From: Derek Small (Fuse) (dwsmall@xxxxxxxxxx)
Date: Fri Apr 21 2000 - 10:47:18 GMT-3
This is a typical limitation of FLSM routing protocols. With a subnet of
the 131.1.x.x network already attached to R22, you will not be able to teach
R22 about subnets with any masks besides the one R2 is already using. If I
assume your loopback addresses all have the form, x.x.x.1, then you can just
use area range statements on R1 to summarize these networks (actually you
would be making the advertisements more granular not summarizing) with an a
mask of /26 instead of /18. If these were real interfaces that supported
systems with addresses that covered the enter scope of the subnet you would
need to add subnets for each summary-subnet, ie.
area 1 range 131.1.64.0 255.255.255.192
area 1 range 131.1.64.64 255.255.255.192
area 1 range 131.1.64.128 255.255.255.192
area 1 range 131.1.64.192 255.255.255.192
area 1 range 131.1.65.0 255.255.255.192
area 1 range 131.1.65.64 255.255.255.192
area 1 range 131.1.65.128 255.255.255.192
area 1 range 131.1.65.192 255.255.255.192
.......
......
area 1 range 131.1.127.192 255.255.255.192
Obviously this would be a pain in the rear, but would be your only option.
Of course in the real world, you would convert the IGRP router to OSPF, or
add a static route, or just have enough foresight to avoid the situation
entirely through good addressing practices.
Thank You
Derek Small
dwsmall@fatkid.com
----- Original Message -----
From: LASSERRE Grégory <gregory.lasserre@arche.fr>
To: ccielab groupstudy <ccielab@groupstudy.com>
Sent: Friday, April 21, 2000 6:56 AM
Subject: Redisributing IGRP in OSPF (2)
>
> Hi everybody,
>
> regarding IGRP-> OSPF redistribution problem i configured the following
> network :
>
> R4500 --- Eth 131.1.1.192/26 --- R1 --- Serial 131.1.
> 1.128/26 --- R10 --- Eth 131.1.10.128/26 --- R22
>
> R4500 has 3 loopbacks : on networks
> - 131.1.64.0/18
> - 131.1.128.0/18
> - 131.1.192.0/18
>
> R4500 and R1 are in area 1
> R1 and R10 in area 0
> R1 is ABR
> R10 ASBR and provide mutual redistribution between OSPF and IGRP
> R22 routing protocol is only IGRP
>
> And here is the Problem : R22 is not able to reach the 3 loopback networks
> on R4500
>
> As you see, in this configuration, it's not possible to solve the problem
> by using :
> 1/ Area range on R1
> 2/ Secondary Address in /16 onR1, R10, and R22
> 3/ Neither Loopback, static routes, or ip default-network on R22
>
> So as for me, it seems that the only solution available is to configure a
> static route
> on R22 ("ip default network" or "ip route" commands)
>
> However i'm not really satisfied by this.
> Does anyone see another solution to solve this ?
>
> (i was thinking policy-routing or tunnelling could help. I will make some
> tests this week end).
>
> Cheers
> Greg.
>
> ------------------------------------------------------------------------
> Gregory LASSERRE Tel. : +33 1 69 18 98 53
> Network Engineer Fax : +33 1 69 28 55 01
> ARCHE Groupe SIEMENS Std : +33 1 69 18 32 32
> FRANCE
>
> E-mail : gregory.lasserre@arche.fr
> ------------------------------------------------------------------------
>
>
>
>
> ------------------------------------------------------------------------
> Gregory LASSERRE Tel. : +33 1 69 18 98 53
> Network Engineer Fax : +33 1 69 28 55 01
> ARCHE Groupe SIEMENS Std : +33 1 69 18 32 32
> FRANCE
>
> E-mail : gregory.lasserre@arche.fr
> ------------------------------------------------------------------------
>
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