Re: How to know which neighbor send the packet

[Gang Xu <gxu@eng.ua.edu>]

Hi, George and Chetan,

Thanks for all you helps. I tried both ways tonight.

First, I tried George's way. However, ip_hdr->src() only returns the
address of the source agent. :-(

I believe Chetan's suggestion is correct, but I still met some problems.

I cann't find 'ifaceGetNode' instproc in ns-node.tcl. I 'grep'ed all the
Node instproc under ~/tcl/lib and still cann't find it. Then I used
hdr_cmn to get the iface_. In my recv() method in C++ code, I use
	hdr_cmn* cmnh = (hdr_cmn*)p;
to get the common header and use
	cmnh->iface()
to get the iface_ member data. I think it should return the link on which
the packet is received. In my otcl code, after I pass the cmnh->iface(), I
use '[[$link fromNode] id]' and get the following message:
	ns: -o141 recvPack 1 514 0 2202008: invalid command name "2202008"
	    while executing
	"$link fromNode"
	...

Did I miss something here? BTW, I am using ns-allinone.

Thanks again for all your helps!
Gang

On Thu, 9 Jul 1998, Chetan Rai wrote:
> 
> On Thu, 9 Jul 1998, George Riley wrote:
> 
> > I believe you can look in the ip_hdr of the packet, and check the
> > ip_hdr->src() value, which indicates the node inthe upper 24 bits.
> > George
> 
> I think Gang wants to find the neighbouring node thru which the packet
> was routed - the Node instproc 'ifaceGetNode' returns this node - the
> incoming interface (required as argument to ifaceGetNode) is in the
> iface_ data member of the cmn header.
> 
> -Chetan
> 
> > 
> > 					
> > 			-George F. Riley (riley@cc.gatech.edu)
> > 		 	-Grad Student Liaison
> > 
> > 
> > On Thu, 9 Jul 1998, Gang Xu wrote:
> > 
> > > Hi,
> > > 
> > > After a node receives a packet, is it possible to check which neighbor
> > > sends the packet to it? 
> > > 
> > > Gang Xu

Gang Xu
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