From: Arvind Yadav (arvindyadav@comcast.net)
Date: Mon Jan 26 2004 - 03:59:26 GMT-3
If the RIP router already has route to any subnet of major net then It will
ignore the routing update from other RIP router for that major net. That is
the default behavour of RIP v1.
As you apply the summary route on R2, It start ignore the update from R4
becuase now it has more specific route.
http://www.cisco.com/en/US/tech/tk364/tk871/technologies_tech_note09186a0080
093fd8.shtml
Arvind
----- Original Message -----
From: "Joe Chang" <changjoe@earthlink.net>
To: "SANCHEZ-MONGE,ANTONIO (HP-France,ex2)" <antonio.sanchez-monge@hp.com>;
"'Hossam'" <sam6626@yahoo.com>
Cc: <ccielab@groupstudy.com>
Sent: Sunday, January 25, 2004 2:59 PM
Subject: Re: RIPv1 -RIP v2 and Summary to Null - Scenario!
> I don't have a lab at hand to test it out, but my guess is that you can
get
> both 10.0.0.0 routes to show up if you disable split horizon on the FR on
> R2. After all, R2 will try to advertise its static route to R4 as
> 10.0.0.0/8.
>
> ----- Original Message -----
> From: "SANCHEZ-MONGE,ANTONIO (HP-France,ex2)"
<antonio.sanchez-monge@hp.com>
> To: "'Hossam'" <sam6626@yahoo.com>
> Cc: <ccielab@groupstudy.com>
> Sent: Sunday, January 25, 2004 7:24 AM
> Subject: RE: RIPv1 -RIP v2 and Summary to Null - Scenario!
>
>
> > Hi Sam,
> >
> > Thanks for the post.
> >
> > The behaviour I have seen is:
> >
> > If a router receives a summary for a major network (10.0.0.0), and it
has
> > already more specific subnetworks directly connected, it will suppress
the
> > summary from the RIPv1 database.
> >
> > Try adding 10.2.4.1/32 as a loopback address in R2 and you will see the
> same
> > behaviour. Null0 is at the end a "virtual local interface" too.
> >
> > The idea behind this is: RIPv1 and classful routing protocols in general
> do
> > not support non-contiguous major networks.
> >
> > Cheers,
> > Ato.
> >
> >
> >
> > -----Original Message-----
> > From: Hossam [mailto:sam6626@yahoo.com]
> > Sent: domingo, 25 de enero de 2004 15:10
> > To: SANCHEZ-MONGE,ANTONIO (HP-France,ex2)
> > Cc: ccielab@groupstudy.com
> > Subject: RE: RIPv1 -RIP v2 and Summary to Null - Scenario!
> >
> >
> > Here you are Antonio,
> > The outputs you asked for at R2 are below ( before using "ip route
> 10.2.4.0
> > 255.255.252.0 null0") .
> >
> > Once i use the above command R2 installs the new to-null route, and the
> > "10.0.0.0" auto-summary learned form R4 starts to count to 180 seconds
> then
> > it goes to the hold and deleted later. See the show rip database below
> after
> > using the above command at the end of this message.
> >
> > This happens while R2 is still recieving the 10.0.0.0 route from R4. But
> for
> > some reason it does't update its database.
> >
> > I hope someone helps!!
> >
> > Note: I snapshot these outputs while both routers were using RIP ver1
> only.
> > No ver2 updates were inter send. But same happens with ver2 at R2 as i
> said
> > in my intial mail.
> >
> >
> > Thanks
> > SAM
> > _____________________________________________________
> > Router 2:
> > Router2#sh ip route
> > 172.16.0.0/16 is variably subnetted, 8 subnets, 5 masks
> > O IA 172.16.136.0/26 [110/782] via 172.16.32.1, 16:40:45,
Serial0/0.23
> > C 172.16.32.0/29 is directly connected, Serial0/0.23
> > O IA 172.16.35.0/30 [110/1562] via 172.16.23.3, 16:40:45,
Serial0/0.32
> > [110/1562] via 172.16.32.3, 16:40:45,
Serial0/0.23
> > O IA 172.16.31.0/30 [110/1562] via 172.16.32.1, 16:40:45,
Serial0/0.23
> > C 172.16.24.0/24 is directly connected, Serial0/0.24
> > C 172.16.23.0/24 is directly connected, Serial0/0.32
> > O E2 172.16.15.0/28 [110/20] via 172.16.32.1, 16:40:46, Serial0/0.23
> > C 172.16.2.0/24 is directly connecte d, Loopback10
> > O E2 192.168.26.0/24 [110/20] via 172.16.32.1, 16:40:46, Serial0/0.23
> > R 192.168.4.0/24 [120/1] via 172.16.24.4, 00:00:20, Serial0/0.24
> > O E2 192.168.5.0/24 [110/20] via 172.16.32.1, 16:40:46, Serial0/0.23
> > 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
> > R 10.0.0.0/8 [120/1] via 172.16.24.4, 00:00:21, Serial0/0.24
> > O E2 10.2.6.0/23 [110/20] via 172.16.32.1, 16:40:47, Serial0/0.23
> > O E2 192.168.6.0/24 [110/20] via 172.16.32.1, 16:40:47, Serial0/0.23
> > O E2 192.168.16.0/24 [110/20] via 172.16.32.1, 16:40:47, Serial0/0.23
> > O E2 192.168.1.0/24 [110/20] via 172.16.32.1, 16:40:47, Serial0/0.23
> > C 192.168.2.0/24 is directly connected, Loopback20
> > O E2 192.168.3.0/24 [110/20] via 172.16.23.3, 16:40:47, Serial0/0.32
> > [110/20] via 172.16.32.3, 16:40:47, Serial0/0.23
> > Router2#
> > Router2#
> > Router2#sh ip rip da
> > 0.0.0.0/0 auto-summary
> > 0.0.0.0/0 redistributed
> > [0] via 0.0.0.0,
> > 10.0.0.0/8 auto-summary
> > 10.0.0.0/8
> > [1] via 172.16.24.4, 00:00:07, Serial0/0.24
> > 10.2.6.0/23 directly connected, Serial0/0.23
> > 172.16.0.0/16 auto-summary
> > 172.16.2.0/24 directly connected, Loopback10
> > 172.16.15.0/28 redistributed
> > [12] via 192.168.1.1,
> > 172.16.23.0/24 directly connected, Serial0/0.32
> > 172.16.24.0/24 directly connected, Serial0/0.24
> > 172.16.31.0/30 redistributed
> > [12] via 192.168.1.1,
> > 172.16.32.0/29 directly connected, Serial0/0.23
> > 172.16.35.0/30 redistributed
> > [12] via 192.168.3.3,
> > [12] via 192.168.3.3,
> > 172.16.136.0/26 redistributed
> > [12] via 192.168.1.1,
> > 192.168.1.0/24 auto-summary
> > 192.168.1.0/24 redistributed
> > [12] via 192.168.1.1,
> > 192.168.3.0/24 auto-summary
> > 192.168.3.0/24 redistributed
> > [12] via 192.168.3.3,
> > [12] via 192.168.3.3,
> > 192.168.4.0/24 auto-summary
> > 192.168.4.0/24
> > [1] via 172.16.24.4, 00:00:09, Serial0/0.24
> > 192.168.5.0/24 auto-summary
> > 192.168.5.0/24 redistributed
> > [12] via 192.168.5.5,
> > 192.168.6.0/24 auto-summary
> > 192.168.6.0/24 redistributed
> > [12] via 192.168.26.6,
> > 192.168.16.0/24 auto-summary
> > 192.168.16.0/24 redistributed
> > [12] via 192.168.26.6,
> > 192.168.26.0/24 auto-summary
> > 192.168.26.0/24 redistributed
> > [12] via 192.168.26.6,
> > ______________________________________________________
> >
> > Router 4:
> > Router4#sh ip route
> >
> > 172.16.0.0/24 is subnetted, 3 subnets
> > C 172.16.24.0 is directly connected, Serial0/0
> > R 172.16.23.0 [120/1] via 172.16.24.2, 00:00:19, Serial0/0
> > R 172.16.2.0 [120/1] via 172.16.24.2, 00:00:19, Serial0/0
> > R 192.168.26.0/24 [120/12] via 172.16.24.2, 00:00:19, Serial0/0
> > C 192.168.4.0/24 is directly connected, Loopback10
> > R 192.168.5.0/24 [120/12] via 172.16.24.2, 00:00:19, Serial0/0
> > 10.0.0.0/22 is subnetted, 1 subnets
> > C 10.1.4.0 is directly connected, FastEthernet0/0
> > R 192.168.6.0/24 [120/12] via 172.16.24.2, 00:00:20, Serial0/0
> > R 192.168.16.0/24 [120/12] via 172.16.24.2, 00:00:20, Serial0/0
> > R 192.168.1.0/24 [120/12] via 172.16.24.2, 00:00:20, Serial0/0
> > R 192.168.3.0/24 [120/12] via 172.16.24.2, 00:00:20, Serial0/0
> > R* 0.0.0.0/0 [120/1] via 172.16.24.2, 00:00:06, Serial0/0
> >
> > Router4#Sh ip rip da
> > 0.0.0.0/0 auto-summary
> > 0.0.0.0/0
> > [1] via 172.16.24.2, 00:00:13, Serial0/0
> > 10.0.0.0/8 auto-summary
> > 10.1.4.0/22 directly connected, FastEthernet0/0
> > 172.16.0.0/16 auto-summary
> > 172.16.2.0/24
> > [1] via 172.16.24.2, 00:00:13, Serial0/0
> > 172.16.23.0/24
> > [1] via 172.16.24.2, 00:00:13, Serial0/0
> > 172.16.24.0/24 directly connected, Serial0/0
> > 192.168.1.0/24 auto-summary
> > 192.168.1.0/24
> > [12] via 172.16.24.2, 00:00:13, Serial0/0
> > 192.168.3.0/24 auto-summary
> > 192.168.3.0/24
> > [12] via 172.16.24.2, 00:00:13, Serial0/0
> > 192.168.4.0/24 auto-summary
> > 192.168.4.0/24 directly connected, Loopback10
> > 192.168.5.0/24 auto-summary
> > 192.168.5.0/24
> > [12] via 172.16.24.2, 00:00:13, Serial0/0
> > 192.168.6.0/24 auto-summary
> > 192.168.6.0/24
> > [12] via 172.16.24.2, 00:00:14, Serial0/0
> > 192.168.16.0/24 auto-summary
> > 192.168.16.0/24
> > [12] via 172.16.24.2, 00:00:14, Serial0/0
> > 192.168.26.0/24 auto-summary
> > 192.168.26.0/24
> > [12] via 172.16.24.2, 00:00:14, Serial0/0
> > Router4#
> > _________________________________________________________
> >
> > Router 2 after using the ip route command (part of the output to avoid
> > repetation)
> >
> > Router2(config)#do sh ip rip da
> > 0.0.0.0/0 auto-summary
> > 0.0.0.0/0 redistributed
> > [0] via 0.0.0.0,
> > 10.0.0.0/8 auto-summary
> > 10.0.0.0/8 is possibly down
> > 10.2.6.0/23 directly connected, Serial0/0.23
> > 172.16.0.0/16 auto-summary
> > 172.16.2.0/24 directly connected, Loopback10
> > 172.16.15.0/28 redistributed
> > [12] via 192.168.1.1,
> > 172.16.23.0/24 directly connected, Serial0/0.32
> > 172.16.24.0/24 directly connected, Serial0/0.24
> > 172.16.31.0/30 redistributed
> > [12] via 192.168.1.1,
> > 172.16.32.0/29 directly connected, Serial0/0.23
> > 172.16.35.0/30 redistributed
> >
> >
> > Thanks
> > SAM
> >
> >
> > From: "SANCHEZ-MONGE,ANTONIO (HP-France,ex2)"
> <antonio.sanchez-monge@hp.com>
> > Add to Address Book
> > To: "'Hossam'" <sam6626@yahoo.com>
> > Subject: RE: RIPv1 -RIP v2 and Summary to Null - Scenario!
> > Date: Sun, 25 Jan 2004 12:05:39 +0100
> >
> > Hi Hossam,
> > Could you post show ip route and show ip rip database for R2 and R4 in
> > the
> > list?
> > Cheers,
> > Ato.
> >
> > -----Original Message-----
> > From: Hossam [mailto:sam6626@yahoo.com]
> > Sent: domingo, 25 de enero de 2004 0:49
> > To: ccielab@groupstudy.com
> > Subject: RIPv1 -RIP v2 and Summary to Null - Scenario!
> >
> > Team,
> > Assume we have R4 and R2. R4 MUST run RIP v.1
> >
> > R4 is conneceted to the backbone via Ethernet with subnet 10.1.4.0/22.
> >
> > R2 is connected to the rest of the network form one side. And to R4
> > via a
> > FR link (with Split horizon on both sides.) from the other side.
> >
> > Diagram:
> >
> > ALL ROUTERS -- R2 --- FR --------R4 ---- BB1(10.1.4.4)
> >
> >
> > R2 is runnning Rv2 with "no auto summary". R2 is recieving v1 updates
> > from
> > R4. R2 is sending v1 and V2 updates to R4.
> >
> > Due to auto summary on R4, i am getting 10.0.0.0/8 in R2 RIP v.2
> > database.
> > Having this route on R2 is a must for the rest of the routers
> > (connected to
> > R2) to reach the backbone.
> >
> > For the scenario requirment i need to configure a static summary route
> > to
> > "10.2.4.0 255.255.252.0" to a null interface on R2.
> > Strangly, Once i configure this summary to null on R2, the classful
> > summary
> > of 10.0.0.0 learnt from R4 is deleted form R2 Routing table!!!
> > Using debug i know that R4 is still sending the 10.0.0.0 to R2. R2
> > Recieves
> > the route but it stops updating it database with it??
> > Does anyone know an explanation??
> > Note: Router 2 is runnig IOS 12.2
> > Thanks
> > SAM
> >
> >
> >
> >
> >
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> >
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