Re: HELP!!!!! auto-cost reference-bandwidth

auto-cost

To control how OSPF calculates default metrics for the interface, use
the auto-cost command in router configuration mode. To assign cost
based only on the interface type, use the no form of this command.

auto-cost reference-bandwidth ref-bw

no auto-cost reference-bandwidth

Syntax Description

reference-bandwidth ref-bw

Rate in megabits per second (bandwidth). The range is 1 to 4294967;
the default is 100.

Defaults

100 megabits per second

Command Modes

Router configuration

Command History

Release
Modification

11.2

This command was introduced.

Usage Guidelines

In Cisco IOS Release 10.3 and later, by default OSPF will calculate
the OSPF metric for an interface according to the bandwidth of the
interface. For example, a 64K link will get a metric of 1562, and a T1
link will have a metric of 64.

The OSPF metric is calculated as ref-bw divided by bandwidth, with
ref-bw equal to 108 by default, and bandwidth determined by the
bandwidth command. The calculation gives FDDI a metric of 1.

If you have multiple links with high bandwidth (such as FDDI or ATM),
you might want to use a larger number to differentiate the cost on
those links.

The value set by the ip ospf cost command overrides the cost resulting
from the auto-cost command.

Examples

The following example changes the cost of the FDDI link to 10, while
the gigabit Ethernet link remains at a cost of 1. Thus, the link costs
are differentiated.

router ospf 1

 auto-cost reference-bandwidth 1000
http://www.cisco.com/en/US/docs/ios/12_0/np1/command/reference/1rospf.html#wp1030598

Thanking You

Yours Sincerely

Divin Mathew John
divinjohn_at_gmail.com
divin_at_dide3d.com
+91 9945430983
+91 9846697191
+974 5008916
PGP PUBLIC KEY BLOCK @ http://www.dide3d.com/divin_Public_PGP_key.txt

On Sun, Apr 5, 2009 at 3:13 AM, Shine Dodo <shinejoseph_at_dodo.com.au> wrote:
>
> Wouter, I agree that your method is correct and the correct value to be
> configured is 5000. But the original poster had a value of 5,000,000 instead
> of 5,000,000,000 and this is incorrect.
>
> Cheers,
> Shine
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> Wouter Prins
> Sent: Saturday, 4 April 2009 7:56 PM
> To: ftt
> Cc: ccielab_at_groupstudy.com
> Subject: Re: HELP!!!!! auto-cost reference-bandwidth
>
> The auto-cost reference should be specified in M. So your answer is fine
> when you do the math, but the configuration is different.
>
> The math:
>
> Metric = Reference/BW of interface
> 5 = Reference/1000000000
> Reference = 5000000000
>
> To get to the M value: 5000000000/10^6 = 5000
>
> 2009/4/4 ftt <femi0802_at_googlemail.com>
>
> > Question => What value should you enter for the ref-bw parameter in the
> > auto-cost command to configure a 1gig link to be a cost of 5 ?
> >
> > My answer is 5000000
> >
> > But solution says 5000
> >
> > Can you help explain this?
> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
> >
> >
> >
> >
> >
> >
> >
> >
>
>
> --
> Wouter Prins
> wp_at_null0.nl
> 0x301FA912
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Sun Apr 05 2009 - 08:04:41 ART