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Community Member

ADSL Bandwidth issue

Firstly, sorry if my problem is a bit mundane, but I've tried everything and everywhere to try and resolve my issue so I'm hoping you gurus might be able to help!

I have a 3620 in which is a 2FE module in which is a WIC1-ADSL card. The router is running c3620-ik9o3s6-mz.123.17a.

All works as it should with a download speed a constant 843Kb/s - as it should be.

I recently purchased a 3640 so I could use larger IOS's. I swapped the FE and DSL module into the 3640. The image is c3640-ik9o3s-mz.124.8a.

All works as it should except the somehow my DSL bandwidth is capped to 300Kb/s.

I have tried several other IOS images, erased everything and started over with no success. I have even installed SDM to try and see if there are any 'default' traffic polocies in place,

attached is the startup-config, any help greatly appreciated.........


Re: ADSL Bandwidth issue


Try to define the bandwidth manually on

interface Dialer1 using the command

bandwidth 843

Hope this will work.


Community Member

Re: ADSL Bandwidth issue

Morning Raj

thanks for the suggestion..........

I specified the bandwidth manually on dialer 1, shut down the ATM0/0 interface then a no shut.

Both dialer 1 and virtual-access 2 sho a bandwidth of 850, but its still 'capped' at bang on 300Kbps.

Hall of Fame Super Bronze

Re: ADSL Bandwidth issue

Have you checked for packets being fragmented ? That's usually a behavior of a DSL connection.

Please read this article on how to address packet fragmentation issues on Cisco IOS.

The article focuses on GRE and IPSec technology as they also fragment packets but this should also apply to DSL.


Community Member

Re: ADSL Bandwidth issue

Thanks for that, I set a tcp adjust-mss value to ensure that fragmentation was not the issue, but unfortunately it made absolutely no difference.

When I run speed tests on the net, it shows the correct download speed, around 8140 and upload around 448 - but highlights a 'throughput' of considerably less.

So there must be some sort of traffic limiting in place - but where?

Community Member

Re: ADSL Bandwidth issue

Examining the config there is an entry;

'resource policy' - what is it? could this be the cause of the problem?

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