mechanika.org

VTP: VLAN Trunking Protocol

mechanik — Wed, 15 Jul 2009 02:19:10 +0000

VTP, What is it. VTP is a protocol created to ease the creation of VLANs on multiple switches, in an environment where there are multiple switches, its easier to setup a single switch as a sort of master switch that tells all of the other switches out on the network, hey, here’s all your VLANs.

Great idea, now for the drawbacks:

1) in VTP adding new switches can be a rather dangerous affair if you’re not careful. Every switch in the network maintains a revision number, and the server (or the client) with the highest revision number in a VTP domain can cause other VLANs to suddenly disappear.

2) Only support VLANs 1-1005, no extended VLAN (1006-4096) support, at least in VTP version 1 and Version 2. Version 3 is currently only supported by CatOS 8.1 and above.

3) VTP shouldn’t be used on sensitive core switches, should be kept in transparent mode.

Things I’ve learned today

mechanik — Sun, 12 Jul 2009 02:38:35 +0000

So today I learned a few things.

First and most importantly, never ever format a switch’s flash memory without making sure there is an IOS image avaialable somewhere.

Second, using a Mac works great for a lot of things, however xmodem file transfer isn’t one of them.

After wiping one of my switches in order to complete the first lab in the BCMSN lab portfolio, I figured hey I’ll get a bit a head and wipeout everything in the flash memory (unfortunately this included the IOS). So to make a long story short, OS X works great for console for almost everything, except i couldn’t figure out how to xmodem a copy of the IOS up to the switch. So after a bit of digging, I found something i hadn’t heard or seen since my days of MacOS 7.0, Zterm. I downloaded zterm and after a minute figuring out how to send the file I’m slowly loading a new IOS.

BCMSN: Countdown to test

mechanik — Wed, 08 Jul 2009 07:00:31 +0000

So as part of my motivation to actually get around to obtaining my CCNP; I went ahead and scheduled my first test. I was going to start withthe BSCI, but decided that of all the tests, I think the BCMSN would be the best place to start. So My current BCMSN test is scheduled for Aug 07.

With that in mind, I’ve been working on getting access to my lab to get all the pieces in order and to make the necessary testing. I should have my Switches in a few days. So that will get me started.