A bit (read:lot) of help re: ADSL/routing. Ideas welcome!

Hello all, first post here.

Some history: Moved into new flat around 2 weeks ago. The flat was built 2007 and is close to the exchange:

Distance:-
Direct:
697 metres
(appx)*
By Road:
805 metres

Courtesy of Kitz.

The choice of LLU providers was poor but there was CPW and C&W LLU kit, so I went with Xilo broadband (who so far have been good).

I'm currently using a Zoom ADSL 2/2 5715 full bridge modem connected to a D-Link DIR-615 Rev D router, running DD-WRT. Both pretty poor pieces of kit!

The line has been syncing at 13.5mbps with a pretty consistent 9dB SNR margin (as dictated by C&W; this is the lowest target profile they'll provide exchange-side, as explained by Xilo).

My current problems are two-fold:

1 (and most importantly) - the connection drops fairly regularly. I'm convinced that this is a result of the poor modem. I'm waiting on a Netgear ADSL modem from a friend to see whether this is the case. The info on the Xilo site gives the majority of disconnects as user-request, and the rest as line-error.

I'm not able to re-establish the PPPoE connection via the DD-WRT routers GUI, as the button is unresponsive (this is only once the connection's died). The modems GUI is accessable, and the stats claim it is connected; the ADSL light on the modem is lit but there is no data throughput whatsoever. A reboot of the modem (from GUI or by pulling plug) allows the router to re-establish the PPPoE connection and all is fine.

This happens fairly regularly (say, 1-10hours or so). Sometimes it'll last a day. This reads to me as a flakey modem (expecially as when we first moved in it managed fine for a good 5 days, and has steadily deteriorated)

I don't think it's a line issue, due to the nature of the disconnects, and I don't think its the router dropping the connection (although this is possible), but I'll know more when I get the replacement modem in-line.
----------

The second thing I think is modem related too tbh but was wondering if anyone had seen this before:

http://twitpic.com/6hfvqc/full

When I connect with "normal" SNR margins the modem stats read 9dB downstream SNR margin and the speed is always 13mbps.

I telnetted into the zoom modem and used the command "adsl configure --snr 50" and as per the picture above the line-stats jumped to 18-21kbps. Brilliant, thought I, a free 5mbps for nowt! This, it turns out was not the case. No combination of router, wireless, wired, PPPoE directly from laptop (as per above picture) can eek more than 13.75mbps from the connection, even when the modem is reportedly syncing at 18mbps!

I'm relatively technically able, but no expert, and all the bits and bobs I've done are cobbled together from forums like this and general problem-solving, but that picture above confounds me. It's like the line goes into the modem at whatever speed, and comes out the other side at 13.7mbps!

Xilo have confirmed that C&W don't cap the connection their end at all, so I've ruled that out.


Anyway, any comments on either of the two bizarre situations are much appreciated!

The last thing really is what I should do going forward; Obviously neither of the devices I'm using are up to scratch (DD-WRT just about rescues the D-Link but it definately has its issues...N won't connect above 72mbps no matter how prodded it gets, due to an inconsistency in the Ralink drivers used)

So, the question really is, what next? If this Netgear modem works well then that's a solution for the Zoom, but as for a router, are there any recommendations? I really want N, ideally I'd like to run 5ghz and 2.4ghz concurrently (due to the fact that I live in an apartment block) although the price of these routers seems prohibitive.

Do people generally think it's better running a seperate modem/router or keeping them in one unit? Other than the Billion 7800N(which everyone seems to love but is £125) are there any lower-priced N router/ADSL combos that have GUIs worth their salt?

Does anyone run a modern decent router with DD-WRT/OpenWRT? Loads of questions I know but hopefully someone can help

Edited by qpop (Fri 09-Sep-11 15:41:14)

Get yourself something cheap that is a good router. I used one of these on the same network before I moved to SKY. You should also check your internal wiring, check your ADSL splitter and remove the ring wire. I had a similar problem and doing all of this plus getting this router fixed it for me.

http://www.ebay.co.uk/itm/TP-Link-TD-W8960N-300Mbps-...

Its not me selling be the way I am keeping mine as a 2nd router.

Check all your MTU settings are the same - OS, router and modem. What OS is it?

If the MTU sizes are different then packets could be getting split all over the place, which would slow things down a lot.

RWIN on your OS is also important - that's the buffer size for incoming data.

I think (from memory and the recognising the screen shot), we've already been down the MTU path.

Matt

Yup, I've just checked, and Windows max MTU Window is set at 1492. that's the setting across the network.

The following picture is the situation right now, I've set the SNR margin to the minimum via telnet, and the DSL modem reports a sync speed of 20mbps -

https://twitpic.com/6iefz5/full

09/09/11 19:42:52
Speed Down 11373.22 Kbps ( 11.1 Mbps )
Speed Up 839.50 Kbps ( 0.8 Mbps )
Port 8095
Server speedtest2.thinkbroadband.com

I just cannot understand this, at all!

The following is the debug log from the modem:

Date/Time Facility Severity Message
2nd day 00:00:42 syslog emerg BCM96345 started: BusyBox v1.00 (2010.05.26-08:36+0000)
2nd day 00:00:42 user warn kernel: memory: 007a0000 @ 00000000 (usable)
2nd day 00:00:42 user debug kernel: On node 0 totalpages: 1952
2nd day 00:00:42 user debug kernel: DMA zone: 1952 pages, LIFO batch:1
2nd day 00:00:42 user debug kernel: Normal zone: 0 pages, LIFO batch:1
2nd day 00:00:42 user debug kernel: HighMem zone: 0 pages, LIFO batch:1
2nd day 00:00:42 user warn kernel: Built 1 zonelists
2nd day 00:00:42 user warn kernel: Kernel command line: root=31:0 ro noinitrd console=ttyS0,115200
2nd day 00:00:42 user warn kernel: brcm mips: enabling icache and dcache...
2nd day 00:00:42 user warn kernel: Primary instruction cache 16kB, physically tagged, 2-way, linesize 16 bytes.
2nd day 00:00:42 user warn kernel: Primary data cache 8kB 2-way, linesize 16 bytes.
2nd day 00:00:42 user warn kernel: PID hash table entries: 32 (order 5: 256 bytes)
2nd day 00:00:42 user warn kernel: Using 120.000 MHz high precision timer.
2nd day 00:00:42 user warn kernel: Dentry cache hash table entries: 2048 (order: 1, 8192 bytes)
2nd day 00:00:42 user warn kernel: Inode-cache hash table entries: 1024 (order: 0, 4096 bytes)
2nd day 00:00:42 user info kernel: Memory: 5624k/7808k available (1501k kernel code, 2164k reserved, 226k data, 76k init, 0k highmem)
2nd day 00:00:42 user warn kernel: KLOB Pool 1 Initialized: 1048576 bytes <0x80600000 ... 0x80700000>
2nd day 00:00:42 user warn kernel: Calibrating delay loop... 239.20 BogoMIPS
2nd day 00:00:42 user warn kernel: Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
2nd day 00:00:42 user warn kernel: Checking for 'wait' instruction... unavailable.
2nd day 00:00:42 user info kernel: NET: Registered protocol family 16
2nd day 00:00:42 user warn kernel: Total Flash size: 2048K with 512 sectors
2nd day 00:00:42 user warn kernel: File system address: 0xbfc10100
2nd day 00:00:42 user warn kernel: Blk# BlkOff Blks MemLen Partition Name
2nd day 00:00:42 user warn kernel: 0 1408 1 1024 NVRAM
2nd day 00:00:42 user warn kernel: 498 0 6 24576 Config 2
2nd day 00:00:42 user warn kernel: 504 0 2 8192 Scratch PAD
2nd day 00:00:42 user warn kernel: 506 0 6 24576 Config 1
2nd day 00:00:42 user warn kernel: Can't analyze prologue code at 80185df4
2nd day 00:00:42 user info kernel: Initializing Cryptographic API
2nd day 00:00:42 user info kernel: PPP generic driver version 2.4.2
2nd day 00:00:42 user info kernel: NET: Registered protocol family 24
2nd day 00:00:42 user warn kernel: Using noop io scheduler
2nd day 00:00:42 user warn kernel: bcm963xx_mtd driver v1.0
2nd day 00:00:42 user warn kernel: brcmboard: brcm_board_init entry
2nd day 00:00:42 user info kernel: Serial: BCM63XX driver $Revision: 3.00 $
2nd day 00:00:42 user warn kernel: ttyS0 at MMIO 0xfffe0300 (irq = 10) is a BCM63XX
2nd day 00:00:42 user info kernel: NET: Registered protocol family 2
2nd day 00:00:42 user info kernel: IP: routing cache hash table of 512 buckets, 4Kbytes
2nd day 00:00:42 user info kernel: TCP: Hash tables configured (established 512 bind 1024)
2nd day 00:00:42 user warn kernel: ip_conntrack version 2.1 (61 buckets, 0 max) - 384 bytes per conntrack
2nd day 00:00:42 user warn kernel: ip_ct_h323: init success
2nd day 00:00:42 user warn kernel: ip_conntrack_pptp version 2.1 loaded
2nd day 00:00:42 user warn kernel: ip_conntrack_rtsp v0.01 loading
2nd day 00:00:42 user warn kernel: ip_nat_h323: init success
2nd day 00:00:42 user warn kernel: ip_nat_pptp version 2.0 loaded
2nd day 00:00:42 user warn kernel: ip_nat_rtsp v0.01 loading
2nd day 00:00:42 user warn kernel: ip_tables: (C) 2000-2002 Netfilter core team
2nd day 00:00:42 user info kernel: Initializing IPsec netlink socket
2nd day 00:00:42 user info kernel: NET: Registered protocol family 1
2nd day 00:00:42 user info kernel: NET: Registered protocol family 17
2nd day 00:00:42 user info kernel: NET: Registered protocol family 15
2nd day 00:00:42 user notice kernel: Ebtables v2.0 registered
2nd day 00:00:42 user info kernel: NET: Registered protocol family 8
2nd day 00:00:42 user info kernel: NET: Registered protocol family 20
2nd day 00:00:42 user warn kernel: VFS: Mounted root (squashfs filesystem) readonly.
2nd day 00:00:42 user info kernel: Freeing unused kernel memory: 76k freed
2nd day 00:00:42 user warn kernel: Algorithmics/MIPS FPU Emulator v1.5
2nd day 00:00:42 user warn kernel: atmapi: module license 'Proprietary' taints kernel.
2nd day 00:00:42 user warn kernel: adsl: adsl_init entry
2nd day 00:00:42 user warn kernel: blaadd: blaa_detect entry
2nd day 00:00:42 user info kernel: Broadcom BCMPROCFS v1.0 initialized
2nd day 00:00:42 user warn kernel: Broadcom BCM6338A2 Ethernet Network Device v0.3 May 26 2010 16:33:17
2nd day 00:00:42 user warn kernel: Config Internal PHY Through MDIO
2nd day 00:00:42 user info kernel: BCM63xx_ENET: 100 MB Full-Duplex (auto-neg)
2nd day 00:00:42 user warn kernel: eth0: MAC Address: 00:25:5E:C5:C3:16
2nd day 00:00:42 user crit kernel: eth0 Link UP.
2nd day 00:00:42 user warn kernel: Broadcom BCM6338A2 USB Network Device v0.4 May 26 2010 16:33:20
2nd day 00:00:42 user warn kernel: usb0: MAC Address: 00 25 5E C5 C3 17
2nd day 00:00:42 user warn kernel: usb0: Host MAC Address: 00 25 5E C5 C3 18
2nd day 00:00:42 user warn kernel: BcmAdsl_Initialize=0xC006A3E8, g_pFnNotifyCallback=0xC0084FE4
2nd day 00:00:42 user warn kernel: AnnexCParam=0x7FFF7EA8 AnnexAParam=0x00003987 adsl2=0x00000003
2nd day 00:00:42 user warn kernel: pSdramPHY=0xA07FFFF8, 0x1B778B 0xDEADBEEF
2nd day 00:00:42 user warn kernel: AdslCoreHwReset: AdslOemDataAddr = 0xA07EF96C
2nd day 00:00:42 user warn kernel: AnnexCParam=0x7FFF7EA8 AnnexAParam=0x00003987 adsl2=0x00000003
2nd day 00:00:42 user warn kernel: dgasp: kerSysRegisterDyingGaspHandler: dsl0 registered
2nd day 00:00:42 user warn kernel: ATM proc init !!!
2nd day 00:00:42 user crit kernel: ADSL G.994 training
2nd day 00:00:42 user info kernel: device usb0 entered promiscuous mode
2nd day 00:00:42 user info kernel: br0: port 1(usb0) entering learning state
2nd day 00:00:42 user info kernel: br0: topology change detected, propagating
2nd day 00:00:42 user info kernel: br0: port 1(usb0) entering forwarding state
2nd day 00:00:42 user info kernel: device eth0 entered promiscuous mode
2nd day 00:00:42 user info kernel: br0: port 2(eth0) entering learning state
2nd day 00:00:42 user info kernel: br0: topology change detected, propagating
2nd day 00:00:42 user info kernel: br0: port 2(eth0) entering forwarding state
2nd day 00:00:42 user info kernel: device nas_0_0_38 entered promiscuous mode
2nd day 00:00:42 user info kernel: entering learning state
2nd day 00:00:42 user info kernel: br0: topology change detected, propagating
2nd day 00:00:42 user info kernel: br0: port 3(nas_0_0_38) entering forwarding state
2nd day 00:00:42 user info kernel: br0: port 1(usb0) entering disabled state
2nd day 00:00:42 user crit kernel: ADSL G.992 started
2nd day 00:00:42 user crit kernel: ADSL G.992 channel analysis
2nd day 00:00:42 user crit kernel: ADSL G.992 message exchange
2nd day 00:00:42 user crit kernel: ADSL link up, interleaved, us=1023, ds=16925
2nd day 00:00:42 user warn kernel: ATM Soft SAR: ATM link connected.
2nd day 00:00:42 user warn kernel: AnnexCParam=0x7FFF7EE8 AnnexAParam=0x00000980 adsl2=0x00000000
2nd day 00:00:42 user crit kernel: ADSL link down
2nd day 00:00:42 user crit kernel: ADSL G.994 training
2nd day 00:00:42 user crit kernel: ADSL G.992 started
2nd day 00:00:42 user crit kernel: ADSL G.992 channel analysis
2nd day 00:00:42 user crit kernel: ADSL G.992 message exchange
2nd day 00:00:42 user crit kernel: ADSL link up, interleaved, us=1023, ds=19635
2nd day 00:00:42 user warn kernel: AnnexCParam=0x7FFF7EE8 AnnexAParam=0x00000980 adsl2=0x00000000
2nd day 00:00:42 user crit kernel: ADSL link down
2nd day 00:00:42 user crit kernel: ADSL G.994 training
2nd day 00:00:42 user crit kernel: ADSL G.992 started
2nd day 00:00:42 user crit kernel: ADSL G.992 channel analysis
2nd day 00:00:42 user crit kernel: ADSL G.992 message exchange
2nd day 00:00:42 user crit kernel: ADSL link up, interleaved, us=1023, ds=20422
2nd day 00:00:42 user warn kernel: AnnexCParam=0x7FFF7EF8 AnnexAParam=0x00000980 adsl2=0x00000000
2nd day 00:00:42 user crit kernel: ADSL link down
2nd day 00:00:42 user crit kernel: ADSL G.994 training
2nd day 00:00:42 user crit kernel: ADSL G.992 started
2nd day 00:00:42 user crit kernel: ADSL G.992 channel analysis
2nd day 00:00:42 user crit kernel: ADSL G.992 message exchange
2nd day 00:00:42 user crit kernel: ADSL link up, interleaved, us=1023, ds=20723

I don't know if that's any help. It has a decent broadcom chipset in it, it would seem.

Most ADSL modems are really crippled routers and tend to be woefully under powered in terms of CPU, hence slow to handle resyncs etc

On the sync'd at 18 but only getting 13 throughput, sounds very like a throughput cap based on sync speeds seen by C&W, unless your RWIN is an unusual value.

Generally single box solutions work best, only time I'd go for a two box solution, would be an ADSL router handling an IP block and a router sitting on an IP address, i.e. no PPPoE going on

In reply to a post by MrSaffron:

Generally single box solutions work best, only time I'd go for a two box solution, would be an ADSL router handling an IP block and a router sitting on an IP address, i.e. no PPPoE going on

I use a two box solution, Thomson TG585v7 set in bridge mode, and Draytek Vigor 2820Vn as my router.

The reason is the ADSL line chip in the Thomson is dramatically superior to the Draytek, but the rest of the router feature set is pretty awful and the user interface diabolical. The Draytek offers all the modern feature set, but its ADSL modem just doesn't do the justice with BE's DSLAMs.

I would never buy an Vigor 100/120 modem only box.