[Freeswitch-users] Problem with rtp streams and stair-stepped (or ramped) increased lag

[Nathan Neulinger]

This instance is running v1.2stable as of a week or so ago. (In a pilot, so trying not to update it very frequently, but 
when I add stuff to the skinny code.)

The interesting thing is - on MOST calls, it's working fine, and even on the calls that are a problem, it works fine, up 
until "something" happens, and then it starts building up the delay.

Even on non-problem calls, I occasionally see a slow/occasional stairstep that doesn't accumulate much, but on the BAD 
calls it accumulates to high delays.

Example call - graphs from voipmonitor:

http://imgur.com/F4S91mr,lAulG2o

-- Nathan

On 06/24/2013 07:38 PM, William King wrote:
> I've seen a similar issue on a small network behind a pfsense router.
> Network diagram is:
> Hard Phones(3+ Yealink and Polycom mix) -> switch -> PFsense -> Comcast
> -> FS conferencing server.
>
> In my case I was seeing ~10 seconds of RTP delay(tested from doing a/b
> response testing), but instant sip handling. The audio was in perfect
> sync coming from the conference server to the 3 endpoints.
>
> Nathan, what version of FS are you running?
>
> I have not yet ruled out that the issue isn't a local network problem.
>
> William King
> Senior Engineer
> Quentus Technologies, INC
> 1037 NE 65th St Suite 273
> Seattle, WA 98115
> Main:   (877) 211-9337
> Office: (206) 388-4772
> Cell:   (253) 686-5518
> william.king at quentustech.com
>
> On 06/24/2013 04:40 PM, Nathan Neulinger wrote:
>> In one particular stream, which is  call mgr <-> FS, the CCM to freeswitch side of the stream shows no issues, but
>> freeswitch to CCM direction shows a number of drifts, some just one ptime worth, others larger.
>>
>> This instance is running as a VM, but allocated significantly more reserved cpu (and very high shares) on a lightly
>> loaded host. Concurrent calls on the FS instance is in the single digits at most at this point. Typical end to end
>> network induced latencies less than 3 ms at most.
>>
>> Any suggestions on what to look at or steps to take here? Certainly not happening on every call, but I do believe I've
>> seen it on both cisco and polycom phone connections. Usually, there is just a slow stairstep over the period of the call.
>>
>> -- Nathan
>>
>> On 06/24/2013 06:24 PM, Nathan Neulinger wrote:
>>> Having some occasional user reports of problem calls where they are fine, and then something happens on the call and lag
>>> increases significantly, sometimes up to 2+ seconds.
>>>
>>> I've got severe examples on both cisco and polycom phones. What I'm seeing looks like the call is going perfectly for a
>>> period of time (sometimes up to a few minutes), and then there is a period of time with higher latency packets, and the
>>> overall delay in the graph increases steadily at that point, and never recovers.
>>>
>>> It sounded like rtp-autoflush-during-bridge might be something relevant, but that's set to the default. Also saw
>>> "rtp-rewrite-timestamps", but unclear if that is necessary here.
>>>
>>> I've got pcap captures of the rtp streams if that'll help any.
>>>
>>> -- Nathan
>>>
>>> ------------------------------------------------------------
>>> Nathan Neulinger                       nneul at mst.edu
>>> Missouri S&T Information Technology    (573) 612-1412
>>> System Administrator - Architect
>>>
>>> _________________________________________________________________________
>>> Professional FreeSWITCH Consulting Services:
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>>> http://www.freeswitchsolutions.com
>>>
>>> 
>>> 
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>>
>
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
>
> 
> 
>
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>
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-- 
------------------------------------------------------------
Nathan Neulinger                       nneul at mst.edu
Missouri S&T Information Technology    (573) 612-1412
System Administrator - Architect