[Ns-developers] tag rework for next release

[Mathieu Lacage]

On Fri, 2009-04-03 at 11:04 -0700, Tom Henderson wrote:

> One thing that I noticed is that packet tags are left out of the 
> Packet::Serialize() process (while byte tags are included).  This is a 
> bit subtle, but it basically means that packets that are sent to another 
> node via an ns-3 channel will retain packet tags but if that ns-3 
> channel happens to utilize a real IP tunnel (in a distributed simulation 
> use case) the packet tags will be stripped.
> 
> It seems like we ought to support packet tags in Serialize, but is there 
> a reason why not?

Lazyness: I can fix this late next week but feel free to beat me to it.

> We ought to document somewhere the interaction between application-level 
> tags and NSC, while this is not yet fixed for NSC.

I doubt it will ever be really fixed in nsc.

> samples/main-packet-tag.cc could be enhanced with a byte example and 
> more commenting.  I would volunteer to contribute this patch if you want.

please, do.

> 
> Also, in udp-echo-server.cc:
> 
>             NS_LOG_INFO ("Received " << packet->GetSize() << " bytes 
> from " <<
>               address.GetIpv4());
> 
> -          packet->RemoveAllTags ();
> +          packet->RemoveAllPacketTags ();
> 
>             NS_LOG_LOGIC ("Echoing packet");
>             socket->SendTo (packet, 0, from);
> 
> 
> Why not remove all byte tags also?  Conceptually, this is a new packet 
> that is being echoed; i.e., it should behave the same as if the packet 
> were freed and a new one generated.

Yes, this makes sense.

> CHANGES.html needs some words upon merge.

yes.