Drastic Speed Drop?

Connection issues, drop outs or speed related faults for ADSL and ADSL2+ services
Rouss3l
Posts: 10
Joined: Thu Apr 29, 2010 5:44 pm
Location: Melbourne

Drastic Speed Drop?

Post by Rouss3l » Fri Apr 30, 2010 7:12 pm

Hey,

Lately I have been experiencing slow speeds compared to what they were. I used to be able to download at about 1mbps now I struggle to get to 300kbps. I have logged a ticket and Exetel insist there is nothing wrong on their end. Here are my stats, and I look forward to any responses. I am on the naked ADSL 2+ plan by the way. And have run isolation tests without anything else connected, with no improvement. Been like this for about 2-3 weeks.

Thanks

http://www.adsl2exchanges.com.au

You are 718 m from ENDS as the crow flies.
Estimated cable length of 1148.8 m.
Estimated speed of 20000

Billion BiPAC 7404
Upstream: 383000
Downstream: 3528700
SNR Margin: 12.0 dB 12.5 dB
Line Attenuation: 29.0 dB 39.0 dB
CRC Errors: 0 0
Latency: Unknown Unknown

Image

gmoolenaar
Posts: 8
Joined: Fri Sep 12, 2008 7:47 am
Location: Victoria

Re: Drastic Speed Drop?

Post by gmoolenaar » Fri Apr 30, 2010 8:14 pm

I would love to get your speeds.

Over the last couple of weeks i also have noticed a huge speed drop. I used to get between 3 and 4 Mb down now I am lucky to get 1.5.

They are currently investigating, however the first support person was quick to suggest a visit to the exchange.
The 2nd support person at least made some change to give a slight improvement which also enabled my to reconnect at ADSL2+ again.

himagain
Posts: 68
Joined: Thu Oct 29, 2009 1:45 pm
Location: australia

Re: Drastic Speed Drop?

Post by himagain » Fri Apr 30, 2010 8:49 pm

Howdy,
Well, my speed drops have been quite drastic recently and quite often well below 1M for long periods.
I've also had extreme problems with VOIP.
I've added a mynetfone backup with a Mitron ADA and it is even worse.
The VOIP side is as important to me as Webbing.
I don't have any need for major downloading and only average around my actual contract rate per month: 5G.

I've seen all sorts of claims for the minimum speed required for VOIP, but in my own experience under 5 starts creating problems for me.
It is bad recently (now) as I'm often under 1G and this creates noise/dropout/connect fails.
On a "good day" - now getting rarer - VOIP works well for me.

What is a sensible basic rating for competent transmission results for VOIP, seriously, fellows?

Cheers?
_______________________________________________________________________
Basic Details: W7 System, Netgear DG834GV.v2, Exetel Naked ADSL2+, OMNI Telephone model 8026
(Was Telstra 8200a+3 Dig.C/less tels. Thrown away!)

Dazzled
Volunteer Site Admin
Posts: 6003
Joined: Mon Nov 13, 2006 1:16 pm
Location: Sydney

Re: Drastic Speed Drop?

Post by Dazzled » Fri Apr 30, 2010 9:07 pm

128 kbps upload is workable. Faster is better. If you don't have a combined router/ATA you will need to enable QoS at this speed.

manic77
Posts: 17
Joined: Thu Apr 24, 2008 4:09 pm

Re: Drastic Speed Drop?

Post by manic77 » Sat May 01, 2010 12:07 pm

can someone from EXETEL answer please?

ITS AT PEAK?
http://public.mrtg.exetel.com.au/bwsumm ... width.html

Test run on 01/05/2010 @ 12:01 PM

Mirror: Exetel
Data: 3 MB
Test Time: 32.2 secs

Your line speed is 761 kbps (0.76 Mbps).
Your download speed is 95 KB/s (0.09 MB/s).

Rouss3l
Posts: 10
Joined: Thu Apr 29, 2010 5:44 pm
Location: Melbourne

Re: Drastic Speed Drop?

Post by Rouss3l » Sat May 01, 2010 12:59 pm

I would like some answers from an exetel rep so I can further deal with this problem.

Dazzled
Volunteer Site Admin
Posts: 6003
Joined: Mon Nov 13, 2006 1:16 pm
Location: Sydney

Re: Drastic Speed Drop?

Post by Dazzled » Sat May 01, 2010 1:11 pm

It looks like only other users are around at the moment, so in the meanwhile, is your upstream attenuation really worse than the downstream? 3500 kbps is a bit less than expected for 29 dB, although I would ignore adsl2exchanges' estimate - they live in fairyland. Try the speed test using a local server or Sydney. 29 dB is usually 2 km away.

Klaas
Posts: 609
Joined: Sat Apr 03, 2004 1:48 pm
Location: Sydney

Re: Drastic Speed Drop?

Post by Klaas » Sat May 01, 2010 3:09 pm

manic77 wrote:can someone from EXETEL answer please?

ITS AT PEAK?
http://public.mrtg.exetel.com.au/bwsumm ... width.html

Test run on 01/05/2010 @ 12:01 PM

Mirror: Exetel
Data: 3 MB
Test Time: 32.2 secs

Your line speed is 761 kbps (0.76 Mbps).
Your download speed is 95 KB/s (0.09 MB/s).
I would really recommend that you use the larger file test (15MB), to get a more consistent average speed. The following two tests were run a minute apart - notice the average download speed on the 3MB test is 30% lower than the 15MB test.

Test run on 01/05/2010 @ 03:03 PM
Mirror: Exetel
Data: 15 MB
Test Time: 9.98 secs
Your line speed is 12.56 Mbps (12557 kbps).
Your download speed is 1.53 MB/s (1570 KB/s).

Test run on 01/05/2010 @ 03:04 PM
Mirror: Exetel
Data: 3 MB
Test Time: 2.86 secs
Your line speed is 8.58 Mbps (8580 kbps).
Your download speed is 1.05 MB/s (1073 KB/s).

Rouss3l
Posts: 10
Joined: Thu Apr 29, 2010 5:44 pm
Location: Melbourne

Re: Drastic Speed Drop?

Post by Rouss3l » Sat May 01, 2010 6:06 pm

Dazzled wrote:It looks like only other users are around at the moment, so in the meanwhile, is your upstream attenuation really worse than the downstream? 3500 kbps is a bit less than expected for 29 dB, although I would ignore adsl2exchanges' estimate - they live in fairyland. Try the speed test using a local server or Sydney. 29 dB is usually 2 km away.
Yeah I found that strange that my upstream attenuation is higher then downstream, when I compared results. I know where my exchange is and easily its less then a 5 min walk. And I have gotten speeds a lot faster then what I am at now, thats the reason I feel there is something not right here.

CoreyPlover
Volunteer Site Admin
Posts: 5922
Joined: Sat Nov 04, 2006 2:24 pm
Location: Melbourne, VIC

Re: Drastic Speed Drop?

Post by CoreyPlover » Sun May 02, 2010 10:53 am

Rouss3l wrote:my upstream attenuation is higher then downstream
That is normal. upstream is a different frequency to downstream

If you would like to take the risk, you can request Exetel organise a technician to test your line from outside your house. It will be $220 fee if they find no fault, but if they do find a fault they fix it for free.

First thing I'd do however is try a different modem. The up and downstream attenuation are actually quite average (though slightly worse than the distance estimates would suggest), meaning even if your line has a fault you should be able to achieve about 6-8Mbps.
I am a volunteer moderator and not an Exetel staff member. As with all forum posts, mine do not constitute any "official" Exetel position. Support tickets may be logged via https://helpdesk.exetel.com.au or residentialsupport@exetel.com.au

Dazzled
Volunteer Site Admin
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Location: Sydney

Re: Drastic Speed Drop?

Post by Dazzled » Sun May 02, 2010 4:59 pm

Upstream attenuation is normally less than downstream. The lowest frequencies are reserved for voice, then the guard band, then the upstream bins, and the downstreams at the highest frequencies. Attenuation is more likely to occur at high frequencies. Higher attenuation occurs for downstream signals (say < mid 50s dB) than for upstream signals from the modem. Rouss3l 's upstream is a high value at 39 dB.

There's an example DMT bin result at http://en.wikipedia.org/wiki/G.DMT#DMT_ ... line_rates or you can look your own up in the telnet CLI interface.

I agree that a modem swap test would be useful.

himagain
Posts: 68
Joined: Thu Oct 29, 2009 1:45 pm
Location: australia

Re: Drastic Speed Drop?

Post by himagain » Tue May 04, 2010 6:28 am

Hi guys,
I have diligently read all the posts here on this subject and am more confused than ever:
I have even added/changed equipment, tested at different times and have extremely inconsistent results.
I can rule out equipment my end - some days I get very good speeds, most very poor and before noon, usually atrocious.
( I changed from Billion to Netgear for a better performance during my "times of trial" just getting a voip connection to work at all serviceably.)

I get excited if I hit the magic 5M, which I was told earlier is needed for voip. Had no idea that upload was critical.....
Comments like "128k speed is workable" baffle me. Don't know what "QOS" means - no adjustment for it on my machine.
Are we talking literal upload speeds here? Does my D/L speed of maybe 5 Mps mean nothing in terms of voip?

E.G. this is 10 secs ago test via Exetel service:
Your current bandwidth reading is:
1.49 Mbps
which means you can download at 190.71 KB/sec. from our servers.
-----------------------------
At this level I put off making voip calls where possible.

In my case, I'm about to give up and go back to a POTS line just for local phone calls. ( I need to use MyNetFone's super virtual no-cost deal for o/seas calls). My ambition to get off copper and not use cellphones seems to be fading fast.

Cheers?
_______________________________________________________________________
Basic Details: W7 System, Netgear DG834GV.v2, Exetel Naked ADSL2+, OMNI Telephone model 8026
(Was Telstra 8200a+3 Dig.C/less tels. Thrown away!)

Dazzled
Volunteer Site Admin
Posts: 6003
Joined: Mon Nov 13, 2006 1:16 pm
Location: Sydney

Re: Drastic Speed Drop?

Post by Dazzled » Tue May 04, 2010 8:45 am

Himagain, routers handle the traffic through them first in, first out. If a data packet arrives when another is being handled it will be queued. If the packets just keep coming from either direction the queue will increase until latency becomes unacceptable for smooth unbroken voice reproduction. Quality of Service (QoS) is a system to allow voice or other specified packets to queue jump at the router. It is usually built-in to combined router/ATAs, but needs to be enabled when a separate router is used. If your line and router are carrying traffic quickly enough, queues are short and in this case QoS may have little effect.

VoIP requires a continuous even flow of packets without excessive delay or jitter which may even get packets out of order. VoIP packets are UDP, and unlike browser traffic, are not re-arranged or resent if errors occur. The ATA can only handle this problem by holding a very small buffer within itself and feeding the "voice engine" from that. Excessive packet delay can lead to the buffer running out and you get a spot of silence.

Since VoIP is two-way traffic, and ADSL is slower upstream than downstream, VoIP packets over ADSL are limited by the upstream speed. The codec used determines the number of packets needed for each minute of sound, and so the bit rate, and you can look this up at https://www.exetel.com.au/members/voip_ ... h_calc.php - G.729 (preferred) uses 8 kbps each way and G.711 uses 8 times as much at 64 kbps. In theory a perfect 256/64 ADSL1 connection will handle VoIP upstream on G.729, but in practice it is a dire audio experience. A 512/128 ADSL1 service works quite well, and I used VoIP (G.729) on one of these in my early days with Exetel. I could not then download or browse at the same time without causing voice breakup, as my elderly router had no QoS. A 1500/256 ADSL1 service with QoS works very well, and I know several country people who use these plans with VoIP every day. Most ADSL2 services easily exceed 256 kbps upstream and work without trouble. Should other traffic get in the queue, QoS kicks in. On my present reliable ADSL2 service I have successfully used an old ATA without any QoS set.

With all the present threads about congestion in Queensland, perhaps you should check the upstream rate you can achieve. VoIP is also intolerant of very high or very variable latency.

himagain
Posts: 68
Joined: Thu Oct 29, 2009 1:45 pm
Location: australia

Re: Drastic Speed Drop?

Post by himagain » Wed May 05, 2010 5:07 pm

Dazzled wrote: Since VoIP is two-way traffic, and ADSL is slower upstream than downstream, VoIP packets over ADSL are limited by the upstream speed. The codec used determines the number of packets needed for each minute of sound, and so the bit rate, and you can look this up at https://www.exetel.com.au/members/voip_ ... h_calc.php - G.729 (preferred)

Most ADSL2 services easily exceed 256 kbps upstream and work without trouble. Should other traffic get in the queue, QoS kicks in. On my present reliable ADSL2 service I have successfully used an old ATA without any QoS set.

With all the present threads about congestion in Queensland, perhaps you should check the upstream rate you can achieve. VoIP is also intolerant of very high or very variable latency.
Hi Dazzled, (should be MY name!)
THanks for your reply.
MY modem has all sorts of alternatives listed like: G:729 AB @ 20ms (and up)
As a late model I guess it should have Qos(?)
How/where can I keep an eye on my upstream rate easily?
I constantly check via the EXetel Speed test but it only gives a connex speed and a download speed rate, which doesn't seem to bear much relativity.
I do know that as my speed drops below 5Mps VOIP gets worse and worse till at 2 I might as well hang up. (None of this is done with heavy net activity - browsing at most and never with downloads simultaneously.)
_______________________________________________________________________
Basic Details: W7 System, Netgear DG834GV.v2, Exetel Naked ADSL2+, OMNI Telephone model 8026
(Was Telstra 8200a+3 Dig.C/less tels. Thrown away!)

Dazzled
Volunteer Site Admin
Posts: 6003
Joined: Mon Nov 13, 2006 1:16 pm
Location: Sydney

Re: Drastic Speed Drop?

Post by Dazzled » Wed May 05, 2010 6:06 pm

Himagain, The nick came from my kids - I suspect it's not flattering. QoS is enabled in most combined ATA/modem/routers. It needs separate configuration in modem/routers feeding an ATA. Older routers may not have the feature, so it's too bad. Whirlpool Database http://bc.whirlpool.net.au/bc/hardware/ ... del_id=478 doesn't list yours.

Your modem status gives the maximum upstream rate you can achieve. In real life there are exchanges and backhaul to consider so you need something to time an upstream transmission to Brisbane or Sydney (since the VoIP proxy server is in Sydney). One possibility is http://speedtest.net/ Actually any upload will do, such as to your free web space using suitable software.

That's enough for sensible people. If you are a geek at heart: The modem (like all linuxes) stores a heap of standard info about current throughput at /proc/net/dev. This can be read using cat (through telnet) at short fixed intervals and the rate computed and graphed, using say a bash or Python script, while a conversation is still taking place. If you really want to monitor your calls closely to diagnose trouble, use Wireshark - see http://wiki.wireshark.org/VoIP_calls. Linux and Windows versions are available. I remember Bilal was doing this here when the Dynalink lag problem was under discussion.

PS It is possible to void your warranty and fit a new operating system to Netgears - see http://oldwiki.openwrt.org/OpenWrtDocs( ... G834G.html I am not sure if it includes SIP though.

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