WAN protocol questions

Posted on 2004-10-11
Last Modified: 2010-04-17
I'm tryng to get some practice with WAN protocols.  At home I have 2 routers. They are connected via a back to back serial cable (PPP encapsulation).  After reading my Cisco book, it appears as if you can configure passwords in between the routers.
I have a few questions

1. Would two routers ever be connected using PPP in the real world?? When?

2. When would you use authentication (ie: pap or chap) on a PPP link?

3. Unrelated: Is it possible to practice configuring your routers for frame? I have two 2501s and a 2600 router.

Question by:dissolved
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Expert Comment

ID: 12282307
Routers connected via PPP encapsulation are very common in the real world. You can find it anywhere you can think of, so it’s really not used in any particular place.

As for pap or chap, usually that isn’t configured on a routers WAN interface, but it won’t hurt to try and set it up as an exercise.  

As for practicing frame relay, you can add the line “frame-relay switching” to your config on one of the routers, and you should be able to configure two routers back to back for practice purposes using frame relay. That command by the way makes the router act like a frame relay switch.

Author Comment

ID: 12282359
Thanks. Quick question. We have multiple sites (at work) that are connected via frame relay.  I'm assuming frame relay uses a separate type of encapsulation (if any) than PPP? New at this, sorry!
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Accepted Solution

Dr-IP earned 500 total points
ID: 12282527
Frame relay is another type of encapsulation, it also very popular as it can be less expensive when it comes to inter office links over point to point T1’s. This is because several connections can be aggregated on a single frame relay backbone since each customer has their own DLCI (data link connection identifier) to identify their traffic from every one else. An easy way of conceptualizing this is to think of it as like VLANing, and the DLCI number it kind of like a VLAN number, and the WAN links are like Ethernet links into a VLANed switch. It’s a lot more complicated than this, but from the view of someone connecting to a frame relay network this view works pretty good.      
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Expert Comment

ID: 12282607
You might want to look at this link as a primer on frame relay. Also I suggest concentrating on it more than the other encapsulation protocols, as it’s the most complicated, and most relevant for you since that is what you are using where you work. Also once you learn frame relay, unless you get into ATM, the others are child’s play in comparison.

Author Comment

ID: 12283434
thanks a lot man

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