Cisco 7600 (7609) as a core BGP router.

Richard A Steenbergen ras at e-gerbil.net
Sat Jul 18 02:24:32 CDT 2009


On Sat, Jul 18, 2009 at 11:09:48AM +0700, Roland Dobbins wrote:
> 
> On Jul 18, 2009, at 4:30 AM, Steven King wrote:
> 
> >We use the 7600 platform as a Customer Border device.
> 
> The 7600 is actually quite a poor choice as an edge device (any edge)  
> due to its caveats regarding NetFlow, ACLs, and uRPF.  It's far better  
> suited to a core role, where it can handle mpps running without the  
> need for these critical edge features.

Funny, I'd argue that they're a terrible choice for a core router, due
to their inability to do line rate on a "any port to any port" traffic
profile, poor MPLS-TE functionality, and all of the caveats regarding
port-channel hashing. I do agree that they're also a poor choice for a
transit/peering edge due to their netflow issues (aka "completely
worthless, don't even bother trying"), ACLs, and route-map suckage in
general, but IMHO the only place they are even remotely usable is a
customer aggregation device.

With a customer agg router you have a lot of control about how you map
the ports <-> fabric channels to avoid intra-channel traffic, on a core
device you have no such luxury and you really don't want your network
taking a crap when your longhaul or even metro traffic shifts around (as
is going to happen on any well connected network). Once you throw in the
need to do MPLS and inter-device traffic rates greater than 10G, they're
an epic disaster in this role. On the other hand, you may not need
netflow on the customer edge if you're doing it on your peering edge, if
you structure your network right you can almost completely avoid having
to do ACLs on them, and the uRPF functionality is probably the least
broken thing about them. You also don't need complex routing policies,
you can hang them off more competent routers as route-reflectors, and
heck a datacenter agg box is probably the only place you want to be
using xenpaks (or even worse, x2) anyways.

But as always, your network requirements may vary. The only real
argument I can come up with against using them as customer aggregation
boxes is that when their interface counters break (which only happens on
days that end in y) you're actually misbilling people, and maybe not in
the direction you'd prefer. :)

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)




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