Subject: RSVP and IP fragmentation

From: Rosella Greco <[email-masked]>
Date: Wed, 24 Apr 2002 12:02:40 +0200

hi all,
      Can someone explain me why classification of packets per TCP\UDP 
port numbers is related to fragmentation of IP packets in RSVP? In 
specific I cannot understand this sentence in RFC2205:
"Because the UDP\TCP port numbers are used for packet classification, 
each router must be able to examine these fields. this raises three 
potential problems. One of this is : it is necessary to avoid IP 
fragmentation of a data flow for which a resource reservation is desired."
I would be very gratefull if some has some time to explain me this 
sentence and how RSVP deals with IP fragmentation.
Thanks very much for your help and attention
Rosella

---

From: "Jiang, Donghua (Jane)" <[email-masked]>
Date: Wed, 24 Apr 2002 06:25:35 -0400

Hi Rosella,

If fragmentation of an IP packet is performed, then only the first fragment
that contains the TCP/UDP header will contain the TCP/UDP port.  The rest
won't.  If packet classification is based on TCP/UDP port, then we won't be
able to classify the rest of the fragments.

Regards,
Jane

-----Original Message-----
From: Rosella Greco [mailto:[email-masked]]
Sent: Wednesday, April 24, 2002 3:03 AM
To: [email-masked]
Subject: RSVP and IP fragmentation

hi all,