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OSPF route summarization on ABR

Hi,

 

i'm stuck with the route summarization on an ospf abr.

 

We have a few hundred teleworkers connected via a service provider which we have a ospf coupling to.

The provider assigns every teleworker a small /29 subnet, which we learn through ospf on all routers in our internal network.

In consultation with our provider these subnets are all from an easy aggregatebale range.

 

What i now want to do is to summarize all these small subnets on the fortigate in one large supernet, to get rid of hundreds of small routes on every routing device in our internal network. (see attached drawing).

From what i read so far, it should be enough to set a range within the area configuration. (https://docs.fortinet.com/document/fortiswitch/6.4.2/administration-guide/865768/ospf-routing)

(https://kb.fortinet.com/kb/documentLink.do?externalID=FD30329)

(https://forum.fortinet.com/tm.aspx?m=152390)

 

The "config summary-address" statement seems to be only for the summary on non-OSPF Routes on an ASBR. Here is my ospf config from the fg1500d device:

 

config router ospf
    set router-id 0.0.0.1
    set restart-mode graceful-restart
    config area
        edit 0.0.0.0
        next
        edit 0.1.0.1
            config range
                edit 1
                    set prefix 10.11.192.0 255.255.240.0
                next
            end
        next
    end
    config ospf-interface
        edit "ospf_vrf0"
            set interface "Transfer_VRF0"
            set ip 10.254.7.1
            set authentication text
            set authentication-key <key>
            set priority 100
            set dead-interval 40
            set hello-interval 10
        next
        edit "ospf_telekom-mpls"
            set interface "MPLS_TCOM"
            set ip 10.254.12.33
            set dead-interval 40
            set hello-interval 10
        next
    end
    config network
        edit 1
            set prefix 10.254.7.0 255.255.255.248
        next
        edit 2
            set prefix 10.254.12.32 255.255.255.248
            set area 0.1.0.1
        next
    end
    config redistribute "connected"
        set status enable
    end
    config redistribute "static"
        set status enable
    end
    config redistribute "rip"
    end
    config redistribute "bgp"
    end
    config redistribute "isis"
    end
end

But when i have a look in the routing table on the core switch i see still all the small subnet routes an no entry for the summarized net at all.

DST             MASK            NEXT                 VRF/ISID         COST   FACE     PROT AGE TYPE PRF
-----------------------------------------------------------------------------------------------------
10.11.200.8     255.255.255.248 10.254.7.1           GlobalRouter     111    606      OSPF 0   IB   120
10.11.200.9     255.255.255.255 10.254.7.1           GlobalRouter     111    606      OSPF 0   IB   120
10.11.200.16    255.255.255.248 10.254.7.1           GlobalRouter     111    606      OSPF 0   IB   120
10.11.200.17    255.255.255.255 10.254.7.1           GlobalRouter     111    606      OSPF 0   IB   120
10.11.200.24    255.255.255.248 10.254.7.1           GlobalRouter     111    606      OSPF 0   IB   120
10.11.200.25    255.255.255.255 10.254.7.1           GlobalRouter     111    606      OSPF 0   IB   120
10.11.200.32    255.255.255.248 10.254.7.1           GlobalRouter     111    606      OSPF 0   IB   120
10.11.200.33    255.255.255.255 10.254.7.1           GlobalRouter     111    606      OSPF 0   IB   120


I have no idea what i'm doing wrong, so any help would be much apprechiated.

 

Best regards, Tim

1 REPLY 1
sta
Staff
Staff

Tim,

your config seems correct, except for maybe the prefix used for the range command.

As it is now, it doesn't cover the routes you show (10.11.200.x), assuming those are the ones you're referring to.

In the diagram, the suggested summary is 10.11.192.0/20, that will indeed cover them.

I'd suggest you fix that first, and if that doesn't work (it should) collect on the fgt:

get router info ospf database router lsa

get router info ospf database brief

 

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