Routed Port

CCNP

Well, after a lot of umming and ahhing, I finally decided to put my head down for two weeks and got my CCNP SWITCH and CCNP TSHOOT done. That on top of my already passed CCNP ROUTE has achieved me a CCNP Routing and Switching from Cisco. 

If you're contemplating going for your CCNP, or are in the process of it, I can only encourage you to give it a shot. It's a good certification and by passing the exams you are demonstrating that you have a solid understanding of routing and switching, and not just as it relates to Cisco.

The only real advice I can offer you is to ensure you really understand the concepts Cisco has outlined in the exam blueprints. That means, STP, OSPF, HSRP and the rest. Know how they work and you won't have a problem.

At the end of it all, you'll know quite a bit more and Cisco will give you one of these little logos.

 

 

Cisco Policy Routing with EEM

I was recently tasked with improving a design for a branch office setup. The setup involves virtuals servers, virtual firewalls and virtual WAN accelerators. The problem that was being seen was two fold;

• A layer 2 connection from the WAN Router to the Firewall. This meant that if the firewall failed, we had no access to the mgmt network
• If the WAN accelerator failed, all traffic to or from the site was black-holed

Proposed Solution

I decided that we needed to solve the two aforemention issues. First, let's use layer 3, and second, let's use some way of detecting if the WAN accelerator fails.

I immediately thought we could simply use a route-map, policy-routing, ip sla and track availability. Much to my dismay however, I discovered the 12.4 IP Services on a Cisco 3560 doesn't support track availability in the set command in route-maps. I banged my head a few times and thought, well, let's give Cisco's EEM (Embedded Event Manager) a go.

Network Diagram

Network Design Proposal

In the above diagram, the Cisco 3560 is the site's router. With this layer 3 solution, if the firewall dies, we can still access the management network which includes other network devices and critically, the VSX Servers.

A Simple Cisco Fabricpath Test

I'm sitting here in the middle of the night (it's now 06:22) waiting for a provider to do some routing in their network to route some traffic over a satellite link. So I thought I might briefly reflect on a Fabricpath test I did this week with four Cisco  Nexus 5596 devices.

Test Scenario

As you can see, it's not a full mesh between the Nexus switches. It will be in further tests, but this was a pure functiona test, i.e. does it work and will there be any packet loss if I start pulling cables during a continous ping?

Host A and Host B are in the same subnet connected to Nexus 2248 FEXs. Fabricpath has been configured on all the links interconnecting the Nexus 5596s . The single links between the Nexus 5596s represent a data centre interconnect (DCI) utilising dark fibre (actual distance will be around 10km).

Test

Ping Host B  continuously from Host A and unplug any redundant cable.

IPv6Forum Certified Silver Engineer

On the 5th April, 2012 I received an E-Mail from the IPv6 Forum informing me that my application for the IPv6 Silver Certified Engineer was successful. This means that I am free to use the logo on the left on my website, blog, publications etc. It also means that the IPv6 Forum recognises that I have a certain set of skills and knowledge pertaining to IPv6. More importantly however, IPv6 Forum is helping people like me to publicise IPv6 and further its momentum around the globe.

On my part, www.cunningtek.com is both available on IPv4 and IPv6. If you query an IPv6 capable DNS server, you should see a AAAA record for wintermute.cunningtek.com to which www.cunningtek.com points.