[c-nsp] EoMPLS or VPLS loop prevention/storm control

[Pshem Kowalczyk]

Hi,


On 10 February 2011 04:12, schilling <schilling2006 at gmail.com> wrote:
> Hi All,
>
> We right now have several bridged campus wide VLAN. It happens several
> times a year where a loop in one of the VLAN will cause our backbone
> to be unavailable. Now we are thinking to better architect the design.
> If we migrate to some platform like ASR9K and use EoMPLS or VPLS, what
> will happen if we have a loop in one of the VLAN?  The simple loop is
> to have a dump switch, connected two ports of it together.

As others pointed it out already - one way to fix the loops is to
split the broadcast domain. If you decide to go the VPLS route with 9k
there are some knobs that help you to alleviate broadcast problems. We
have quite a few VPLS services out there and we use the following
parameters to tune the VPLS

storm-control unknown-unicast pps xyz1
storm-control multicast xyz2
storm-control broadcast pps xyz3

That significantly helps with mis-behaving equipment. If your topology
is more like a tree than a mesh you can also use

split-horizon group

to ensure that packets do not get forwarded some way.

kind regards
Pshem