Subject: Resources in RSVP

From: Srikanth Uppuluri <[email-masked]>
Date: Fri, 09 Feb 2001 18:31:23 +0530

Hello,
   I am  a newbie to RSVP. I have the following basic doubts..

    When we talk about resource reservation:

1) What EXACTLY do we mean RESOURCES? Can someone give me a clear
definition ?

2) Once we know what these are, how do we actually allocate them? The
exact procedures for admission control and packet scheduling are not
mentioned in the draft. What exactly does it comprise in implementing
packet scheduling?

Thanks
Srikanth Uppuluri

---

From: David Charlap <[email-masked]>
Date: Fri, 09 Feb 2001 10:53:55 -0500

> 1) What EXACTLY do we mean RESOURCES? Can someone give me a clear

RSVP reserves resources according to the IntServ spec.  See RFC 2210 and
related documents.

Resources are specified in the form of a token-bucket description
(average bandwidth, peak bandwidth, bucket size).  Also included are
minimum and maximum packet size.  When guaranteed service is requested,
the data rate and a slack factor are also specified.

RSVP is extensible, however.  It can theoretically reserve resources
other than those specified by RFC 2210.  For example, the MPLS working
group defined a "class of service" CType for the Flowspec object in
their RSVP-TE document.

Of course, inventing your own type of Flowspec object will not be very
useful without support from other router vendors.

> mentioned in the draft. What exactly does it comprise in implementing

This is beyond the scope of RSVP.

The hardware or software that does your packet forwarding is responsible
for maintaining reservations.  You shouldn't have to know the details of
what's involved unless you are designing new forwarding hardware or
software.  In order to implement RSVP, you only need a programmatic
interface to your forwarding subsystem so that you can make and destroy
resource reservations in response to incoming RSVP messages.

-- David