[c-nsp] Lot of input errors on a NPE-G1 interface

[Phil Mayers]

On 05/23/2012 08:18 PM, Chris Gotstein wrote:
> %Warning: portfast should only be enabled on ports connected to a single
> host. Connecting hubs, concentrators, switches, bridges, etc… to this
> interface when portfast is enabled, can cause temporary bridging loops.
>
> My understanding of this was a router would be included as well since
> it's used to connect multiple hosts.

If you don't enable portfast, you have to suffer the STP state 
transitions, which lead to delays in traffic forwarding after link-up.

Portfast basically means: "This port is unlikely to be connected to 
another bridge or hub, so skip the LISTENING/LEARNING transitions and 
jump straight to forwarding; if it goes wrong, STP will close the loop 
shortly."

It's not magic; and it should be enabled on all host ports. Routers are 
hosts, at layer2.