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

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

• 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.

• /neighbors/neighbor/transport/config/tcp-mss
• /neighbors/neighbor/transport/config/mtu-discovery

• /neighbors/neighbor/transport/state/tcp-mss
• /neighbors/neighbor/transport/state/mtu-discovery

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