This is a wired connection all over the topology. By combining, I mean N3 will take incoming packets from N1 and N2, add some headers/payload to the packets (causing a delay at N3), and then send the new packets to N4. So, if N3 gets Packet1 and Packet 2 from N1, N2 respectively, the outgoing packets to N4 will be Packet1' and Packet2' (i.e. same header, but slightly modified by N3).
Now, I have already been using the 2nd suggestion you made here, i.e. to have a UDP flow from N1->N4 and N2->N4. But that's precisely what I don't want to do ... I want to have a flow N1->N3, and another flow, N2->N3, and send packets from these incoming flows over the flow N3->N4. In other words, I want a single flow on the link between N3 and N4. (One way of doing this might have been to have a packet sink at N3, and then adding a CBR source at N3 with data rate equal to the sum of the CBR rates of N1 and N2. But I need end to end latency measurements and other calculations for packets from N1/N2 to N4, so the flow must be continuous.) Any solutions/suggestions for that would be much appreciated. Thanks. -- Ragib On Mon, Jul 21, 2008 at 3:31 PM, Farhana Ashraf <[EMAIL PROTECTED]> wrote: > Combining two flows into one, does this means after getting one packet from > N1, and one packet from N2, N3 will: > 1. change the two packets, and send the two packets to N4? is it using > wireless channel or wired? > or, 2. N3 will combine the two packets, have its own one packet to send to > N4? > > For case 1 (wireless), you can: > have two CBR flows, one from N1 and N4, and the other from N1 to N4. > set the distances between the the nodes such that, the flow from N1 to N4 > has to go through N3. similar thing for flow2. > then hack MAC layer to change the packet information at N3. > > for wired, you just have to connect the nodes in the network, as you > described. > but have the two CBR flows, one N1->N4, other N2->N4. > hack MAC layer to change packet at N3. > > There may be other simple ways for doing it. But, this is how I probably > would have done it. > > Thanks > Farhana > > On Mon, Jul 21, 2008 at 3:04 PM, Ragib Hasan <[EMAIL PROTECTED]> wrote: >> >> Hi everyone, >> >> I am quite new to NS-2, and am stuck with this problem: how do I merge >> two incoming flows into a single outgoing flow? >> >> Here is the scenario: I have two CBR generators running at two nodes >> N1, N2, which send data over UDP links to N3. In turn, N3 is connected >> to another node N4, where we have an application that will use the >> packets. >> >> What I want to do is this: I want to generate timestamped/sequence >> numbered packets at N1 and N2. N3 is to have two incoming flows of >> these packets, and I want to merge these incoming flows at N3, do some >> processing (i.e. add a processing overhead latency), and send the >> combined flow to N4, which will examine the packet sequence numbers >> and delays. >> >> In other words, N3 is to merge the two incoming flows into a single >> outgoing flow to N4. >> >> This might be trivial to solve, but as I said, I am very new to NS-2, >> and can't find a solution. So, it will be great if anyone can tell me >> what to do and/or direct me to the appropriate documentation. >> >> Thanks in advance. >> >> Ragib >> >> -- >> Ragib Hasan >> PhD Candidate >> Dept of Computer Science >> University of Illinois at Urbana-Champaign >> 201 N Goodwin Avenue >> Urbana IL 61801 >> >> Website: >> http://www.ragibhasan.com >> http://netfiles.uiuc.edu/rhasan/www >> > >
