02-26-2009 02:24 AM - edited 03-06-2019 04:15 AM
Hi...
I have 3 devices-A,B,C.
A&B are already running ospf.C is to be enabled with ospf.Herein i'am little confused with redistribution being done on A and the configs.
Attached are the existing configs of all 3 devices with important information.
Also,i am not sure..y only 4 routes are tagged in device A and redistributed to ospf.
Device B has a FastEthernet0/0/1 which has to put in ospf along with the respective/correct interface from Dev C.
Would it be ok if i jst put fa1/0/1 on Dev C and fa0/0/1 on dev B to a new ospf area or will i require any further redistribution or filtering.
Please help me get the correct config for deviceC.
Pls reply asap.Thanks!
Solved! Go to Solution.
03-01-2009 07:55 AM
02-26-2009 02:40 AM
Hi
You are right, you will need to put fa1/0/1 into the OSPF process on Dev C and Fa0/0/1 on Dev B. This will form an OSPF adjacency will will start to pass routing updates.
As you already have a static route on Dev A and B for 10.96.0.0 /16, you don't have to add that network to OSPF on Dev C ( unless you want to, then you can remove the static routes).
Also, on Dev A, A better/tidier way of advertising default is with the default-information originate instead of the command :-
network 0.0.0.0 255.255.255.255 area 0 statement
02-26-2009 03:00 AM
thanks for replyin..so jst gettin ospf enabled on C like:
router ospf 58
network 10.96.0.2 area 100
& network 10.96.0.1 area 100(on B)
would suffice here..no need to worry abt anything further to be redistributed/filtered on C?
also, dev B has this route ip route 10.16.0.0 255.255.0.0 10.16.1.30, den why is dev A again redistributing it in ospf with tag.
ip route 10.16.0.0 255.255.0.0 10.16.1.58 tag 43
wouldnt it cause confusion as to which route is better?
02-26-2009 03:15 AM
I not sure why you have so many area's unless you plan to summarize.
Dev B
router ospf 58
network 10.96.0.0 0.0.0.3 area 100
Dev C config
router ospf 58
network 10.96.0.0 0.0.0.3 area 100
( and if you want network 10.96.40.9 )
network 10.96.40.0 0.0.0.255 area 100
(I have chosen a 0.0.0.255 as I don't know your subnet mask for the network)
I cannot tell you if filtering and redistribution is needed as you have not said what you need to happen, ie You don't want network x to make it to router x or I need to make sure network x does get to router x.
If looks like you have multiple exit points for 10.16.0.0 /16, so you need to decide which you want to use as primary and adjust accordingly, as of now it's a closest wins situation.
The static routes will beat the OSPF learned routes as the prefix is the same but the AD's will be different ( static is 1 OSPF is 110).
02-27-2009 08:05 AM
Thanks for your reply.what if we need to have the Dev C also come under backbone area 0.How will be the config for this case.Since Dev C at present doesnt have anyother link coming to it except the one directly from Router B.Router B is hooked to Dev A.Pls suggest?
02-27-2009 08:12 AM
Your right, I got so caught up with why you need multi areas I forgot about Area 0. You will need to virtaul Link from Dev C into Dev A for this to work, or if you do not need multiple areas, (which in a network your size you dont), then I would collapse all the routers into area 0.
Let me know if you need help setting it up, here is a link for you to read
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801ec9ee.shtml')">http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801ec9ee.shtml
02-27-2009 08:32 AM
because from what i understand, in future if any additional segment is connected to Dev C..it must be fused together n accessible.currently its only link is via B.Pls do help in setting this up, if u can.
Could it have any issues on operation of Dev A due to any route looping or other probs if we are pull dev C also to backbone area.
also..would it mean that all 3 routers would only run area 0.
thanks in advance!
02-27-2009 08:36 AM
I would recommend putting all the routers in area 0 as virtual links will bring more complexity than you need with a 3 router setup.
If you do want/have to use virtual links I will happily give you an example config using your setup.
02-27-2009 08:43 AM
that would be really helpful...
there are some other devices which are currently not running ospf but are connected via provider links to the Dev A,which i guess would be later on made to run ospf.
02-28-2009 08:03 AM
Hi
I will need to put this into a lab so I will need your complete configs (minus sensitive IP's and passwords), or I can build a similar network with bogus IP's, which would you prefer.
02-28-2009 09:16 AM
no worries...you can use the same ones as mine..jst want this config seen.Will b waiting for your reply..
also am i correct if i say that this should need a virtual link?
Thanks buddy..
02-28-2009 01:56 PM
Hi
I must be suffering from a lack of sleep, we don't need a virtual link at all as area 0 already extends to Dev B all we need to do is put the interface that connects Dev_B to Dev C into area 0 and bam, all done
Dev B
router ospf 58
network 10.96.0.0 0.0.0.3 area 0
Dev C config
router ospf 58
network 10.96.0.0 0.0.0.3 area 0
( and if you want network 10.96.40.9 )
network 10.96.40.0 0.0.0.255 area 0
(I have chosen a 0.0.0.255 as I don't know your subnet mask for the network)
Also, check you have the interface that connects Dev A - B in area 0 as well.
Sorry to mess you around :-s
Just in case you are intrested, here is a nice link to a simple Virtual Link config example
hxxp://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801ec9ee.shtml
03-01-2009 06:17 AM
03-01-2009 07:55 AM
Hi mate
Paste your config in for the 2 devices.
03-04-2009 12:14 AM
hey thanks!it was a gateway config probs..its solved..
thanks for your help with both cases!
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