From: Daniel Garrity (ccie@garrityfamily.com)
Date: Thu Nov 21 2002 - 15:06:38 GMT-3
Richard,
I also did not see where they are coming up with bandwidth 2000 or OSPF
cost 50.
The pre-configs set R6's s1 interface to a clock of 64k. Based on a 64k
leased line the OSPF cost would be 156. So the bandwidth statement
should be set to 64.
If this link is supposed to represent a T1 line then, the OSPF cost
would need to be about 64. Bandwidth of 1540.
BUT, when you look at the final configs for R6, they set the clock rate
to 2000000. Based on that it fits with a bandwidth statement of 2000.
Seems to be a discrepancy in this lab.
Dan
-----Original Message-----
From: Richard Chung [mailto:richung@cisco.com]
Sent: Thursday, November 21, 2002 7:03 AM
To: Dotun Oni; ccielab@groupstudy.com
Subject: Re: Bootcamp lab2; OSPF cost
Dotun,
Thanks for the reply.
What I don't understand is why this question wants to get cost=50? I do
not
see any requirements for that.
At 02:31 AM 11/21/2002, Dotun Oni wrote:
>Richard,
>
>for 2-L:
>
>interface s1
>bandwidth 2000 ------------- OSPF will use a cost of 50 as follows:
>
>Remember that you need to convert 2000kpbs to bps in calculating cost.
>
>i.e.
>
>cost = 100,000,000/BW(in bps) = 100,000,000/(2000 x 1000) = 50
>
>the reverse goes for 2-P
>
>
>interface s0
>ip ospf cost 50 ----------reflects cost for a bandwidth of 2000kbps
>
>HTH
>
>
>D
>
>
>>From: Richard Chung <richung@cisco.com>
>>Reply-To: Richard Chung <richung@cisco.com>
>>To: ccielab@groupstudy.com
>>Subject: Bootcamp lab2; OSPF cost
>>Date: Wed, 20 Nov 2002 22:59:47 -0500
>>
>>Hi, all,
>>
>>Can somebody help me to understand the config for 2-L? - Configure R6
so
>>that S1 interface speed is correctly reflected in the OSPF metrics
>>without using the "ip ospf cost xxx" command.
>>
>>Another one. 2-P: Config R8 using the "ip ospf cost xxx" such that the
>>speed of the link for interface S0 is correctly reflected in the OSPF
metrics.
>>
>>I understand OSPF metric = 100,000,000/BW. But why it wants to get
cost=50?
>>
>>Thanks.
>
>
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