Archive for May, 2013

Multicast, MPLS and MDT’s, oh my!

Here, as promised, is my first post of real substance!  I’ve been building a new core network for the health system I work at and one of the requirements was to enable multicast across the wired as well as wireless network.  Seems fairly straightforward at first, enable PIM on all interfaces that could potentially carry multicast traffic, set up your RP’s (auto-rp, bsr, or manually) and off you go.

Well, the new core network is MPLS based, and has a set of firewalls filtering traffic between VRF’s so there is a bit more to getting multicast to work which I will walk through here.  I also have a mix of Cisco Nexus 7k’s in my core and 6500’s in my distribution layers and there is a caveat that needs to be addressed which I will go over as well.

The network is a pair of Nexus 7k’s as the core of the MPLS network with 6509’s hung off of them acting as building distribution PE’s.  Routing between VRF’s is handled by an “Interchange” router that is northbound of the core switches and an ASA in transparent mode, sits in between the core and interchange routers handing firewall duties for each VRF:

network overview
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