Solved: OSPF area range command doesn't work

devyatkin · ‎01-18-2013

Hello All,

I have three routers R1-R2-R3. R1-ASBR,Area600. R2-ABR,Area600,Area0,Area8(Totally NSSA). R3 - Area8.

I tried to summarize routes from Area8 with area 0 range 10.176.0.0 255.255.0.0 but it doesn't work. I can't see summary route on R1 and in R2 OSPF Database.

Also, I have output

R2#show ip ospf

Routing Process "ospf 1" with ID 10.159.210.0

..

Area BACKBONE(0) (Inactive)

Number of interfaces in this area is 1 (1 loopback)

Area has no authentication

SPF algorithm last executed 00:40:12.540 ago

SPF algorithm executed 6 times

Area ranges are

10.176.0.0/16 Passive Advertise

Number of LSA 5. Checksum Sum 0x035D1A

Number of opaque link LSA 0. Checksum Sum 0x000000

Number of DCbitless LSA 0

Number of indication LSA 0

Number of DoNotAge LSA 0

Flood list length 0

Area 8

Number of interfaces in this area is 1

It is a NSSA area

Perform type-7/type-5 LSA translation

...

Area 600

Number of interfaces in this area is 1

...

Configuration of routers below:

+++++++++++++++++++++++

R1

!

interface Loopback0

ip address 10.1.1.1 255.255.255.0

!

interface FastEthernet1/0

ip address 10.170.100.1 255.255.255.252

!

router ospf 1

summary-address 10.0.0.0 255.0.0.0

redistribute connected subnets

network 10.170.100.1 0.0.0.0 area 600

!

++++++++++++++++++++++++

R2

!

interface Loopback0

ip address 10.159.210.0 255.255.255.255

!

interface FastEthernet1/0

ip address 10.170.100.2 255.255.255.252

!

interface FastEthernet1/1

ip address 10.159.176.1 255.255.255.252

!

router ospf 1

area 0 range 10.176.0.0 255.255.0.0

area 8 nssa no-summary

network 10.159.176.1 0.0.0.0 area 8

network 10.159.210.0 0.0.0.0 area 0

network 10.170.100.2 0.0.0.0 area 600

!

++++++++++++++++++++++++++++++++++++

R3

!

interface Loopback100

ip address 10.176.254.1 255.255.255.255

!

interface FastEthernet1/0

ip address 10.159.176.2 255.255.255.252

!

router ospf 1

area 8 nssa

network 10.159.176.2 0.0.0.0 area 8

network 10.176.254.1 0.0.0.0 area 8

!

++++++++++++++++++++++++++++++++++++++

Could anyone say what is wrong?

Thanks!

Peter Paluch · ‎01-18-2013

Hi,

I tried to summarize routes from Area8 with area 0 range 10.176.0.0 255.255.0.0 but it doesn't work

If you want to summarize routes from area 8 then the area range command must refer to area 8, not to area 0. Replace the command with:

area 8 range 10.176.0.0 255.255.0.0

As a rule, the area range command always refers to the area that is being summarized (the source area), not the area into which the summary shall be advertised.

Best regards,

Peter

View solution in original post

turnera · ‎01-18-2013

Try putting the word advertise after the area 0 range statement.

router ospf 1

area 0 range 10.176.0.0 255.255.0.0 advertise

There is probably something else missing but this is what I see so far.

devyatkin · ‎01-18-2013

Just have tried. No changes.

turnera · ‎01-18-2013

Do a "clear ip ospf proc" and let the tables repopulate.

Peter Paluch · ‎01-18-2013

Hi,

I tried to summarize routes from Area8 with area 0 range 10.176.0.0 255.255.0.0 but it doesn't work

If you want to summarize routes from area 8 then the area range command must refer to area 8, not to area 0. Replace the command with:

area 8 range 10.176.0.0 255.255.0.0

As a rule, the area range command always refers to the area that is being summarized (the source area), not the area into which the summary shall be advertised.

Best regards,

Peter

turnera · ‎01-18-2013

Nice catch Peter. I looked right past that.

Here is link to a good video of OSPF Route Summarization. Hopefully this helps as well.

https://learningnetwork.cisco.com/docs/DOC-8553

devyatkin · ‎01-18-2013

Peter, thanks!

R2#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R2(config)#router ospf 1

R2(config-router)#area 8 range 10.176.0.0 255.255.0.0

OSPF: This range in different area 0

R2(config-router)#no area 0 range 10.176.0.0 255.255.0.0

R2(config-router)#area 8 range 10.176.0.0 255.255.0.0

R2(config-router)#

R2(config-router)#do show ip ospf

Routing Process "ospf 1" with ID 10.159.210.0

Supports only single TOS(TOS0) routes

Supports opaque LSA

Supports Link-local Signaling (LLS)

Supports area transit capability

It is an area border and autonomous system boundary router

Redistributing External Routes from,

Initial SPF schedule delay 5000 msecs

Minimum hold time between two consecutive SPFs 10000 msecs

Maximum wait time between two consecutive SPFs 10000 msecs

Incremental-SPF disabled

Minimum LSA interval 5 secs

Minimum LSA arrival 1000 msecs

LSA group pacing timer 240 secs

Interface flood pacing timer 33 msecs

Retransmission pacing timer 66 msecs

Number of external LSA 1. Checksum Sum 0x02D2C0

Number of opaque AS LSA 0. Checksum Sum 0x000000

Number of DCbitless external and opaque AS LSA 0

Number of DoNotAge external and opaque AS LSA 0

Number of areas in this router is 3. 2 normal 0 stub 1 nssa

Number of areas transit capable is 0

External flood list length 0

Area BACKBONE(0) (Inactive)

Number of interfaces in this area is 1 (1 loopback)

Area has no authentication

SPF algorithm last executed 00:00:51.840 ago

SPF algorithm executed 4 times

Area ranges are

Number of LSA 5. Checksum Sum 0x036218

Number of opaque link LSA 0. Checksum Sum 0x000000

Number of DCbitless LSA 0

Number of indication LSA 0

Number of DoNotAge LSA 0

Flood list length 0

Area 8

Number of interfaces in this area is 1

It is a NSSA area

Perform type-7/type-5 LSA translation

Area has no authentication

SPF algorithm last executed 00:00:54.532 ago

SPF algorithm executed 5 times

Area ranges are

10.176.0.0/16 Active(2) Advertise

Number of LSA 4. Checksum Sum 0x01ADB6

Number of opaque link LSA 0. Checksum Sum 0x000000

Number of DCbitless LSA 0

Number of indication LSA 0

Number of DoNotAge LSA 0

Flood list length 0

Area 600

Number of interfaces in this area is 1

Area has no authentication

SPF algorithm last executed 00:01:00.648 ago

SPF algorithm executed 5 times

Area ranges are

Number of LSA 6. Checksum Sum 0x04AB97

Number of opaque link LSA 0. Checksum Sum 0x000000

Number of DCbitless LSA 0

Number of indication LSA 0

Number of DoNotAge LSA 0

Flood list length 0

R2(config-router)#do show ip route

10.0.0.0/8 is variably subnetted, 6 subnets, 4 masks

O E2 10.0.0.0/8 [110/20] via 10.170.100.1, 00:01:13, FastEthernet1/0

C 10.159.176.0/30 is directly connected, FastEthernet1/1

O 10.176.254.1/32 [110/2] via 10.159.176.2, 00:01:13, FastEthernet1/1

C 10.159.210.0/32 is directly connected, Loopback0

O 10.176.0.0/16 is a summary, 00:01:13, Null0

C 10.170.100.0/30 is directly connected, FastEthernet1/0

R2(config-router)#

R1#show ip route

10.0.0.0/8 is variably subnetted, 6 subnets, 5 masks

C 10.1.1.0/24 is directly connected, Loopback0

O 10.0.0.0/8 is a summary, 00:06:32, Null0

O IA 10.159.176.0/30 [110/2] via 10.170.100.2, 00:05:58, FastEthernet1/0

O IA 10.159.210.0/32 [110/2] via 10.170.100.2, 00:05:58, FastEthernet1/0

O IA 10.176.0.0/16 [110/3] via 10.170.100.2, 00:00:04, FastEthernet1/0

C 10.170.100.0/30 is directly connected, FastEthernet1/0

R1#

Peter Paluch · ‎01-18-2013

Hello,

You are very welcome!

Just for your information, if a virtual link has been configured and is active in a non-backbone area (i.e. this area is a transit area), then the backbone networks internal to area 0 will not be summarized when advertising them into this transit area. This is stated in RFC 2328, Section 12.4.3:

      If an area is capable of carrying transit traffic (i.e.,
      its TransitCapability is set to TRUE), routing
      information concerning backbone networks should not be
      condensed before being summarized into the area.  Nor
      should the advertisement of backbone networks into
      transit areas be suppressed.  In other words, the
      backbone's configured ranges should be ignored when
      originating summary-LSAs into transit areas.

Best regards,

Peter