Stability Issues with Cisco 877 on ADSL 2+

ffc_sup — Wed, 05 Sep 2012 13:25:11 GMT

I have a Cisco 877 Router on one of my BT ADSL 2+ business connections which is also used for VPN connectivity to our main office. This router was completely stable on the connection until a month or so ago. Now from cold boot after several days the connection becomes unusable, slowing to a crawl and dropping packets all over the place whilst getting alot of CRC errors, until it is restarted.

Initially I got BT to do some line tests which checked out OK. Since then I have plugged into the master socket, replaced the filter, cable, and router itself for a brand new one via Cisco TAC but am still experiencing the problem.

http://www.cisco-bt-portal.com/iusr/DSL/Product_Bulletin_DSL.pdf

States that for my model of router I should check the following:

Latest recommended STM Firmware

(Sept 15th, 2011)

The Current best firmware based on significant further development testing:-

v 0.0.26

- http://www.cisco-bt-portal.com/iusr/DSL/adsl_alc_20190_0.0.026.bin

Current recommendation would be as follows :-

1. Use the correct firmware, as advised above.

2. For lines >5500m (i.e. >60dB) consider dropping to ADSL2 (or even ADSL1) for

line-stability.

Eg. # interface atm 0

# dsl operating-mode adsl2|adsl1

3. Consider ADSL Line changes to enforce line-stability conditions

Most DSL services will normally dynamically renegotiate to optimize the line-profile

and under line errors. Normally this occurs almost transparently to the end user, but

in cases where ADSL has been used for business critical services (such as VoIP)

stability is often a more paramount concern.

The following provider changes should optimize for line-stability (done by BTWC)

- BT WBC: Change Stability profile from “Standard” to “Stable”

- BT WBC: Enabled Interleaving

BT Line testing: Ask BT for a “long duration Background Noise and Impulse Noise

test” performed on the line. (Note: This type of line-testing

is service interrupting).

4. In the final <1% of extreme 5500m-6000m environments or where there is poor

EMI noise conditions (i.e. manufacturing and construction with high EMI interference

such as high-voltage machinery in some cases) then consider a line-conditioner,

which may help address this.

i.e.

http://www.broadbandbuyer.co.uk/Shop/Reviews.asp?ProductID=8138

I am currently running the 0.0.26 firmware on this router. Without it, it won't even connect. IOS version is 15.1(1)T4

My question is:

What can I do to improve the stability on this line, and how should I go about getting the changes implemented as above i.e. getting the line stability settings on the line changed.

Do you have any other suggestions or tests that can be done on the line?

Re: Stability Issues with Cisco 877 on ADSL 2+

darkulap — Fri, 07 Sep 2012 00:18:16 GMT

I am also using the Cisco 877 router and would want to know how can I increase its range using BT ADSL?

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Stability Issues with Cisco 877 on ADSL 2+

Re: Stability Issues with Cisco 877 on ADSL 2+