Subject: Re: [Dime] End-to-end & Hop by hop in case of redirect message

From: rajithr 70236 <[email-masked]>
Date: Fri, 13 Apr 2007 14:11:26 +0800

I think it is better to change the hop-by-hop id. Consider a cross over b/w the retransmitted original request & the redirect indication response. If you use the same hop-by-hop id for the redirected request, you may require additional checks during transaction match as the duplicate response to the retransmitted original request & the original response to the redirected request will have the same hop-by-hop id.

For end-to-end id, I think it is better to retain it. This may be useful in cases where Diameter agents itself process the redirect indication & send out the redirected request.

Hope this helps.

Rajith
Hi all,

i have a doubt regarding hop-by-hop and end-to-end id of a redirecting request message.

>From the RFC3588 seciotn 6.1.7

"When a redirect agent receives a request whose routing entry is set to REDIRECT, it MUST reply with an answer message with the 'E' bit set, while maintaining the Hop-by-Hop Identifier in the header, and include the Result-Code AVP to DIAMETER_REDIRECT_INDICATION.  Each of the servers associated with the routing entry are added in separate Redirect-Host AVP.  The receiver of the answer message with the 'E' bit set, and the   Result-Code AVP set to DIAMETER_REDIRECT_INDICATION uses the hop-by-  hop field in the Diameter header to identify the request in the   pending message queue (see Section 5.3) that is to be redirected.  If no transport connection exists with the new agent, one is created, and the request is sent directly to it."

My doubt is while sending out the request to the new agent, what are the values of hop-by-hop id and End-to-End id? i mean are they same as the original request message? or they need to be chanegd with new values?

Thanks & Best Regards,
Chandu

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From: "Asveren, Tolga" <[email-masked]>
Date: Fri, 13 Apr 2007 07:55:20 -0400

hop-by-hop Id is better kept per Diameter connection, it is used mainly
to delete requests from retransmission buffer. It needs to be unique on
a given connection so that it can be used for that purpose. So, in the
scenario described, hop-by-hop Id for the new connection (the connection
for the host which is indicated in the redirect response) needs to be
used, which BTW could be the same like the one in the original request
just by coincidence.

End-to-end Id is used by the receiver of the request for duplicate
detection. Considering that the original request did not make it to the
final destination, end-to-end Id may be reused but I don't see any
advantage of it. I would just use a new one. After redirection, it is a
new request from base protocol point of view.

   Thanks,
   Tolga

-----Original Message-----
From: rajithr 70236 [mailto:[email-masked]] 
Sent: Friday, April 13, 2007 2:11 AM
To: Valesh Chandu
Cc: [email-masked]
Subject: Re: [Dime] End-to-end & Hop by hop in case of redirect message

I think it is better to change the hop-by-hop id. Consider a cross over
b/w the retransmitted original request & the redirect indication
response. If you use the same hop-by-hop id for the redirected request,
you may require additional checks during transaction match as the
duplicate response to the retransmitted original request & the original
response to the redirected request will have the same hop-by-hop id.

For end-to-end id, I think it is better to retain it. This may be useful
in cases where Diameter agents itself process the redirect indication &
send out the redirected request.

Hope this helps.

Rajith