Subject: rsvp: using RRO as ERO

From: Rohit Chhapolia <[email-masked]>
Date: Wed, 11 Aug 1999 12:13:14 -0400

RSVP tunnel draft authors,

In the section 4.4.3, for Handling RRO, it is mentioned that:
   The newly added subobject must be this router's IP address.  The
   address to be added should be the interface address of the outgoing
   Path messages. ...

   ...The destination node initiates the RRO process by adding
   an RRO to Resv messages.  The processing mirrors that of the Path
   messages.  The only difference is that the RRO in a Resv message
   records the path information in the reverse direction.

Section 4.4.2 says that:
   Third, RRO syntax is designed so that, with minor changes, the whole
   object can be used as input to the EXPLICIT_ROUTE object.  This is
   useful if the sender receives RRO from the receiver in a Resv
   message, applies it to EXPLICIT_ROUTE object in the next Path message
   in order to "pin down session path".

Let's take the network shown below.

   A (IP1) ------> (IP2) B (IP3) ------> (IP4) C (IP5) -----> (IP6) D

IPx is the IP address of interfaces and -> is the direction of PATH msg flow.

When A receives the RESV message, should the RRO be (i) IP6, IP4, IP2 or
(ii) IP5, IP3 and IP1 (just reverse of what RRO what will be received by D)?
In the second case, it will be difficult to use RRO as ERO at A.

Rohit

-- 
Rohit Chhapolia
Ficon Technology, Inc.
mailto:[email-masked]
http://www.ficon-tech.com