Switch on Aaron's Worthless Words

ASIC Programmability from Barefoot Networks

Mon, 30 Jan 2017 00:00:00 +0000

Full disclosure : I was lucky to be among a group of networking influencers invited to Silicon Valley to visit some networking companies and see what they were offering to the market. I was flown out and given accommodations at the expense of Gestalt IT - the company that organized the event. I was given some swag by each company, but I was never paid to write a positive review on the product. Heck, I’m not even expected to write at all.

News - Cisco Announces EOL Schedule for 6500s

Fri, 01 Apr 2011 00:00:00 +0000

This is a surprise, but Cisco has announced the end of life of the 6500 switches that we all know and love. Usually Cisco gives a platform a few more years after they decide to retire it, but the schedule only gives the 6500s one more year of service. I’m sure this goes back the success and recent expansion of the Nexus line of switches.

Here’s the lowdown from Cisco.

Stubby Post - Null VTP Domain Scare

Wed, 05 Jan 2011 00:00:00 +0000

Remember a few weeks back when I had a bad day? I was actually at HQ that day to do some work for a project, but that got put off due to the extenuating circumstances. When we finally got back around to do the work, we wound up adding a switch in the data center to extend a VLAN over to a rack.

Stubby Post - VTP Clients Send Updates

Tue, 18 May 2010 00:00:00 +0000

VTP clients send VLAN updates. Did you know that?

I had a VTP server and client in the same VTP domain, and, when I cabled up the trunk, the client overwrote the VLAN database on the server.

The moral of the story is that the best revision number will win no matter what the operating mode of the switch.

SWITCH - Epic Regression

Tue, 11 May 2010 00:00:00 +0000

Just because I like giving more money to Pearson Vue, I took the BCMSN test today to see how I would do. I passed with no problem.

In my mind, the CCNP is a technical certification, so I expect to be tested on technical topics. Are there topics beyond technology that P-levels should know? Of course there are, but I really don’t think whole chunks of the test should be about a preparation plan and rollback procedures. The BCMSN had a lot more technical questions at a much higher level of expertise; it seems much better suited to the CCNP track than the SWITCH test did.

SWITCH - Epic Fail

Thu, 06 May 2010 00:00:00 +0000

I did my standard 2ish-hour drive to the closest testing center today to take the SWTCH test (642-813). Utter failure. That’s 3 for those scoring at home.

The test was the absolute worst I’ve ever taken. I know that I complain a lot, but this is totally justified in my eyes. My 4th grade spelling tests were better than this. I’ve seen kindergarten plays with better production value.

First of all, it was poorly written. Whoever wrote those questions has a few pieces of information about English sentence structure missing from their skill set. A sentence needs a verb, right? Well, a lot of the sentences were missing those. It’s kind of important to know what the whole point of the sentence is, or is that too much to ask? The “drag this over here” exercise questions all started with the same 13-word phrase that left the question so long that it was unreadable. A couple of commas would have been nice in some. Others I just had to infer from the answers what they were trying to ask.

Stubby Post - UplinkFast

Wed, 28 Apr 2010 00:00:00 +0000

I’ve got a few switches daisy chained together with single links and have enabled UplinkFast on them. This switch is not the root bridge; F0/24 is the root port and F0/23 is a blocked alternate port. I’ve got debug spanning-tree uplinkfast on to help out.

SW3#sh span | incl 0/2[34]
Fa0/23           Altn BLK 3019      128.23   P2p
Fa0/24           Root FWD 3019      128.24   P2p

Now let’s unplug F0/24 and see what happens.

Stubby Post - Path Cost of EtherChannels

Tue, 27 Apr 2010 00:00:00 +0000

I was doing some STP labs tonight and found something that caught me off guard a bit. I had been meddling with some EtherChannels between a pair of 3750s earlier today, and I forgot to reset the configs before starting on the STP stuff. One my secondary root switch, I ran a show spanning-tree vlan 1 to see what status the ports were in, and I noticed the root path cost.

SWITCH – STP Exercise #1 Solution

Sat, 24 Apr 2010 00:00:00 +0000

Did you guys have any trouble with the solution to the STP exercise? Let’s work through it and see what happens. I got a few responses to the solution, and everyone seems to get the same answer, so I assume we’re all right.

Before we get started, I wanted to mention the tie breakers since there can be ties in STP. If there is a tie in any calculation, the same tie breakers are used, so I’ll list them here to use as we move through the calculations.

SWITCH - STP Exercise #1

Thu, 22 Apr 2010 00:00:00 +0000

Here’s an STP exercise for you. Given the bridge priorities, MAC addresses, and interface types in the diagram, calculate the root bridge, root ports, designated ports, and blocked ports. You can click on the image to enlarge it. I’ll post a solution in the next few days. As always, feel free to comment and ridicule my utter idiocy. Be gentle, though; I don’t usually post exercises like this.

Send any configuration BPDUs questions my way.