Re: [ns] forwarding mcast packets

["Jingyi" <eehjy@ust.hk>]

----- Original Message ----- 
From: "Per Olesen" <polesen@nordija.com>
To: "list-ns-users" <ns-users@ISI.EDU>
Sent: Wednesday, December 05, 2001 8:45 AM
Subject: [ns] forwarding mcast packets


> Hi,
> 
> I have a problem forwarding IP multicast packets from a multicast classifier. 
> In my classifier, I determine which next hop(s) that should receive the 
> packet. The next hop is identified by a node id and OTcl name.
> 
> Then I do a lookup on the node name using TclObject::lookup() and then I call 
> recv(pkt) on the reference returned.

You may want to take a more careful look at the classifier. What slot_[] returns is the next hop link HEAD, instead of the next hop node. A packet can only be forwarded from the ns object it is at to an object the current object targets (i.e., directly connected to).
Hope this helps.

Jerry


> 
> But the packet never seems to reach its destination (nothing seems to happen).
> I do this, with the packet I forward:
> 
>       Packet* packetCopy = pkt->copy();
> 
>       hdr_cmn->prev_hop_ = node_id_; // node id of forwarding node
>       hdr_cmn->next_hop_ = nextnodeid; //node id of next hop node
>       hdr_cmn->addr_type() = NS_AF_INET; 
>       hdr_cmn->direction() = hdr_cmn::DOWN;
> 
>       next->recv(packetCopy, hndl);
> 
> What could I be doing wrong?
> 
> Regards, Per
> 
>