On Wednesday, October 19, 2011 06:49:31 AM Bradford Chatterjee wrote: > The biggest operational issue that we've encountered is > that having PE features enabled on your P routers makes > your core vulnerable to quite a few more bugs. It's not > necessarily a deal breaker but you do need to be aware > of it.
Indeed - the edge needs features, which means code upgrades, which means problems for your core. We relegate P/PE combinations for new, small PoP's where cost is a factor, and the customer base is small/simple that the basic features we have in the device would be more than sufficient to fend off any kinky deployments. Another area which is one of concern for P/PE designs is QoS. We were particularly hit by our Juniper's on this one. Traditionally, Juniper remarks packets with your QoS values on egress. The problem with this in a P/PE design is that you likely have one QoS policy for you core traffic, and another for your edge traffic. If you remark on egress, how is the router to know which traffic is transit and which is edge, as sometimes it's 'popping' and other times it's 'swapping'? Of course, newer line cards from Juniper now support ingress remarking (closer to the customer), but the majority of deployments out there still don't. Suffice it to say, ingress remarking on Juniper kit is only advanced on the older hardware, i.e., M-series routers with IQ2E-enabled PIC's. The MX with it's MX-3D line cards is still far from perfect, but better than the previous DPC's. In 'c-nsp' context, I'm not sure whether any Cisco kit has an ingress remarking deficiency, or egress remarking affinity (all the Cisco kit we have remarks on ingress just fine), but it's something you want to make sure you don't get into with the kit you deploy for P/PE functions. Cheers, Mark.
signature.asc
Description: This is a digitally signed message part.
_______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
