Monthly Archives: July 2014

Recognizing IP MTU Issues

At some point, Network engineers will likely face some type of issue with MTU or maximum transmittable unit. Their first experience with this may be an eye opening and time consuming effort. After resolving the issue, those with a thirst … Continue reading

Posted in How-To | 2 Comments

Explanation: TunnelX temporarily disabled due to recursive routing

I wanted to take a few minutes to share a scenario that some seem to struggle with. This scenario is a routing issue that sometimes occurs when an interior routing protocol allows routes to leak back through a tunnel. To … Continue reading

Posted in Design | 4 Comments

IP Subnetting Part 3: Understanding the Binary

I’ve often stated how simple subnetting really is. While each individual concept is rather simple, it is the combination that make the holistic process challenging. If we, as humans, could look at the process more like computers and network devices, … Continue reading

Posted in Career | 1 Comment

Using Cisco’s DevNet “All-in-One VM” as a Free Router Lab

I know many have been [not so patiently] waiting for the arrival of a┬áCisco┬ávirtual lab. Although I haven’t heard any official release date for VIRL or CML, there is a small scale virtual router lab available today. This lab is … Continue reading

Posted in Career | Comments Off on Using Cisco’s DevNet “All-in-One VM” as a Free Router Lab

Asking for Clarity

I have a lot of discussions with vendors, peers and other friends in the business. One of the things that I find challenging is the nuances with the language of technology. Our conversations include things like traffic flow, NAT, SDN, … Continue reading

Posted in Career | 1 Comment

Community Spotlight —

I’ve been reading articles by Jeremy Stretch for several years now. His site,, may be best know for the useful cheat sheets that cover everything from IGP routing protocols to Wireshark Display filters. This site doesn’t end with cheat … Continue reading

Posted in Other | Comments Off on Community Spotlight —