NetWorld Tips from William Caban

Networking Lab Series: LAB 1 PART 2

William Caban — Sun, 10 Jan 2010 22:57:58 +0000

This is the second part of the Networking Lab Series: LAB 1. Lets start with some review questions and analysis from PART 1: What happened when you did the mutual redistribution CE to PE between EIGRP and BGP? Besides the “redistribute bgp xxx” under EIGRP, What was required for EIGRP to advertise the routes learned from BGP into [...]

What is the MPLS VPN Label?

William Caban — Mon, 04 Jan 2010 21:01:20 +0000

In the MPLS world the concept of labels and stacking labels are used all the time. When running MPLS L3VPNs each route from the CE will end up with at least two MPLS labels: one commonly referred to as the VPN Label and the other referred as the IGP label. Lets explore what really is the [...]

Networking Lab Series: LAB 1 PART 1

William Caban — Sat, 02 Jan 2010 22:11:02 +0000

Many of my friends have asked me to mentor them or do customized training for them, well, even when I want, I can’t have the time on regular basis. So, I have decided to post some exercises here so they can go step by step. (I should warn that this is not for beginners). NOTE: THE [...]

Accessing the hidden console of VIPs of a 7500

William Caban — Wed, 30 Apr 2008 11:47:00 +0000

The 7500 platform use the VIP (Versatile Interface Processor) for WAN interfaces. When dCEF is active the actual processing of the packets is done by these interfaces. Each one has its own CPU, memory, etc. The troubleshooting of this VIPs is difficult from the main IOS. In order to gain access to a deeper level [...]

Tunnel-less VPN with Cisco Group Encrypted Transport (GET) – Part1

William Caban — Thu, 21 Feb 2008 02:52:00 +0000

Nowadays, the requirement for encrypted communication between business locations is part of the standard requirements from our customers. More and more regulatory laws force the use of encrypted communication. The classic scalability issue with IPSec site-to-site encryption is that it requires each location to have a VPN to every other location. In other words, we will [...]

Expanding a VMWare Virtual Disk

William Caban — Thu, 21 Feb 2008 02:17:00 +0000

My primary OS is Linux but I have VMWare machines with Windows and other OSes, for testing of tools and softwares. I keep a basic installation of the Windows OS (XP, Server, etc) in a VMWare machine and keep it updated and patched. Whenever I need to do a software evaluation, I simply use a copy [...]

Cisco Router as DHCP Server

William Caban — Fri, 01 Feb 2008 00:31:00 +0000

All Cisco Layer3 switches & routers, have the capability to run a DHCP server. Sooner or latter you will find yourself with the need to configure a router as a DHCP Server. The configuration is quiet straight forward. Lets say we have the following interface to our LAN: ! interface FastEthernet 0/0 description Uplink to Users Segment ip [...]

Cisco’s Core Dumps to an FTP

William Caban — Mon, 14 Jan 2008 20:35:00 +0000

There are times when you will need to capture a core dump of a Cisco device that has been crashing. Core dumps contains a copy of the router’s entire memory contents. In some circumstances this will help technical support to determine what is causing the crash of your network device or will help the developers to [...]

My Cisco Virtual Lab Topology I

William Caban — Mon, 14 Jan 2008 18:22:00 +0000

I have real Cisco routers and switches but most of the time I rather use virtual devices based on Dynamips. They are portable with my laptop, don’t consume additional electricity and provide me with and environment to test features anywhere I go with my laptop. I use it to test QoS, MPLS, IP routing (with [...]

Calculating Frame-Relay map-class parameters

William Caban — Mon, 24 Dec 2007 13:55:00 +0000

Have you struggle to understand what seems like black magic behind the calculation of the parameters of a frame-relay map? Well, I did for a long time. Frame-relay is one of those technologies that isn’t going to disappear anytime soon. So if you are a consultant you will find yourself implementing QoS over frame-relay. Now Cisco [...]