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New Member

WAN Technologies and Internet

Hi all,

I am teaching CCNA (semester 4- WAN Technologies).When I have lecture chapter 4- ISDN and DDR how to configure them between two or three remote sites. One of my students asked me Do we configure the T1 or E1 speed for the Internet speed? If no how to make it works with the Internet?

what is the purpose of PPP, ISDN, and Frame-relay network?

Coul you please give me some advices!!


New Member

Re: WAN Technologies and Internet

specifiying bandwidth on an interface is always a good thing, but keep in mind that most interfaces have a default if not specified (i.e Serial Interface defaults to 1.544Mbps)... from a routing protocol perspective this is very important to specify for route computation, selection, etc.

As for the purpose of PPP, ISDN & FR, I would recommend consulting the DocCD. Keep in mind these are all layer 2 technologies.


Re: WAN Technologies and Internet

You should program the speed of your ISDN and Frame Relay links because it is used to calculate the best route in some routing protocols. You do not need to input the speed it will not hurt. It is a best practice idea. Useally you would not access the Internet via an ISDN line. ISDN is mostly used for backup link access if your primary line fails. Frame Relay is mostly used in a point to multipoint application where your headquarters has a T-1 and your remote branches use Frame Relay PVC's to get to your headquarters. PPP is a protocol that you can use for your serial link and ISDN lines. The PPP protocol mechanism has the ability to relay important information about your layer 2 and layer 1 mediums. It works well with ISDN that is why PPP is used for ISDN lines. It is also a standard that is used with third party vendor links. You can use PPP to interface with a Nortel router line. I hope I helped and answered your questions.....