TCP bandwidth limit

• This filter should be configured with the type URL type.googleapis.com/envoy.extensions.filters.network.tcp_bandwidth_limit.v3.TcpBandwidthLimit.

• v3 API reference

Overview

The TCP bandwidth limit filter is a network filter that limits the bandwidth on the downstream connection. It can be configured to limit read and write bandwidth independently, using a token bucket algorithm similar to the HTTP bandwidth limit filter.

• read_limit_kbps limits data read from the downstream connection.

• write_limit_kbps limits data written to the downstream connection.

The filter works by:

• Consuming tokens from a token bucket when data passes through

• Buffering data when insufficient tokens are available

• Using timers to refill tokens and resume data flow when bandwidth becomes available

Example configuration

The following example configuration limits read bandwidth to 1 MiB/s and write bandwidth to 512 KiB/s:

name: envoy.filters.network.tcp_bandwidth_limit
typed_config:
  "@type": type.googleapis.com/envoy.extensions.filters.network.tcp_bandwidth_limit.v3.TcpBandwidthLimit
  stat_prefix: bandwidth_limiter
  read_limit_kbps: 1024   # 1 MiB/s
  write_limit_kbps: 512   # 512 KiB/s
  fill_interval:
    nanos: 50000000       # 50ms

Statistics

The TCP bandwidth limit filter outputs statistics in the <stat_prefix>. namespace.

Name	Type	Description
read_enabled	Counter	Total number of times the read limit was applied to incoming data
write_enabled	Counter	Total number of times the write limit was applied to outgoing data
read_throttled	Counter	Total number of times read data was throttled
write_throttled	Counter	Total number of times write data was throttled
read_total_bytes	Counter	Total bytes read
write_total_bytes	Counter	Total bytes written
read_bytes_buffered	Gauge	Current number of bytes buffered for read
write_bytes_buffered	Gauge	Current number of bytes buffered for write
read_rate_bps	Gauge	Current read rate in bytes per second
write_rate_bps	Gauge	Current write rate in bytes per second

Runtime

The TCP bandwidth limit filter can be runtime feature flagged via the runtime_enabled configuration field.