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26652
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Cisco 887VA and BT ADSL

dataIP
Level 1
Level 1

I have a question that we don't seem to be able to resolve with BT... We experience random disconnects, in that the sync is present but the PPP session drops. Unplugging the DSL cables and re-inserting after the sync is lost always makes the router re-establish its PPP session. This can happen from once a week to a couple of times per day.

BT have suggested many things, but none are leading to a solution. We can rule out the obvious that BT always ask... master socket, different router (new 887VA of the same type). Power is clean, supplied from UPS.

I have the document Product_Bulletin_DSL.pdf, which is supposed to discuss correct operation with BT systems, but this morning ran in to BT stating that they don't support Cisco and wouldn't really go any further.

I did ask if they could access http://www.cisco-bt-portal.com/iusr/DSL/Product_Bulletin_DSL.pdf but we didn't seem to get very far.

As far as I can tell there is a BT specific version of firmware for this DSL connection, vdsl.bin-35d_d23j, it is referenced in the document but I don't seem to be able to access it from the link.

Also, I have what I belive o be the latest ios ready to apply, but CCP won't let me load it.. we get a message something to the effect of "wrong image for this router". As far as I can tell, it is correct... I obtained it from the Cisco downlaod area.

I am unsure of what DSL firmware in contained within, so maybe best to also load the vdsl.bin-35d_d23j (if I can get hold of it).

Any sugesstions on this problem?

31 Replies 31

Hi Paolo,

Thanks again for the reply.

I will check today if our other connection is actually using BT equipment, or if it is LLU and therefore using different equipment.

The part I missed out of my post was that both of these connections are to the same local exchange in the same town, but you are quite right, I had missed to point that they could still be different DSLAM equipment in that same building.

Using the BT supplied equipment is difficult, it won't let us tunnel and get IPv6 connectivity which we need on this site. It is fine for a test, but our outages vary sometimes a few a day, sometimes none for a week.

Upgrading IOS this morning too.

If the ISP modem is stable, you can set it in bridge mode, ask ISP to give either 'bridged IP' or PPPoE encapsulation, then configure everything you need on the cisco.

Progress is that we have upgraded to IOS image to Version 15.2(4)M1 which should be the most recent.

Still using the A2pv6C035d_d23j firmware.

BT have now changed the noise margin from 3dB to 6dB.

Stable for the last 24 hours, but still monitoring. As mentioned before, sometime we have no drops for a week or more, then can be several a day at other times.

On a high attenuation circuit like your, random drops are somehow inevitable. The point is that the router must be able to re-establish the circuit without manual intervention. Some people uses EEM scripts for that, but in my opinion these are kludges.

Be interesting to hear if you have had any more issues with this.  We are currnetly undertaking a refresh of all our remote sites with BT. We are moving to a managed ADSL connect solution where BT supply and support all the equipment including the Cisco 887VA routers!! 

I wait with baited breath to see if we get the same issues!!!

Tim

Still seeing occasional drops with this setup.

Interesting information from Tim above... BT supplying and supporting the 887VA... we continually get told (by BT) that they DON'T support Cisco! I think they seem to get confused with supporting as in "giving a working config", as opposed to supporting as in "DSLAM will function with".

BT caused us an 8 day outage on this connection a few months ago and were unable to fix it (at their exchange end) in a timely manner.

Will probably be migrating this ADSL connection to an FTTC connection in the near future. Will still be using the same 887VA and the same circuit... we will see how that goes.

Mark

Hi Mark

could you post a working configuraiton for your router? I have the BT imange  vdsl.bin-35d_d23j and the latest IOS on my 886VA.

When I do a sh vdsl controller 0 I get the message

"VDSL is down" and then further down the list "Modem is idle"

The standard BT hub works

Just want to sanity check my BT settings with someone else.

Thanks

Rod

Hi Rod,

Just sent you a PM with the config.

I am mostly happy that it is right, but I don't want to be posting up the config as a 'solution' yet as it may mislead others.

Thanks Mark

Will look at it tomorrow.

Rod

Good Morning All,

I have a similar issue here in Australia with this router and AAPT. Did this firmware fixed the issue?

Hi Stuart,

It did not work for me. I installed the correct BT ADSL firmware and IOS version 15.2. I also applied config from a working 887 router.

I've had to install and old type 800 until I get the time to investigate.

CD did not establish for me on the 886VA

Rod

Thanks Rod,

We also applied this firmware to 20 routers in the last few days and one router today I upgraded to IOS 15.3. One thing to note about Bt and their phone line, is your router near the mdf or a new line? As BT known to use old lines and they can be noisy. I had a case when the building air/con was creating enough noise that cause Cisco 857 to disconnect. It only got fixed when they redo the cable between the mdf and the wall plug.

Sent from Cisco Technical Support iPhone App

Hi Stuart

If it were noise on the line I would expect my old 877 not to CD - however I do take on board your point about noise as i've had issues with BT in the past regarding the same problems. The noise levels are quite low mind you ( 5db)...

Hi Rod,

Just as an update to this... my original problem was with the 887VA which is of course ADSL over POTS. I han't spotted yours was an 886VA which I believe is ADSL over ISDN. I didn't have any experience with that one and am unsure if the firmware I spoke about was correct for that configuration.

Maybe that is why there was no carrier detected.

I had a quick look at the original Cisco/BT document and didn't see discussions for the ISDN option. I hope I didn't mislead you.

dataIP
Level 1
Level 1

An update for everyone on this thread:

We didn't really manage to get the setup 100% stable. The new firmware and OS seeemd to help, but still had some times when it would drop off the network.

Paolo is, I think, on the right track. Clearly whatever the issue, the router should detect the condition and re-establish... and it is not doing so. So, in my mind there is at least a firmware issue, in that the router doesn't properly handle the disconnect issue. It is a seperate question as to why the drop occurs in the first place.

We managed to get BT to physically test the line at the premises and found that there were issues that remote testing did not pickup. (As it happens we knew the engineer they sent out, and he made extra efforts to make sure things were 100% even though it may previously have counted as acceptable). Corrosion was found in the street cabinet and a junction at the top of the pole. Both issues being corrected gave us a more stable connection (to be fair, this was the same time as firmare was changed, so I can't be 100% which item made the difference).

As it happens we have now moved this connection to FTTC. Same line, same 887VA and have this working too. No drops detected so far with this configuration. I do seem to have a possible issue with MTU.... but maybe that is for another thread.

Thanks for everyones thoughts and help on this one.

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