Difference between using subinterfaces and using FR Map?

Paul Boz

Admittedly I don't work with frame relay very much, so my understanding may be a bit sub par. Essentially I want to know what the differences are between using subinterfaces and using frame relay map commands? I've seen hub/spoke networks set up using both, and both support the broadcast command, so what gives? Is it just two ways of doing it? is one way better than the other?

EdTheLad

A quick reply as im busy testing, a subinterface can be either p2p or multipoint.A p2p subinterface doesnt use the map command, you just specify the dlci using "interface-dlci".If you are using a multipoint subinterface it behaves like a regular physical interface, you can use either inverse-arp or disable inverse-arp.If you wanna use inverse arp you must specify the dlci that is on the subinterface using "interface-dlci" and let arp take care of the mapping.If you wanna disable inverse-arp, use the "frame-relay-map" command.

Paul Boz

Why would you want to disable ARP and use the frame relay map command? overhead?

EdTheLad

Security and stability, to be in control of your mappings.If you had a customer hanging off your FR cloud you wouldn't want them to effect your local mappings with their bad config.

Paul Boz

Right, thank you for the clarification. In fact, since I have your attention, can you recommend a quality book on frame relay?

Thanks Ed.

EdTheLad

I can't really think of anything off hand, i usually use multiple books as i've got hundreds of ebooks to search through.If you can get your hands on a BCRAN knowledgenet or Cisco training academy course notes it would be a good start.

Pash

http://www.amazon.com/Cisco-Certification-Bridges-Routers-Switches/dp/0130903892/ref=sr_1_3/002-1202226-9508043?ie=UTF8&s=books&qid=1180949717&sr=8-3 - as reccommended by Turgon, i will pick myself up a copy when im back onto Cisco.