Spanning tree portfast

[mrmayanksaini]

Our client has many remote sites in different location and each site is with a WAN router and a 3750 X switch. Switch is working as a layer 3 switch and the uplink connected to WAN router is a layer 3 interface. They have configuered " Spanning tree portfast" on the uplink going to WAN router. Is that required to configure "spanning tree portfast" over that uplink to WAN router?

[Reza Sharifi]

Spanning tree  Portfast should be enabled on ports connecting to hosts (PCs, laptops, printers, etc...) your uplink port is routed port, so there is no STP involved.

HTH

[Rolf Fischer]

Hi,

there's no possibility for the occurrence of a bridging-loop between the router and the switch, so it's safe to configure portfast.

Without portfast, after re-initialization the link, no traffic would be forwarded for 30 seconds (2x forward delay), so from a convergence perspective this is a meaningful optimization.

in case of a routed port, STP portfast makes no sense (I've overlooked that, sorry).

Hope that helps

Rolf