What is GRE tunnel bandwidth?

[Tod Larson]

What does the GRE tunnel bandwidth transmit feature do? The default is 8000 kbs but I do get much more than 8meg throughput so I'm having trouble understanding and validating an implementation.

Below is what I find on cisco.com but I don't understand since this makes it seem like my throughput would be limited to 8meg. Thank you.

tunnel bandwidth

To set the transmit bandwidth used by the tunnel interface, use the tunnel bandwidth command in interface configuration mode. To restore the default setting, use the no form of this command.

tunnel bandwidth {receive | transmit} bandwidth

no tunnel bandwidth

Syntax Description

receive

Specifies the bandwidth to be used to receive packets through the tunnel.

Note This keyword is no longer used and will be removed in future releases.

transmit

Specifies the bandwidth to be used to send packets through the tunnel.

bandwidth

Bandwidth, in kbps. Range is from 0 to 2147483647. Default is 8000.

Defaults

8000 kbps

Command Modes

Interface configuration

Command History

Release

Modification

12.3(7)T

This command was introduced.

Usage Guidelines

Use the tunnel bandwidth command to specify the capacity of the satellite link.

Examples

The following example shows how to set the satellite tunnel bandwidth to 1000 kbps for transmitting packets using Rate Based Satellite Control Protocol:

Router(config)# interface tunnel 0

Router(config-if)# tunnel bandwidth transmit 1000

Related Commands

Command

Description

tunnel destination

Specifies the destination for a tunnel interface.

tunnel mode

Sets the encapsulation mode for a tunnel interface.

tunnel source

Sets the source address of a tunnel interface.

[Richard Burts · Accepted solution]

Tod

It is fairly common to assume that the interface bandwidth would control the rate of the interface. But that is not the case. The bandwidth command on an interface is informational and does not, by itself, exert any control.

The bandwidth statement can be used by other processes. For example the calculation of the routing metric for EIGRP is calculated using the configured bandwidth. Many network monitoring and reporting tools use the bandwidth to calculate the usage of the interface. And some QoS and Rate Limiting tools can use the bandwidth to calculate how to limit traffic.

I believe that there is a reference in what you found that says the tunnel bandwidth was used by rate limiting tools:

how to set the satellite tunnel bandwidth to 1000 kbps for transmitting packets using Rate Based Satellite Control Protocol:

HTH

Rick

[Tod Larson]

So "transmit bandwidth" looks like a feature that was put in place to support features such as satellite control protocol. But in reality, only scp would use this and I'm not running scp so I can ignore the parameter.

[Richard Burts]

Tod

If I understand correctly what you are trying to do and to understand, then yes you can ignore the GRE tunnel bandwidth transmit parameter.

HTH

Rick