Building Core Networks with BGP, OSPF and MPLS

Do you need advanced knowledge and skills needed in designing and implementing core MPLS networks? We have developed exactly the course you need.

The Building Core Networks with BGP, OSPF and MPLS (NIL_BCMPL) course focuses on MPLS applications such as MPLS VPN (with special attention to Internet access from a VPN), Any Transport over MPLS (AToM), Carrier Supporting Carrier (CsC) and MPLS Traffic Engineering (MPLS TE). As a prerequisite for MPLS deployment the routing protocols are explained as well - the Open Shortest Path First (OSPF) and Border Gateway Protocol (BGP). The scalability issues of the protocols as well as multiprotocol BGP are addressed as well. Several practice labs enable you to gain the necessary experience in deploying the MPLS-based core networks.

MPLS Traffic Engineering without a Link State routing protocol

You've probably heard the joke about the honest salesmen: it's not that they're lying, what they know isn't true. I had a similar problem recently: in the 10 MPLS traffic engineering myths and half truths I wrote “Half-truth: MPLS TE only works with OSPF and IS-IS routing protocols.” Ivan Kuchin understood that as “You can run MPLS TE without OSPF or IS-IS.” Although I haven't written that anywhere, I also thought that was the case … so let me try to weasel out of this mess.

I remember being involved in a situation years ago (around the 12.0T release) where someone wanted to use MPLS TE without IS-IS (which was the only supported protocol in those days) and somehow the solution was to set up tunnels using explicit paths, where you have to specify hop-by-hop IP addresses. When you think about it, it makes perfect sense: if you list every IP address in the path, there is no need for constraint-based path calculation (PCALC). However, as it turns out, the later additions to MPLS TE (loose source routing, address exclusion, inter-area MPLS TE, inter-AS MPLS TE) changed the IOS code sufficiently that even the hop-by-hop tunnels cannot be set up without operational OSPF or IS-IS:

• In order to have MPLS TE running on a router, you need an MPLS TE router-id, and you can only specify that in OSPF or IS-IS routing protocol.
• Even though the hop-by-hop explicit path is static, the router wants to run PCALC for every hop in the path. If the next-hop IP address is not in the OSPF topology database, the router will not even try to set up the tunnel.

If you want to run MPLS TE in your network, you thus need to run OSPF or IS-IS, even though you might not want to use them for IP packet forwarding. For example, you could enable one of them only on the links actually used for MPLS TE and set the distance to 255 to prevent their routes from getting into the IP routing table (and I've tested it in the lab before writing this post).

Hands-on MPLS Traffic Engineering

I've written a lot about MPLS Traffic Engineering (not nearly as much as I would like, but there are always time constraints), as I believe this technology has interesting applications in Enterprise networks (and we all know that a lot of Service Providers are using it anyway). You might have seen my 10 MPLS Traffic Engineering Myths or the Perfect Load Balancing article … and if you don't know what I'm talking about, there's always the introductory Traffic Engineering the Service Provider Network.

The major problem of MPLS TE is that it's complex and that networking engineers usually lack the hands-on skills, and this is where we can help you: we've just rolled out the revised MPLS TE lab exercises. Compared to remote lab offerings from other sources, these lab exercises are very focused: you get step-by-step instructions (but no recipes, that would spoil the learning process), preconfigured equipment (so you don't have to configure IP addresses or IP routing protocols to get the job done) and detailed solutions explaining which task is achieved using a specific set of configuration commands.

I was able to get a discount for my readers: if you click this link and type in the promotion code 42B078 (expires on January 15th, 2008), you'll get a one week subscription to the MPLS TE remote lab bundle for €56. As this is a subscription offering, you can run the lab exercises as often as you like within a week of the purchasing date. And if you need one more argument to be persuaded, check the lab topology; you can experiment in a preconfigured nine router network :)

MPLS Traffic Engineering myths

Did you believe MPLS TE was a quality-of-service feature? Did someone persuade you it's mandatory to run OSPF or IS-IS if you want to deploy MPLS TE? I've collected a few more myths like these two and explained the actual facts behind them in an article published by SearchTelecom.

MPLS Traffic Engineering essentials

The MPLS traffic engineering essentials article I wrote for TechTarget describes the fundamentals of MPLS Traffic Engineering, how it compares to traditional traffic engineering available in Frame Relay and ATM networks and what are the distinctive benefits of using MPLS versus a legacy WAN technology.

Introduction to Traffic Enginnering

In the TechTarget article Traffic engineering's role in next-generation networks I'm describing why one would need traffic engineering in a Service Provider network, what options were available using the “legacy” WAN technologies and what you can do to deploy traffic engineering in a modern end-to-end IP network.