From: fwells12 (fwells12@xxxxxxxxxxx)
Date: Tue Jan 09 2001 - 01:17:03 GMT-3
I suspect those print-outs were from already running configs.
My understanding of the gist of the original question, was he was wondering
how the initial routes were inserted into the table at boot time etc.
Perhaps I misunderstood.
Keep up the good work Chuck.
----- Original Message -----
From: Chuck Larrieu <chuck@cl.cncdsl.com>
To: frank wells <fwells12@hotmail.com>; <ccielab@groupstudy.com>
Sent: Monday, January 08, 2001 6:35 PM
Subject: RE: routing table question
> I'm looking at the outputs of a number of show ip route commands in the
> Slattery/Burton book. I wish I could say that what I am seeing is logical,
> and unified. It's not. It seems to depend upon the routing protocol in
> questions, the address itself ( prefix length ) and such variables as
> metric. I see printed examples here of more specific routes appearing
before
> connected, or after.
>
> I don't have enough outputs in front of me to be certain, but it also
> appears that interface number may be a factor. For example, in some of the
> prints, the order "appears" to be loopback, ethernet, serial.
>
> Chuck
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> frank wells
> Sent: Monday, January 08, 2001 12:15 PM
> To: ccielab@groupstudy.com
> Subject: Re: routing table question
>
> The router puts all directly connected routes in first because it finds
> those quickest. It will then add the static routes followed by routes
> learned via a routing protocol. Routes are given an administrative
distance
> (weight) depending on the routing protocol they were learned from.
> Administrative Distance is used to choose the most trustworthy routing
> protocols' route over other less trustworthy routing protocols. See Later.
> What it advertises is a whole different discussion...
>
> When performing a route lookup, it uses the following ordered criterion to
> determine the best route to the destination network:
>
> 1 Host address
> 2 A subnet
> 3 A group of subnets (summary route etc)
> 4 A major network address
> 5 A group of major network addresses (supernet)
> 6 Default route or network etc
>
> For administrative distance, the route with the lowest weight will
> ordinarily be the one added to the route table:
>
> Table:
>
> Connected Interface 0
> Static Route 1
> Eigrp Summary Route 5
> External BGP 20
> Eigrp 90
> IGRP 100
> OSPF 110
> IS-IS 115
> RIP 120
> EGP 140
> External Eigrp 170
> Internal BGP 200
> Unknown 255
>
> Pick up a copy of Routing TCP/IP by Jeff Doyle. It rules.
>
>
>
>
> >From: David M Anderson <dma@cisco.com>
> >Reply-To: David M Anderson <dma@cisco.com>
> >To: ccielab@groupstudy.com
> >Subject: routing table question
> >Date: Mon, 08 Jan 2001 11:34:22 -0800
> >
> >I thought I would include a subject line this time...
> > >Date: Mon, 08 Jan 2001 11:32:27 -0800
> > >To: ccielab@groupstudy.com
> > >From: David M Anderson <dma@cisco.com>
> > >
> > >I have a real simple question that I just don't seem to see the answer
> >to. In which order are routes added to a routing table? I have tried to
> >see if it is metrics, routing protocol, order learned.....etc. It seems
to
> >be the order learned, but I am not sure about that. Can anyone clarify?
> > >
> > >Thanks,
> > >David
> >
> >David Anderson
> >Lab Engineer
> >(408) 853-5515
> >dma@cisco.com
> >
> > | |
> > :|: :|:
> > :|||: :|||:
> > .:|||||||:..:|||||||:.
> >C I S C O S Y S T E M S
> >
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