ISCW: DSL encapsulating PPP with ethernet or atm

gojericho0

Study both methods and have no experience with DSL (use cable at home). Was wondering if anyone could explain to me why a company would use one encapsulation method over another?

I know that PPP is needed for session establishment like a circuit, authentication and stuff.

This is an assumption on my part, but I think Ethernet encapsulation would be better because it can handle larger load of bandwidth.

It is also not clear to me how this encapsulation of PPP works. I need a diagram or something. Should I picture it as a tunnel like a l2tp vpn?

Any help to clear this up would greatly be appreciated

tech-airman

gojericho0 wrote:

Study both methods and have no experience with DSL (use cable at home). Was wondering if anyone could explain to me why a company would use one encapsulation method over another?

I know that PPP is needed for session establishment like a circuit, authentication and stuff.

This is an assumption on my part, but I think Ethernet encapsulation would be better because it can handle larger load of bandwidth.

It is also not clear to me how this encapsulation of PPP works. I need a diagram or something. Should I picture it as a tunnel like a l2tp vpn?

Any help to clear this up would greatly be appreciated

gojericho0,

Do you remember PPP for a serial link at the CCNA level?

gojericho0

yup, its used to encapsulate point-to-point serial links

tech-airman

gojericho0 wrote:

yup, its used to encapsulate point-to-point serial links

gojericho0,

Encapsulate at which OSI model layer?

gojericho0

Layer2

nice343

are you ntalking about pppoe ?

gojericho0

yes, and where the encapsulation takes place and terminates at. I'm assuming it either occurs on the client or subscribers modem\router, inorder for the provider to keep track of the sessions in a multiaccess network, but not sure where it terminates at.

PPPoE i can understand its use and think most subscribers would have this since they are normally connected to an ethernet network

PPPoA confuses me because i'm picturing a bunch of end users connecting to the dsl modem with an ATM connection. Also ATM is also the protocol uses on the DSL network. It just seems a little redundant

dtlokee

It will depend on how you terminate the DSL connection. If its an Ethernet handoff from the modem to the router then it's PPPoE. If you're using an ADSL WIC in the router then it's PPPoA.

gojericho0

dtlokee wrote:

It will depend on how you terminate the DSL connection. If its an Ethernet handoff from the modem to the router then it's PPPoE. If you're using an ADSL WIC in the router then it's PPPoA.

Ok, that makes sense!

Next questions is if using a DSL modem that also acts as a router, you would not need PPPoE\PPPoA since the router would be changing the encapsulation from ethernet to ATM correct?