Subject: Use of RSVP over shared media

From: sivakumarg <[email-masked]>
Date: Thu, 03 Apr 97 16:00:00 PST

Hi,

I have a doubt reg. the use of RSVP over Shared Media.
Suppose the following scenario where H1 is RSVP capable
host, H2 is non-RSVP capable and R1 is a RSVP capable router.

                         Shared Media Cloud
                              __
            +---+          __/  \__             +---+
            | H1|         /        \            |R1 |
            |   |<------>| 10 Mbps  |<--------->|   |
            +---+         \__    __/            +---+
                             \__/
                             /|\
            +---+             |
            | H2|             |
            |   |<-------------
            +---+

Further assume that H1 has requested and has been granted a
bandwidth of x Mbps (x < 10 Mbps). The effective bandwidth
received by H1 depends on other stations on the cloud like
H2. If H2 pumps traffic into the cloud, then H1 cannot
receive x Mbps, even though R1 has granted that reservation.
In this case how does RSVP handle this situation?.

I had raised a similar doubt some time back (only diff was
that the shared cloud was between RSVP capable routers) and
I received replies saying that RSVP currently does not
support Shared Media between routers. But I have seen some
public domain software for traffic control which support
ethernet media.  Is it possible to support Shared Media
with RSVP even if it is only between end-node and router?

Siva

---

From: "Eric S. Crawley" <[email-masked]>
Date: Thu, 3 Apr 1997 08:20:08 -0500

Siva,

Yes, there are some problems using IntServ over shared media.  This is
being discussed in the Integrated Services over Specific Link Layers
(issll) working group.  You might want to look at
draft-ietf-issll-is802-framework-01.txt for some decomposition of the
problem(s).

	Eric