Re: PIM : detecting duplicate packet
John Zwiebel <[email protected]>
| Newsgroups | gmane.ietf.magma |
|---|---|
| Message-ID | <[email protected]> |
These topologies are not the same. In the first the RFC expects you to create (S,G) state but continues to receive mpackets down the RPT until there is an assert from R1 which signals that data is indeed arriving on the SPT. To get the assert, there are indeed duplicate packets on the LAN. In the second case, since the RPF to the RP and the RPF to the source are the same router (Rs), there isn't anyway for Rr to know if the SPT is completely set up (assuming more routers between Rs and the source), so Rr marks the SPT as up as soon as it creates (S,G) state. On Dec 10, 2006, at 9:41 AM, tajay wrote: > Hi, > I am confused about behaviour on lan interfaec. > On the lan interface we can have multiple neighbors on the same > interface that time incoming interface remains same but still > packet can come from different neighbors. > > I am just giving one simple network topology as example. > > > > R1 R2 > | | > | | > |----------------| > | > | > | > R3 > | > | > Receiver > > R3 has > RPF_interface(S)= R1 and > RPF_interface(RP) = R2 > After switching to SPTree R3 may receive 2 packets..?? > > > > or following topology > > > > RP > | > | > | > Rs------Sender > | > | > | > Rr > | > | > Receiver > In above topology at Rr, RPF_interface(S) and RPF_interface(RP) > are same. > > > Ajay > > > -- > Open WebMail Project (http://openwebmail.org) > > > ---------- Original Message ----------- > From: [email protected] > To: tajay <[email protected]> > Cc: [email protected] > Sent: Sun, 10 Dec 2006 17:49:11 +0100 > Subject: Re: [magma] PIM : detecting duplicate packet > >> Quoting tajay <[email protected]>: >> >>> Hi, >> Hello, >> You dont really need to detect that a packet is duplicated. >> It is sufficient to detect if a native multicast packet from a >> given source S has been received by the incoming interface of the >> source tree for S >> (and this interface is different from the incoming interface of the >> shared tree for the same group) >> >> cheers >> Jean-Jacques >> >>> Most of the opimization algorithms in PIM depends on detecting >>> duplicate packets. >>> e.g >>> (1) sending register stop once RP starts receiving duplicate packets >>> (2) DR @ source sends prunes (S,G) from RPTree whenever it >>> receives duplicate >>> packets from source. >>> >>> Is there any specific way to identify duplicate packets? And how >>> feasible it >>> is to detect duplicate packets at very high rate traffic? >>> >>> Ajay >>> >>> >>> -- >>> Open WebMail Project (http://openwebmail.org) >>> >>> >>> _______________________________________________ >>> magma mailing list >>> [email protected] >>> https://www1.ietf.org/mailman/listinfo/magma >>> > ------- End of Original Message ------- > > > _______________________________________________ > magma mailing list > [email protected] > https://www1.ietf.org/mailman/listinfo/magma