Chuck,
Null 0 creation is not automatic for OSPF, you must manually enter it.
Question #2, isn't the creation of the route to null 0 established behaviour
> on Cisco routers when summarization is invoked, no matter what the
protocol
> involved?
----- Original Message -----
From: "Chuck Larrieu" <[EMAIL PROTECTED]>
To: "Nigel Taylor" <[EMAIL PROTECTED]>; "Cisco Group Study"
<[EMAIL PROTECTED]>; "CCIE_Lab Group Study" <[EMAIL PROTECTED]>
Sent: Wednesday, January 10, 2001 12:28 PM
Subject: RE: ISIS and OSPF redistribution Weirdness - Update
> Nigel, question #1, can you ping from domain to domain? Particularly from
> IS-IS to OSPF?
>
> Question #2, isn't the creation of the route to null 0 established
behaviour
> on Cisco routers when summarization is invoked, no matter what the
protocol
> involved?
>
> I was planning on doing a couple of the Slattery exercises later this
week.
> I like your idea of substituting IS-IS in there. When I have completed the
> exercises, I will try what you did and report back. I do wish Mentor
allowed
> the saving of multiple sets of configurations from their pods. I use the 6
> router open lab for the complex scenarios, but can only save a singe set
of
> configs. So I have to choose wisely.
>
> Chuck
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of
> Nigel Taylor
> Sent: Wednesday, January 10, 2001 4:26 AM
> To: Cisco Group Study; CCIE_Lab Group Study
> Subject: ISIS and OSPF redistribution Weirdness - Update
>
> Hi All,
> I was working with redistribution between OSPF and IS-IS domains and got =
> this=20
> route in the table and wondered if anyone have seen this and could =
> explain. I'm=20
> using the example from Slattery/Burton pg. 297 (ex. #10). I've replace =
> the EIGRP=20
> process with Isis and in summarizing the ospf routes into isis I get the =
> following=20
> route in the RIB of the router doing the redistribution/summarization...
>
> Relevant configs...on the router performing redistribution.
>
> !
> router ospf 200
> log-adjacency-changes
> summary-address 182.18.0.0 255.255.0.0
> redistribute isis metric 300 metric-type 1 subnets
> network 172.16.253.4 0.0.0.3 area 0
> network 172.16.254.0 0.0.0.255 area 0
> distribute-list 4 out
> !
> router isis=20
> summary-address 172.16.0.0 255.255.0.0 =20
> redistribute ospf 200 =20
> net 48.0001.0000.0000.0001.00
>
>
>
> r2_01#sh ip ro
> 172.16.0.0/16 is variably subnetted, 9 subnets, 5 masks
> O IA 172.16.2.252/30 [110/139] via 172.16.254.1, 02:35:35, Ethernet0
> C 172.16.254.0/24 is directly connected, Ethernet0
> C 172.16.253.4/30 is directly connected, Loopback0
> O 172.16.253.9/32 [110/11] via 172.16.254.1, 02:35:35, Ethernet0
> O IA 172.16.2.32/27 [110/144] via 172.16.254.1, 02:35:35, Ethernet0
> O IA 172.16.2.4/30 [110/202] via 172.16.254.1, 02:35:35, Ethernet0
> i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0
> O IA 172.16.1.0/24 [110/74] via 172.16.254.1, 02:35:36, Ethernet0
> O IA 172.16.2.0/24 [110/138] via 172.16.254.1, 02:35:36, Ethernet0
> 182.18.0.0/16 is variably subnetted, 6 subnets, 2 masks
> i L1 182.18.4.0/24 [115/20] via 182.18.1.1, Serial1
> i L1 182.18.5.0/24 [115/20] via 182.18.2.2, Serial0
> O 182.18.0.0/16 is a summary, 02:21:02, Null0
> C 182.18.1.0/24 is directly connected, Serial1
> C 182.18.2.0/24 is directly connected, Serial0
> i L1 182.18.3.0/24 [115/20] via 182.18.2.2, Serial0
> [115/20] via 182.18.1.1, Serial1
>
>
> Connected ISIS router which sees the summarized route...
>
> r4_02c#sh ip ro
> Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area=20
> N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
> U - per-user static route, o - ODR
>
> Gateway of last resort is not set
>
> i L2 172.16.0.0/16 [115/40] via 182.18.1.2, Serial0
> 182.18.0.0/16 is variably subnetted, 6 subnets, 2 masks
> C 182.18.4.0/24 is directly connected, TokenRing0
> i L1 182.18.5.0/24 [115/20] via 182.18.3.1, Serial1
> i L2 182.18.0.0/16 [115/40] via 182.18.1.2, Serial0
> C 182.18.1.0/24 is directly connected, Serial0
> i L1 182.18.2.0/24 [115/20] via 182.18.3.1, Serial1
> [115/20] via 182.18.1.2, Serial0
> C 182.18.3.0/24 is directly connected, Serial
>
>
>
> i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0
>
> I'm thinking that this route is being suppressed but on the connected =
> isis=20
> routers within it's routing domain I get this summarized route to the =
> ospf networks.=20
> What does the "su" represent in the table. And if this is being =
> suppressed why is=20
> it showing up in the RIB at all. I know BGP allows the suppression of =
> routes and=20
> was unaware that IGP's did this as well. Is this only specific to =
> isis..?
> Has anyone encountered this and knows what it means. Off to check the =
> RFC's.
> =20
> Nigel..
>
>
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