Why Is MPLS Segment Routing Better than LDP?

A while ago I made a statement along the lines of “MPLS segment routing is the best thing that happened to MPLS control plane in a decade”. Obviously some MPLS-focused engineers disagree with that and a few years ago I decided to write a lengthy blog post explaining the differences between using MPLS SR with IGP (or BGP) versus more traditional IGP+LDP approach.

Obviously, I wasn’t making any progress on that front, so the only way forward was to record a short video on the topic which didn’t work well either because the end-result was a set of three videos (available with free or paid ipSpace.net subscription).


  1. What about scalability of segment routing regarding label space (range)?
    1. In a single routing domain you'd still need one label for every next hop on every switch in the network... and if you get beyond a few thousand devices then the SR fans will quickly point out you can use a controller that pushes label stacks into ingress nodes (or a gazillion other combinations of slightly-misused protocols).

      However, if you have a problem of that size, you might get better results by involving someone who did it before as opposed to collecting random tidbits from blogs and videos :D
  2. If these are free videos you should really make them available on youtube, why?

    2.Big Bucks
    3.So I can watch them on my telly (easily)

    1. Thanks for the suggestions. However...

      #1: Obviously you found them, so that’s not a big deal (and I prefer having an intelligent conversation with fellow engineers over vanity metrics anyway)

      #2: When you figure out how to make Big Bucks with niche technology videos please let me (and dozens of others) know. There’s a bit of a difference between spouting opinions and nonsense and getting millions of followers and creating technical content that gets a few hundred views.

      #3: What happened to “I liked them” or “You got it all wrong” or whatever instead of complaining about your pet inconvenience?

      Enjoy the weekend! Ivan
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