[asterisk-users] tcpdum

[michel freiha]

You are right Jeff...Thanks a lot

Regards

On Tue, Dec 16, 2008 at 12:35 AM, Jeff LaCoursiere <jeff at jeff.net> wrote:

>
> I'll assume that you suspect that asterisk is adding latency that you
> would like to tune.  There is no simple variable that will affect latency
> as far as I know, but certainly one thing to look at is codec translation.
> Make sure your inbound and outbound paths are using the same codec, or
> latency will be added for sure.
>
> You can use tcpdump to measure the latency and the effect of anything you
> do to attempt tuning in a rough way - each packet has a timestamp at the
> beginning measured in ten thousandths (I think?) of a second.  You should
> be able to see the RTP packet arrive and then leave again... just subtract
> the timestamps for your added latency.
>
> Cheers,
>
> j
>
> On Mon, 15 Dec 2008, michel freiha wrote:
>
> > Dear Sir,
> >
> > What I'm interested to is to know how much time the rtp packets takes
> from
> > the time it access the asterisk server,to when it'll leave
> > Is this function or variable exist anywhere?
> >
> > Regards
> > On Mon, Dec 15, 2008 at 10:55 PM, Jeff LaCoursiere <jeff at jeff.net>
> wrote:
> >
> >>
> >> No.  TTL in the header is about hop traversal.  Each IP router that
> >> forwards the packet will reduce this number in the live packet until it
> >> reaches zero, when it will be dropped.  I believe this is to eliminate
> >> route loops creating packet storms.
> >>
> >> FWIW this is how traceroute works - it sends out packets with
> continually
> >> increasing TTLs and the router that drops the packet will send back a
> >> notification, so you can "trace" each hop...
> >>
> >> What is it you are trying to do or measure?
> >>
> >> j
> >>
> >> On Mon, 15 Dec 2008, michel freiha wrote:
> >>
> >>> Dear Sir,
> >>>
> >>> There is no relation between TTL and the latency on asterisk server?
> >>>
> >>> Regards
> >>>
> >>> On Mon, Dec 15, 2008 at 10:39 PM, Jeff LaCoursiere <jeff at jeff.net>
> >> wrote:
> >>>
> >>>>
> >>>> TTL is part of the UDP header (Time To Live).  It isn't really about
> the
> >>>> voice at all.
> >>>>
> >>>> Length 345 is the number of bytes in the packet.
> >>>>
> >>>> j
> >>>>
> >>>> On Mon, 15 Dec 2008, michel freiha wrote:
> >>>>
> >>>>> *Dear All,
> >>>>> I run the below tcp dump on my asterisk server
> >>>>>
> >>>>> tcpdump -i eth0 -n -s0 -v udp port 5060
> >>>>>
> >>>>> I got the following result
> >>>>>
> >>>>> 20:29:48.596867 IP (tos 0x10, ttl  64, id 0, offset 0, flags [DF],
> >> proto
> >>>> 17,
> >>>>> length: 373) SIP_PROXY_IP.5060 > Asterisk_IP.5060: UDP, length 345
> >>>>>
> >>>>> What i need to know please what TTL means specifically and what is
> the
> >>>> best
> >>>>> value og TTL and what is the lengh vale mean
> >>>>>
> >>>>> Regards*
> >>>>>
> >>>>
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> >>
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