Explanation. First we have to say this is an unclear question and it is wrong

First we have to say this is an unclear question and it is wrong. The “frame-relay map ip” statement is correct thus none of the four answers above is correct. But by the way we wish to explain about “global DLCI” in practical so you can understand it.

First we should remember that DLCI numbers are always only locally significant. “Global DLCI” is just a term to describe local DLCI numbers in a different manner and helps the documentation more easily.

First let’s see what happens if we use local DLCI as usual understanding:

Local DLCIs create a mess of notes!

With each connection, you have to note the DLCI number for that connection. For example, on router A we assign DLCI 100 for connection to router C; DLCI 200 to router D & DLCI 300 to router E. All of these numbers must be written on the links connecting to the corresponding routers. Now you can imagine we have about 100 routers, how many notes do we have to write?

That’s the reason why “global DLCI” comes into play. Notice that “global DLCI” term does not change the way DLCI works, it just changes the way we understand. The picture below demonstrates how this term is used.

Global DLCIs help reduce the number of notes

In fact, both of the pictures above have the same configuration. And we should understand that “all connections to router C should be assigned DLCI 100 at the partner router of router C”. The same thing for router A “all connections to router A should be assigned DLCI 400 at routers C, D and E”.

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