Hi Dale, I think SIP does not retransmit messages. Pacekt loss rate when Speech is enabled is seen upto 10%.
After further investigation in last two days, we found that by increasing priority of network Task we have gained more performance on Speech test and very very less packet loss is seen(0.05%) than before. Samba. -----Original Message----- From: Worley, Dale R (Dale) [mailto:[email protected]] Sent: Monday, 21. March, 2011 17:22 To: Sambasiva Rao MANCHILI; [email protected] Cc: Sambasiva Rao Manchili Subject: RE: [Sip-implementors] SIP UDP packet loss? ________________________________________ From: [email protected] [[email protected]] On Behalf Of Sambasiva Rao MANCHILI [[email protected]] When we are simulating just SIP signalling messages between our two test systems at the rate of greater than 500 UDP packets per second, we observed some of Subscribers fail Signalling.After further investigations it is found that UDP packets are lost consequently Signalling is failing for some subscribers intermittently. _______________________________________________ It's difficult to tell what might be going wrong and what might be done to fix it because UDP is, by specification, unreliable. As a result, various components of UDP implementations (including the transceiver hardware, the low-level drivers, and the UDP stack, often feel free to cope with various problem situations by discarding packets. After all, you are dealing with a data flow of maybe 5 megabits per second. If you want reliable transfer of data at speeds comparable to the capacity of the system, you need to use a protocol with reliability features. Another question to ask is what is the overall packet loss rate. You should be seeing losses less than 1%, and given that SIP will retransmit UDP requests, no single UA should see a large enough string of losses to cause failure of signaling. Perhaps the UAs do not retransmit UDP requests like they should? Dale This email and any attachment may contain confidential information which is intended for use only by the addressee(s) named above. If you received this email by mistake, please notify the sender immediately, and delete the email from your system. You are prohibited from copying, disseminating or otherwise using the email or any attachment. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
