Hi All,
I would like to know how the fabric fragmentation works and how a network-interface MTU configuration affects this feature.
Currently I have a LAN and WAN interface for 2 routers which peer with each other. LAN MTU on both interfaces are configured as 1600, and WAN is configured as 1500 (left as default). When I enable path-mtu-discovery for the neighborhood used to facilitate the peering, I get a maximum path MTU of 1998.
In this case, does the network-interface MTU get overwritten for traffic between these two peers? Technically if I generate traffic on the LAN side of router-1, destined for a service on the LAN side of router-2 (with DF bit set), I should theoretically be able to send 1600 byte packets end to end, correct?
Also - is there something I need to enable in configuration for path-mtu to be taken into account, or does that happen automatically?
Regards
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Morne Vermeulen
Core Engineer
+27 (0) 10 141 8512
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