From: Peter van Oene (pvo@usermail.com)
Date: Thu Oct 31 2002 - 10:20:54 GMT-3
Since it is using both, it might simply be marking the first in the
list. I'd have to mess with it a bit to figure out if it actually marks
two paths in the bgp rib, but what you are seeing doesn' t seem that abnormal.
Pete
At 09:15 PM 10/30/2002 -0500, Stefan L. Dozier wrote:
>I'm working from Parkhurst's BGP-4 Command and Configuration
>Handbook, chapter 7 pages 114-117 with Figure 7-1 labbed up!
>
>I understand the "best-path algorithm" and that by default BGP
>only installs the best path in the ip routing table. I also
>understand the value of the maximum-paths command in that it
>allows up to six paths to the same dest to be installed in the
>ip routing table.
>
>On to the lab scenario!
>
>Initially config'd, the bgp table and ip routing table on
>RouterA displays expects results.
>
>RouterA#sh ip bgp
>BGP table version is 20, local router ID is 10.1.2.1
>Status codes: s suppressed, d damped, h history, * valid, > best, i -
>internal
>Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
>* 172.17.1.0/24 10.1.2.2 0 0 1 i
>*> 10.1.1.2 0 0 1 i
>
>RouterA#sh ip route bgp
> 172.17.0.0/24 is subnetted, 1 subnets
>B 172.17.1.0 [20/0] via 10.1.1.2, 00:10:00
>
>After the "maximum-paths 2" command was added to the bgp process
>on RouterA.
>
>RouterA#sh ip bgp
>BGP table version is 21, local router ID is 10.1.2.1
>Status codes: s suppressed, d damped, h history, * valid, > best, i -
>internal
>Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
>*> 172.17.1.0/24 10.1.2.2 0 0 1 i
>* 10.1.1.2 0 0 1 i
>RouterA#sh ip route bgp
> 172.17.0.0/24 is subnetted, 1 subnets
>B 172.17.1.0 [20/0] via 10.1.2.2, 00:01:38
> [20/0] via 10.1.1.2, 00:01:38
>
>While the ip routing table displays expected results, I can't
>find any information on why when I use the maximum-paths command
>it seems to break the best-path algorithm and chooses the path
>with the higher router-id as indicated above! And since Parkhurst
>didn't find it necessary to paste the bgp table after insertion
>of the maximum-paths command under the BGP process, I'm kinda
>suspicious! I am missing something here?
>
>Stefan
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