Showing posts from January, 2011

How the Internet went out in Egypt

Good Article. Egypt is just blocking access to their DNS servers. Another good reason to use Goggle's Public DNS servers:,
How the Internet went out in Egypt

4900M connection to HP Virtual Connect Flex 10 - Not Working

Update: The configuration on the HP Virtual Connect side was incorrect. Once the server team reconfigured their side, all was good. Today I am posting something I submitted to

The customer has consultants configuring the HP side of things. I was asked to configure a Catalyst 4900M to work with the HP Virtual Connect Flex-10. From the Cisco side, this is not complex.

Tomorrow I am going onsite. I will open a TAC case on the way and sit beside the server guys.

4900M connection to HP Virtual Connect Flex 10

I'm Trying to connect a HP-C7000 blade server with a Virtual Connect Flex 10 connection with 10Gb links to a Catalyst 4900M. I have no control of the HP side.

From the HP guide, we are following "HP Virtual Connect Ethernet Cookbook" "Scenario 1:5 - VLAN Tagging (802.1q) with Shared Uplink Set (SUS) with Link Aggregation using LACP (802.3ad) - VMware ESX"

On the 4900M, LLDP sees the Virtual Connect and LCAP up with 2 active links.

Show i…

Do we need spanning tree ?

I had an interesting experience last week at a customers. I happened to be onsite to discuss why 4 Catalyst 4500 chassis had failed in 6 months. Each of them had similar symptoms, packets would no longer pass through them and a "show module" would either show the modules as not present or failed.

First we need a description of how the network is designed. This network is divided into "Network A" and "Network B". The separate networks represent the "business users" and the "operations users and systems". At the core of the network they have a single Catalyst 6500 with down links to Network A and Network B Catalyst 4500 switches.

The respective Catalyst 4500s have multiple down links to their respective Network A and Network B distribution Catalyst 4500s. These Catalyst 4500s have uplinks to access-layer switches. Each wiring closet has two switches, one for each network. If it is not clear, there are NO redundant links. There should be …

Introducing BillyC5022

Welcome to my Blog
I have worked in the IT industry since 1994. I survived the Internet boom or the 90's, Y2K, the VoIP boom in the 2000's, and now I am diving headfirst into Virtualization.
I am also married to a wonderful woman and the father of 5 daughters...Ages 1, 4, 5, 6, 9.
I am CCIE 5022, Routing and Switching. I currently work on Routing & Switching, Firewalls & VPNs, Unified Communications, Data Center Architectures. I am now jumping into Virtualization with Cisco Unified Computing Systems (UCS), VMware, NetApp, and EMC.
Customized Search Engine for Networking and Virtualization The custom Google search engine at the top of the page has been optimized to search domains and websites related to Cisco, VMware, NetApp, and EMC. It is currently referencing 66 distinct urls including YouTube pages for Cisco, VMware, NetApp, and EMC. Many urls are for respected websites and blogs relating to this technology. If you have any suggestions for websites to be included, let me…

The Begining

I am starting this blog to share my thoughts, provide a customized search tool, and aggregate the blogs I follow. More to come.