Frame Relay Question

[bnorton916]

Using packet tracer I set up a frame relay switch(CloudPT), with 3 routers connecting to it(multi-point).(youtube had a video on it)
I set-up the dlci's in the CloudPT.

The only thing I did on the routers was something like this:

interface Serial0/3/0
bandwidth 64
ip address 10.1.1.102 255.255.255.0
encapsulation frame-relay
!

Everything works just fine. All my routers can ping each other.

But no where did I map any dlci's on the router?

How does the router know which dlci to use if there is no mapping?

R2#show frame-relay map
Serial0/3/0 (up): ip 10.1.1.101 dlci 201, dynamic, broadcast, CISCO, status defined, active
Serial0/3/0 (up): ip 10.1.1.103 dlci 203, dynamic, broadcast, CISCO, status defined, active

Or rather where did this mapping come from?

What am I missing?

Thanks,
Bill

 

[unclerico]

Since you posted in the Certification forum, I'll nudge you in the right direction, but I won't give you the answer. Hint: Look at the interaction between LMI Status messages and Inverse ARP.

 

[bnorton916]

Ok, so somehow, InverseArp let the router know the mapping for dlci and ip address.

True or false: InverseArp will normally take care of dlci mappings unless one of the routers doesn't support inverseArp. In this case you must manually enter to the dlci to ip address on all the routers. ???

Thanks,

Bill

 

[unclerico]

Mostly true. I say mostly because the second you enter a frame-relay map statement on a multipoint subinterface or the physical interface itself, InARP is disabled. Also, on a point-to-point subinterface InARP is ignored.

 

[bnorton916]

Ah, didn't know this about InARP.

Thanks,

Bill

 

[burtsbees]

Aren't you going to tell him the issues with iARP, Uncle? Lol.

How ya been, bro?

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