[c-nsp] EC flow hash computation w/MPLS

[Peter Rathlev]

On Tue, 2008-01-15 at 19:29 +0100, Oliver Boehmer (oboehmer) wrote:
> assuming we're talking about PFC3*, we hash on the underlying IP header
> for L3VPN and "regular" LDP LSPs and on bottom label otherwise (e.g.
> L2VPN/EoMPLS). PFC3 can look at most 3 labels deep for an IP header,
> which should be enough for most situations.

It's a 7600/Sup720-3B acting as MPLS PE in a data center, so we only
have the two labels for regular L3VPN, nothing fancy. So the "MPLS:
Label or IP" line from "show etherchannel load-balance" means IP if
present, else label. And when IP is present, the EC uses the regular
configured IP load-balance (from "port-channel load-balance <X>"). Hope
I got that right. :-)

On Tue, 2008-01-15 at 10:30 -0800, Tim Stevenson wrote:
> > The context is that I'm trying to find out how the WS-X6704-10GE
> > compares to using Etherchannels on e.g. a WS-X6748-SFP.
> 
> The EC decision criteria is identical on these two linecards.

Thanks, but I was more thinking about the difference between using
10Gig uplinks compared to using N-port 1Gig ECs. We're currently using
two 4-port 1Gig ECs from a WS-X6748-GE-TX as uplinks and have to
"expand" this. I'd prefer the 10Gig solution, but I think the bean
counters would prefer we just add more ports to the EC, buying a new
6748 module if necessary. We have eight of these aggregators, each
needing a 6704-10GE.

So I guess I'm looking for arguments for (and against) using 10Gig
instead of EC, apart from the naturally non-perfect load sharing
inherent in EC.

Thank you both. :-) 


Regards,
Peter