[TelstraClear] Trouble with VFX phone via Motorola SB5101i

Forums › One New Zealand (including Vodafone, WxC, Farmside) › [TelstraClear] Trouble with VFX phone via Motorola SB5101i

peng1nz

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#114653 26-Feb-2013 18:00

I recently switched phone service to xnet and using SPA122 ATA. I am having all sorts of issues getting reliable phone service and xnet tech support have starting pointing the finger at the Motorola cable modem (model SB5101i). This is quite an old modem now, it was issued to me several years ago. Maybe it is getting long in the tooth and not so good for voice data? Do Telstra supply any alternative modem (or later model) that may provide a better QOS?

The issues I am having are:
1) Lost packets in the upstream data. eg. a lost syllables every 10 seconds or so.
2) Lost audio in the downstream data eg. blocks of 15 seconds or so of no downstream audio.
3) 'disconnect tone' on some outbound and inbound calls.

I have tried lots of things like DMZ and port forwarding in the Router (D-Link DIR600) and also connecting the ATA direct to modem rather than via the Router. Seems better with direct connection but then internet service really suffered. My router is fairly busy but mostly with internal routing not to internet.

Any advice appreciated.

DoomlordVekk

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#770676 26-Feb-2013 18:49

Penginz, the SB5101i is a good wee DOCSIS 2 cable modem. GIven the capacity in the cable network, it will deliver you more than 15Mb downstream and at least 2Mb upstream. it would be highly unlikely to be the surfboard cable modem (not withstanding any piece of electronic equipment can fail).

Within the TCL network, if you go point your browser at speedtest.telstraclear.co.nz and run a couple of tests, you should see what you can get.

As far os Quality of Service on any internet service, best efforts apply sorry. Short of asking (and paying) for a business link from one of the international providers, your traffic will ride best efforts across the international links, to it's destination. Even in NZ, some of the peering links are quite full.

Have you had a look to see the network route that your packets go through to get to VFX?
If it's jumping across a small peering link or something like that, it could explain sub-optimal packet performance.

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sbiddle

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#770688 26-Feb-2013 19:49

The cable modem isn't likely to be the cause of VoIP issues as it's nothing but a layer 2 bridge, it's more likely to be your router.

peng1nz

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#770978 27-Feb-2013 11:35

Thanks Doomlord...

DoomlordVekk: Penginz, the SB5101i is a good wee DOCSIS 2 cable modem. GIven the capacity in the cable network, it will deliver you more than 15Mb downstream and at least 2Mb upstream. it would be highly unlikely to be the surfboard cable modem (not withstanding any piece of electronic equipment can fail).

Yes I know I am clutching at straws here.

Within the TCL network, if you go point your browser at speedtest.telstraclear.co.nz and run a couple of tests, you should see what you can get.

Usually I get 10m/2m results. However last night I got 3m download and an error on the upload (it did not start). Same result at speedtest.net.
Also some web pages would not load, but other would. Some slow, some pretty instant. Weird stuff.
I turned off QOS and the DMZ in my Router and things seem to be better. This morning I got 15m/2m speedtest.net.

Have you had a look to see the network route that your packets go through to get to VFX?

How do I do that?

sbiddle

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#771004 27-Feb-2013 12:00

Just to clarify something from my last post (and your first one), a different modem isn't going to make any difference to QoS as the modem doesn't have anything to do with QoS since it's only a layer 2 bridge.

How are you testing speeds, wired or wireless?

peng1nz

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#771280 27-Feb-2013 20:54

Thanks for clarifying that QoS thing.
Speed tests were via wireless. signal strength is 'Excellent'.
(yes I know I should ideally do it wired to eliminate wireless. Next time it plays up I will.)

Since turning off the DMZ and QoS in the router I have no internet issues. Phone still dodgy though. Should I have expected the QoS in the Router to improve voip performance? How does the Router know what port has the voip data?
I am starting to suspect the Router. Any recommendations for an alternative wireless router? I see JB hifi have Netgear WNR1000 for $43. Is that worth a go?

I would run the ATA first in line with bridge mode but the internet seems to really get choked through it. I should perhaps ask about that in the voip or xnet forums.

sbiddle

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#771293 27-Feb-2013 21:03

No idea how the QoS works in that router, I don't go near D-link equipment. In routers you classify traffic by 802.1p/DCSP a source/destination or port range.

Wired also needs to be used for testing, in an urban enviroment 2.4Ghz is pretty much useless these days.

coffeebaron

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#771305 27-Feb-2013 21:16

A Cisco SRP521 should do the job nicely, just not a nice price tag :(

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peng1nz

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#771317 27-Feb-2013 21:36

ok. Why would SRP521 be better? Would it replace the router and ATA?

coffeebaron

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#771319 27-Feb-2013 21:40

peng1nz: ok. Why would SRP521 be better? Would it replace the router and ATA?

Yes, so cable modem into SRP521. SRP521 will do VoIP, Routing, QoS, Wi-Fi.
I think a couple of others here on Geekzone have this setup, so will be able to advise your more.

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