From: Nick Shah (nshah@connect.com.au)
Date: Sat Sep 14 2002 - 20:24:28 GMT-3
Dan, Further to what you have already said...
* Prior to 12.0 the behaviour of summary address was flaky (or loosely
defined).
* For VLSM/FLSM redistribution scenarios involving OSPF, always be sure that
the 2 ways of summarization are :
Area range
Summary address
This is common knowledge, however their application is sometimes confused.
If you have a single ospf area (that means the router is not an ABR)
bordering with the FLSM protocol, then you cant really generate the 'area
range', you can generate onthe ABR, but that 'summarised route' will not be
injected on this 'internal area router'. So the 'trick' will be to somehow
create an ABR on this router, how do you do that ? eg. you can create a
loopback and assign it to some other area, and then you can create the
summary. That will work
The other way to create a sumarry (using summary address) and make it work
is to learn a subnet 'of the network that you want to summarise' from other
means (redistribution). So for eg. you want to inject 150.1.1.0/25
summarised to 150.1.1.0/24, then create a loopback and redistribute it into
the OSPF area, then you can create a summary. That summary can now be safely
injected into IGRP/RIP.
Then there is area 0 range, that behaviour is also slightly flaky. The idea
is that all 'area ranges' are created for inserting into the backbone (and
thru the backbone to another areas). Since area 0 is the backbone, you
shouldnt ideally need to create 'area 0 range' . Depending on the IOS
flavour you can create an area 0 range ( I have seen it working of most of
12.1 trains)
However once again in doing this, you 'must' remember that for using area
range, the router has to be an ABR, and for usign summary address, the
router has to be ASBR (However, for 'summary address', atleast one subnet
has to be learnt from redistribution).
There are a couple other non-standard ways besides this, but they are
outside the scope of discussion.
rgds
Nick
----- Original Message -----
From: Daniel Garrity <ccie@garrityfamily.com>
To: <ccielab@groupstudy.com>
Sent: Sunday, September 15, 2002 7:14 AM
Subject: RE: OSPF summary-address and redistribution
> I have run into this exact problem. All documentation states that the
> command summary-address is used to summarize networks
> that are redistributed into OSPF. But, I have also seen labs where it is
> used to summarize OSPF networks before their redistribution into FLSM
> routing protocols (IGRP and RIP). Fatkid Redistribution 501 and Case
> Study #3 from Cisco CCIE Lab Practice Kit (Satterlee and Hutnik) are
> prime examples. Both use the summary-address to summarize a network
> before redistribution into IGRP. Both examples are using IOS version
> 11.2. My lab is setup with IOS version 12.1 (15) and when I attempted
> these labs both would not work using the summary-address command. I had
> to use the area range command instead for the route to be redistributed
> into IGRP.
>
> In looking at the routing tables from the fatkid lab, provided by
> fatkid. I noticed that his summarized network were showing up as a
> summary entry in his table. On version 12.1, no such summary was
> present.
>
> To see if somehow the function of this command had changed, I reload my
> ASBR router with IOS version 11.2 and checked the routing table. Sure
> enough I now showed the summary route in the routing table. Also the
> routes were now showing up in my IGRP table as well.
>
> Somehow the function of this command has be changed to just allow
> summarization into OSPF, instead of bi-directional summarization. Again,
> all documentation states that the command summary-address is used to
> summarize networks
> that are redistributed into OSPF. So it looks like Cisco might have
> adjusted the function of this to match it's original intent.
>
>
> This is just conjecture on my part. If anyone has more concrete
> information please help.
>
> Dan Garrity
>
>
>
>
> Copies of my show run and routing table are included.
>
>
> The networks in question for this lab (fatkid 501) are 170.10.1.0 and
> 170.10.13.0.
>
>
>
>
> NOTE: R4 is my ASBR and R1 is my IGRP backbone.
>
> R4#wr t
> Building configuration...
>
> Current configuration : 2082 bytes
> !
> version 12.1
> no service single-slot-reload-enable
> service timestamps debug uptime
> service timestamps log uptime
> no service password-encryption
> !
> hostname R4
> !
> !
> !
> !
> !
> !
> ip subnet-zero
> ip tcp synwait-time 5
> no ip domain-lookup
> !
> !
> !
> !
> interface Loopback0
> ip address 170.10.4.1 255.255.255.0
> ip ospf network point-to-point
> !
> interface Ethernet0
> ip address 170.10.13.4 255.255.255.192
> !
> interface Serial0
> ip address 170.10.30.4 255.255.255.0
> no fair-queue
> !
> interface Serial1
> ip address 192.19.15.4 255.255.255.0
> clockrate 64000
> !
> interface TokenRing0
> ip address 170.10.20.4 255.255.255.0
> ring-speed 16
> !
> router ospf 69
> log-adjacency-changes
> area 2 virtual-link 170.10.5.1
> summary-address 170.10.1.0 255.255.255.0
> summary-address 170.10.13.0 255.255.255.0
> redistribute rip subnets
> redistribute igrp 69 subnets
> network 170.10.4.0 0.0.0.255 area 3
> network 170.10.13.0 0.0.0.63 area 2
> distribute-list disout out
> !
> router rip
> redistribute ospf 69
> redistribute igrp 69
> passive-interface Ethernet0
> passive-interface Loopback0
> passive-interface Serial0
> passive-interface Serial1
> network 170.10.0.0
> default-metric 3
> !
> router igrp 69
> redistribute ospf 69
> redistribute rip metric 1 10 125 125 1500
> passive-interface Ethernet0
> passive-interface Loopback0
> passive-interface Serial1
> passive-interface TokenRing0
> network 170.10.0.0
> default-metric 64 3 255 1 1500
> !
> ip classless
> ip http server
> !
> !
> ip access-list standard disout
> route-map disout deny 10
> match route-type external
> !
> !
> alias exec r show ip route
> alias exec xr show ipx route
> alias exec c show running-config
> alias exec i show ip int brief
> alias exec xi show ipx int brief
> alias exec o show ip ospf
> alias exec t config term
> alias exec b show ip bgp
> alias exec e show ip eigrp
> alias exec xe show ipx eigrp
> !
> line con 0
> exec-timeout 0 0
> privilege level 15
> logging synchronous
> length 42
> line aux 0
> privilege level 15
> line vty 0 4
> exec-timeout 0 0
> privilege level 15
> logging synchronous
> no login
> length 42
> !
> end
>
> R4#show ip route
> Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> 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, ia - IS-IS
> inter area
> * - candidate default, U - per-user static route, o - ODR
> P - periodic downloaded static route
>
> Gateway of last resort is not set
>
> 170.10.0.0/16 is variably subnetted, 11 subnets, 3 masks
> R 170.10.40.0/24 [120/1] via 170.10.20.3, 00:00:16, TokenRing0
> O 170.10.1.0/28 [110/74] via 170.10.13.5, 00:03:02, Ethernet0
> O E2 170.10.2.0/24 [110/20] via 170.10.13.5, 00:03:02, Ethernet0
> R 170.10.3.0/24 [120/1] via 170.10.20.3, 00:00:16, TokenRing0
> C 170.10.4.0/24 is directly connected, Loopback0
> O 170.10.5.0/24 [110/11] via 170.10.13.5, 00:03:02, Ethernet0
> O E2 170.10.12.0/24 [110/20] via 170.10.13.5, 00:03:03, Ethernet0
> C 170.10.13.0/26 is directly connected, Ethernet0
> C 170.10.20.0/24 is directly connected, TokenRing0
> I 170.10.21.0/24 [100/8976] via 170.10.30.1, 00:01:07, Serial0
> C 170.10.30.0/24 is directly connected, Serial0
> C 192.19.15.0/24 is directly connected, Serial1
> R4#
>
>
> R1#
> R1#show ip route
> Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> 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, ia - IS-IS
> inter area
> * - candidate default, U - per-user static route, o - ODR
> P - periodic downloaded static route
>
> Gateway of last resort is not set
>
> 170.10.0.0/24 is subnetted, 10 subnets
> I 170.10.40.0 [100/10002010] via 170.10.30.4, 00:00:22, Serial3
> I 170.10.2.0 [100/158253] via 170.10.30.4, 00:00:22, Serial3
> I 170.10.3.0 [100/10002010] via 170.10.30.4, 00:00:22, Serial3
> I 170.10.4.0 [100/89456] via 170.10.30.4, 00:00:22, Serial3
> I 170.10.5.0 [100/158253] via 170.10.30.4, 00:00:22, Serial3
> I 170.10.12.0 [100/158253] via 170.10.30.4, 00:00:22, Serial3
> I 170.10.13.0 [100/10002010] via 170.10.30.4, 00:00:22, Serial3
> I 170.10.20.0 [100/89019] via 170.10.30.4, 00:00:23, Serial3
> C 170.10.21.0 is directly connected, Loopback0
> C 170.10.30.0 is directly connected, Serial3
> R1#
>
>
>
> With Version 11.2
>
>
> R4#
> R4#wr t
> Building configuration...
>
> Current configuration:
> !
> version 11.2
> service timestamps debug uptime
> service timestamps log uptime
> no service password-encryption
> no service udp-small-servers
> no service tcp-small-servers
> !
> hostname R4
> !
> !
> ip subnet-zero
> ip tcp synwait-time 5
> no ip domain-lookup
> !
> interface Loopback0
> ip address 170.10.4.1 255.255.255.0
> !
> interface Ethernet0
> ip address 170.10.13.4 255.255.255.192
> !
> interface Serial0
> ip address 170.10.30.4 255.255.255.0
> no fair-queue
> !
> interface Serial1
> ip address 192.19.15.4 255.255.255.0
> clockrate 64000
> !
> interface TokenRing0
> ip address 170.10.20.4 255.255.255.0
> ring-speed 16
> !
> router ospf 69
> summary-address 170.10.1.0 255.255.255.0
> summary-address 170.10.13.0 255.255.255.0
> redistribute rip subnets
> redistribute igrp 69 subnets
> network 170.10.4.0 0.0.0.255 area 3
> network 170.10.13.0 0.0.0.63 area 2
> distribute-list disout out
> area 2 virtual-link 170.10.5.1
> !
> router rip
> redistribute ospf 69
> redistribute igrp 69
> passive-interface Ethernet0
> passive-interface Loopback0
> passive-interface Serial0
> passive-interface Serial1
> network 170.10.0.0
> default-metric 3
> !
> router igrp 69
> redistribute ospf 69
> redistribute rip metric 1 10 125 125 1500
> passive-interface Ethernet0
> passive-interface Loopback0
> passive-interface Serial1
> passive-interface TokenRing0
> network 170.10.0.0
> default-metric 64 3 255 1 1500
> !
> ip classless
> ip http server
> !
> ip access-list standard disout
> route-map disout deny 10
> match route-type external
> !
> !
> alias exec r show ip route
> alias exec xr show ipx route
> alias exec c show running-config
> alias exec i show ip int brief
> alias exec xi show ipx int brief
> alias exec o show ip ospf
> alias exec t config term
> alias exec b show ip bgp
> alias exec e show ip eigrp
> alias exec xe show ipx eigrp
> !
> line con 0
> exec-timeout 0 0
> privilege level 15
> logging synchronous
> length 42
> line aux 0
> privilege level 15
> line vty 0 4
> exec-timeout 0 0
> privilege level 15
> logging synchronous
> no login
> length 42
> !
> end
>
> R4#show ip route
> Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> 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
>
> 170.10.0.0/16 is variably subnetted, 13 subnets, 3 masks
> R 170.10.40.0/24 [120/1] via 170.10.20.3, 00:00:11, TokenRing0
> O 170.10.1.0/28 [110/74] via 170.10.13.5, 00:01:50, Ethernet0
> O 170.10.1.0/24 is a summary, 00:02:39, Null0
> O E2 170.10.2.0/24 [110/20] via 170.10.13.5, 00:01:50, Ethernet0
> R 170.10.3.0/24 [120/1] via 170.10.20.3, 00:00:11, TokenRing0
> C 170.10.4.0/24 is directly connected, Loopback0
> O 170.10.5.0/24 [110/11] via 170.10.13.5, 00:02:15, Ethernet0
> O E2 170.10.12.0/24 [110/20] via 170.10.13.5, 00:01:50, Ethernet0
> C 170.10.13.0/26 is directly connected, Ethernet0
> O 170.10.13.0/24 is a summary, 00:02:40, Null0
> C 170.10.20.0/24 is directly connected, TokenRing0
> I 170.10.21.0/24 [100/8976] via 170.10.30.1, 00:00:28, Serial0
> C 170.10.30.0/24 is directly connected, Serial0
> C 192.19.15.0/24 is directly connected, Serial1
> R4#
>
> R1#show ip route
> Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> 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, ia - IS-IS
> inter area
> * - candidate default, U - per-user static route, o - ODR
> P - periodic downloaded static route
>
> Gateway of last resort is not set
>
> 170.10.0.0/24 is subnetted, 11 subnets
> I 170.10.40.0 [100/10002010] via 170.10.30.4, 00:00:55, Serial3
> I 170.10.1.0 [100/158253] via 170.10.30.4, 00:00:55, Serial3
> I 170.10.2.0 [100/158253] via 170.10.30.4, 00:00:55, Serial3
> I 170.10.3.0 [100/10002010] via 170.10.30.4, 00:00:55, Serial3
> I 170.10.4.0 [100/89456] via 170.10.30.4, 00:00:55, Serial3
> I 170.10.5.0 [100/158253] via 170.10.30.4, 00:00:55, Serial3
> I 170.10.12.0 [100/158253] via 170.10.30.4, 00:00:55, Serial3
> I 170.10.13.0 [100/158253] via 170.10.30.4, 00:00:56, Serial3
> I 170.10.20.0 [100/89019] via 170.10.30.4, 00:00:56, Serial3
> C 170.10.21.0 is directly connected, Loopback0
> C 170.10.30.0 is directly connected, Serial3
> R1#
>
>
>
>
> -----Original Message-----
> From: Claudine DEMAR [mailto:lkcnet00@hotmail.com]
> Sent: Friday, September 13, 2002 5:14 AM
> To: ccielab@groupstudy.com
> Subject: OSPF summary-address and redistribution
>
>
> Hello,
>
> Quick a confirmation regarding the OSPF summary-address command.
> I've read everwhere that this command is only used to summarise networks
>
> that are redistributed into OSPF. Netherless, I could see some
> corrections(like the fatkid red501) where it seems that this command is
> used
> to summarise OSPF networks before their redistribution into another RP.
> Trying it imy lab, I can not make this work. Can anybody confirm that
> the
> summary address ONLY summarise networks that are redistributed into
> OSPF. If
> there are other use for this command, can you provide a good working
> example. Maybe there's something else to be configured to make it work
> ...
>
> Let me know.
> Many thanks,
>
> Claudine
>
>
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