Re: OSPF Distance Command .!

#chris

thats exactly whts happening here.! but router-id plays an important role
here. and i am pretty sure the example would have a distance command like
this

distance 90 0.0.0.0 255.255.255.255 ACL_NAME

and ACL_NAME having which network A.D to alter.! in that case there's no
conflicts on which LSA. Which route. Which specific route. What i infer from
these are like in case OSPF does load balancing thru 2 or more paths then
the A.D of all routes to the particular destination in the same protocol
will be same no matter what...so in this case to prefer a route better than
the rest i think we gotta play with the metric.. and A.D normally is used to
Prefer a route in a ROUTING PROTOCOL than the OTHER PROTOCOL. for eg. you
have 20.1.1.0/24 in both EIGRP and RIP. want to use RIP routes to be there
in your routing table you play with A.D.
Thanking You

Yours Sincerely

Divin Mathew John
divinjohn_at_gmail.com
divin_at_dide3d.com
http://www.dide3d.com
+91 9945430983
+91 9846697191
+974 5008916
PGP PUBLIC KEY BLOCK @ http://www.dide3d.com/divin_Public_PGP_key.txt
Sent from Bangalore, KA, India

On Fri, May 22, 2009 at 7:33 PM, Divin Mathew John <divinjohn_at_gmail.com>wrote:

> @Paul
> I think you getting confused with the NSSA Type 7 to Type 5 Conversion at
> the ABR. in that case if you have more than one ABR then the Type 7 to type
> 5 conversion is done by the ABR having the highest router-id.
> Thanking You
>
> Yours Sincerely
>
> Divin Mathew John
> divinjohn_at_gmail.com
> divin_at_dide3d.com
> http://www.dide3d.com
> +91 9945430983
> +91 9846697191
> +974 5008916
> PGP PUBLIC KEY BLOCK @ http://www.dide3d.com/divin_Public_PGP_key.txt
> Sent from Bangalore, KA, India
>
> On Fri, May 22, 2009 at 7:05 PM, Paul Cosgrove <paul.cosgrove_at_gmail.com>wrote:
>
>> Hi Chris,
>>
>> Would be interested to see your scenario and ios version. External route
>> calculation is quite different to that of intra area routes. I can't think
>> how you would see the same thing if you have a similar topology (three
>> routers) and are changing the distance of a router in a similar position
>> (instead of matching against a third router reach via the p2m subnet). The
>> forwarding address should not be set on a p2m, and each router will have /32
>> for its neighbors. If I remember correctly (which I might not) you should
>> only have a single external LSA in that case, the one learned from the
>> router with the highest RID (assuming costs to the ASBR are equal).
>>
>> If the forwarding address were set you could certainly see something
>> similar, as you may have multiple paths to an address which is directly
>> connected to either spoke. Without that set I would have thought you would
>> only have one path, unless your topology involved more devices. Will have
>> to try it out, and then figure out what I've missed..... :-)
>>
>> Paul.
>>
>>
>>
>>
>> Chris Breece wrote:
>>
>>> Hey Paul,
>>>
>>> The scenario I saw these results was a point-to-multipoint frame
>>> network....
>>> no DR involved. The router was the hub and the two spokes were
>>> advertising
>>> an external E1 to the hub. The distance command using the router ID of
>>> one
>>> of the spokes, changed the AD for the route to both of the spokes.
>>>
>>> Chris
>>>
>>>
>>>
>>>
>>> On Fri, May 22, 2009 at 2:04 AM, Paul Cosgrove <paul.cosgrove_at_gmail.com
>>> >wrote:
>>>
>>>
>>>
>>>> This does not sound like a bug, just that your R1-R2 link is an OSPF
>>>> network type which has a DR elected. The DR acts as a pseudonode which
>>>> has
>>>> 0 cost connections to each of the routers on that subnet; so it is a
>>>> virtual
>>>> router located between R1 and R2. It is the DR pseudonode which is
>>>> advertising the link. When you apply your distance command it only has
>>>> an
>>>> effect if the router you match is advertising the subnet, i.e. if it is
>>>> the
>>>> DR. You have two equal cost paths to the pseudonode, so if your
>>>> distance
>>>> command matches the pseudonode, the AD of both will be changed.
>>>>
>>>> Hope this helps,
>>>>
>>>> Paul.
>>>>
>>>>
>>>> Divin Mathew John wrote:
>>>>
>>>>
>>>>
>>>>> This is wht i got in the end of the day.
>>>>>
>>>>> R1-----R0------R2 and there is a connection between R1 and R2. So R0
>>>>> has
>>>>> 2
>>>>> paths to that segment between R1 and R2.
>>>>> R1
>>>>> interface Loopback0
>>>>> ip address 100.100.0.100 255.255.255.0
>>>>> !
>>>>> interface Loopback1
>>>>> ip address 100.100.1.100 255.255.255.0
>>>>> !
>>>>> interface Loopback2
>>>>> ip address 100.100.2.100 255.255.255.0
>>>>> !
>>>>> interface Loopback3
>>>>> ip address 100.100.3.100 255.255.255.0
>>>>> !
>>>>> interface Serial0/0
>>>>> ip address 10.1.1.1 255.255.255.252
>>>>> serial restart-delay 0
>>>>> !
>>>>> interface Serial0/1
>>>>> ip address 20.1.1.1 255.255.255.252
>>>>> serial restart-delay 0
>>>>> !
>>>>> interface Serial0/2
>>>>> no ip address
>>>>> shutdown
>>>>> serial restart-delay 0
>>>>> !
>>>>> interface Serial0/3
>>>>> no ip address
>>>>> shutdown
>>>>> serial restart-delay 0
>>>>> !
>>>>> router ospf 1
>>>>> router-id 100.100.100.100
>>>>> log-adjacency-changes
>>>>> network 10.1.1.1 0.0.0.0 area 0
>>>>> network 20.1.1.1 0.0.0.0 area 0
>>>>> network 100.100.0.100 0.0.0.0 area 0
>>>>> network 100.100.1.100 0.0.0.0 area 0
>>>>> network 100.100.2.100 0.0.0.0 area 0
>>>>> network 100.100.3.100 0.0.0.0 area 0
>>>>> distance 90 22.22.22.22 0.0.0.0 SELECT_12.1.1.0_from_R1
>>>>> !
>>>>> ip http server
>>>>> ip forward-protocol nd
>>>>> !
>>>>> !
>>>>> !
>>>>> !
>>>>> ip access-list standard ONLY_R1_LOOPBACKS
>>>>> permit 1.1.0.0
>>>>> ip access-list standard SELECT_12.1.1.0_from_R1
>>>>> permit 12.1.1.0
>>>>> ip access-list standard SELECT_12.1.exit
>>>>> !
>>>>> !
>>>>> All router-id Hardcoded. all processes cleared. clear ip route * done.
>>>>>
>>>>>
>>>>> R0's Routing Table
>>>>> when R2's ROUTER-ID is lower than R1, A.D of the both the paths gets
>>>>> changed
>>>>> to the one configured on the Distance command.
>>>>> R0#sir
>>>>> Codes: C - connected, S - static, 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
>>>>> i - IS-IS, su - IS-IS summary, 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
>>>>>
>>>>> 1.0.0.0/24 is subnetted, 1 subnets
>>>>> O 1.1.0.0 [110/65] via 10.1.1.2, 00:02:07, Serial0/0
>>>>> 2.0.0.0/24 is subnetted, 1 subnets
>>>>> O 2.2.0.0 [110/65] via 20.1.1.2, 00:02:07, Serial0/1
>>>>> 100.0.0.0/24 is subnetted, 4 subnets
>>>>> C 100.100.0.0 is directly connected, Loopback0
>>>>> C 100.100.1.0 is directly connected, Loopback1
>>>>> C 100.100.2.0 is directly connected, Loopback2
>>>>> C 100.100.3.0 is directly connected, Loopback3
>>>>> 20.0.0.0/30 is subnetted, 1 subnets
>>>>> C 20.1.1.0 is directly connected, Serial0/1
>>>>> 10.0.0.0/30 is subnetted, 1 subnets
>>>>> C 10.1.1.0 is directly connected, Serial0/0
>>>>> 12.0.0.0/30 is subnetted, 1 subnets
>>>>> O 12.1.1.0 [90/128] via 20.1.1.2, 00:02:08, Serial0/1
>>>>> [90/128] via 10.1.1.2, 00:02:08, Serial0/0
>>>>>
>>>>> When R1's Router-ID is Lower than R2 and R1 hasnt reached the FULL
>>>>> state
>>>>> with R0. The route thru R2 is shown with A.D of 90(specified in the
>>>>> config.]
>>>>> R0#sir
>>>>> Codes: C - connected, S - static, 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
>>>>> i - IS-IS, su - IS-IS summary, 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
>>>>>
>>>>> 2.0.0.0/24 is subnetted, 1 subnets
>>>>> O 2.2.0.0 [110/65] via 20.1.1.2, 00:00:09, Serial0/1
>>>>> 100.0.0.0/24 is subnetted, 4 subnets
>>>>> C 100.100.0.0 is directly connected, Loopback0
>>>>> C 100.100.1.0 is directly connected, Loopback1
>>>>> C 100.100.2.0 is directly connected, Loopback2
>>>>> C 100.100.3.0 is directly connected, Loopback3
>>>>> 20.0.0.0/30 is subnetted, 1 subnets
>>>>> C 20.1.1.0 is directly connected, Serial0/1
>>>>> 10.0.0.0/30 is subnetted, 1 subnets
>>>>> C 10.1.1.0 is directly connected, Serial0/0
>>>>> 12.0.0.0/30 is subnetted, 1 subnets
>>>>> O 12.1.1.0 [90/128] via 20.1.1.2, 00:00:09, Serial0/1
>>>>>
>>>>> After R0 -- R1 FULL state
>>>>> R0#sir
>>>>> Codes: C - connected, S - static, 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
>>>>> i - IS-IS, su - IS-IS summary, 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
>>>>>
>>>>> 1.0.0.0/24 is subnetted, 1 subnets
>>>>> O 1.1.0.0 [110/65] via 10.1.1.2, 00:00:01, Serial0/0
>>>>> 2.0.0.0/24 is subnetted, 1 subnets
>>>>> O 2.2.0.0 [110/65] via 20.1.1.2, 00:00:01, Serial0/1
>>>>> 100.0.0.0/24 is subnetted, 4 subnets
>>>>> C 100.100.0.0 is directly connected, Loopback0
>>>>> C 100.100.1.0 is directly connected, Loopback1
>>>>> C 100.100.2.0 is directly connected, Loopback2
>>>>> C 100.100.3.0 is directly connected, Loopback3
>>>>> 20.0.0.0/30 is subnetted, 1 subnets
>>>>> C 20.1.1.0 is directly connected, Serial0/1
>>>>> 10.0.0.0/30 is subnetted, 1 subnets
>>>>> C 10.1.1.0 is directly connected, Serial0/0
>>>>> 12.0.0.0/30 is subnetted, 1 subnets
>>>>> O 12.1.1.0 [110/128] via 20.1.1.2, 00:00:02, Serial0/1
>>>>> [110/128] via 10.1.1.2, 00:00:02, Serial0/0
>>>>>
>>>>>
>>>>> I haven't beeen able to reason why this happens..? but it happens.! and
>>>>> "Say
>>>>> you have 2 paths to a destination network, then the A.D of the route
>>>>> thru
>>>>> the Nieghbour with the lowest Router-ID is applied to the other routes
>>>>> thru
>>>>> different nieghbors or paths" I have no idea why..!
>>>>>
>>>>> any ideas?
>>>>>
>>>>> when R
>>>>> Thanking You
>>>>>
>>>>> Yours Sincerely
>>>>>
>>>>> Divin Mathew John
>>>>> divinjohn_at_gmail.com
>>>>> divin_at_dide3d.com
>>>>> http://www.dide3d.com
>>>>> +91 9945430983
>>>>> +91 9846697191
>>>>> +974 5008916
>>>>> PGP PUBLIC KEY BLOCK @ http://www.dide3d.com/divin_Public_PGP_key.txt
>>>>> Sent from Bangalore, KA, India
>>>>>
>>>>> On Fri, May 22, 2009 at 5:52 AM, Chris Breece <cbreece1_at_gmail.com>
>>>>> wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> Hey Divin,
>>>>>>
>>>>>> I ran into this same thing on Wednesday. I tried to use the distance
>>>>>> command in the same fashion. I wanted to prefer some routes to go to
>>>>>> one
>>>>>> neighbor instead of another. I got the same results as you show below.
>>>>>> If
>>>>>> there was another available next-hop, it changed the AD for both
>>>>>> paths.
>>>>>>
>>>>>> I ended up doing "distance 255 1.1.1.1 0.0.0.0 Named_ACL". This
>>>>>> effectively
>>>>>> deleted one of the routes out of my routing table. In that scenario, I
>>>>>> lost
>>>>>> my redundant route... but it seemed to fit the requirements.
>>>>>>
>>>>>> I don't know that its a bug, but I can confirm another human being saw
>>>>>> the
>>>>>> same issue you did :P
>>>>>>
>>>>>> Chris
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Thu, May 21, 2009 at 4:13 PM, Divin Mathew John <
>>>>>> divinjohn_at_gmail.com
>>>>>>
>>>>>>
>>>>>>> wrote:
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> I have this problem. i am trying to change the A.D of a particular
>>>>>>> path
>>>>>>> in
>>>>>>> OSPF using distance command. My config is pasted below.
>>>>>>> Topology
>>>>>>>
>>>>>>> R0
>>>>>>> interface Loopback0
>>>>>>> ip address 100.100.0.100 255.255.255.0
>>>>>>> !
>>>>>>> interface Loopback1
>>>>>>> ip address 100.100.1.100 255.255.255.0
>>>>>>> !
>>>>>>> interface Loopback2
>>>>>>> ip address 100.100.2.100 255.255.255.0
>>>>>>> !
>>>>>>> interface Loopback3
>>>>>>> ip address 100.100.3.100 255.255.255.0
>>>>>>> !
>>>>>>> interface Serial0/0
>>>>>>> ip address 10.1.1.1 255.255.255.252
>>>>>>> serial restart-delay 0
>>>>>>> !
>>>>>>> interface Serial0/1
>>>>>>> ip address 20.1.1.1 255.255.255.252
>>>>>>> serial restart-delay 0
>>>>>>> !
>>>>>>>
>>>>>>> router ospf 1
>>>>>>> log-adjacency-changes
>>>>>>> network 10.1.1.1 0.0.0.0 area 0
>>>>>>> network 20.1.1.1 0.0.0.0 area 0
>>>>>>> network 100.100.0.100 0.0.0.0 area 0
>>>>>>> network 100.100.1.100 0.0.0.0 area 0
>>>>>>> network 100.100.2.100 0.0.0.0 area 0
>>>>>>> network 100.100.3.100 0.0.0.0 area 0
>>>>>>> distance 90 12.1.1.1 0.0.0.0 SELECT_12.1.1.0_from_R1
>>>>>>> !
>>>>>>> ip access-list standard SELECT_12.1.1.0_from_R1
>>>>>>> permit 12.1.1.0
>>>>>>>
>>>>>>> R0#show ip ospf neighbor
>>>>>>>
>>>>>>> Neighbor ID Pri State Dead Time Address
>>>>>>> Interface
>>>>>>> 20.1.1.2 0 FULL/ - 00:00:37 20.1.1.2
>>>>>>> Serial0/1
>>>>>>> 12.1.1.1 0 FULL/ - 00:00:33 10.1.1.2
>>>>>>> Serial0/0
>>>>>>>
>>>>>>> R0#sir
>>>>>>> Codes: C - connected, S - static, 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
>>>>>>> i - IS-IS, su - IS-IS summary, 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
>>>>>>>
>>>>>>> 1.0.0.0/24 is subnetted, 1 subnets
>>>>>>> O 1.1.0.0 [110/65] via 10.1.1.2, 00:01:35, Serial0/0
>>>>>>> 2.0.0.0/32 is subnetted, 1 subnets
>>>>>>> O 2.2.0.2 [110/65] via 20.1.1.2, 00:01:35, Serial0/1
>>>>>>> 100.0.0.0/24 is subnetted, 4 subnets
>>>>>>> C 100.100.0.0 is directly connected, Loopback0
>>>>>>> C 100.100.1.0 is directly connected, Loopback1
>>>>>>> C 100.100.2.0 is directly connected, Loopback2
>>>>>>> C 100.100.3.0 is directly connected, Loopback3
>>>>>>> 20.0.0.0/30 is subnetted, 1 subnets
>>>>>>> C 20.1.1.0 is directly connected, Serial0/1
>>>>>>> 10.0.0.0/30 is subnetted, 1 subnets
>>>>>>> C 10.1.1.0 is directly connected, Serial0/0
>>>>>>> * 12.0.0.0/30 is subnetted, 1 subnets
>>>>>>> O 12.1.1.0 [90/128] via 20.1.1.2, 00:01:36, Serial0/1
>>>>>>> [90/128] via 10.1.1.2, 00:01:36, Serial0/0*
>>>>>>>
>>>>>>> according to my distance command only the route from R1 should have
>>>>>>> changed
>>>>>>> its A.D. but here even though i specified the ROUTER-ID of the router
>>>>>>> whose
>>>>>>> path i need to change the A.D it doesn't change that... it changes
>>>>>>> the
>>>>>>> A.D
>>>>>>> of all paths to the destination..! is this a BUG?
>>>>>>>
>>>>>>>
>>>>>>> Thanking You
>>>>>>>
>>>>>>> Yours Sincerely
>>>>>>>
>>>>>>> Divin Mathew John
>>>>>>> divinjohn_at_gmail.com
>>>>>>> divin_at_dide3d.com
>>>>>>> http://www.dide3d.com
>>>>>>> +91 9945430983
>>>>>>> +91 9846697191
>>>>>>> +974 5008916
>>>>>>> PGP PUBLIC KEY BLOCK @
>>>>>>> http://www.dide3d.com/divin_Public_PGP_key.txt
>>>>>>> Sent from Bangalore, KA, India
>>>>>>>
>>>>>>>
>>>>>>> Blogs and organic groups at http://www.ccie.net
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________________________________
>>>>>>> Subscription information may be found at:
>>>>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> Blogs and organic groups at http://www.ccie.net
>>>>>
>>>>> _______________________________________________________________________
>>>>> Subscription information may be found at:
>>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>>
>>>>>
>>>>
>>>
>>> Blogs and organic groups at http://www.ccie.net
>>>
>>> _______________________________________________________________________
>>> Subscription information may be found at:
>>> http://www.groupstudy.com/list/CCIELab.html
>>>
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Fri May 22 2009 - 19:37:34 ART