Hi
What ever we received from GEI driver is being sent to  user and no where lost 
in between after receiving from GEI dribver by ETHER and then to  IP stack and 
then to  SIP subscriber.

What we observed is the number of packets sent to  GEI driver on Side-A is not 
equal to number or packets received on Side-B from GEI Driver.
This means it is lost inbetween GEI driver on one side to GEI Driver on other 
side.  Can this happen ?  Did you come across such behaviour ?
We use gei825xxVxbEnd driver.

Thanks for your time.
Samba.

-----Original Message-----
From: Uttam Sarkar (usarkar) [mailto:[email protected]]
Sent: Monday, 21. March, 2011 16:24
To: Sambasiva Rao MANCHILI; [email protected]
Cc: Sambasiva Rao Manchili
Subject: RE: [Sip-implementors] SIP UDP packet loss?

There could be bottle neck in your application. Maybe it's unable to read all 
the UDP packets from the network.
You need to find out what is the capacity of your application.

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Sambasiva 
Rao MANCHILI
Sent: Sunday, March 20, 2011 2:31 PM
To: [email protected]
Cc: [email protected]
Subject: [Sip-implementors] SIP UDP packet loss?

Hallo  Sip Implementors,
I am not a SIP expert of application layer. I am part of Test System 
Development where we simulate the SIP traffic over different transport types 
like UDP,TCP and SCTP.
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.

To overcome this we then increased the udp.recvspace and udp.sendspace and 
socketbuffer size in our Networking stack.
This helped the packet loss to reduce by 10%.  Before increasing buffers we 
have Faults rate of ~8 to 10%  on Signalling after increasing buffers we have 
fault rate of 0.9% over Signalling.
*Qeury 1*:- Is increasing buffer space is a solution or workaround for our 
Network stack  to overcome packet loss ?

Default values of our Network stack  were 40K for udp.recvspace and 9K for 
udp.sendspace and socketbuffers are 256K.
We changed these values in our Network stack  to 256K  for udp.recvspace, 256K 
for udp.sendspace and socketbuffers to 1024K.
This change has reduced packet loss but can could not make 0% packet loss.
 I understand UDP is not reliable transport, but I am looking for solution 
which can reduce Packet loss to less than 1%.  When I enabled speech path codec 
G.729/ G.711 I see still more packet loss of 15%.

Query2:- Can you please suggest us what should be the right values for such 
buffer space if this is right approach ?

We have yet to enable the voice transmission as a next immediate step, then 
again SIP RTP UDP packets will further increase based on the codec chosen and 
this will cause even more packet loss.

Query3:-  What is the ultimate  solution for eliminating packet loss both on 
Signalling and on speech path ?

Thank you in advance for your time.
Samba.
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