21CN :(

Our office currently has two long lines (54dB) and we've found in the past that 21CN destabilises them. Our ISP has said that BT is now putting pressure on them to migrate us to 21CN. If we lose that option our office basically loses its internet connection. What irks me most is that our exchange (Bicester) was upgraded to support FTTC over a year ago but BT chose not to upgrade the cabinet.

We're hopeful of getting fibre to the site at some point but in the meantime it seems we're in danger of losing connectivity.

How do you mean "destabilises"? How does this manifest itself?
I've seen several reports of people have problems with their old routers and being advised to upgrade to routers known to work with 21CN. Is this the problem? What routers are you using?

Two lines, so what you do is migrate one line and once that has shown it works you do the second.

BT Wholesale is putting pressure on in the form that the old 20CN services are more expensive than 21CN and it is just about taking new orders in some areas http://www.thinkbroadband.com/news/5230-bt-wholesale...

As for the destabilises, with perhaps 25% of UK phone lines being this length or more, then we would expect many many more posts with problems. The vast majority are down to things like wiring issues that ADSL never exposed, or using old hardware that never got firmware updates to fix ADSL2+ bugs in it, or people not upgrading firmware.

You don't have to take the 21CN service, you could elect for another LLU provider, or your ISP could make sure that the lines are set to a fixed speed profile on 21CN if you are convinced you will have problems.

In reply to a post by BatBoy:

How do you mean "destabilises"? How does this manifest itself?
I've seen several reports of people have problems with their old routers and being advised to upgrade to routers known to work with 21CN. Is this the problem? What routers are you using?

If I could get the TBBQM graphs for early 2011 to load I could show you a before/after/back again sequence. The best I can do is pick one from earlier this year:

My Broadband Ping

Then today's:

My Broadband Ping

The 2011 sequence was as clear as day. We know from the ISP when the initial migration took place and we can see the reversion. Up until the migration it's a clean graph. Then a red bar as the line reconnects. Then packet loss and drops every few hours. Then exactly to the minute as far as the graph resolution shows we are moved back to 20CN and stability returns.

I didn't ask our ISP for the exact date/time of this recent migration but it was after I said "It's been bad for the last month or so" he responded with "Oh, hang on. Someone migrated you to 21CN recently."

The router is a Cisco 154x and has an Alcatel chipset which the ISP agent said probably doesn't help.

As for migrating one line at a time I don't think that will help. We have a bonded solution.

Edited by Andrue (Wed 10-Oct-12 11:47:14)

Which means the issue may be nothing to do with 21CN ADSL2+ but more to do with the WBC backhaul network and how the ISP manages the traffic/volumes it purchases etc

If latency performance is critical to business then its reconsider the bonded solution and look at the Ethernet options. Very little in the way of latency SLA for WBC.

In reply to a post by MrSaffron:

Which means the issue may be nothing to do with 21CN ADSL2+ but more to do with the WBC backhaul network and how the ISP manages the traffic/volumes it purchases etc

If latency performance is critical to business then its reconsider the bonded solution and look at the Ethernet options. Very little in the way of latency SLA for WBC.

We don't care about latency at all. What we care about is a complete lack of throughput which is what we're getting half a dozen times a day at the moment. Last night's outage caused our overnight synchronisation to fail despite it's supposed ability to handle errors. Our ISP thinks we will get migrated back later today so I'm pretty certain I'll be able to show you a graph for tomorrow that is almost completely clear of red.

So what are the router stats for both lines now then?

Nothing on the current BQM shows any problems with throughput, the yellow and blue simply shows some rises in latency consistent with you using the connection.

http://www.thinkbroadband.com/ping/share/68ee2ecbcb5...
Shows clearly when I went to bed and when I started using the connection this morning.

You can always force your routers to run in G.DMT mode.

In reply to a post by MrSaffron:

So what are the router stats for both lines now then?

I agree strongly here. Go and do it now, before they migrate you back. The line statistics will be important.

Include as much detail as you can - SNR, Bit loading, connection times & error counts. And try to keep some of those over time, before the migration happens.

Just to help later. For now, collecting data is important...

Nothing on the current BQM shows any problems with throughput, the yellow and blue simply shows some rises in latency consistent with you using the connection.

Or worse, the yellow & blue just show what is going on in the ISP network, or the 20CN link, and not your line alone.

I've been doing almost nothing on mine whatsoever. You certainly can't see where I went to bed! My Broadband Ping

In reply to a post by MrSaffron:

So what are the router stats for both lines now then?

I don't know - they manage the router. The agent just agreed that their systems showed the same problems ours do.

Nothing on the current BQM shows any problems with throughput, the yellow and blue simply shows some rises in latency consistent with you using the connection.

Sigh. At least one of us is confused here. To my understanding (based on several years of use but clearly you'd know better) the TBBQM display for our office connection shows it dropping several times a day and for today's graph virtually dead for about two hours around mid-night. The latter being confirmed by the error log from our synchronisation process.

Are you telling me that the TBBQM graph I posted is just 'business as usual' and a perfectly healthy line with no problems? That certainly isn't our experience and for every long red line we see in that graph there will have been a corresponding 'Connection to server lost' from all Outlook clients and/or a plaintive cry from someone in our office asking if the internet connection has failed.

Those are the kinds of things that only seem to happen a lot after our lines are migrated to 21CN and the correlation to the TBBQM seems pretty obvious to me. If that's an invalid assumption then clearly TBBQM is useless and I might as well stop using it.

Edited by Andrue (Wed 10-Oct-12 14:50:32)