From: Oliver Ziltener (ziltener@netcloud.ch)
Date: Tue May 20 2003 - 18:10:07 GMT-3
To solve the problem, I have to set on every router (R2, R4, R5, R6) within
the same area the summary-address 192.168.100.0 255.255.255.240 and then get
R1 only the summary route!
thanks
Oliver
-----Urspr|ngliche Nachricht-----
Von: Adam Asay [mailto:aasay@cerberian.com]
Gesendet: Dienstag, 20. Mai 2003 21:36
An: Oliver Ziltener
Betreff: Re: Help: ISIS summarisation
I am sorry Oliver, I miss understood your problem. I see the
summarization problem you are talking about now. Would you mind sending
me all of the configurations for routers 1 and 2?
Thanks
Adam
On Tue, 2003-05-20 at 11:30, Adam Asay wrote:
> Oliver,
>
> Whenever a router is performing route summarization the routing table
> will show the summarized route, and the more specific routes in the
> routing table.
>
> The specific routes will be shown in the routing table because they are
> directly connected, and not being learned via the routing protocol you
> are using.
>
> You will also see the summarized route with a next hop of null 0. This
> is OK. Since you are summarizing the routes your routing table should
> always contain the more specific routes, and will make the routing
> decision based on the specific routes. Also if there are other networks
> that your router is not aware it gives the router a chance to drop any
> packets destined for these addresses. For example in your topology if
> router 4 tried to send a packet to 172.16.5.1, it would think this route
> is available via R1. When the packet reaches R1 it will go ahead and
> drop it because it does not contain a route to this network.
>
> I hope this helps.
>
> Adam Asay
> Sr Systems Engineer
> www.cerberian.com
>
>
> On Tue, 2003-05-20 at 09:55, Oliver Ziltener wrote:
> > I have this setup:
> >
> >
> > R1 ----- R2 ----- R5/R6/R4
> >
> >
> > R1 is in area 0001
> > R2,R4,R5,R6 in area 0100
> > Alle router are is-type L1/L2
> >
> > The links between R2 and R5/R6/R7 are FR p2p with a /30 mask.
> > On R1, I have 3 loopbacks.
> >
> > The summarisation of the loopbacks into Area 0100 works fine-i receive
only
> > the summary!
> > The summarisation of the p2p links into Area 0001 works as expected, I
got
> > the summary and the 3 more specific ones.
> >
> > Any idea why i get the more specific and the summary on R1??
> >
> > And second, I discoverd also, when i do "clear ip route " the Summary
null0
> > router will till the next reload not appear in the routing
table...?Bug???
> >
> > thanks
> > Oliver
> >
> > R1#
> > router isis
> > summary-address 172.16.0.0 255.255.252.0
> > passive-interface Loopback10
> > passive-interface Loopback11
> > passive-interface Loopback12
> > passive-interface Loopback13
> > net 49.0001.1111.1111.1111.00
> > log-adjacency-changes
> >
> > R1#
> > 172.16.0.0/16 is variably subnetted, 5 subnets, 2 masks
> > i su 172.16.0.0/22 [115/0] via 0.0.0.0, Null0
> > C 172.16.0.0/24 is directly connected, Loopback10
> > C 172.16.1.0/24 is directly connected, Loopback11
> > C 172.16.2.0/24 is directly connected, Loopback12
> > 192.168.100.0/24 is variably subnetted, 4 subnets, 2 masks
> > i L2 192.168.100.8/30 [115/30] via 192.168.200.2, Ethernet0/1 <<more
> > specific
> > i L2 192.168.100.4/30 [115/30] via 192.168.200.2, Ethernet0/1 <<more
> > specific
> > i L2 192.168.100.0/30 [115/30] via 192.168.200.2, Ethernet0/1 <<more
> > specific
> > i L2 192.168.100.0/28 [115/20] via 192.168.200.2, Ethernet0/1
> > <<<<<Summary!
> > R1#
> >
> >
> > R2#
> > router isis
> > summary-address 192.168.100.0 255.255.255.240
> > net 49.0100.2222.2222.2222.00
> > log-adjacency-changes
> >
> > R2#
> > 172.16.0.0/22 is subnetted, 1 subnets
> > i L2 172.16.0.0 [115/10] via 192.168.200.1, Ethernet0/0<<<only the
summary
> > C 192.168.100.8/30 is directly connected, Serial0/0.6
> > C 192.168.100.4/30 is directly connected, Serial0/0.5
> > i su 192.168.100.0/28 [115/10] via 0.0.0.0, Null0
> > C 192.168.100.0/30 is directly connected, Serial0/0.4
> > R2#
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