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2013-07-03

Cisco Live 2013 Insights – Catalyst 3850

Cisco Live is obviously the biggest networking event of the year, and Cisco likes to use all the attention to show off some of their new gear. I must say I was impressed with the Enterprise offerings including the 6807-XL, the 6880-X, the 4451-X, and the Sup 8-E for the 4500-E. Those boxes definitely gave me a bit of a tingle when I was checking them out, but my eyes opened up when I saw the 3850. The Catalyst 3850 is the next version of the 3k line of switches and the successor to the 3750-X.

2008-11-24

Configuring Dedicated Trunks for the CSM

Did you catch the article on setting up fault tolerance on the CSM?  In that article, I mentioned that Cisco recommends a dedicated trunk for the FT VLAN if you have two HA CSMs in two chassis.  Discuss amongst yourselves while I drone on. Why should you set up a dedicated trunk for this stuff?  […]

2008-11-06

Using Probes on the CSM

There are three different ways that a CSM checks for the health of the servers — active probes, inband health checking, and inband HTTP monitoring.  Let’s talk about active probes. Active probes (or just probes) typically send traffic to one of the RIPs of a serverfarm, do some stuff, and give a pass or fail […]

2008-10-27

Using MAC Access-lists

We ran into this today, and, though I knew it existed, I never actually saw it in the wild.  I’m talking about MAC access-lists. In the example setup, we have a DMZ off of a firewall that contains a whole mess of servers — email, web, ftp, etc.  These should all be in the DMZ […]

2008-10-10

Configuring Fault Tolerance on the CSM

Like (nearly) everything in the Cisco world, you can set up your CSM to fail over to another module when the primary dies a horrible death.  You can have two in the same chassis or even have them in separate chassis — the process is the same no matter how you have it set up.  […]

2008-07-14

Back to Basics — CAM Table Population

At the office, we reprovision servers like it’s going out of style.  It happens so often that my cabling documentation rarely matches what’s actually out in field, which is a pretty big problem when you’re trying to find to what switch port a server is connected.  I finally relegated myself to asking for the MAC […]

2008-05-15

Storm Control

We run a large number of LANs all over the country that are “controlled” by the particular business unit. We manage the gear, but, since they have the money and have to pay for anything we do, they make the final decision on what gets put in. Sometimes that gets out of hand, as you […]

2008-04-18

Getting Started with EtherChannel

In my professional life at some point, I came across someone who had a stack of Catalyst 2950 switches all trunked together with their Internet routers connected to the top of the stack. This was all well and good until they kept adding hosts to the “middle” of the stack, then they had all sorts […]

2008-03-21

Trunking on a Catalyst Switch

If you didn’t now already, trunks are connections between switches that carry traffic for all VLANs. It allows you to have, say, VLAN 10 and VLAN 20 on two switches appear as the same network. Unless you’re a really small shop, you’ve already dealt with trunks, so there’s no need for an introduction. Let’s say […]