Subject: Re: IPV4: Enable IP_ID sequencing for all traffic (inquiring mindswant to know why its set to zero)

From: Christoph Lameter <[email-masked]>
Date: Wed, 16 Jul 2008 17:37:07 -0500

Templin, Fred L wrote:

> The other implied use for IP_ID is as a uniquifier for
> duplicate packet detection (DPD), e.g., to detect routing
> loops in the network. But, 16 bits doesn't give sufficient
> uniqueness for today's data rates anway, so flooding-based
> protocols like Simplified Multicast Forwarding (SMF) really
> can't use IP_ID by itself for that purpose.

Well yes that was how the issue came about.

> SEAL extends the IP_ID to 32 bits. With 32 bits, it makes
> sense to set it as monotonically-incrementing for every
> packet out since a network-based DPD mechanism could
> potentially make use of it. Also, 32 bits avoids the ID
> wraparound issue such that a segmentation and reassembly
> mechanism can be used even at high data rates.
> 
> SEAL is specified in 'draft-templin-seal', and is also
> implemented at:
> 
>   http://osprey67.com/seal

Ahh... interesting. Maybe that would help. I will have a look at that.