Catalyst With Routers Connected FastPort

[mendezjm]

I have a Catalyst 6509.

It has connected various servers and three WAN routers.

What is the best way to configure the interfaces? fastport?

Best Regards.

[robho]

It is not recommended to enable stp portfast on those ports connected to a router, switch, bridge, etc. What I do suggest is to disable trunking and channel-negotiation on them.

RH

[milan.kulik]

Hi,

IMHO, there are some exceptions from this general rule:

"router on the stick", e.g.

If you are connecting a L3 device which is not running STP, and there is no negotiation on the trunk, portfast on the switch port just skips an extra 30-50 sec delay. And this can help to decrease effective routing start-up time, e.g.

Regards,

Milan

[robho]

Like I mentioned, it is not recommended yet is configurable. If enabled, it has to be done with caution. I have seen corner cases where the router was "accidentally" configured for transparent bridging and caused a loop.

Cat6500 (enable) set spantree portfast 3/4 enable

Warning: Spantree port fast start should only be enabled on ports connected to a single host. Connecting hubs, concentrators, switches, bridges, etc. to a fast start port can cause temporary spanning tree loops. Use with caution.

Cat6500 (enable)

RH