Re: [lp-wan] Fw: re-order header field request

["weigengyu" <[e-mail]>]

Hi Carles,

Suppose that one packet is partitioned into two fragments.

Because the Dtag indicates two fragments belonged to one packet,
the Rule ID in the second fragment is repeated, or redundent, isn't it?

If the Rule ID is not exist in the second fragment,
the receiver can process it according to the Dtag which is the same in two 
fragments.
Is there any confusions at the receiver side?

Regards,

Gengyu WEI
Network Technology Center
School of Computer
Beijing University of Posts and Telecommunications
-----原始邮件----- 
From: Carles Gomez Montenegro
Sent: Wednesday, June 21, 2017 2:07 PM
To: weigengyu
Subject: Re: [lp-wan] Fw: re-order header field request


Hi Gengyu,

> Why each successive fragment must contain a Rule ID?
> It is known that the DTag is used as an indication of fragments belonged
> to
> the same IPv6 packet.
> A Rule ID in the first fragement can be passed to the receiver how to do
> HC
> compression,
> but the successive fragments containing a Rule ID just send a redundent
> information to the receiver.
> Right?

The Rule ID is needed to provide a receiver with information on what type
of content is being carried (and how it has to be handled). Note that not
all IPv6 packets will require fragmentation, and then losses may happen,
also non-fragmented packets may be interleaved with fragments, etc.

Cheers,

Carles


> Regards,
>
> Gengyu WEI
> Network Technology Center
> School of Computer
> Beijing University of Posts and Telecommunications