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Bandwidth command

I have a internet link, 512kbps downlink and 256kbps uplink, i not sure which figure to state in the bandwidth command on the serial interface. example bandwidth xxxx

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Blue

Re: Bandwidth command

Leon,

Yes, the bandwidth statement should match the true outbound bandwidth of 256kb. This will prevent you from reserving more than 75% of the available bandwidth with your CBWFQ. The 25% is left for router overhead. You can fudge this a bit by overstating the bandwidth, but it's usually not a good idea.

Please rate helpful posts.

Dave

6 REPLIES
Community Member

Re: Bandwidth command

bandwidth 512

hieu

Blue

Re: Bandwidth command

The bandwidth command is used for calculating route metrics in dynamic routing protocols and is used when service policies reserve bandwidth for traffic classes. The clock signals on a serial interface are what determines the actual transmission rate. If you have an external DSU/CSU it will control the clock rate.

So unless you have another path to the Internet, or are using CBWFQ, it won't make any difference if you use 256 or 512.

Please rate helpful posts.

Community Member

Re: Bandwidth command

Thanks for replying, The serial interface is connected to a SDM 300A satellite modem, "the internet link is via satellite service ". I did configure Quality of service using CBWFQ to reserve bandwidth for some applications in case of congestion. I have a default static route to my service provider. So do i still need to specify the bandwidth command on the serial interface ?.

Blue

Re: Bandwidth command

Leon,

Yes, the bandwidth statement should match the true outbound bandwidth of 256kb. This will prevent you from reserving more than 75% of the available bandwidth with your CBWFQ. The 25% is left for router overhead. You can fudge this a bit by overstating the bandwidth, but it's usually not a good idea.

Please rate helpful posts.

Dave

Community Member

Re: Bandwidth command

Thanks Dave, for the information, God bless you.

Leon.

Community Member

Re: Bandwidth command

Typically the bandwidth command applies to outbound traffic so you would go with the up rate or 256k.

Using the bandwidth command it's always better to start lower and move up. One runs the risk of saturating the line if too much bandwidth is specified.

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