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  • 1.  Multiple areas adjacency on same physical link

    Posted 02-28-2024 22:43
    Edited by LEEBAHI 02-28-2024 22:45

    Hi everyone,

    Currently we are running OSPFV2 between our two DC connected by L2 pipe by a service provider (SP)

    DC1 gig0/0/1.199------SP1----------0/0/1.199-gig-DC2

    DC1 and DC2 are running OSPFV2 on gig 0/0/0.199  which  has subnet 199.199.199.0/30, DC1 ( 199.199.199.1) and DC2 ( 199.199.199.2) see themselves as neighbors in area 0.

    DC1 and DC2 has many spokes sites in area 1. In order to avoid suboptimal routing  between DC and  a spoke  ( if spoke loses its connection to DC) because intra area routes are preferred over inter-area routes, we needed to establish another OSPF adjacency between DC1 and DC2 in area 1. Since  provider only expects single vlan tag traffic from DC1 and DC2, we therefore set up another IP under gig 0/0.199 on DC 1 and DC2 . 200.200.200.1/30 and 200.200.200.2/30 and place this subnet in area 1 by using:

    DC1:

    set protocols ospf area 0.0.0.1 interface 200.200.200.1 interface-type p2p

    DC2:

    set protocols ospf area 0.0.0.1 interface 200.200.200.2  interface-type p2p

    This allows DC1 and DC2 to see OSPF neighbors in two different areas on same physical link gig 0/0/0.199

    DC1 sees following:

    199.199.199.2   gig 0/0/.199  full ( area 0)

    200.200.200.2 gig 0/0.199  full ( area 1)

    Everything is working as expected.

    If we want to replace OSPFV2 with OSPF3 ream ipv4-unicast .  But I do not see any command that allows me to run OSPF3 on single physical link  like we do in OSPFV2

    EXAMPLE:

    DC1:

    int gig 0/0/1.199

    199.199.199.199.1/30

    200.200.200.1/30

    set protocol ospf area 0.0.0.0 interface gig 0/0/1.199 

    set protocol ospf area 0.0.0.1 interface 200.200.200.1 

    But not such option available in OSPF3

    Thanks !!



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    Be kind!!
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  • 2.  RE: Multiple areas adjacency on same physical link
    Best Answer

    Posted 03-01-2024 02:32

    Hello,

    Have you checked "multiarea adjacency" -  secondary interface for your case or you need to run ospf3?

    set protocol ospf area 0.0.0.0 interface gig 0/0/1.199

    set protocol ospf area 0.0.0.1 interface gig 0/0/1.199 secondary

    In this case you don't need secondary IP ( 200.200.200.1/30). 



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    CHINGIZ MAMMADOV
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  • 3.  RE: Multiple areas adjacency on same physical link

    Posted 03-01-2024 21:49

    That is exactly I was looking !!



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    Be kind!!
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