[Asterisk-Users] RE: Ast 1.0.7, IP-500's with unmanaged switch...remote end missing bits of audio

[Marty Mastera]

> Hi Marty -
> 
> > The complaint from the users is that calls "cut out", 
> "kinda like when 
> > you have spotty cell coverage". Doesn't seem to matter whether the 
> > call is incoming or outgoing, although it might be true 
> that my users 
> > hear the remote party cut out, while the remote party 
> doesn't notice 
> > the same from my users...
> >
> > Location 1:
> >
> > - SDSL 1.5 Mpbs with static IP, Netopia 4652 SDSL router (enabled 
> > "Prioritize Delay Sensitive Data" to recognize tos=lowdelay per 
> > Netopia
> > support)
> > - Dell PowerEdge SC420 with TDM04B (currently only using one port.  
> > the single analog line is call forward on busy to my IAX provider)
> > - Asterisk CVS-v1-0-02/22/05 using IAX to connect to my 
> provider over 
> > the public internet - I have run pings for an extended 
> period of time 
> > against my provider's server and get no packet loss.
> > - In IAX.conf: tos=lowdelay, jitterbuffer=yes, also enabled 
> > "Prioritize Delay Sensitive Data" on the Netopia to support 
> > tos=lowdelay per Netopia support
> > - Average ping time to my provider: 160 ms with no packet loss
> > - 8 Polycom IP-500's running SIP 1.4.1.0040 and bootrom 2.6.1 using 
> > ulaw only
> > - Small Business Server 2003 set up as DC for the network
> > - Two network laser printers
> > - 24 port unmanaged switch (all phones are home run back to a patch 
> > panel, patched from there into a switch port.  The DSL 
> modem, printers 
> > and server are patched into the switch in the same way)
> > - 8 pc's running XP Pro, all plugged into the switch port 
> on the back 
> > of the IP-500's
> >
> > Location 2:
> >
> > - Full rate data T1
> > - Dell PowerEdge SC1420 with no TDM hardware at all (this location 
> > connects SIP directly to the T1 providers BroadSoft switch and does 
> > not go over the public internet)
> > - Asterisk 1.0.7 - using SIP to connect with my provider 
> (not across 
> > public internet, not natted since the Cisco IAD does the 
> SIP mangling 
> > for us)
> > - Average ping time to the broadsoft switch: 42 ms
> > - 8 Polycom IP-500's running SIP 1.4.1.0040 and bootrom 2.6.1 using 
> > ulaw only
> > - Small Business Server 2003 set up as DC for the network
> > - One network printer
> > - 24 port unmanaged switch (all phones are home run back to a patch 
> > panel, patched from there into a switch port.  The DSL 
> modem, printers 
> > and server are patched into the switch in the same way)
> > - 8 pc's running XP Pro, all plugged into the switch port 
> on the back 
> > of the IP-500's
> 
> I was rather interested to read about the problem you're 
> having.  We have a similar setup, and we've been experiencing 
> the same problems.  
> We have a Dell PE1600SC in the main office, and SC420's in 
> our remote offices.  Main office has a full T1 with a Cisco 
> 1721.  One remote office has a full T1 (but we're actually 
> using a DSL backup for IAX
> traffic) with a Cisco 1751, and the other remote office has 
> SHDSL with a Linksys.  There are a mixed bag of managed and 
> unmanaged 3Com switches, and one office has 3Com hubs.  We 
> are running the same CVS HEAD version 
> (CVS-HEAD-04/09/05-08:01:41) on all machines.  I was able to 
> mitigate things with a lot of jitterbuffer on the IAX, QoS 
> rules on our router, and using our idle backup ISP 
> connections for all the IAX traffic.  It is to the point 
> where the sound quality is acceptable, but it is not 
> commercial quality - not like Vonage or Broadvoice.  We still 
> have drops and pops, and the quality is close to what it 
> should be, but the remote IAX connections are NOT as good as 
> the "local" calls on the same asterisk box, even though it's 
> all the same codec.
> 
> This makes me wonder if perhaps the SC420's are the problem.  
> I know that I had a bit of a problem getting a driver 
> installed for the broadcom NIC that is in them.  I think that 
> the linux driver is a very recent addition for this chipset.  
> Do you have any other suspicions?
> 
> I did notice that you said you have 160 ms latency between 
> your offices.  That is a bit high.  Our is only 20-40 ms 
> between our various offices.
> 
> Maybe I'll try a different NIC in one of the SC420's.
> 
> - Noah
> 

Are you using vlans at any of these locations?  Just to clarify, my two
locations don't interface with each other.  They are two different
clients of ours each connecting only to the PSTN (one via IAX, the other
via SIP).  I should also mention that the "cutting-out" is not an issue
all the time, it is intermittent and I haven't been able to pin it down
to one thing in particular (ie it has been reported with everyone in the
office and on the phones, as well as on a Sunday when only the owner was
in the office and using his phone.

Thanks,

Marty