From: Godswill Oletu (oletu@inbox.lv)
Date: Sat Jul 15 2006 - 11:55:03 ART
Andras,
The best path selection algorithm will look into the routing table to
determine which IGP route to use.
If the router in question received both RIP & OSPF routes for the same
destination, the RIP routes will not make it to its routing table because
the router will pick the OSPF route because of its more favored AD and that
is the route that the BGP selection algorithm will consider.
You can only compare metric among the same IGP, comparing metric among
different IGP is like comparing apples to orange. EG a metric of 20 to OSPF
is a very very good metric infact it is the default metric when you
redistribute into OSPF, but to RIP a metric of 20 do not only mean that, the
route is dead, it means that the route is DEAD LONG LONG TIME AGO!
Godswill Oletu
CCIE #16464
----- Original Message -----
From: "Kulcsar Andras Benjamin" <Kulcsar.Andras@kfki-lnx.hu>
To: "Cisco certification" <ccielab@groupstudy.com>
Sent: Saturday, July 15, 2006 10:31 AM
Subject: BGP Bestpath selection
> Hi everybody,
>
> Rule number 8 says: Prefer the path with the lowest IGP metric to the BGP
> next hop.
>
> What happens if the IGP metrics are not comparable? I mean the first
path's
> next hop is learned via OSPF, the other's is learned via RIP. Is simply
the
> numerically lowest metric chosen?
>
> Regards,
> Andras
>
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