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Re: IP/ROHC tunnel with IPv6 - flow label

 

Hi,

> I´d like to identify the flow that is appended in rohc packet payload.
> For example, suppose a video packet (with ipv6 header) arrives at the
> rohc compressor. This video packet (P1) has a flow identifier on his
> "flow-label" field. It would be nice if the resulting compressed
> packet had a ipv6 header with the same flow identifier ("flow-label
> field) of the original packet (P1). This could allow network
> management of the compressed packets in many different forms (Qos,
> policy-routing).
> Is there any roadmap to implement something like this in rohc tunnel?

OK, you would like to identify the tunnel encapsulation with the same
label as the transported packets.

It would be possible to assign some QoS mark (flow label for IPv6 and
TOS/DSCP for IPv4) to the tunnel encapsulation. However, it wouldn't
be straight to map the QoS of encapsulation and the QoS of transported
packet.

The IP/ROHC tunnel performs packing to minimize bandwidth consumption:
one IP/ROHC packet contains the equivalent of up to 5 transported
packets. If they got the same flow label, there is no problem. But if
they got different flow labels, which one to choose? Several solutions
are possible: take the flow label of the 1st packet, don't pack
together packets with different flow labels...

Before modifying the IP/ROHC source code, you'll have to choose a
strategy :)

Regards,
Didier


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