>
>Oscar Rau
>[EMAIL PROTECTED] asked,
Let's put these in context. At the physical layer, WAN oriented
implementations are Data Terminal Equipment (DTE) at the host or
(usually) router side.
Host
Upper Layers
Transport
Data Link Data Link
Physical DTE---DCE Physical DCE Physical ---DTE Physical
| |
Transmission medium-------------|
The external physical interface between a DTE and DCE is RS-232,
V.35, or other serial specifications.
The DCE converts to and from the actual transmission format on the medium.
On a dialup link over POTS, the DCEs are modems.
You can have null cables between DTE and DCE.
On digital media, the DCE might be DSU's or CSU's that convert to the
line format.
If POTS is considered the general dial service, Frame, X.25, HDLC,
and ATM do not use it. POTS generally implies a modem modulation
specification, with PPP running over it.
IBM mainframes attach to routers with SDLC, not HDLC.
>I have some questions about HDLC and WAN protocols.
>
>Is HDLC via serial interface between router and mainframe? and
>between router and router?
>If HDLC is done between router to router, is it over WAN using POTS?
>
>Do WAN technologies such as Frame Relay, X.25, HDLC and ATM networks use POTS?
>
Thanks you for any info.
=
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
