Hashing function for PSAMP

["Saverio Niccolini" <Saverio.Niccolini@netlab.nec.de>]

Dear all,
I would like to ask a simple question to the list.
As you have seen in the "Sampling and Filtering Techniques for IP Packet
Selection" draft we have tried to give suggestions on which is the best
hash function in order to do packet sampling.

Hash Functions Suitable for Packet Selection
1. IPSX
(2. BOB)

Hash Functions Suitable for Packet Digesting
1. CRC-32
(2. BOB)

Thinking about it and doing some additional tests it turned out that:
1) IPSX can only accepts 16 bytes as input --> it is not useful for IPv6
packets.
Do we want to stay with IPSX that is 7 times faster than BOB but can not
be used with IPv6 packets? What is the list feeling about this?

2) BOB is faster than CRC-32 (on software implementation) and achieves
as good collision probability as CRC-32.
Do we still want to recommend CRC-32 because we believe that hardware
implementation of CRC-32 are already out or we just would like to
promote BOB to recommended and CRC-32 as optional?

I am asking this because we are going to submit a new version of the
draft and we would definitely like to fix this issue.

Thanks in advance for your comments,
Saverio

============================================================
Dr. Saverio Niccolini
Research Staff Member
Network Laboratories, NEC Europe Ltd.
Kurfuerstenanlage 36, D-69115 Heidelberg
Tel.     +49 (0)6221 90511-18
Fax:     +49 (0)6221 90511-55
e-mail:  saverio.niccolini@netlab.nec.de
============================================================


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