Thanks much to Chuck, for your clarification!!!
Thomas N.
""Chuck Larrieu"" wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> as I suggested in my private note, there are two things to consider.
>
> thing 1 is how routes are put into routing tables.
>
> thing 2 is how forwarding decisions are made.
>
> forget the static route for a minute. suppose you had a router that was
> simultaneously running EIGRP and OSPF, or OSPF and RIPv2, or EIGRP and
> IS-IS. never mind the specifics, but if the router learns about a router
> 10.50.0.0/16 via one of the protocols, and 10.48.0.0/12 from the other,
what
> happens, in terms of what is placed into the routing table?
>
> one must separate the routing table from the processes that place routes
> into routing tables.
>
> in the case you state, yes indeed the router "believes" there are two
> networks out there. same as it would if you were to place two static
> routes - 10.50.1.1/32 and 10.50.0.0/16 Perhaps we should say
"destinations"
> in order to be a bit more clear?
>
> In the case you present, the two networks are 10.48.0.0/12, which includes
> 10.48.0.1 through 10.63.255.254, and the 10.50.0.0/16, which includes
> 10.50.0.1 through 10.50.255.254
>
> if a packet arrives at the router interface, and the destination address
is
> 10.50.x.y, then so long as the routing table is intact, the forwarding
> choice will be the /16 network. If the 10.50.0.0/16 route has been
flushed,
> due to a failure, then that route will have been removed from the routing
> table, leaving the /12 net as the choice.
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
> Thomas N.
> Sent: Monday, September 10, 2001 10:20 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Question on routing [7:19083]
>
>
> Hi All,
>
> First, let me sorry for the inaccurate information in the puzzle. The
> static IP address 10.48.0.0 is with 12 bits subnet mask (255.240.0.0, NOT
> 255.224.0.0). I didn't have my subnet calculator last time. So, the
scope
> of IP address for 10.48.0.0/255.240.0.0 will include 10.48.0.0 to
> 10.63.255.255.
>
> Well, for more specific information, I am setting up a lab in which routes
> are learning dynamically with EIGRP while having a static routing pointing
> for a dummy VPN boxes for redundancy. These VPN boxes only do static
> mapping for routes. If the primary link between the two hub sites
(learning
> through EIGRP) got killed, the first hub site is supposed to route its
> spokes and its subnets to reach the other hub and other spokes with static
> routes. However, instead of putting a bundle of static routes, I decided
to
> use summaried routes (10.48.0.0/255.240.0.0) to cover. Thing is not that
> simple. The router might think 10.48.0.0/12 and 10.50.0.0/16 as two
> separate networks. If following the "more specific rule", the 10.50.0.0
> network should act as the primary even it has administrative distance of
90.
> So the 10.48.0.0/12 should be ignored even it has an administrative
distance
> of 1. In this case, I don't even need the floating static route (make a
> static route with admin. distance greater than 90), in order to make the
> static route as the secondary route for backup. Should my analyze
correct?
> I might setup the lab and see what the routers will act. However, I would
> like to test my theory and analyzing... Please give me your thought!
> Thanks!
>
> Thomas N.
>
>
> ""David Goddard"" wrote in message
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > Thomas,
> >
> > This question has a lot of strange inaccuracies in it, but here we go...
> >
> > 1. The routing path chosen will always use the "longest match rule", in
> > other words between 10.50.0.0/16 and 10.32.0.0/12 the route chosen will
be
> > the 10.50.0.0/16.
> >
> > 2. Your mask is bad for the static route... if you want routes 10.32.0.0
> to
> > 10.63.0.0 to be included, the static route would read:
> >
> > ip route 10.32.0.0 255.224.0.0 serial 1
> >
> > 3. Enabling eigrp requires the command ROUTER EIGRP 200, not just EIGRP
> 200
> >
> > 4. When you add the network statements
> > network 172.16.1.0
> > network 172.16.2.0
> > to your EIGRP process, it will come out simply as
> > network 172.16.0.0
> > and enable the EIGRP process on both Serial 0 and Serial 1 of both
> routers.
> > So although you may think that you didn't put in the network statement
on
> > router A for 172.16.2.0, it will still enable EIGRP on Serial 1. So when
> > Serial 0 goes down, routing will still continue over Serial 1.
> >
> > Try testing your configs out in a lab and you'll see pretty quickly what
I
> > mean.
> >
> > Dave
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=19382&t=19083
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