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Standard User brisouth
(newbie) Mon 07-Sep-09 23:55:14
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ADSL Line syncs OK but low download speeds


[link to this post] 		 
Hello,

I am looking for any advice to try to get a problem resolved. over 3 weeks ago everything was working OK, then during a call my voice service failed. The broadband was working but I couldn't get a dial tone. BT advised there was a problem at the exchange and promptly fixed it. While fixing it I lost the broadband service. When the voice service came back my broadband service was very slow. BT advised as it wasn't a problem with the voice service I'd need to take it up with my provider, which is Demon.
Demon have told me that it is my router that is at fault, so I borrowed a router and they tell me now that one modem is lying and the other modem is faulty.

I can't get the BT speed checker to work on my line, but have done regular tests with the speed checker from this site and the results have been pretty consistent:

Speed Down 315.27 Kbps ( 0.3 Mbps )
Speed Up 554.41 Kbps ( 0.5 Mbps )

At the time of the voice service failure I was on an 8MB ADSL service, with expected performance of 6MB due to distance from exchange, and was achieving 4.5MB - 5MB. However, when I raised the fault the initial response from Demon was that my upgrade to ADSL2+ had failed back in May, so they have since implemented the ADSL2+ upgrade, which made no difference to the down speed, but has made the connection drop regularly.
After hours on the phone to Demon Technical support, many e-mails I do not appear to be getting any resolution. It appears that most obvious source of the error is what BT did to fix the voice, but I would appreciate any help to try and get my broadband speed back.

Here are the logs/stats of various tests using both routers:
TEST 1
Linksys WAG54GS - latest firmware

Setings:
Encapsulation	RFC 2364 PPPoA
Multiplexing		VC
Qos Type		UBR
Virtual Circuit	VPI 0
				VCI 38
DSL Modulation	ADSL2+

Login			bt_test@startup_domain

Log:
Sat, 2000-01-01 00:00:12 - ADSL G.992 started
Sat, 2000-01-01 00:00:16 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:00:19 - br0: topology change detected, propagating
Sat, 2000-01-01 00:00:19 - br0: port 1(eth0) entering forwarding state
Sat, 2000-01-01 00:00:25 - ADSL link up, fast, us=915, ds=0
Sat, 2000-01-01 00:00:31 - ADSL link down
Sat, 2000-01-01 00:00:35 - ADSL G.994 training
Sat, 2000-01-01 00:00:42 - ADSL G.992 started
Sat, 2000-01-01 00:00:47 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:00:55 - ADSL link up, fast, us=767, ds=0
Sat, 2000-01-01 00:01:01 - ADSL link down
Sat, 2000-01-01 00:01:05 - ADSL G.994 training
Sat, 2000-01-01 00:01:12 - ADSL G.992 started
Sat, 2000-01-01 00:01:17 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:01:25 - ADSL link up, fast, us=683, ds=0
Sat, 2000-01-01 00:01:31 - ADSL link down
Sat, 2000-01-01 00:01:35 - ADSL G.994 training
Sat, 2000-01-01 00:01:42 - ADSL G.992 started
Sat, 2000-01-01 00:01:46 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:01:55 - ADSL link up, fast, us=811, ds=0
Sat, 2000-01-01 00:02:01 - ADSL link down
Sat, 2000-01-01 00:02:05 - ADSL G.994 training
Sat, 2000-01-01 00:02:12 - ADSL G.992 started
Sat, 2000-01-01 00:02:17 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:02:25 - ADSL link up, fast, us=728, ds=0
Sat, 2000-01-01 00:02:31 - ADSL link down
Sat, 2000-01-01 00:02:35 - ADSL G.994 training
Sat, 2000-01-01 00:02:42 - ADSL G.992 started
Sat, 2000-01-01 00:02:47 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:02:55 - ADSL link up, fast, us=679, ds=0
Sat, 2000-01-01 00:03:01 - ADSL link down

TEST 2
Linksys WAG54GS - latest firmware

Setings:
Encapsulation	RFC 2364 PPPoA
Multiplexing		VC
Qos Type		UBR
Virtual Circuit	VPI 0
				VCI 38
DSL Modulation	ADSL2+

Login			<demon login>

Log:
Sat, 2000-01-01 00:00:12 - ADSL G.992 started
Sat, 2000-01-01 00:00:16 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:00:19 - br0: topology change detected, propagating
Sat, 2000-01-01 00:00:19 - br0: port 1(eth0) entering forwarding state
Sat, 2000-01-01 00:00:25 - ADSL link up, fast, us=915, ds=0
Sat, 2000-01-01 00:00:31 - ADSL link down
Sat, 2000-01-01 00:00:35 - ADSL G.994 training
Sat, 2000-01-01 00:00:42 - ADSL G.992 started
Sat, 2000-01-01 00:00:47 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:00:55 - ADSL link up, fast, us=735, ds=0
Sat, 2000-01-01 00:01:01 - ADSL link down
Sat, 2000-01-01 00:01:05 - ADSL G.994 training
Sat, 2000-01-01 00:01:12 - ADSL G.992 started
Sat, 2000-01-01 00:01:17 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:01:25 - ADSL G.992 message exchange
Sat, 2000-01-01 00:01:26 - ADSL link up, fast, us=679, ds=0
Sat, 2000-01-01 00:01:32 - ADSL link down
Sat, 2000-01-01 00:01:35 - ADSL G.994 training


TEST 3
Linksys WAG54GS - latest firmware

Setings:
Encapsulation	RFC 2364 PPPoA
Multiplexing		VC
Qos Type		UBR
Virtual Circuit	VPI 0
				VCI 38
DSL Modulation	G.dmt

Login			<demon login>

Log:
Sat, 2000-01-01 00:00:07 - ADSL G.992 started
Sat, 2000-01-01 00:00:09 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:00:14 - ADSL link up, fast, us=832, ds=4192
Sat, 2000-01-01 00:00:19 - br0: topology change detected, propagating
Sat, 2000-01-01 00:00:19 - br0: port 1(eth0) entering forwarding state
Sat, 2000-01-01 00:00:20 - ADSL link down
Sat, 2000-01-01 00:00:23 - ADSL G.994 training
Sat, 2000-01-01 00:00:25 - ADSL G.992 started
Sat, 2000-01-01 00:00:28 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:00:32 - ADSL G.992 message exchange
Sat, 2000-01-01 00:00:33 - ADSL link up, fast, us=736, ds=4064
Sat, 2000-01-01 00:00:38 - Initialize LCP.
Sat, 2000-01-01 00:00:38 - Plugin pppoa loaded.
Sat, 2000-01-01 00:00:38 - PPPoA Plugin Initialized
Sat, 2000-01-01 00:00:38 - Plugin pppoa called.
Sat, 2000-01-01 00:00:38 - PPPoATM setdevname_pppoatm - SUCCESS
Sat, 2000-01-01 00:00:38 - Options file - /etc/ppp/options.0.38.
Sat, 2000-01-01 00:00:38 - pppd 2.4.1 started by root, uid 0
Sat, 2000-01-01 00:00:38 - setting line discipline hook
Sat, 2000-01-01 00:00:38 - connect_pppoatm_ses...Enter
Sat, 2000-01-01 00:00:38 - connect_pppoatm_ses: socket created fd - 0x6.
Sat, 2000-01-01 00:00:38 - connect_pppoatm_ses: setsockopt called.
Sat, 2000-01-01 00:00:38 - connect_pppoatm_ses: connect successful.
Sat, 2000-01-01 00:00:38 - Calling line discipline hook
Sat, 2000-01-01 00:00:38 - Setting pppoatm line discipline.
Sat, 2000-01-01 00:00:38 - vc encaps.
Sat, 2000-01-01 00:00:38 - using channel 1
Sat, 2000-01-01 00:00:38 - Using interface ppp0
Sat, 2000-01-01 00:00:38 - Connect: ppp0 <-->
Sat, 2000-01-01 00:00:38 - LCP is allowed to come up.
Sat, 2000-01-01 00:00:39 - ADSL link down
Sat, 2000-01-01 00:00:42 - ADSL G.994 training
Sat, 2000-01-01 00:00:44 - ADSL G.992 started
Sat, 2000-01-01 00:00:47 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:00:51 - ADSL G.992 message exchange
Sat, 2000-01-01 00:00:52 - ADSL link up, fast, us=736, ds=4000
Sat, 2000-01-01 00:00:58 - ADSL link down
Sat, 2000-01-01 00:01:01 - ADSL G.994 training
Sat, 2000-01-01 00:01:03 - ADSL G.992 started
Sat, 2000-01-01 00:01:06 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:01:07 - Terminating on signal 15.
Sat, 2000-01-01 00:01:07 - LCP down.
Sat, 2000-01-01 00:01:10 - ADSL G.992 message exchange
Sat, 2000-01-01 00:01:11 - ADSL link up, fast, us=736, ds=4160
Sat, 2000-01-01 00:01:13 - Connection terminated.
Sat, 2000-01-01 00:01:13 - Exit.
Sat, 2000-01-01 00:01:17 - ADSL link down
Sat, 2000-01-01 00:01:20 - ADSL G.994 training
Sat, 2000-01-01 00:01:22 - ADSL G.992 started
Sat, 2000-01-01 00:01:25 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:01:29 - ADSL G.992 message exchange
Sat, 2000-01-01 00:01:30 - ADSL link up, fast, us=736, ds=4096
Sat, 2000-01-01 00:01:36 - ADSL link down
Sat, 2000-01-01 00:01:39 - ADSL G.994 training
Sat, 2000-01-01 00:01:41 - ADSL G.992 started
Sat, 2000-01-01 00:01:44 - ADSL G.992 channel analysis
Sat, 2000-01-01 00:01:48 - ADSL G.992 message exchange
Sat, 2000-01-01 00:01:49 - ADSL link up, fast, us=704, ds=4096
Sat, 2000-01-01 00:01:55 - ADSL link down


TEST 4 - return to original modem

D-Link DSL-504
VPI				0
VCI				38
Encapsulation	PPPoA VC mux
Login			<demon login>

Line condition after a couple of minutes:
Protocol	 		ADSL State		Showtime
				Data Path		Fast
				Operation Mode	 G.DMT

                                                     Downstream           Upstream
Line Status	ADSL Link Speed               4320   kbps          672   kbps
                        SNR                        5.0 dB                  0.0 dB
                        ATEN                      30  dB                  13  dB
Line Error           ADSL layer      FEC    0                          0
                                            CRC   2248                     2
                        ATM layer       HEC   1931                     4
Frame Counter                                 61                         64

Loop Distance:   About  6  K ft.



Line condition after approx 10 mins

Protocol			ADSL State	 	Showtime
				Data Path	 	Fast
				Operation Mode	 G.DMT

                                                     Downstream          Upstream
Line Status    ADSL Link Speed            4320   kbps          672   kbps
                        SNR                        5.0 dB                  0.0 dB
                        ATEN                      30  dB                  13  dB
Line Error      ADSL layer   FEC             0                         5
                                    CRC            20034                   8
                   ATM layer    HEC            17286                  20
Frame Counter                                  299                      272

Loop Distance:   About  6  K ft.
Standard User yarwell
(sensei) Tue 08-Sep-09 08:53:31
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Re: ADSL Line syncs OK but low download speeds


[re: brisouth] [link to this post] 		 
I can't get the BT speed checker to work on my line

is this because you are on C&W LLU now ?

From the stats below I would note that the downstream sync speed is low for the reported attenuation, have you done the usual test in the test socket behind the master etc.

Secondly the error rates are quite high and you are on Fast Path, switching to Interleaving should help with this, make a request by email to Demon asking for Interleaving to be turned on to improve stability.

Line condition after approx 10 mins

Protocol ADSL State Showtime
Data Path Fast
Operation Mode G.DMT

Downstream Upstream
Line Status ADSL Link Speed 4320 kbps 672 kbps
SNR 5.0 dB 0.0 dB
ATEN 30 dB 13 dB
Line Error ADSL layer FEC 0 5
CRC 20034 8
ATM layer HEC 17286 20

Phil

MaxDSL - goes as fast as it can and doesn't read the line checker first.

MaxDSL diagnostics
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