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

Phil Mayers p.mayers at imperial.ac.uk
Thu May 24 04:31:52 EDT 2012


On 05/24/2012 06:16 AM, David Farrell wrote:
> On 23/05/2012 20:27, Phil Mayers wrote:
>> If you don't enable portfast, you have to suffer the STP state
>> transitions, which lead to delays in traffic forwarding after link-up.
> I wondered what people's feelings/experiences were with respect to
> completely disabling STP where appropriate?
>
> I have 100% control over topology and some PtP dotq trunk links, I
> thought of placing 'spanning-tree bpdufilter enable' rather than
> 'portfast trunk' on these ports. I have no need to to send or receive
> STP BPDUs on these ports, even though the underlying technology is
> Ethernet. Hosts are a mixture of L3 switches and routers, but
> configuration should limit the extent of the broadcast domains in
> question to exist only on the PtP link.

We run PVST, and do indeed disable STP completely on VLANs which are 
used for directed routed ptp links i.e. are only on one port, and only 
make one hop.

We don't disable it on the whole port because often the port is carrying 
other vlans which are PVST enabled (e.g. between an HSRP master&slave / 
STP primary&secondary root switch pair).

We do have some links which carry a routed p2p only, but even then we 
just disable STP on the vlan, not the port.

Obviously if you're running MST or classic STP this per-vlan approach 
isn't available, and you can only do per-port.


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