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Re: loss of original packet type info when tracing multiple protocols.
Only packets generated by the mac-802.11 protocol such as RTS, CTS and ACK
packets have PT_MAC as the packet type in the common header (if you look at
mac-802_11.cc, you'll notice the packet type is set to PT_MAC only in sendRTS,
sendCTS and sendACK methods). I dont think the packet type is changed to
PT_MAC for packets generated by higher layer protocols.
Satish
> Hi,
>
> - How does one retain the original information in the common header -
> the packet type being the most important- when using nodes consisting of
> multiple protocol layers and tracing for some of these layers is
> required?
>
> Consider for example a node containing a MAC layer and a TCP agent.. The
> ns/cmu trace objects generate their traces by looking at the packet type
> field in the common header. For a MAC packet, the type therefore needs
> to be changed from PT_TCP to PT_MAC in the sending MAC object (I know
> this is being done in mac-802_11.cc when a Packet is passed to the
> channel). On the receiving MAC side, the packet type should be changed
> back to PT_TCP but I don't see how this information can be retained. I
> also don't see how / if this is being done by the MAC object in
> mac-802_11.cc
>
> I guess there are ways to avoid it, e.g. packing the original (TCP/IP)
> packet into the data field of the Packet transmitted by MAC (and
> unpacking at the MAC receiver) or using an additional header to store
> the information contained in the original common header, but I'd really
> like to know how the people from CMU did this in mac-802_11
>
> Regards, Sjoerd Janssen.
>
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