Skip to content

bgp_tcp_mss_path_mtu

Jump to bottom
Github Action edited this page Oct 9, 2024 · 2 revisions

RT-1.21: BGP TCP MSS and PMTUD

Summary

  • Validate changes in TCP MSS value is allowed and takes effect.
  • Validate DUT's PMTUD compliance.

Topology

  • ATE:port1 <-> port1:DUT1:Port2 <-> port1:DUT2

Procedure

  • Establish BGP sessions as follows:
    • ATE:port1 --- eBGP-IPv4/IPv6 ---- DUT1:port1.
    • ATE:port1 ---- iBGP IPv4 ---- DUT2:port1.
  • Verify that the default TCP MSS value is set below the default interface MTU value.
  • Change the Interface MTU on the DUT1:port1 port as well as ATE:port1 to 5040B
  • Configure IP TCP MSS value of 4096 bytes on the DUT1:port1.
  • Re-establish the EBGP sessions by tcp reset.
  • Verify that the TCP MSS value is set to 4096 bytes for the IPv4 and IPv6 EBGP sessions.
  • Establish iBGP session with MD5 enabled between ATE:port1 and DUT2:port1.
  • Ensure that the MTU on the DUT1:port1 towards ATE1:port1 is left at default (1500B) while the ATE1:port1 interface towards DUT1:port1 is set at 5040B. Please also make sure that the DUT2:port1 MTU is set at 5040B as well.
  • Enable PMTUD on DUT2:port1.
  • Re-establish the IBGP sessions by tcp reset.
  • Validate that the min MSS value has been adjusted to be below 1500 bytes on the tcp session.

OpenConfig Path and RPC Coverage

paths:
  ## Config Parameter Coverage
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/transport/config/tcp-mss:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/transport/config/mtu-discovery:

  ## Telemetry Parameter Coverage
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/transport/state/tcp-mss:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/transport/state/mtu-discovery:

rpcs:
  gnmi:
    gNMI.Subscribe:
    gNMI.Set:

Minimum DUT platform requirement

N/A

Clone this wiki locally