Have you hacked the recv function of MAC layer to add the processing delay?
On Mon, Jul 21, 2008 at 3:40 PM, Ragib Hasan <[EMAIL PROTECTED]> wrote: > 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 > >> > > > > >
