BT Internet Cisco 877 Router
We have a fairly large client all using Cisco 877 Router’s and all use BT Broadband (20mb) Recently we had a particular fault that went on for weeks at a single site and BT were determined it was not an issue with them. We tried an alternative router (Draytek, Linksys) and this held the connection without a problem.
The internet would drop between minutes, hours or days and was getting worse. When the connection was established it was showing a SNR of -1db so I knew there was a fault. You can view the noise by type “show dsl interface atm 0“
Maybe the issue is to do with the Cisco 877 and I know they can be very sensitive. After some research and digging around I came across the 4.0.18 ADSL Firmware release from Cisco that specifically targets BT Internet. At first we were using the firmware that came with the 12.4 IOS range (3.0.14)
I updated the IOS to the 15.1.T IOS range which put the 4.0.17 Firmware on but the CD (Carrier Detect) light was still blinking and not detecting a signal. I loaded the 4.0.18 fix which can be downloaded from Cisco (Download Software –> Routers –> Branch –> 877 –> ADSL Firmware)
You need to rename the file to adsl_alc_20190.bin and place in the root of flash. Reboot the router and it will detect and automatically load this Firmware version. To verify run the “show dsl int atm 0” command to see the Firmware Version used.
After the reboot the Router CD light stayed solid and a healthy connection was made and the internet started working.
Note: Although Cisco say not to roll out this fix unless necessary we have done this to over 50 sites some with the issue and some with not and have not yet suffered a problem.
Any more information or help needed please contact me.