BATS Protocol Next

Basic concepts

• IOContext: The context of the IO operation, which is responsible for watching the IO events for those registered connections. In each process, it is required to have at least one IOContext instance and this only one IO context instance can be shared by multiple protocol instance BatsProtocol.
• BatsProtocol: The protocol instance of BATS protocol, which can start a new connection to remote server or wait for a new connection from remote client. It must be initialized with a IOContext instance.
• BatsConfiguration: The configuration interface of BATS protocol, which is used to set the transmission mode, congestion control and other parameters.
• IBatsConnection: The connection of BATS protocol, which is used to send and receive messages. IBatsConnection is managed by BATS protocol core, users can't create or destroy it directly.
• Callback functions: There are two callback functions in BATS protocol, ListenCallback is used to receive listen related events, and ConnectionCallback is used to receive connection related events. In most cases, the asynchronous events are emitted by IOContext's thread while the direct failure of API calls are emitted by the users' thread.

About BRTP

BRTP (BATS Reliable Transport Protocol) is a reliable transport protocol of user space. It employs a novel coding scheme (BATS™) to achieve high throughput and low latency.

Outstanding features of BRTP:

• Insensitivity to packet loss
  • High bandwidth utilization
  • Lower transmission latency
  • Lower retransmission rate (compared with classic ARQ)
• Fine tuned congestion control(bbr)

Test tools

./bin/bats_iperf -h
[2025-09-29 13:21:33.386] [info] System Information: sizeof(int): 4, 64-bit system (LP64)
[2025-09-29 13:21:33.386] [info] Welcome to spdlog version 1.15.3  !
* Linux/Unix platform
BATS Iperf version: v1.0(437f43e)  Build date: Sep 29 2025 12:20:08 Compiler: gcc11 Release
Usage: bats_iperf [options]
Options:
  -t <time>        : Test duration in seconds (default: 10)
  -i <interval>    : Interval for reporting results in seconds (default: 1)
  -I <interface>   : The name of the interface
  -P <num_streams> : Number of parallel streams (default: 1)
  -r               : Enable reverse mode (server to client)
  -p <port>        : Port number to use for the data channel (default: 5201); and
                     The port of signaling channel is set to `port - 1`.
  -m <mode>        : Protocol mode (0: BTP, 1: BRTP, 2: BRCTP, 3: TRANSPARENT, default: BTP)
                     When run as server, this option is ignored.
  -s               : Run as server
  -c <host>        : Run as client and connect to <host>
  -f <file>        : Run as client to send the file
  -l <logfile>     : Log file to write iperf output (default: stdout)
  -L <logfile path>: Log path to write bats protocol log (default: )
  -b               : Max allowed sending rate in Mbps, only valid for clients
  -h               : Show this help message
  -d               : Emit debugging output
  -T               : Show precise time wall clock in the reports
  -C               : Enable the data compression

Logging output of a loopback test with the network coding enabled protocol BRTP:

About file transfer mode, check details in bats_iperf file transfer mode

Performance matrix of BRTP

Loss Rate/Latency	10ms	30ms	50ms	70ms	100ms
0.0%	949.5 Mbps	940.1 Mbps	927.81 Mbps	979.71 Mbps	928.81 Mbps
2.0%	888.33 Mbps	907.4 Mbps	757.49 Mbps	719.43 Mbps	484.99 Mbps
4.0%	879.99 Mbps	811.36 Mbps	683.54 Mbps	485.85 Mbps	573.06 Mbps
6.0%	853.18 Mbps	762.74 Mbps	662.22 Mbps	540.73 Mbps	495.30 Mbps
8.0%	800.47 Mbps	720.81 Mbps	555.95 Mbps	430.73 Mbps	428.17 Mbps
10.0%	786.96 Mbps	759.27 Mbps	510.21 Mbps	455.38 Mbps	382.22 Mbps

Tip

Definitions and abbreviations

• 1. All tests were tested with the fixed Bandwidth 1000Mbps
• 2. Latency: the one-way delay of the link/path.
• 3. Loss Rate: the packet loss takes effect on the bidirection of the link/path.
• 4. Data format in the cell:
     [Delivery rate]
  • Delivery rate: The average receiving rate during the test.
• 5. Latency and Loss Rate are simulated in Oasis.

Performance matrix of TCP BBR

Loss Rate/Latency	10ms	30ms	50ms	70ms
0.0%	938.0 Mbps	913.0 Mbps	622.0 Mbps	432.0 Mbps
10.0%	461.0 Mbps	270.0 Mbps	175.0 Mbps	13.4 Mbps

Tip

• Using the same test environment as BRTP.
• Kernel version: 5.15.0-153-generic