Hi Praveen, Its Embedded Multimedia Terminal Adaptor. Its used as a Cable Modem/MTA in the Cable architecture to connect to CMTS. If you go to Cablelabs website, you'll get lot of information about this.
Vivek. ________________________________ From: praveena ss <[email protected]> To: Vivek Singla <[email protected]> Cc: "WORLEY, Dale R (Dale)" <[email protected]>; "[email protected]" <[email protected]> Sent: Thu, June 17, 2010 2:49:04 PM Subject: Re: [Sip-implementors] Retransmission of BYE Hi Vivek, what exactly eMTA is? Regards, Praveen On Thu, Jun 17, 2010 at 11:42 PM, Vivek Singla <[email protected]> wrote: Thanks everyone for the responses to my query. I really appreciate it. > >So the Cseq value would remain the same in the 2nd and the 3rd BYEs here. > >And the 3rd BYE will get the 200OK from the P-CSCF since P-CSCF maintains the >information for that transaction until 64*T1. And after 64*T1 if P-CSCF gets >the BYE, it'll respond with 481. > >Thanks, >Vivek. > > > > > > > > > >________________________________ >From: "WORLEY, Dale R (Dale)" <[email protected]> >To: Vivek Singla <[email protected]>; >"[email protected]" ><[email protected]> >>Sent: Thu, June 17, 2010 8:26:35 AM >Subject: RE: [Sip-implementors] Retransmission of BYE > > >________________________________________ >From: [email protected] >[[email protected]] On Behalf Of Vivek Singla >[[email protected]] > >I have a scenario here in the lab : > >eMTA P-CSCF > >Invite--------------------> > ><----------------------------180 > ><---------------------------200OK > >ACK----------------------------> > >BYE------------------------------> > ><--------------------------------407 > >BYE-----------------------------> > ><---------------------------------200OK > >BYE---------------------------------> > ><------------------------------------200OK > > > >In this scenario the second BYE ( after 407 ) gets the 200OK but after 500ms >and therefore sends the third BYE ( retransmission ). > >1) The CSeq in second and third BYEs are same ( CSeq: 3 BYE ). Is this correct? > >2) The P-CSCF after its gets the 3rd BYE ( retransmission ), sends the 200OK >back. Shouldn't it send 4xx saying that no transaction exist? I am thinking >since P-CSCF has already sent 200OK for 2nd BYE, it has terminated the >transaction and Dialog on its side. So any retransmissions of BYE from UAC >should be responded back with 4xx. >>_______________________________________________ > >The 3rd BYE has the same CSeq (and branch value) as the 2nd because it is a >retransmission of the 2nd BYE, that is, a duplicate copy. (Note that the >network is permitted to deliver more than once a packet that has been sent, so >the UAS (P-CSCF in this case) must be prepared to receive duplicate copies.) >When the UAS receives a duplicate of a request that it has already responded >to, it does not re-process the request, but rather retransmits the response >that it sent to the first copy of the request. This is all detailed in RFC >3261. > >Dale >_______________________________________________ >Sip-implementors mailing list >[email protected] >https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
