Eric Stewart: Running Off At The Mouth

So yes – spending a lot of time with the new load balancers and finding out all sorts of things about their operation I didn’t know about, that (at least in this case) were fairly easy to fix.

The thing is carrying actual, important, production traffic now.  Most if it is short lived web-based stuff; short enough that the transfer completes well before a failed session establishment on the firewall is noticed.  But someone was noticing, and it took me doing many packet captures to figure out exactly what was going wrong (and realize it was actually my fault).

In which I regale you with a tale involving the salacious behavior of the Catalyst 6500 when compared to the more chaste Nexus 7K line.

Attempting (in my scatterbrained manner) to cover all the bases of an interesting issue I encountered recently and failed to fix without assistance. It illustrates why I’m not a CCIE yet, and why, no matter what you see, you shouldn’t assume anything when working through odd issues.

A revisit to an earlier post and why what I outlined there was a bad idea. Using Bank Chaining, while allowing you to use more banks for ACLs, has its penalties …

$JOB doesn’t have as much of a testing environment as one might like to have, so sometimes you discover issues during implementation that, once you resolve them, you can’t go back and pick apart. An issue with the vPC Peer link appears to have prevented one of our 7710’s going into our data center from properly forming an OSPF adjacency with the DR.

I get an error message while pasting in some VLAN interfaces:

ERROR: Module 1, 2, 10 returned status: Tcam will be over used, please enable bank chaining and/or turn off atomic update.If bank-chaining is enabled on other modules and this is a new linecard insertion,please enable bank-chaining prior to reloading this module.

Well, this (I think) is what it means, and how I resolved the situation.

Having been silent about my Cisco Nexus 7700 work for a while, I come across something that irked me a little bit while trying to configure our 7700 pair to replace the 6500s, involving Virtual Port Channels. So here’s what Virtual Port Channels are and how they basically work, as well as one or two things that you might want to be aware of. So, this may end up getting quite long …

It is possible on the Nexus 7700 line, with certain optics, to break out 40Gb (and eventually 100Gb) to 4x10Gb interfaces (no one knows for sure what 100Gb will do – it will either be 8x10Gb or 10x10Gb). In this post I go over how $JOB is doing it (at least with the 40Gb) and what you need to be aware of. I do touch a little bit on the 100Gb breakout future and explain why we were looking to do it.

We racked our Nexus 7710 recently. Here’s some of the things you might need to know regarding getting this monster of a chassis into a rack.

So we powered on our first to arrive Nexus 7706s (two of them). Here’s some notes so far.