[c-nsp] Etherchannel and variable latency on member links

[Peter Rathlev]

Hi,

We have some bandwidth issues between two sites, experiencing "out
discards" on interfaces.

The connection is currently between 2+2 switchports in WS-X6516-GBIC
cards and they're connected by ~4 km SM connection with LX GBICs. The
redundancy is blocked by STP.

To increase bandwidth in a cost effective way we were thinking of just
merging these two link in an etherchannel. The only concern is that the
two paths aren't exactly the same, and differ in length by about 20%.
This is of course not much on such a short stretch, but how does
etherchannels handle this?

As far as I can understand the loadsharing is strictly deterministic, so
out-of-order frames shouldn't be a problem. I assume the switch itself
doesn't care about the difference; we plan to use LACP as we do on all
other etherchannels.

Should we be nervous about this? Anybody running traffic through
etherchannels like that and can give thumbs up or down to this?

Regards,
Peter