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Cisco 877 on ADSL2+

Plusnet Alumni (retired) paulmh5
Plusnet Alumni (retired)
Posts: 170
Registered: 11-04-2011

Cisco 877 on ADSL2+

I'm just looking to find some other PN users out there who have a Cisco router on adsl2+ annex A with an uncapped upstream?
On good old ADSL1 the line is nice and stable but now I've been upgraded to 2+ I cant get sync for more than a few seconds with the router giving a Defect: LCDf error.
I've done some asking about/Google searching and I get the impression the 877s have issues with up-capped upstream speeds.  If someone can prove that wrong I'd be grateful  Smiley
Thanks
Plusnet Staff - Lead Network Design/Delivery Engineer
6 REPLIES
prichardson
Grafter
Posts: 1,503
Registered: 05-04-2007

Re: Cisco 877 on ADSL2+

Paul,
What IOS and and firmware version are you using?
There is a known defect between the Alcatel modem and BT MSANs that quick update should fix in most cases.
You may also find a "dsl noise-margin 3" on ATM0 (enable "service internal" first) may assist in at least maintaining sync long enough to get a better in-sight.
For the record, there are some proven results that it performs worst on Annex A and had some of the best results when used on Annex M.
Plusnet Alumni (retired) paulmh5
Plusnet Alumni (retired)
Posts: 170
Registered: 11-04-2011

Re: Cisco 877 on ADSL2+

I'm running 12.4.(25)T5 and I've tried a fair selection of firmware, 3.0.33 and 3.0.43 being the main ones.  I tried 4.0.17 for a laugh but that does state its for Annex M.
I'm not sure there is a higher IOS version I can go to without looking at the version 15 sets but I'm not 100% sure I'll have enough memory in the box I've got to run it.
Plusnet Staff - Lead Network Design/Delivery Engineer
AJJ
Grafter
Posts: 42
Registered: 19-04-2011

Re: Cisco 877 on ADSL2+

Hi,
Im trying to get an 877 configured too - did you manage to have any joy or still suffer from the connection drops?
My connection seems fairly stable but just zapped the speed right down (PN tech support said it was showing a lot of disconnects but there seemed to be no loss of service my end?)
thanks
AJJ
Plusnet Alumni (retired) paulmh5
Plusnet Alumni (retired)
Posts: 170
Registered: 11-04-2011

Re: Cisco 877 on ADSL2+

I bit more in-depth searching around Phil's post does seem to show there are a lot of reported problems between the Alcatel chipset in the Cisco router and the Huawei/Infineon MSANs used by BT for the delivery of ADSL2+.  I know BT use two different makes of MSAN so I'm use if the problem exists on the Fujitsu ones.
This differs from ADSL1 due to BT using traditional DSLAMs for that.
I'm using a good old Thompson for the time being just to get online, I'm going to keep searching to see if there is a bette DLS firmware around but judging by some the long running posts I've read on the Cisco site I dont expect this to be fixed now the 887 is out (and uses a Broadcom chip).
Plusnet Staff - Lead Network Design/Delivery Engineer
prichardson
Grafter
Posts: 1,503
Registered: 05-04-2007

Re: Cisco 877 on ADSL2+

Some further info.
For those using the Cisco 877. BT have been extensively involved with Cisco and have even gone to the lengths of purchasing third party code to develop a new microcode for the Alcatel 20190 chipset. A test microcode was launched mid September (0.0.26) and Cisco ratified this on November 29th, along with briefing to all service providers from BT to this on November 30th.
Cisco released a download Available Here
Recommended ISO for this is as follows: 12.4(3)T or later - Preferred: 12.4(15)T or or 15.01M - latest sub-release
We have been working with a number of corporates that use this extensively in their setups since September and has proved to work very well.
David_W
Rising Star
Posts: 2,296
Thanks: 30
Registered: 19-07-2007

Re: Cisco 877 on ADSL2+

I've been using that one for a while but yesterday went back to 4.0.018, the new version incorrectly reports SNR (measured it at 10 rather than 6) so speeds were lower than they should be.  I've also run into a problem where I'm getting SNR drops which cause the ADSL to go blergh and it doesn't disconnect and reconnect, the internet stays down (shut/no shut on atm0/0.1 does nothing, clear int atm0/0.1 does nothing either).  All in all, not very impressed that the Cisco won't do what a Technicolor will  Embarrassed