Confused on FR DLCI Mapping Question

stunnedsoup

The confusion level in my brain for frame-relay PVC statuses is starting to climb higher and higher.

I'm reviewing Boson right now and was presented with the following question:

...see attachment

--Yes, my selected answer "D" was a bit off and a was more of a random guess because I thought for sure "B" was ruled out.

The reason I ruled out "B" was because my study notes (which I memorized) stated that a PVC Status of "Deleted" means that "either the LMI is not exchanged between the router and the local switch, or the switch does not have DLCI configured on the local switch." Note the words in bold and then note the words in choice "B" -- the word "incorrect" in choice "B" tells me that DLCI was actually configured, but configured incorrectly. That being the case, I figured that since it was probably configured then I can rule it out because "Deleted" means the DLCI is NOT configured, not misconfigured/incorrectly configured.

Now, when I look at the definition for an "INACTIVE" state, it says "the PVC is not up end-to-end. This may be because either there is no mapping (or incorrect mapping) for the local DLCI in the frame-relay cloud or the remote end of the PVC is Deleted."

(This is what I studied straight off the Cisco support docs site)

Well...maybe I answered my own question since "no mapping" is apparently the same as "incorrect mapping."

Boson's explanation says "the Deleted status...indicates that the DLCI that is configured on the router does not exist on the Frame Relay switch."

I'm probably making this harder than it really is. But boy, I am getting pretty confused because I don't know what definition to rely on.

james43026

I think you are making this more complicated than it has to be. Look at it this way.

PVC=active: This simply means that your frame relay provider has configured their equipment with the correct DLCI, you configured your equipment with the correct DLCIs, and both routers are talking to eachother.

PVC=Inactive: This simply means that both your provider and yourself appear to have configured everything correctly, as far as the DLCI's, but the PVC connection hasn't been established yet. Remember this is from the perspective of the router that you are connected to. It could mean that the router at the other end has it's interface shutdown. Or maybe the provider never even setup a DLCI at the other end.

PVC=deleted: This means one of two things, either your provider hasn't finished setting up the DLCI in their frame relay switches, or you mapped the DLCI manually and you mapped the wrong one, or the provider mapped the wrong DLCI, it basically means that through LMI messages the frame relay switch you are connected to said "Hey, I have no record of that PVC on the interface you are connected to".


I will also quote cisco.

ACTIVE— The PVC is operational and can transmit packets.
•INACTIVE—The PVC is configured, but down.
•DELETED—The PVC is not present (DTE device only), which means that no status is received from the LMI protocol.


http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/12sfrsdg.html#wp1023451

stunnedsoup

I appreciate the reply. Yea, after taking a step back and looking at it from a few feet away I actually was making this a lot harder than it should be.

james43026

I'm glad I could help.