I am sure this is a dumb question

But please can someone put me out of my misery and answer it?! I know this is a simple answer but I am having something of a brainfreeze and its bugging me

I am watching the nuggets for BSCI and will be building a lab shortly to go through the lab portfolio. In the nuggets, Jeremy creates sub interfaces on his serial connections. What I dont understand is how these connect up physically!

So assuming I have R1 as my backbone router, connecting to R2 and R3. I notice Jeremy has a serial interface that is up but he creates sub interfaces, which is fine. What I dont understand is how 1 physical interface can be connected to R2 and R3?? I get the fact these are sub interfaces but I still need to be able to connect to both routers? It would make more sense to me if he has 2 serial interfaces, and created sub interfaces for those

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Comments

DPG

Was there a frame relay switch between the routers?

colink24

DPG wrote: »

Was there a frame relay switch between the routers?

I considered this but he doesnt show it in his topology

DPG

Which video in particular?

networker050184

Most likely frame relay as DPG pointed out.

ColbyG

That's how FR works, they're virtual connections via DLCIs.

mikej412

colink24 wrote: »

I considered this but he doesnt show it in his topology

Is the topology a cloud with DLCIs at the ends of the connections?

Is there any frame relay as part of the configuration?

billscott92787

Chances are like everyone else said it is a frame-relay cloud/topology that is using sub-interfaces.

colink24

mikej412 wrote: »

Is the topology a cloud with DLCIs at the ends of the connections?

Is there any frame relay as part of the configuration?

The topology shows no cloud, and the show commands he uses do not show the frame relay config (if it exists). His topology just shows the routers connected back to back via serial links, yet his config is on sub interfaces

I think its best to assume its frame relay, but boy its annoying he doesnt take you through his lab setup prior to the vids!

colink24

DPG wrote: »

Which video in particular?

Router redistribution, I think video 16 or 17 in the series