Administrative Distance and the longest-match rule apply to two separate
processes. Remember, there is a route installation process and a route
lookup process. AD matters only during the installation process.
When a router receives an update for the identical route from more than
one routing protocol, it uses AD to determine which to actually place
into the routing table. After this point, AD is irrelevant.
When the router is choosing a route for a specific destination then the
longest-match rule comes into play and the router will *always* choose
the route associated with the longest matching prefix in the table.
I hope that makes sense. I haven't finished my first cup of coffee so
I can't be held responsible for my ramblings. If that doesn't make
sense, let me know and I'll rephrase it.
Regards,
John
>>> "Wright, Jeremy" 8/22/01 8:17:08 AM >>>
So for example, if you have the following 10.1.1.0/28 OSPF
10.1.0.0/24 EIGRP
10.1.1.0/26 Static
Which route will be chosen? Thanks for the help.
-----Original Message-----
From: McCallum, Robert
[mailto:[EMAIL PROTECTED]]
Sent: Wednesday, August 22, 2001 8:32 AM
To: 'Wright, Jeremy'; [EMAIL PROTECTED]
Subject: RE: Quick CCIE Written Question
[7:16797]
In a nut shell yes and no. i.e.
Admin distance is the winner by means that the lower
the
admin distance the better, so a route learned from EIGRP will get into
the
routing table despite having a longer match route which was learned
from say
OSPF. BUT if you have two routes learned from the same admin distance
then
the longest
match ALWAYS wins.
Basically once the route is in the routing table then
the
longest match is the outmost winner.
-----Original Message-----
From: Wright, Jeremy [mailto:[EMAIL PROTECTED]]
Sent: 22 August 2001 14:19
To: [EMAIL PROTECTED]
Subject: Quick CCIE Written Question [7:16797]
Does the longest match rule always override
administrative
distance??
[EMAIL PROTECTED]
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=16809&t=16797
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