[c-nsp] ISP / MPLS "POP" design

[CiscoNSP List]

Thanks Phil,

> 
> IS-IS can scale to a larger number of devices in a single "area" and
> overall network.  Really depends on how many devices you are talking
> about.  For smaller deployments it usually comes down to who is supporting
> the network and what they are more familiar with.


Cheers - Im going to try IS-IS on some spare 7200's

> 
> So you are backhauling most of your customer endpoints from another
> carrier's Layer2 network, correct?  You could re-create the L3 interfaces
> on both PE devices and use a mechanism like EEM (embedded event manager)
> to keep the backup link to the other 7200 down until the link to the
> primary 7200 failed. That way the L3 interfaces would be down until a
> failure occurred, and no manual intervention would be needed.


Thanks - I have looked into EEM....just not 100% confident with it.....Ill test it out, and see how it goes.

> 
> Another option may be to use flex-links on the 4948 and then use a
> protocol like 802.3ah.  The backup flex-link would block traffic from
> going to the 7200 so the 802.3ah PDUs never make it to the 7200 and it
> treats the interface as down.  That's a long-shot I don't really know if
> that's supported at all.


Thanks - Flex-link sounds very interesting - Ill see if it is supported on the 4948.

> 
> Otherwise you could use VRRP on the 7200s if you have a /29 to burn for
> each customer. 

For vrf links, /29 wouldnt be a problem...Inet tails it would.

> 
> There are other solutions on newer boxes/software like multi-chassis LACP,
> but I don't think anything you listed there supports it.

Cheers - Yes, dont think the 4948 supports it.

Thanks again for your replies.