[asterisk-users] Re: Very high ping times from 7960 phones

Rich Adamson radamson at routers.com
Mon Sep 25 04:28:58 MST 2006

Tomislav Parčina wrote:
> In article <451446B1.1080002 at peachnet.com>, techsupport at peachnet.com says...
>> I'm sure other people are using 7960 phones so maybe someone could have 
>> a quick look at what time sip show peers reports? When I do a 'sip show 
>> peers' all my cisco 7960 phones report times > 150ms. Every single one. 
>> I've scoured the settings on the 7960's and have looked and looked for 
>> why this might be the case. Cisco ata's (186) on the same network report 
>> ~ 10 ms. An xlite softphone reports ~ 5ms regardless of what computer 
>> it's installed on.
> I have two 7960 phones with 7.4 firmware and sip show peers tells me that response time is 70 and 72 ms.
> Hope this helps.

I can't tell you why either, but a ping from a linux command line shows 
sub-millisecond response (phone and asterisk on same lan segment), while 
the qualify response time is around 79 milliseconds.

Just taking a pure guess (without doing any packet sniffing) is the 
qualify method sends a sip packet to the phone and waits for a response. 
It is entirely possible that qualify ping might involve multiple packet 
interactions. Also, the qualify ping must essentially pass through all 
of the asterisk code, IP stack, etc, on both ends. That value would be 
greater then a simple icmp ping.

There are no settings in the cisco phones that would impact this.

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