilter)
+
+        val bondStateChangedIntentFilter = IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED)
+        registerReceiver(object: BroadcastReceiver() {
+            @SuppressLint("MissingPermission")
+            override fun onReceive(context: Context, intent: Intent) {
+                Log.info("ACTION_BOND_STATE_CHANGED")
+                val extras = intent.extras
+                if (extras != null) {
+                    for (key in extras.keySet()) {
+                        Log.info("$key: ${extras.get(key)}")
+                    }
+                }
+            }
+        }, bondStateChangedIntentFilter)
     }
 
     private fun checkPermissions() {
@@ -144,9 +190,7 @@ class MainActivity : ComponentActivity() {
         initBluetooth()
         setContent {
             MainView(
-                appViewModel,
-                ::becomeDiscoverable,
-                ::runScenario
+                appViewModel, ::becomeDiscoverable, ::runScenario
             )
         }
 
@@ -182,6 +226,8 @@ class MainActivity : ComponentActivity() {
                 "rfcomm-server" -> appViewModel.mode = RFCOMM_SERVER_MODE
                 "l2cap-client" -> appViewModel.mode = L2CAP_CLIENT_MODE
                 "l2cap-server" -> appViewModel.mode = L2CAP_SERVER_MODE
+                "gatt-client" -> appViewModel.mode = GATT_CLIENT_MODE
+                "gatt-server" -> appViewModel.mode = GATT_SERVER_MODE
             }
         }
         intent.getStringExtra("autostart")?.let {
@@ -195,19 +241,24 @@ class MainActivity : ComponentActivity() {
 
     private fun runScenario() {
         if (bluetoothAdapter == null) {
-            return
+            throw IOException("bluetooth not enabled")
         }
 
         val runner = when (appViewModel.mode) {
             RFCOMM_CLIENT_MODE -> RfcommClient(appViewModel, bluetoothAdapter!!, ::createIoClient)
             RFCOMM_SERVER_MODE -> RfcommServer(appViewModel, bluetoothAdapter!!, ::createIoClient)
             L2CAP_CLIENT_MODE -> L2capClient(
-                appViewModel,
-                bluetoothAdapter!!,
-                baseContext,
-                ::createIoClient
+                appViewModel, bluetoothAdapter!!, baseContext, ::createIoClient
             )
+
             L2CAP_SERVER_MODE -> L2capServer(appViewModel, bluetoothAdapter!!, ::createIoClient)
+            GATT_CLIENT_MODE -> GattClient(
+                appViewModel, bluetoothAdapter!!, baseContext, ::createIoClient
+            )
+            GATT_SERVER_MODE -> GattServer(
+                appViewModel, bluetoothAdapter!!, baseContext, ::createIoClient
+            )
+
             else -> throw IllegalStateException()
         }
         runner.run()
@@ -281,7 +332,7 @@ fun MainView(
                         keyboardController?.hide()
                         focusManager.clearFocus()
                     }),
-                    enabled = (appViewModel.mode == RFCOMM_CLIENT_MODE) or (appViewModel.mode == L2CAP_CLIENT_MODE)
+                    enabled = (appViewModel.mode == RFCOMM_CLIENT_MODE || appViewModel.mode == L2CAP_CLIENT_MODE || appViewModel.mode == GATT_CLIENT_MODE)
                 )
                 Divider()
                 TextField(
@@ -349,24 +400,45 @@ fun MainView(
                         keyboardController?.hide()
                         focusManager.clearFocus()
                     }),
-                    enabled = (appViewModel.scenario == PING_SCENARIO)
+                    enabled = (appViewModel.scenario == PING_SCENARIO || appViewModel.scenario == SEND_SCENARIO)
                 )
                 Divider()
-                ActionButton(
-                    text = "Become Discoverable", onClick = becomeDiscoverable, true
-                )
                 Row(
                     horizontalArrangement = Arrangement.SpaceBetween,
                     verticalAlignment = Alignment.CenterVertically
                 ) {
                     Text(text = "2M PHY")
                     Spacer(modifier = Modifier.padding(start = 8.dp))
-                    Switch(
-                        enabled = (appViewModel.mode == L2CAP_CLIENT_MODE || appViewModel.mode == L2CAP_SERVER_MODE),
+                    Switch(enabled = (appViewModel.mode == L2CAP_CLIENT_MODE || appViewModel.mode == L2CAP_SERVER_MODE || appViewModel.mode == GATT_CLIENT_MODE || appViewModel.mode == GATT_SERVER_MODE),
                         checked = appViewModel.use2mPhy,
-                        onCheckedChange = { appViewModel.use2mPhy = it }
-                    )
-
+                        onCheckedChange = { appViewModel.use2mPhy = it })
+                    Column(Modifier.selectableGroup()) {
+                        listOf(
+                            "BALANCED", "LOW", "HIGH", "DCK"
+                        ).forEach { text ->
+                            Row(
+                                Modifier
+                                    .selectable(
+                                        selected = (text == appViewModel.connectionPriority),
+                                        onClick = { appViewModel.updateConnectionPriority(text) },
+                                        role = Role.RadioButton,
+                                    )
+                                    .padding(horizontal = 16.dp),
+                                verticalAlignment = Alignment.CenterVertically
+                            ) {
+                                RadioButton(
+                                    selected = (text == appViewModel.connectionPriority),
+                                    onClick = null,
+                                    enabled = (appViewModel.mode == L2CAP_CLIENT_MODE || appViewModel.mode == L2CAP_SERVER_MODE || appViewModel.mode == GATT_CLIENT_MODE || appViewModel.mode == GATT_SERVER_MODE)
+                                )
+                                Text(
+                                    text = text,
+                                    style = MaterialTheme.typography.bodyLarge,
+                                    modifier = Modifier.padding(start = 16.dp)
+                                )
+                            }
+                        }
+                    }
                 }
                 Row {
                     Column(Modifier.selectableGroup()) {
@@ -374,7 +446,9 @@ fun MainView(
                             RFCOMM_CLIENT_MODE,
                             RFCOMM_SERVER_MODE,
                             L2CAP_CLIENT_MODE,
-                            L2CAP_SERVER_MODE
+                            L2CAP_SERVER_MODE,
+                            GATT_CLIENT_MODE,
+                            GATT_SERVER_MODE
                         ).forEach { text ->
                             Row(
                                 Modifier
@@ -387,8 +461,7 @@ fun MainView(
                                 verticalAlignment = Alignment.CenterVertically
                             ) {
                                 RadioButton(
-                                    selected = (text == appViewModel.mode),
-                                    onClick = null
+                                    selected = (text == appViewModel.mode), onClick = null
                                 )
                                 Text(
                                     text = text,
@@ -400,10 +473,7 @@ fun MainView(
                     }
                     Column(Modifier.selectableGroup()) {
                         listOf(
-                            SEND_SCENARIO,
-                            RECEIVE_SCENARIO,
-                            PING_SCENARIO,
-                            PONG_SCENARIO
+                            SEND_SCENARIO, RECEIVE_SCENARIO, PING_SCENARIO, PONG_SCENARIO
                         ).forEach { text ->
                             Row(
                                 Modifier
@@ -416,8 +486,7 @@ fun MainView(
                                 verticalAlignment = Alignment.CenterVertically
                             ) {
                                 RadioButton(
-                                    selected = (text == appViewModel.scenario),
-                                    onClick = null
+                                    selected = (text == appViewModel.scenario), onClick = null
                                 )
                                 Text(
                                     text = text,
@@ -435,20 +504,29 @@ fun MainView(
                     ActionButton(
                         text = "Stop", onClick = appViewModel::abort, enabled = appViewModel.running
                     )
+                    ActionButton(
+                        text = "Become Discoverable", onClick = becomeDiscoverable, true
+                    )
                 }
                 Divider()
-                Text(
-                    text = if (appViewModel.mtu != 0) "MTU: ${appViewModel.mtu}" else ""
-                )
-                Text(
-                    text = if (appViewModel.rxPhy != 0 || appViewModel.txPhy != 0) "PHY: tx=${appViewModel.txPhy}, rx=${appViewModel.rxPhy}" else ""
-                )
+                if (appViewModel.mtu != 0) {
+                    Text(
+                        text = "MTU: ${appViewModel.mtu}"
+                    )
+                }
+                if (appViewModel.rxPhy != 0) {
+                    Text(
+                        text = "PHY: tx=${appViewModel.txPhy}, rx=${appViewModel.rxPhy}"
+                    )
+                }
                 Text(
                     text = "Status: ${appViewModel.status}"
                 )
-                Text(
-                    text = "Last Error: ${appViewModel.lastError}"
-                )
+                if (appViewModel.lastError.isNotEmpty()) {
+                    Text(
+                        text = "Last Error: ${appViewModel.lastError}"
+                    )
+                }
                 Text(
                     text = "Packets Sent: ${appViewModel.packetsSent}"
                 )
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Model.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Model.kt
index a58e344..5b69949 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Model.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Model.kt
@@ -25,6 +25,7 @@ import java.util.UUID
 
 val DEFAULT_RFCOMM_UUID: UUID = UUID.fromString("E6D55659-C8B4-4B85-96BB-B1143AF6D3AE")
 const val DEFAULT_PEER_BLUETOOTH_ADDRESS = "AA:BB:CC:DD:EE:FF"
+const val DEFAULT_STARTUP_DELAY = 3000
 const val DEFAULT_SENDER_PACKET_COUNT = 100
 const val DEFAULT_SENDER_PACKET_SIZE = 1024
 const val DEFAULT_SENDER_PACKET_INTERVAL = 100
@@ -34,6 +35,8 @@ const val L2CAP_CLIENT_MODE = "L2CAP Client"
 const val L2CAP_SERVER_MODE = "L2CAP Server"
 const val RFCOMM_CLIENT_MODE = "RFCOMM Client"
 const val RFCOMM_SERVER_MODE = "RFCOMM Server"
+const val GATT_CLIENT_MODE = "GATT Client"
+const val GATT_SERVER_MODE = "GATT Server"
 
 const val SEND_SCENARIO = "Send"
 const val RECEIVE_SCENARIO = "Receive"
@@ -47,8 +50,10 @@ class AppViewModel : ViewModel() {
     var mode by mutableStateOf(RFCOMM_SERVER_MODE)
     var scenario by mutableStateOf(RECEIVE_SCENARIO)
     var peerBluetoothAddress by mutableStateOf(DEFAULT_PEER_BLUETOOTH_ADDRESS)
+    var startupDelay by mutableIntStateOf(DEFAULT_STARTUP_DELAY)
     var l2capPsm by mutableIntStateOf(DEFAULT_PSM)
     var use2mPhy by mutableStateOf(true)
+    var connectionPriority by mutableStateOf("BALANCED")
     var mtu by mutableIntStateOf(0)
     var rxPhy by mutableIntStateOf(0)
     var txPhy by mutableIntStateOf(0)
@@ -98,6 +103,11 @@ class AppViewModel : ViewModel() {
         if (savedScenario != null) {
             scenario = savedScenario
         }
+
+        val savedConnectionPriority = preferences.getString(CONNECTION_PRIORITY_PREF_KEY, null)
+        if (savedConnectionPriority != null) {
+            connectionPriority = savedConnectionPriority
+        }
     }
 
     fun updatePeerBluetoothAddress(peerBluetoothAddress: String) {
@@ -220,6 +230,14 @@ class AppViewModel : ViewModel() {
         }
     }
 
+    fun updateConnectionPriority(connectionPriority: String) {
+        this.connectionPriority = connectionPriority
+        with(preferences!!.edit()) {
+            putString(CONNECTION_PRIORITY_PREF_KEY, connectionPriority)
+            apply()
+        }
+    }
+
     fun clear() {
         status = ""
         lastError = ""
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Packet.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Packet.kt
index 0ccd8cf..b1cf174 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Packet.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Packet.kt
@@ -17,6 +17,7 @@ package com.github.google.bumble.btbench
 import android.bluetooth.BluetoothSocket
 import java.io.IOException
 import java.nio.ByteBuffer
+import java.nio.ByteOrder
 import java.util.logging.Logger
 import kotlin.math.min
 
@@ -37,11 +38,16 @@ abstract class Packet(val type: Int, val payload: ByteArray = ByteArray(0)) {
                 RESET -> ResetPacket()
                 SEQUENCE -> SequencePacket(
                     data[1].toInt(),
-                    ByteBuffer.wrap(data, 2, 4).getInt(),
-                    data.sliceArray(6..<data.size)
+                    ByteBuffer.wrap(data, 2, 4).order(ByteOrder.LITTLE_ENDIAN).getInt(),
+                    ByteBuffer.wrap(data, 6, 4).order(ByteOrder.LITTLE_ENDIAN).getInt(),
+                    data.sliceArray(10..<data.size)
+                )
+
+                ACK -> AckPacket(
+                    data[1].toInt(),
+                    ByteBuffer.wrap(data, 2, 4).order(ByteOrder.LITTLE_ENDIAN).getInt()
                 )
 
-                ACK -> AckPacket(data[1].toInt(), ByteBuffer.wrap(data, 2, 4).getInt())
                 else -> GenericPacket(data[0].toInt(), data.sliceArray(1..<data.size))
             }
         }
@@ -57,16 +63,24 @@ class ResetPacket : Packet(RESET)
 
 class AckPacket(val flags: Int, val sequenceNumber: Int) : Packet(ACK) {
     override fun toBytes(): ByteArray {
-        return ByteBuffer.allocate(1 + 1 + 4).put(type.toByte()).put(flags.toByte())
+        return ByteBuffer.allocate(6).order(
+            ByteOrder.LITTLE_ENDIAN
+        ).put(type.toByte()).put(flags.toByte())
             .putInt(sequenceNumber).array()
     }
 }
 
-class SequencePacket(val flags: Int, val sequenceNumber: Int, payload: ByteArray) :
+class SequencePacket(
+    val flags: Int,
+    val sequenceNumber: Int,
+    val timestamp: Int,
+    payload: ByteArray
+) :
     Packet(SEQUENCE, payload) {
     override fun toBytes(): ByteArray {
-        return ByteBuffer.allocate(1 + 1 + 4 + payload.size).put(type.toByte()).put(flags.toByte())
-            .putInt(sequenceNumber).put(payload).array()
+        return ByteBuffer.allocate(10 + payload.size).order(ByteOrder.LITTLE_ENDIAN)
+            .put(type.toByte()).put(flags.toByte())
+            .putInt(sequenceNumber).putInt(timestamp).put(payload).array()
     }
 }
 
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Pinger.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Pinger.kt
index d5d375e..be00644 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Pinger.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Pinger.kt
@@ -19,8 +19,6 @@ import java.util.logging.Logger
 import kotlin.time.Duration.Companion.milliseconds
 import kotlin.time.TimeSource
 
-private const val DEFAULT_STARTUP_DELAY = 3000
-
 private val Log = Logger.getLogger("btbench.pinger")
 
 class Pinger(private val viewModel: AppViewModel, private val packetIO: PacketIO) : IoClient,
@@ -36,8 +34,8 @@ class Pinger(private val viewModel: AppViewModel, private val packetIO: PacketIO
     override fun run() {
         viewModel.clear()
 
-        Log.info("startup delay: $DEFAULT_STARTUP_DELAY")
-        Thread.sleep(DEFAULT_STARTUP_DELAY.toLong());
+        Log.info("startup delay: ${viewModel.startupDelay}")
+        Thread.sleep(viewModel.startupDelay.toLong());
         Log.info("running")
 
         Log.info("sending reset")
@@ -48,19 +46,23 @@ class Pinger(private val viewModel: AppViewModel, private val packetIO: PacketIO
 
         val startTime = TimeSource.Monotonic.markNow()
         for (i in 0..<packetCount) {
-            val now = TimeSource.Monotonic.markNow()
-            val targetTime = startTime + (i * viewModel.senderPacketInterval).milliseconds
-            val delay = targetTime - now
-            if (delay.isPositive()) {
-                Log.info("sleeping ${delay.inWholeMilliseconds} ms")
-                Thread.sleep(delay.inWholeMilliseconds)
+            var now = TimeSource.Monotonic.markNow()
+            if (viewModel.senderPacketInterval > 0) {
+                val targetTime = startTime + (i * viewModel.senderPacketInterval).milliseconds
+                val delay = targetTime - now
+                if (delay.isPositive()) {
+                    Log.info("sleeping ${delay.inWholeMilliseconds} ms")
+                    Thread.sleep(delay.inWholeMilliseconds)
+                    now = TimeSource.Monotonic.markNow()
+                }
             }
             pingTimes.add(TimeSource.Monotonic.markNow())
             packetIO.sendPacket(
                 SequencePacket(
                     if (i < packetCount - 1) 0 else Packet.LAST_FLAG,
                     i,
-                    ByteArray(packetSize - 6)
+                    (now - startTime).inWholeMicroseconds.toInt(),
+                    ByteArray(packetSize - 10)
                 )
             )
             viewModel.packetsSent = i + 1
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Ponger.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Ponger.kt
index b2ddb7e..16c366b 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Ponger.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Ponger.kt
@@ -14,6 +14,7 @@
 
 package com.github.google.bumble.btbench
 
+import java.util.concurrent.CountDownLatch
 import java.util.logging.Logger
 import kotlin.time.TimeSource
 
@@ -23,6 +24,7 @@ class Ponger(private val viewModel: AppViewModel, private val packetIO: PacketIO
     private var startTime: TimeSource.Monotonic.ValueTimeMark = TimeSource.Monotonic.markNow()
     private var lastPacketTime: TimeSource.Monotonic.ValueTimeMark = TimeSource.Monotonic.markNow()
     private var expectedSequenceNumber: Int = 0
+    private val done = CountDownLatch(1)
 
     init {
         packetIO.packetSink = this
@@ -30,6 +32,7 @@ class Ponger(private val viewModel: AppViewModel, private val packetIO: PacketIO
 
     override fun run() {
         viewModel.clear()
+        done.await()
     }
 
     override fun abort() {}
@@ -58,5 +61,10 @@ class Ponger(private val viewModel: AppViewModel, private val packetIO: PacketIO
 
         packetIO.sendPacket(AckPacket(packet.flags, packet.sequenceNumber))
         viewModel.packetsSent += 1
+
+        if (packet.flags and Packet.LAST_FLAG != 0) {
+            Log.info("received last packet")
+            done.countDown()
+        }
     }
 }
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Receiver.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Receiver.kt
index 71055c1..1dc1750 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Receiver.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Receiver.kt
@@ -14,6 +14,7 @@
 
 package com.github.google.bumble.btbench
 
+import java.util.concurrent.CountDownLatch
 import java.util.logging.Logger
 import kotlin.time.DurationUnit
 import kotlin.time.TimeSource
@@ -24,6 +25,7 @@ class Receiver(private val viewModel: AppViewModel, private val packetIO: Packet
     private var startTime: TimeSource.Monotonic.ValueTimeMark = TimeSource.Monotonic.markNow()
     private var lastPacketTime: TimeSource.Monotonic.ValueTimeMark = TimeSource.Monotonic.markNow()
     private var bytesReceived = 0
+    private val done = CountDownLatch(1)
 
     init {
         packetIO.packetSink = this
@@ -31,6 +33,7 @@ class Receiver(private val viewModel: AppViewModel, private val packetIO: Packet
 
     override fun run() {
         viewModel.clear()
+        done.await()
     }
 
     override fun abort() {}
@@ -62,6 +65,7 @@ class Receiver(private val viewModel: AppViewModel, private val packetIO: Packet
             Log.info("throughput: $throughput")
             viewModel.throughput = throughput
             packetIO.sendPacket(AckPacket(packet.flags, packet.sequenceNumber))
+            done.countDown()
         }
     }
 }
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Sender.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Sender.kt
index ed45cdd..50af553 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Sender.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Sender.kt
@@ -16,11 +16,10 @@ package com.github.google.bumble.btbench
 
 import java.util.concurrent.Semaphore
 import java.util.logging.Logger
+import kotlin.time.Duration.Companion.milliseconds
 import kotlin.time.DurationUnit
 import kotlin.time.TimeSource
 
-private const val DEFAULT_STARTUP_DELAY = 3000
-
 private val Log = Logger.getLogger("btbench.sender")
 
 class Sender(private val viewModel: AppViewModel, private val packetIO: PacketIO) : IoClient,
@@ -36,8 +35,8 @@ class Sender(private val viewModel: AppViewModel, private val packetIO: PacketIO
     override fun run() {
         viewModel.clear()
 
-        Log.info("startup delay: $DEFAULT_STARTUP_DELAY")
-        Thread.sleep(DEFAULT_STARTUP_DELAY.toLong());
+        Log.info("startup delay: ${viewModel.startupDelay}")
+        Thread.sleep(viewModel.startupDelay.toLong());
         Log.info("running")
 
         Log.info("sending reset")
@@ -47,20 +46,32 @@ class Sender(private val viewModel: AppViewModel, private val packetIO: PacketIO
 
         val packetCount = viewModel.senderPacketCount
         val packetSize = viewModel.senderPacketSize
-        for (i in 0..<packetCount - 1) {
-            packetIO.sendPacket(SequencePacket(0, i, ByteArray(packetSize - 6)))
+        for (i in 0..<packetCount) {
+            var now = TimeSource.Monotonic.markNow()
+            if (viewModel.senderPacketInterval > 0) {
+                val targetTime = startTime + (i * viewModel.senderPacketInterval).milliseconds
+                val delay = targetTime - now
+                if (delay.isPositive()) {
+                    Log.info("sleeping ${delay.inWholeMilliseconds} ms")
+                    Thread.sleep(delay.inWholeMilliseconds)
+                }
+                now = TimeSource.Monotonic.markNow()
+            }
+            val flags = when (i) {
+                packetCount - 1 -> Packet.LAST_FLAG
+                else -> 0
+            }
+            packetIO.sendPacket(
+                SequencePacket(
+                    flags,
+                    i,
+                    (now - startTime).inWholeMicroseconds.toInt(),
+                    ByteArray(packetSize - 10)
+                )
+            )
             bytesSent += packetSize
             viewModel.packetsSent = i + 1
         }
-        packetIO.sendPacket(
-            SequencePacket(
-                Packet.LAST_FLAG,
-                packetCount - 1,
-                ByteArray(packetSize - 6)
-            )
-        )
-        bytesSent += packetSize
-        viewModel.packetsSent = packetCount
 
         // Wait for the ACK
         Log.info("waiting for ACK")
diff --git a/pyproject.toml b/pyproject.toml
index 7038551..03e1176 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -153,7 +153,7 @@ disable = [
 ]
 
 [tool.pylint.main]
-ignore = "pandora" # FIXME: pylint does not support stubs yet:
+ignore=["pandora", "mobly"] # FIXME: pylint does not support stubs yet
 
 [tool.pylint.typecheck]
 signature-mutators = "AsyncRunner.run_in_task"