Subject: Applications running on RSVP Aware Host End

From: Neetu Gupta <[email-masked]>
Date: Tue, 06 Jun 2000 12:17:18 +0530

Hello,
    I've a doubt. Please clarify it.

    We are implementing both Integrated Signaling and Diff Serv LSPs
using RSVP in the MPLS Domain.

    Now, my question is: Do the Applications running on the Host machine
have to be RSVP Aware only or not? Can we run a general Application? If
we can, then how will the Type of Service byte in the IP Header be set
specifying the Class of Service with which the data packets of the
Application will be sent.

-neetu

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From: Snigdho Bardalai <[email-masked]>
Date: Tue, 06 Jun 2000 10:24:59 -0500

> Application will be sent.

Hi Neetu,

If you expect to have a DiffServ compliant application the IP header TOS
bits should contain the DiffServ DSCP values like expedited, assured
services etc.

But if you expect to support Integrated Services the TOS bits in the IP
header may not have any significance.

Snigdho

--
Snigdho C. Bardalai
Phone - (972) 479-2951
Fax   - (972) 479-4724
Email - [email-masked]

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From: Neetu Gupta <[email-masked]>
Date: Wed, 07 Jun 2000 10:01:03 +0530

Snigdho,
    What do you mean by Diff Serv Compliant Application?
Does that mean that when the application runs on the host end, DSCP will be
set in the IP Header?

So we cannot run general applications on the host that cannot set DSCP value
in the IP Header?
-neetu

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From: Neetu Gupta <[email-masked]>
Date: Wed, 07 Jun 2000 14:47:32 +0530

Snigdho,
    When the LSPs are created using Integrated Signalling protocol, the entry
is made in the Forwarding Engine, that contains a label for the information:
Source Address, Source Port, Destination Address, DestPort, Protocol, Class of
Service. This Class of Service can be the value specified for the Class of
Service in the Service Level Agreement with the Customer.
So, when the data packet comes, all these above mentioned fields are matched
with the fields in the IP Header of the Packet including  Class of Service
that is matched to TOS byte.
So, can't we map Class of Service to any of the DSCP values, and specify the
corresponding DSCP value for COS in the agreement with the Customer?

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From: Snigdho Bardalai <[email-masked]>
Date: Wed, 07 Jun 2000 09:21:19 -0500

> corresponding DSCP value for COS in the agreement with the Customer?

Sure you can - technically !!! It may not always be acceptable, but instead of
your customer being aware of such mappings you could perform the mapping
at an ingress LER. You must keep in mind that IntServ and DiffServ services
do not match in terms of service characteristics, so mapping services
could be tricky.

Snigdho