IPv6 Training (Cisco) Using the “bandwidth” (IPv6) Interface Command
The “bandwidth” (IPv6) Interface Command
I wrote this article because lately, I’ve been receiving a lot of emails asking me the following question; “Does Cisco have an IOS command that I can use to control the bandwidth usage on my router’s main interfaces or sub-interfaces?”
Well, to quickly answer the question; “Yes”. Cisco created the Cisco IOS “Interface” command named “bandwidth”.
The “bandwidth” (interface) command has been around for quite some time now, but, if you’re administrating an IPv6 network, your routers will need to run Cisco IOS 12.4(6)T or higher; because Cisco did not include IPv6 support in earlier IOS versions.
Now, for those who are new comers to the “bandwidth” (interface) command; network administrators (like you) use the command to set the inherited and received bandwidth values for a router’s interface or sub-interface.
In other words; network administrators (like you) use the “bandwidth” command to tell (inform) a router’s interface to only “communicate” (route) at a specific bandwidth to the higher-level protocols.
So, technically the “bandwidth” (interface) command is not adjusting the bandwidth of the physical interface; it’s only setting (controlling) the bandwidth in which the interface communicates (routes) and receives traffic.
Below is the correct syntax of the “bandwidth” (interface) command:
router(config-if)#bandwidth {kbps | inherit [kbps] | receive[kbps]}
Now, you need to keep in mind that the “bandwidth” (interface) command is mostly used by network administrators that are administrating Wide Area Networks (WANs) not Local Area Networks (LANs).
And, if you need to restore an interface’s communication (routing) bandwidth back to normal (the default), all you need to do is type the word “no” in front of the command like you see below:
router(config-if)#no bandwidth {kbps | inherit [kbps] | receive[kbps]}
The “bandwidth” (Interface) command argument and Keywords explained:
kbps – This argument is the intended bandwidth, in kilobits per second. Valid values are 1 to 10000000. For a full bandwidth DS3 line, enter the value 44736.
inherit – This optional keyword is used for the inherited bandwidth. In other words, this keyword is used to specify how a sub-interface inherits the bandwidth of its main interface.
receive - This optional keyword is used for the receiver bandwidth. In other words, when using this keyword you are telling the interface to be asymmetrical. (asymmetrical means the interface can transmit at a specific bandwidth and receive at specific bandwidth).
Well, as you can see; the “bandwidth” (interface) command is a pretty intense and useful command for network administrators that are over seeing Wide Area Networks. I hope this article was very informative; but, if you need to learn more about the command. I suggest you visit my website were you’ll find the latest information regarding Cisco IPv6 Design and Implementation Techniques.
To your success,
Charles Ross
CCNP #CSCO10444244