Archive for February, 2009

6PE – IPv6 over MPLS

6PE is a really cool feature which allows IPv6 islands to communicate with each other over an MPLS/IPv4 core network.  IPv4 addresses space is fast running out so familiarising yourself with IPv6 is probably a good idea.
Consider the toplogy below.

Service providers can leverage their MPLS networks to deliver IPv6 solutions without having to rearchitect their [...]

BGP – Remove Private AS

The video below shows how to remove a private AS from BGP as-path list.
Consider the topology below.
AS65300 peers eBGP with R1.  R1 then peers eBGP with R2.
R1 is then configured to remove all private ASs in the as-path when it advertises BGP routes to R2.
Watch the video below or download and watch it on your [...]

OSPF down bit and domain tag

Both the OSPF down bit and domain tag are modifications in OSPF which are used as loop prevention mechanisms.  Why are there two mechanisms you ask.  This is because type 5 LSAs do not contain the options field in the header.  The options field is where the down bit is set.  In LSA type 5 [...]

Controlling MPLS Label Distribution – Video

I was looking through my archives to remember how to configure “controlling label distribution” and realised that I had not not made a video for this subject, so here goes.
Consider the topology below.

As we all know, LDP assigns a Label for each IGP prefix and connected route in the RIB.  Therefore when we use the [...]