Operation — My EtherealMind

Basics: Cisco VLAN Trunking Protocol – Transparent Discard and Passing VTP Packets

11th April 2012 By Greg Ferro 7 Comments

It’s a common discussion about when Cisco VTP protocol is actually forwarded through Cisco switches and when it’s isn’t. I’ve always gotten it somewhat confused and when I stumbled across some old notes on the topic I had an ah-hah moment. I’m answering the equation about when using VTP in your network, which versions are risky – that’s risky is terms of how do you prevent VTP updates from ‘crossing’ a switch.

Filed Under: Basics, Blog, Operation Tagged With: Cisco, Operation, vtp

My Way of Selecting a Cisco IOS Release With a Bug Scrub

8th March 2012 By Greg Ferro 14 Comments

Cisco is known for shipping products early to deliver new features quickly. But this leads to a reputation for buggy code which has customers report bugs (and Cisco fixing them). This means that you should never buy a newly released Cisco product unless you are willing to take this risk. This post looks a my process for analysing this risk and then selecting an IOS version by performing a bug scrub. In this case, I’ve been asked whether the Cisco C3750-X switches are ready for live deployment.

Filed Under: Blessay, Blog, Cisco, Design Tagged With: Cisco, IOS, Operation

ASA 5520 and ASA 5540 With Only One DIMM Memory Socket – Counterfeit Hardware

20th December 2011 By Greg Ferro 1 Comment

There is a significant numbers of ASA5110 chassis that have been reworked to look and act like ASA5520 or ASA5540 firewalls. Refer this bug toolkit for more details.

Filed Under: Blog, Cisco, Operation, Security Tagged With: Operation

Ethernet Jumbo Frames, Full Duplex and Why Jumbo Frames Are 9000 Bytes)

3rd December 2011 By Greg Ferro 19 Comments

I’ve been doing some research into Ethernet and the use of Jumbo frames for some content I’ve been writing and come across something interesting. The documents state that Jumbo frames can only be used on Full Duplex Ethernet connections.

Filed Under: Blog, Musing, Storage Tagged With: Design, ethernet, Operation

Routing Protocols and Computation in Silicon

27th November 2011 By Greg Ferro 2 Comments

I got this question and I guess it may not be obvious to everyone so I’ll have a shot at answering it.

Technology advances in ASIC hardware have resulted in substantial improvements in switching performances of routers and switches. However, the routing processes are still dependent on CPU speeds. What are the existing limitations in router/switch models which prevent route computations from being performed in hardware?

Filed Under: Blog, Design Tagged With: deepdive, Operation, routing, silicon

Modular Data Centre – On the Highway

22nd November 2011 By Greg Ferro 5 Comments

Saw this modular data centre rolling down the highway today.

Filed Under: Blog Tagged With: data, datacenter, Design, Operation

HP Abolishes Software Licensing for Wired Ethernet Switches

20th November 2011 By Greg Ferro 6 Comments

HP Networking has announced no more software licenses on their networking kit.

Filed Under: Blog Tagged With: hp, Operation, product, software

Fibre Connectors

14th July 2011 By Greg Ferro 16 Comments

A short summary of the Fibre Cable Connectors, description and some notes on usage. This is summary notes and intended for reference.

Filed Under: Basics, Blog, Design, Operation Tagged With: Design, Operation

Those Non-IOS Files on the Flash. Are They Useful ?

8th June 2011 By Greg Ferro 4 Comments

When you first receive a router from a Cisco warehouse, it comes with a complete collection of IOS add ons. A common question is whether these files are used for anything ?