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Setting bandwidth on a Cisco 837

Hi,

I have a Cisco 837 which s connected on a DSL connection with 2mbit down and 128kbit up. I'm just having a play with SDM and am trying work out how it figures the bandwidth utilisation?

As in, it will show the bandwidth as being 100% though the connection is using ... say 100kbytes download and 10kbytes upload.

I notice that there is a "bandwidth 640" line in my config. Why is this set at this figure? Is it a standard setting or specific to the connection speed?

As is probably obvious from my post, I'm not an expert on this by any means but do have a general understanding (I think :) ) ...

Any help would be appreciated ...

Cheers, Steve

Reply to
Steve
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For Cisco router, each interface type will have a default bandwidth.

You can confiugre it by

conf t interface bandwidth end

AFAIK, you can only configure one bandwidht value - not one for up and another for down

Reply to
Merv

Thanks for the reply. So is this the setting for upstream or downstream? I think I've seen somewhere that it's the upstream bandwidth, in which case for my config it should be set to:

bandwidth 128

But if it's downstream it should be set to:

bandwidth 2000

Currently, I can get downstream speeds (in certain cases) of roughly my maximum speed so I'm guessing it's upstream, otherwise I'd be limited to 640kbit, rather than the 2000kbit it actually is.

Should this be set to a slightly higher amount to allow for overhead?

When I do a "show controllers atm 0" it shows under "Interleave" the speed to be 2560 and 160 which I presume are settings for downstream and upstream?

In which case am I going to be pretty much okay setting the bandwidth setting to 160?

Many thanks for any help ... :)

Cheers, Steve

Reply to
Steve

The "bandwidth" command on Cisco interfaces has no effect on the actual throughput of the connection. All it is for is metic calculations for link state routing protocols. It has no effect on your usable 'bandwidth'.

Chris.

Reply to
Chris

Ahhh, righto - thanks for that. So it really doesn't matter what it's set at ... and 640 is fine?

Okay, another question then (which is kinda related) - how does SDM measure bandwidth. When I look at the "Dialer0,Bandwidth Usage" graph, it's often showing at 100% even though the throughput isn't at 100% of the link ....any ideas? If I can't use that, is there some other way of getting these kinds of info/graphs?

Many thanks ... again ...

Steve

Reply to
Steve

If the router is/will be polled using SNMP, then the setting of bandwidth needs to be set to the correct bandwidth value in order to get correct link utilization values

Reply to
Merv

Thanks for that. I changed the setting to be: bandwidth 2000 Now the graph for SDM shows correctly. Excellent! :)

Many thanks again to all for the help.

Steve

Reply to
Steve

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