In a recent post I talked about Using Config Replace For Managing Router & Switch Initial Configs.  This is a great feature that can be useful to quickly switch between initial configs and a default config while labbing on your routers without having to write erase and reload - which can be very time consuming.  However, I previously assumed that this required a staged "blank" config in the router's flash, because regular IOS and IOS-XE don't have a built in text editor such as vi/nano/pico... Read More

This weekend while working on content updates for CCIE R&S Version 5, I ran into an interesting problem.  In order to test some nuances of routing protocol updates and packet fragmentation, I was trying to generate BGP UPDATE messages that would exceed the transit MTU.  To do this I manually created a bunch of Loopback interfaces and did a redistribute connected into BGP.  When I looked at the packet capture details, I started to realize how many routes I'd actually need in order to fill up the... Read More

For a limited time we are publishing the Route Redistribution videos from our CCIE Routing & Switching Advanced Technologies Class for public viewing.  These videos cover all aspects of Route Redistribution needed for the CCIE R&S Lab Exam outside of the scope of MPLS, and will also be useful for any engineers looking for more information on how the Route Redistribution process works. Read More

One common problem that causes candidates to fail the CCIE Routing & Switching Lab Exam is the lack of complete IP reachability to various segments used in the network topology. However, due to the short time constraints of the lab exam itself it can be difficult to dedicate enough time to properly verify that reachability exists between all relevant segments. In order to solve this problem two very useful features can be implemented during the lab exam, TCL scripting on the routers and macro... Read More