Re: Linux Frame-Relay and misc

[Guy Harris <guy () alum mit edu>]

On Sat, Oct 18, 2003 at 01:35:18AM +0200, Krzysztof Halasa wrote:
> Guy Harris <guy () alum mit edu> writes:
> > It can also be Q.933 call control, which is what I was really asking
> > about - i.e., it's more than just LMI (Q.933 annex A), it's Q.933 in its
> > entirety.
> >
> > I think the 0x08 stuff from RFC 2427 is for stuff other than DLCI 0 (or
> > the D-channel, if you have one).
>
> It seems it's for both LMI 0 (certainly) and for other things.
> Not sure if you can have D-channel on FR (isn't it an ISDN-only
> thing?)

Well, Q.922 is entitled "ISDN DATA LINK LAYER SPECIFICATION FOR FRAME
MODE BEARER SERVICES"; I have the impression you can connect to a Frame
Relay network over an ISDN link (i.e., the user-to-network interface, if
that's the right term, is over an ISDN basic rate or primary rate
connection).  The page at

        http://www.frforum.com/basicguide/chap3.html

says

        ISDN and Switched Access for PVCs and SVCs
        Access on demand for PVCs and SVCs, whether via Integrated
        Services Digital Network (ISDN) or switched access is another
        method to reach the frame relay network.  Access on demand holds
        a great deal of promise for remote locations accessing
        high-speed frame relay implementations.

        In switched access, a circuit-switched connection to the frame
        relay switch can be established using the existing voice
        network.  An indication is then sent to the switch that a frame
        relay call is being established; the switch makes the connection
        and bills the call appropriately.  The customer pays only for
        the use of the local loop when needed, without requiring PVCs at
        the user-to-network interface.  The same benefits are true for
        ISDN access and E.164 addressing and lead to true, any-to-any
        connectivity through ISDN or switched access.
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