Multicast and Frame Relay

Can someone explain to me how EIGRP has the ability to send multicast traffic over a multipoint Frame Relay network with no additional configuration like OSPF? Does it treat it just like a collection of point to point circuits for each neighbor?

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Comments

aueddonline

I don't think eigrp would have anything to do with it because it's a unicast routing protocol, it's PIM you want to look at

gojericho0

I guess then i'm kind of confused. I currently don't have PIM configured and am using EIGRP on a multicast subinterface. It is still using a multicast subint to send hellos and updates to its neighbors.
The neighbors are configured with a PPP subinterface and it seems to be working fine.

I'm just confused because I didn't think multicast was supported on a NBMA network and it appears to be working. Thats why I was wondering if the EIGRP application was doing something???

aueddonline

oh right, sorry read the post wrong, i thought you were doing multicast

why don't you do some debugs and you can see how it's sending the messages, I think the main point with eigrp over NBMA networks is the persentage it uses on the link

sorry for confusing you

marlon23

Hi, by adding broadcast keyword to the frame-relay map statement you're telling router to send a broadcast & multicast traffic towards that address. With EIGRP, it is straigh-forward, it will create a hello packet and just send it to the other site. With OSPF, it is more complex becouse of variety of network types defined inside protocol. When OSPF sees that network doesnt have broadcast capability (based on ospf network type of interface), it just wont send the hellos over that link even if there is a broadcast keyword on the map statement.

gojericho0

marlon23 wrote:

Hi, by adding broadcast keyword to the frame-relay map statement you're telling router to send a broadcast & multicast traffic towards that address.

Thats the piece of the puzzle I was missing! Thanks. I like all the features of the OSPF network types...it really gives granular control of the type of designs and scalability to use.