Basic MPLS/VPN with Cisco IOS

This is a quick tutorial for basic MPLS/VPN with Cisco IOS configuration. The tutorial exemplifies basic PE to P to PE configuration on three Cisco 7200s running in GNS3 with IOS. R2 is configured as a route reflector P node and R4, R6 and R3 are PE node route reflector clients. The IGP is OSPF with R2 as the ABR. Loopback1 …

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How Headers Encapsulate in the OSI stack

How Headers Encapsulate in the OSI stack: Part 2 of some refreshers. We send application data or payload by encapsulating or framing each layer within the previous layer. We looked at each one individually and now here is how they look when each layer is wrapped inside the previous layer.  Figure 1. Here is how application data gets passed to each …

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How I Learned to Hate the DCI

Internet

How I Learned to Hate the DCI: Layer 2 data center interconnects (DCI) is still alive and well. I blame VMware with vMotion and now every other Hypervisor vendor on the planet. Live workload migration is certainly vital to most operations. The further up the stack that happens the more flexibility you have with choosing more layers beneath you to reach for in …

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What are Ethernet, IP and TCP Headers in Wireshark Captures

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If I could go back in time when I was a n00b kid wanting to go from zero to a million in networking, the one thing I would change would be spending about 6 months on the fundamentals of networking headers and framing before ever touching a single peice of vendor gear. Ethernet, IP and Transport headers (L2-L4) are the …

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Why the NOS will decouple

Over the next couple of years some of us expect the networking industry to have some fairly significant changes. There are really two options: A distributed approach we have today or a controller based centralized model. We  have today just that, autonomous devices building adjacencies to one another, exchanging what it hopes are the best healthy paths to send next hop traffic …

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Network Processor Units (NPU) FTW

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OTV configuration notes

Quick notes on OTV. I have not put this on lab gear yet so there may be typos. It does require licensing so make sure you have that budgeted, if not its a 20kish surprise which sucks.

#The Overlay interface ID (int overlay1) must match at both sites. A Vlan can only be assigned to one overlay.

#Join-interface. From …

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February 2012 SDN Thoughts

I commented on a blog post earlier and I am recording my updated thoughts to review over the next few years to see how wrong I was. My initial business cases still have not changed much from 4 months ago. It has always been and will be about money. What will drive this is the ability to commoditize networking vendors and level …

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