Blog

One of the security factors I’ve heard espoused about IPv6 is that the large address space (128 bits: 64 bits of network and 64 bits of host address) makes it [...]

TTCP (Test TCP, see ftp.arl.mil/~mike/ping.html.] I shared the modified version with other people, some of whom made other improvements (see the source file header comments for who did what). Later, [...]

VoIP troubleshooting is a pretty interesting problem. (See my earlier blog entry regarding my talk at VoiceCon Fall 2007.) There are a large number of tools that look at packets [...]

A lot of people have misconceptions about the CCIE (Cisco Certified Internetwork Expert) program and its numbering. I was consulting at Cisco in 1993 when I first heard about the [...]

Good network design follows long-established principles like hierarchical design and information hiding. Basic network protocols exhibit this through data encapsulation. Lower layers hide their operation from the upper layers, allowing [...]

I’m doing a presentation at VoiceCon next week in San Francisco’s Moscone Center titled Troubleshooting IP Telephony Networks. This presentation will be quite a bit different than other similarly titled [...]

Cisco has implemented a number of features that allow us control over packet prioritization, which allows us to give priority treatment to specific applications. One of these features is the [...]

I’m studying for my CCIE recertification and was reading up on Rapid Spanning Tree (RSTP) operation. Cisco has a really nice white paper on its operation, with a lot of [...]

Today I am speaking at the Cisco User Group meeting in Des Moines, Iowa. The topic that resonates with Cisco user groups is Networking Tips & Best Practices. A previous [...]

When I was in college at Vanderbilt University, and then later at the University of Maryland, computing was done on a central mainframe. (Yes, the dark ages of computing.) In [...]

We were invited to speak at the annual Morgan Stanley CTO Summit that was held this week in San Mateo, CA. This summit is where Morgan Stanley hears what promising [...]

I recently attended a Cisco event billed as a ‘mini-Networkers’ in Columbia, MD. It was a full day of Cisco presentations about a variety of technologies and was attended by [...]