Why is Mikrotik Pushing MPLS?

Funny you should ask yourself that, because I’ve been asking myself the same thing ever since I saw that the feature was added. I personally administer a network that includes a chunk of MPLS, but before then, it was just another buzz word. When I say it contains MPLS I mean we actually do MPLS on our equipment, not that we are running on a providers MPLS network…we are the provider! This means that I have become pretty familiar with it…which makes me wonder why Mikrotik bothered with it…:)

So, after hearing me blab, why is Mikrotik pushing MPLS? Simple answer is performance. In a nutshell, what MPLS does is to take the routing table and compile it into a forwarding table. The MPLS packets then get tagged with an MPLS label. Now, your routing decisions more or less are a layer 2 forwarding decision. Now your backbone routes only need to keep track of the MPLS labels and L2 forward based on that. This gives you a performance boost. I saw them present some number that were showing increases of I believe around 25% throughput at the MUM.

This sounds like a great feature, which makes you wonder why say, Cisco, doesn’t push MPLS as an optimizer…that’s because it isn’t an optimizer for them. Sometime before I could drive a car, Cisco came out with fast switching. It was based off of the netflow concept. The idea is route once, switch many. It would take the first packet in a flow and run it across the interface ACLs and the route table. It would then give all the subsequent packets in the same flow the same forwarding procedure. This was more efficient, but was still processor based. They then came out with CEF, Cisco Express forwarding.

CEF takes the route table and compiles it into a binary table so that all routing decisions are handled in hardware! This way the processor doesn’t even get invoked in the normal forwarding process. In Cisco, if you want to run MPLS, you first enable CEF. Soooo, with Cisco, you are running MPLS on top of an already super efficient system! So Cisco’s implementation is in hardware, where as Mikrotik is still all software based.

To me the most interesting part of MPLS is running VRFs (Virtual Routing and Forwarding instances). This is often called MPLS VPNs. What it basically allows you to do is run overlapping addressing on the same routing infrastructure. I can have 100 companies running 10.X.X.X subnets over my routed infrastructre with no problems!

I plan to compare Mikrotik’s MPLS implementation to Cisco pretty soon. I want to see how the VRFs compare…do they support route leaking with filtering? If they do, how well does it interoperate with Cisco?