Message-ID: <0251888E076E2B45A72536425D4D001461EBA1@snexu01.mcdata.com>
From: Siva Vaddepuri <Siva.Vaddepuri@mcdata.com>
To: "'Joshua Tseng'" <jtseng@NishanSystems.com>,
   Kevin Gibbons
	 <kgibbons@NishanSystems.com>,
   "'ips@ece.cmu.edu'" <ips@ece.cmu.edu>
Cc: "'Black_David@emc.com'" <Black_David@emc.com>
Subject: RE: Clarification regarding iSNS Message Format
Date: Wed, 2 Apr 2003 21:03:13 -0800 
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Thanks.

Siva
-----Original Message-----
From: Joshua Tseng [mailto:jtseng@NishanSystems.com]
Sent: Wednesday, April 02, 2003 8:51 PM
To: Siva Vaddepuri; Kevin Gibbons; Joshua Tseng; 'ips@ece.cmu.edu'
Cc: 'Black_David@emc.com'
Subject: RE: Clarification regarding iSNS Message Format


Siva,

The authentication block is a MUST for Broadcast/Multicast messages (see
section 7.2) and a SHOULD NOT (see section 5.5) for unicast messages.

Originally there was a flag to indicate the presence of the authentication
block in the iSNS flags.  Somehow it disappeared in revision -05 (that was
in November 2001 and I don't have any record of why it was removed, but my
guess is that it was an accident).  It needs to be put back in.  We should
probably make bit 18, which would indicate "authentication block present".

Thanks for this catch.

Josh

-----Original Message-----
From: Siva Vaddepuri [mailto:Siva.Vaddepuri@MCDATA.com] 
Sent: Wednesday, April 02, 2003 1:50 PM
To: 'Kevin Gibbons'; Joshua Tseng; 'ips@ece.cmu.edu'
Subject: Clarification regarding iSNS Message Format


Hi,

Can anybody clarifiy requirements for Authentication Block in iSNS Message? 
- Is it a MUST for Broadcast/Multicast packets?
- Is it MUST-NOT for Unicast packets?

If Authentication block is optional for unicast packets how do we determine
iSNS Packet boundaries in TCP Session?

iSNS Message
   Byte   MSb                                        LSb 
   Offset 0                   15 16                   31 
          +---------------------+----------------------+ 
        0 |   iSNSP VERSION     |    FUNCTION ID       | 4 Bytes 
          +---------------------+----------------------+ 
        4 |     PDU LENGTH      |       FLAGS          | 4 Bytes 
          +---------------------+----------------------+ 
        8 |   TRANSACTION ID    |    SEQUENCE ID       | 4 Bytes 
          +---------------------+----------------------+ 
       12 |                                            |  
          |                PDU PAYLOAD                 | N Bytes 
          |                    ...                     | 
          +--------------------------------------------+ 
     12+N | AUTHENTICATION BLOCK (Multicast/Broadcast) | L Bytes 
          +--------------------------------------------+ 
                   Total Length = 12 + N + L 


Thanks,
Siva

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