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Slight Connection Instability - Suggestions?

Zlatan

Member
I’m on UKFSN’s Home MAX 30 but am having a few connection issues which I’d be very grateful with some help identifying the exact cause. I’ve provided all the information that I think would be relevant to show the symptoms and possible causes of the problem but if there’s anything I’ve neglected to include let me know.

The most noticeable problem is that my connection drops out for short periods of time, generally less than a minute. Disconnecting and reconnecting generally solves this but often the connection returns by the time I decide to disconnect.

As well as connection drop outs the ping is quite high. My line connects at 3.5Mbit while my brother is on 512Kbit connection with BT Internet. On the same Quake 3 server with us both using the same model router he gets a ping of 30 while mine is about double, generally showing about 63 in game.

These are the only observable problems and wouldn’t be a major issue but I do some online trading and the trading platform doesn’t handle connection interruptions well so a minor interruption can cause it to lose the data feed. I had a few problems with it lately that caused trades to go a bit wrong so thought I best sort it out.

So they’re the problems, now about my usage. I use a Netgear DG834 wired router with the PCs connected by no more than 2 metre long cables. The router reports my line noise as:

Line Attenuation:
Down 47db
Up 14.5 db

Noise Margin
Down: 7db
Up: 23db

I don’t actually know if that’s good or bad.

I’ve been running L8NC for a few weeks and every graph pretty much looks the same. Here are the graphs for the last few days:

http://i13.tinypic.com/48c1zz8.png
http://i14.tinypic.com/2vnnlw1.png
http://i14.tinypic.com/3zlg3g3.png

Some of the blue ping spikes are probably me downloading things but others are to do with the connection. I’m not sure what the reason for the red packet loss spikes are but they seem to occur around lunch time, which could be something to do with people taking their lunch breaks in offices. I initially thought these periods of packet loss could be the short periods of connection loss but the percentage generally only ever looks to be about 5% so it does not seem likely that this small amount of packet loss could result in the connection dropping for up to a minute. I should point out that I am generally not using the connection at lunch, which is when these periods of packet loss occur most.

Below are my usage figures for the last seven months, which are a lot more than I expected:

17 Feb 2006 - 16 Mar 2006 35.35 GB 2.12 GB
17 Mar 2006 - 16 Apr 2006 34.17 GB 0.79 GB
17 Apr 2006 - 16 May 2006 46.67 GB 0.82 GB
17 May 2006 - 16 Jun 2006 32.5 GB 1.18 GB
17 Jun 2006 - 16 Jul 2006 26.43 GB 1.32 GB
17 Jul 2006 - 16 Aug 2006 35.22 GB 2.12 GB
17 Aug 2006 - 16 Sep 2006 19.97 GB 1.13 GB

I’m on the 30GB peak 300GB off peak package and as you can see average usage is 1.35GB peak and 32.90GB off peak so although though my usage is quite high it’s well within the limits of the account. I try to respect the other users of the network, which is why I download exclusively during off peak hours so I hope this would be enough to keep me off the bad boy pipe.

I can think of four possible reasons for my connection problems:

1) A poor connection between the exchange and my house.
2) I’ve used the connection too much and been put on the bad boy pipe resulting in poor performance.
3) EntaNET network issues in general.
4) Router issues.

Reading the other threads I now notice that the bad boy pipe is officially no longer in service so that seems to rule that out, though there is the possibility that they do take some action against people with high usage.

While it’s possible, it seems quite unlikely that the ping of 60 I get (compared to my brother’s ping of 30 on the same server with the same router) is a result a poor connection to the exchange and it seems more likely that this extra latency is being added in the EntaNET network. The frequency of the packet loss during busy periods also suggest possible issues with the EntaNET network. Therefore, a move to a lower contention EntaNET account or a different ISP may be the solution.

However, as stated earlier the packet loss is only ever about 5% which should result in the connection dropping for up to a minute. The connection loss may be a problem with the router’s handling of this packet loss and a new router may be the solution.

It is difficult to identify the problem so I’d be grateful for some help. The see if the ping is due to the network or the connection I would be grateful if someone on Entanet would ping 194.109.69.94 (a quake server) and post their results. For reference I get the below results, with the values being about the same every time.

Pinging 194.109.69.94 with 32 bytes of data:

Reply from 194.109.69.94: bytes=32 time=49ms TTL=247
Reply from 194.109.69.94: bytes=32 time=52ms TTL=247
Reply from 194.109.69.94: bytes=32 time=53ms TTL=247
Reply from 194.109.69.94: bytes=32 time=59ms TTL=247

Ping statistics for 194.109.69.94:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 49ms, Maximum = 59ms, Average = 53ms

Reading around the forum I did see that the Netgear DG834GT is a recommended router for problem lines, which apparently has a different chipset to my Netgear DG834. Do you think a new router would be the solution?

Since the packet loss occurs during busy times would a lower contention UKFSN account help? If so can you switch to a lower contention Office Max account without getting BT Wholesale involved?

Also, a few days ago I received an email notification that Be’s ADSL2+ is now available in my area. I’m not that interested in the extra speed but an improvement in connection consistency would be desirable. Would ADSL2+ sort out the problems or could it accentuate them?

Any other suggestions about the possible cause or suggested solutions would be very gratefully received.

Thanks a lot for your advice.

Edit
That seemed a lot shorter when I wrote it. Er, sorry for going on so much. I thought it would be best to try and include as much information as possible but maybe I overdid it.
 

Mel

ULTIMATE Member
I've got the Netgear DG834G which is the same chipset as yours (TI AR7), according to some of the posts I've seen including one where someone had both a dg834g and a dg834gt (broadcom chipset) the TI chipset, in some cases it can actually be better than the broadcom on long lines. It has been suggested that it depends on the manufacturer of the equipment at the exchange :shrug: (I have also read a couple of posts that TI AR7 is not great for ADSL2)
The L8NC graphs look fairly normal to me.

You can get more stats out of netgear by using Telnet.
you have to put it in debug mode http://www.routerlogin.com/setup.cgi?todo=debug

Then from a console window:-

telnet www.routerlogin.com

cat /proc/avalanche/avsar_modem_stats

This should give you more detailed stats such as the total number of CRC errors.

Alternatively here's a quick hack that exploits a vulnerability in the firmware of the dg834g to copy the same modem stat file to the modems log (the current log will be cleared) and avoid the above :-

http://192.168.0.1/setup.cgi?todo=ping_test&c4_IPAddr=1%26%2Fbin%2Fcat%20%2Fproc%2Favalanche%2F%2Amodem%2A%20>%20%2Fvar%2Flog%2Fmessages&next_file=log.htm

Also if you have any hardwired extensions check out this item about ring wires http://yarwell.blogspot.com/2005_08_01_yarwell_archive.html


You can find out your line's 'BRAS' profile by using BT's new performance tester.

http://www.speedtester.bt.com
 

Zlatan

Member
Thanks a lot for all that information. Here are the detailed stats for the router:

http://i13.tinypic.com/477z9yr.gif

I don’t know what most of it means :) 24540 CRC errors sounds like a lot but then I suppose compared to the volume of packets that get sent it might not be that many. It’s hard to know if that’s good or bad.

I restarted the router and ran the BT speed test:

IP profile for your line is - 3000 kbps
DSL connection rate: 448 kbps(UP-STREAM) 3776 kbps(DOWN-STREAM)
Actual IP throughput achieved during the test was - 2789 kbps

It’s interesting that connecting at a greater speed than the “IP profile.” Is this perhaps a problem?

I am using an extension, which may be a problem. It’s getting a bit late now so I’ll have a read of that site about ring wires tomorrow but it looks like there’s some good information on it.

One question, when you say the “TI AR7 is not great for ADSL2” is that the router that Be give away with the service?

Thanks again for the help.
 

Unicast

ULTIMATE Member
I'm on an Entanet connection as well, and my pings look the same as yours, so I guess that they're quite normal for an Enta connection. Perhaps Boggits might look in and comment on them? :shrug:

As for your connection drops these may be due to your internal telephone extension wiring, or a dogdy adsl filter on one of your phones. Looking back through your post the noise margin on the "down" side of your connection is only 7dB. You might find that if this dips slightly you'll lose the connection causing your modem to resync with the exchange. This is a fairly common occurence on long lines - this happens on my line from time to time.

Another thing to bear in mind is that adslmax works right on the limits fo your line, and it only takes the smallest amount of intereference to cause the line to drop. For gaming you might be better off on a fixed speed connection, say 1 or 2Mb? Fixed speed connections are far more stable than max will ever be.

Code:
unicast@unicast-laptop:~$ ping 194.109.69.94
PING 194.109.69.94 (194.109.69.94) 56(84) bytes of data.
64 bytes from 194.109.69.94: icmp_seq=1 ttl=245 time=50.9 ms
64 bytes from 194.109.69.94: icmp_seq=2 ttl=245 time=50.5 ms
64 bytes from 194.109.69.94: icmp_seq=3 ttl=245 time=51.2 ms
64 bytes from 194.109.69.94: icmp_seq=4 ttl=245 time=50.9 ms
64 bytes from 194.109.69.94: icmp_seq=5 ttl=245 time=49.9 ms
64 bytes from 194.109.69.94: icmp_seq=6 ttl=245 time=50.3 ms
64 bytes from 194.109.69.94: icmp_seq=7 ttl=245 time=51.0 ms
64 bytes from 194.109.69.94: icmp_seq=8 ttl=245 time=50.3 ms
64 bytes from 194.109.69.94: icmp_seq=9 ttl=245 time=50.7 ms
64 bytes from 194.109.69.94: icmp_seq=10 ttl=245 time=50.2 ms
64 bytes from 194.109.69.94: icmp_seq=11 ttl=245 time=50.2 ms
64 bytes from 194.109.69.94: icmp_seq=12 ttl=245 time=50.8 ms
64 bytes from 194.109.69.94: icmp_seq=13 ttl=245 time=50.9 ms
64 bytes from 194.109.69.94: icmp_seq=14 ttl=245 time=51.0 ms
64 bytes from 194.109.69.94: icmp_seq=15 ttl=245 time=50.2 ms
64 bytes from 194.109.69.94: icmp_seq=16 ttl=245 time=52.1 ms
64 bytes from 194.109.69.94: icmp_seq=17 ttl=245 time=50.4 ms
64 bytes from 194.109.69.94: icmp_seq=18 ttl=245 time=50.1 ms
64 bytes from 194.109.69.94: icmp_seq=19 ttl=245 time=50.5 ms

--- 194.109.69.94 ping statistics ---
19 packets transmitted, 19 received, 0% packet loss, time 18081ms
rtt min/avg/max/mdev = 49.929/50.685/52.155/0.527 ms
Code:
unicast@unicast-laptop:~$ tracepath 194.109.69.94
 1:  192.168.1.65 (192.168.1.65)                            0.282ms pmtu 1500
 1:  192.168.1.1 (192.168.1.1)                              4.375ms
 2:  192.168.1.1 (192.168.1.1)                            asymm  1   6.283ms pmt                           u 1464
 3:  telehouse-east.dsl.enta.net (87.127.229.1)            70.150ms
 4:  gi1-8.telehouse-east2.bdr.enta.net (62.249.192.125)  asymm  7  71.178ms
 5:  te5-1.telehouse-east.bdr.enta.net (87.127.236.33)    asymm  6  70.861ms
 6:  853.gi0-0.amsterdam.core.enta.net (87.127.246.2)     asymm  7  78.688ms
 7:  ams-ix.sara.xs4all.net (195.69.144.48)               asymm  9  79.831ms
 8:  0.so-6-0-0.xr2.3d12.xs4all.net (194.109.5.5)         asymm 10  80.527ms
 9:  0.so-3-0-0.cr2.3d12.xs4all.net (194.109.5.94)        asymm 11  80.279ms
10:  quake3-05.xs4all.nl (194.109.69.94)                  asymm 11  82.012ms rea                           ched
     Resume: pmtu 1464 hops 10 back 11
 

Mel

ULTIMATE Member
I notice from that you are on interleave which inproves the connection stability at the cost of latency hence a higher ping.

The IP profile should be lower than you sync rate to avoid packet loss, so that's normal.

Interference is picked up by the ring wire on all internal telephone extensions and it can reduce your SNR margin, as can poor extension wiring. Short extensions away from sources of electrical interference are unlikely to be a problem.
Best way to test for this is to remove the lower faceplate of the BT master socket


and plug your router directly into the test point behind it (preferably when you are having problems) see if it improves the connection and make a note of the router's stats to see if there is any improvement. You should check your stats again after putting everything back, because I have noticed the dg834g only appears to check the line for noisy channels when it is powered up or rebooted and also the reported SNR tends to fall over a number of days.


I'm not sure which chipset the BE supplied router's use - wish I had the opportunity to find out :(

One disadvantage of the Netgear dg834 and other TI ar7 chipset based routers is it is not very (well as far as I know not at all) tweakable, some other routers either allow you to reduce the reported SNR, or maybe even limit the max sync rate either of which should result in a lower sync rate and improved stability.
 
Last edited:

Zlatan

Member
Thanks a lot for all the advice. I’m really impressed by how knowledgeable you have and your help is very much appreciated. Thanks also for pinging that server. It’s good to know the high ping isn’t an issue with my connection.

I think going back to a 1Mbit line would be a good idea as I never had these problems before it changed to ADSL MAX. Unfortunately it seems most ISPs only offer ADSL MAX these days so I’m not sure if that’s possible.

I’ll try connecting the router to the test put and leave it there for a day or so and see if that offers any improvement. If it does I might leave the router permanently by the main socket and run a network cable upstairs to a hub.

I’m still undecided whether to give Be a try. Entanet’s 300GB off peak allowance is fantastic and it’s great not to have to worry about download limits as long as you download off peak. Be are supposed to offer unlimited downloads but it seems the ISP definition of unlimited is often very different from the dictionary definition. Plus Be seem to be growing quite rapidly and this often leads to problems with ISPs.

One other question; I have two physical phone lines to my house and both have ADSL on them (the other is for company use). If I wanted to get a third line installed would it mean having to dig up the garden to put it in?

If it wouldn’t mean digging up the garden it might be worth getting a third line an trying Be on that. Unfortunately I got the garden replaced with paving stones to save having to cut it so having to get it all dug up and put down again would be quite expensive.

Thanks again for the help. I’ll let you know what the results of connecting the router to the test port where when I’ve done it.
 

Mel

ULTIMATE Member
If you get a lot of disconnections I think BT's system is supposed to automatically increase your minimum SNR margin which might prevent the disconnections (I notice your SNR had dropped to 2dB in those stats) Once you've checked it is not a problem with your internal telephone wiring (or sorted it if it is) you should try having a word with your ISP before switching back to 1mbps. I would also borrow another router if you can to see if it does make a difference.

If you can get the stability issue sorted you may then be able to get them to turn off interleave to reduce your ping although you obviously need it at the moment because interleave improves the error correction.

As far as digging up the garden goes, the only thing I can suggest is opening up the BT junction box on the outside wall of your house and seeing if you have a spare pair of wires. Make sure you're not caught by a passing BT engineer though!

If it does I might leave the router permanently by the main socket and run a network cable upstairs to a hub.
If you do that you will need to either disconnect the ring wire or the whole extension if it is not required, or use a faceplate filter as mentioned in Yarwell's article.
 
Last edited:
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