interfacial absentia

[k0mbachi]

With regard to the two questions below, at what OSI layer would the "serial interface" be located? Would or would not answer C be correct in the second question? Can a frame-relay configuration be properly configured without an actual frame relay connection? Can a standard modem be used to configure a ppp connection?

Which of the following commands would assign DLCI 301 to a serial interface?
A. dlci 301
B. frame-relay dlci301
C. frame-relay interface-dlci 301
D. interface-dici 301

Answer: C
ID#3436

Which of the following methods can be used by a router to assign layer 3 addresses to layer 2 frame relay DLCIs?
A. inverse ARP
B. frame-relay map statements
C. frame-relay interface-dlci statements
D. access lists

Answer: A, B, C
ID#3453; this needs to be checked; Cisco Flash only recognizes Inverse ARP and frame-relay map statements

 

[dogbert2]

Actually, it is A and B only, because there is NO reference to Layer 3 in the statement, but if you configure the interface (if a single frame-relay connection) with a IP address (or assign the IP address to each subinterface), then taken as a whole, the interface commands (properly
typed in) will cause layer 2 and 3 mappings to occur for FR

 

[k0mbachi]

I understand that Inverse ARP is traversing the layers to pick up the IP address from an upper layer. Granted, response C seems to be only defining the DLCI on the local layer, thus I'll change the answer to the question.

Is the process you're describing done by the frame-relay map statements? While I've worked in environments that use frame relay, I've never had the pleasure of configuring same.

 

[gdschertz]

first question c is correct. second question if i read it right a and b are correct, you add the ip address to the subinterface and that associates it with the dlci.

Yes you can corectly configure an unconnected frame-relay interface but untill you have a frame-relay connection there will be no way to test it. you can set a cisco router to imulate frame-relay switch and test your configs that way.

the frame-relay map ip xxx.xxx.xxx.xxx is used on point to multipoint interfaces. the frame-relay interface-dlci is used on point to point sub interfaces.
The serial interface would be on the physical layer, framerelay would be the datalink layer protocol, with ip as the layer three protocol.

 

[k0mbachi]

Thanks, gdschertz. I just found this link:

http://www.frforum.com/basicguide/toc.html

for a bit of extended study.