Cell Relay Archive

[jeffm@team.iglou.com (Jeff Mcadams)]

Thus spake Kostas Kapetanakis
>Hello all,

>I have 2 questions conerning L2TP.

>Are there any documents describing how the L2TP works when the client
>and the LAC are connected through an ATM connection, a PVC, soft PVC or
>SVC?

L2TP really deals with the encapsulation from the LAC to the LNS...it
typically encapsulates PPP, but conceivably it could encapsulate other
protocols...and I believe there are some documents available specifying
encapsulating ethernet directly in L2TP as well as some others.  Could
ATM cells be encapsulated directly into L2TP?  Uhm...I don't see why
not, though it would be...uhm...odd.

>2)From what I understood PPP is a layer 2 service and I assume that it
>cannot be used over ATM.

Sure, there are docs for PPPoverATM...though I'm not terribly familiar
with it myself.

>Is that so? Can we use PPP over ATM or it is completely nonsense?  I
>ask this in order to find out if the following scenario can exist:
>Having a tunneled PPP connection to a remote LAN using an ATM
>connection instead of a dial up connection with the LAC.

To my knowledge, its not uncommon to run PPPoATM to a concentrator of
some type, and decapsulate the PPP out of the ATM and then
re-encapsulate it into L2TP to be transported to a LNS.
-- 
Jeff McAdams                            Email: jeffm@iglou.com
Head Network Administrator              Voice: (502) 966-3848
IgLou Internet Services                        (800) 436-4456