EIGRP interface BW command

EIGRP bandwidth control over Serial Subinterfaces

Hi All,

Lets consider a t1 link on a routers serial interface. The link is having 4 PVC. 2 are on s1/0.1 and one on s1/0.2 and one more on the s1/0.3. If i issue no command of bandwidth control, then how the EIGRP is going to use this BW for each PVC on serial S1/0.1 and on S1/0.2 or S1/0.3.

I could understand under defaults, each interface would have around (1544/3=) 515 Kbps. But how about the 2 PVC existing on the Serial S1/0.1.

Documentation ref will also be helpful.

Cheers!

Ravi

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vmiller

610 posts sinceMar 13, 2002

1. Mar 29, 2011 9:15 AM  in response to: ravindra Krishna

Re: EIGRP bandwidth control over Serial Subinterfaces

Bandwidth values for physical interfaces are set at statrup time (based

on the hardware)

for subinterfaces (logical) youset it yourself.

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ravindra Krishna

26 posts sinceOct 26, 2010

2. Apr 7, 2011 8:17 AM  in response to: vmiller

Re: EIGRP bandwidth control over Serial Subinterfaces

Hi,

As said earlier I have not specified any BW command. Please let us know how the BW is distributed on default conditions. A ref document will also be helpful.

Cheers!

Ravi

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vmiller

610 posts sinceMar 13, 2002

3. Apr 7, 2011 8:42 AM  in response to: ravindra Krishna

Re: EIGRP bandwidth control over Serial Subinterfaces

There are default bandwidth definitions for all interfaces, its nothing you set. For serial, the default is t-1 speeds

bandwidth

#

To set a bandwidth value for an interface, use the bandwidth interface configuration command. Use theno form of this command to restore the default values.

##

bandwidth kilobitsno  bandwidth

##

Syntax Description

# kilobits

# Intended bandwidth in kilobits per  second. For a full bandwidth DS3, enter the value 44736.

##

Default

#

Default bandwidth values are set during startup and can be  displayed with the EXEC command show interfaces.

http://www.cisco.com/en/US/docs/ios/11_0/router/command/reference/rinterfc.html#wp1396

Its an old reference.

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ravindra Krishna

26 posts sinceOct 26, 2010

4. Apr 8, 2011 12:04 PM  in response to: vmiller

Re: EIGRP bandwidth control over Serial Subinterfaces

Lets consider a t1 link on a routers serial interface. The link is having 4 PVC. 2 are on s1/0.1 and one on s1/0.2 and one more on the s1/0.3. If i issue no command of bandwidth control, then how the EIGRP is going to use this BW for each PVC on serial S1/0.1 and on S1/0.2 or S1/0.3.

I could understand under defaults, each interface would have around (1544/3=) 515 Kbps. But how about the 2 PVC existing on the Serial S1/0.1.

I think I got the answer:

Since, we have not specified any BW command the default is 1544so for subinterfaces with one PVC, each would you use around (1544*50%=)772Kbps for EIGRP traffic.

And for the subinterface with 2 PVC it would be round (1544*(1/2)*50%=)386 Kbps.

Hope now this is absolutely right!

Below are ref links:

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094063.shtml#nbma