OSPFv3 LSAs Example (Single Area)

Routing Tables

R1#show ipv6 route ospf | be 110
O   2001:A:A:30::/64 [110/74]
     via FE80::5054:FF:FE11:C0FE, GigabitEthernet2
     via FE80::5054:FF:FE08:E390, GigabitEthernet1

R2#show ipv6 route ospf | be 110
O   2001:A:A:20::/64 [110/74]
     via FE80::5054:FF:FE16:D3E5, GigabitEthernet1

R3#show ipv6 route ospf | be 110
O   2001:A:A:10::/64 [110/74]
     via FE80::5054:FF:FE0E:A92, GigabitEthernet1

• The next hop for each route is the link-local address of the next-hop router, gleaned from the Type 8 LSA.

LSDB Summary

R1#show ipv6 ospf data

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

ADV Router       Age         Seq#        Fragment ID  Link count  Bits
 1.1.1.1         518         0x80000004  0            2           None
 2.2.2.2         435         0x80000006  0            2           None
 3.3.3.3         442         0x80000007  0            2           None

                Net Link States (Area 0)

ADV Router       Age         Seq#        Link ID    Rtr count
 3.3.3.3         457         0x80000001  7          2

                Link (Type-8) Link States (Area 0)

ADV Router       Age         Seq#        Link ID    Interface
 1.1.1.1         545         0x80000001  7          Gi1
 2.2.2.2         519         0x80000001  8          Gi1
 1.1.1.1         563         0x80000001  8          Gi2
 3.3.3.3         616         0x80000001  8          Gi2

                Intra Area Prefix Link States (Area 0)

ADV Router       Age         Seq#        Link ID    Ref-lstype  Ref-LSID
 1.1.1.1         545         0x80000002  0          0x2001      0
 2.2.2.2         457         0x80000003  0          0x2001      0
 3.3.3.3         457         0x80000003  0          0x2001      0
 3.3.3.3         457         0x80000001  7168       0x2002      7

Router LSAs (Type 1)

R1#show ipv6 ospf database router adv-router 1.1.1.1

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

  LS age: 449
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Router Links
  Link State ID: 0
  Advertising Router: 1.1.1.1
  LS Seq Number: 80000004
  Checksum: 0x83B1
  Length: 56
  Number of Links: 2

    Link connected to: another Router (point-to-point)
      Link Metric: 64
      Local Interface ID: 7
      Neighbor Interface ID: 8
      Neighbor Router ID: 2.2.2.2

    Link connected to: another Router (point-to-point)
      Link Metric: 64
      Local Interface ID: 8
      Neighbor Interface ID: 8
      Neighbor Router ID: 3.3.3.3


R1#show ipv6 ospf database router adv-router 2.2.2.2 

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

  LS age: 371
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Router Links
  Link State ID: 0
  Advertising Router: 2.2.2.2
  LS Seq Number: 80000006
  Checksum: 0x4327
  Length: 56
  Number of Links: 2

    Link connected to: a Transit Network
      Link Metric: 10
      Local Interface ID: 7
      Neighbor (DR) Interface ID: 7
      Neighbor (DR) Router ID: 3.3.3.3

    Link connected to: another Router (point-to-point)
      Link Metric: 64
      Local Interface ID: 8
      Neighbor Interface ID: 7
      Neighbor Router ID: 1.1.1.1


R1#show ipv6 ospf database router adv-router 3.3.3.3

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

  LS age: 381
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Router Links
  Link State ID: 0
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000007
  Checksum: 0x451F
  Length: 56
  Number of Links: 2

    Link connected to: a Transit Network
      Link Metric: 10
      Local Interface ID: 7
      Neighbor (DR) Interface ID: 7
      Neighbor (DR) Router ID: 3.3.3.3

    Link connected to: another Router (point-to-point)
      Link Metric: 64
      Local Interface ID: 8
      Neighbor Interface ID: 8
      Neighbor Router ID: 1.1.1.1

• There is no IPv6 addressing information contained in OSPFv3 Type 1 LSAs. These LSAs are only used to build the topology. The topology includes which routers exist in the area and how they interconnect. A transit network is a broadcast domain. Notice that each interface has an ID instead of an IP address. A p2p link simply lists the router on the other end, and the local and remote interface IDs

• Another difference compared to OSPFv2 is that the link state ID is 0. In OSPFv2 the link state ID is the RID that originates the LSA. However, in OSPFv2 it is redundant information, as the RID is listed twice, in the advertising router ID field and the link state ID field. In OSPFv3, there is no need to populate the link state ID so it is just set to 0.

Network LSAs (Type 2)

R1#show ipv6 ospf database network 

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Net Link States (Area 0)

  LS age: 441
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Network Links
  Link State ID: 7 (Interface ID of Designated Router)
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000001
  Checksum: 0x1BC6
  Length: 32
        Attached Router: 3.3.3.3
        Attached Router: 2.2.2.2

• The OSPFv3 Type 2 LSA also does not list any addressing information. It is simply used to build the topology, and includes information about broadcast domains. The DR advertises this LSA, just as in OSPFv2. The LSA simply lists the attached routers.

Link LSAs (Type 8) - R1's Perspective

R1#show ipv6 ospf data link adv-router 1.1.1.1

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Link (Type-8) Link States (Area 0)

  LS age: 579
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet1)
  Link State ID: 7 (Interface ID)
  Advertising Router: 1.1.1.1
  LS Seq Number: 80000001
  Checksum: 0x128F
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE12:722F
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:10::
  Prefix Length: 64, Options: None

  LS age: 596
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet2)
  Link State ID: 8 (Interface ID)
  Advertising Router: 1.1.1.1
  LS Seq Number: 80000001
  Checksum: 0x59CE
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE1A:6C95
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:20::
  Prefix Length: 64, Options: None

R1#show ipv6 ospf data link adv-router 2.2.2.2

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Link (Type-8) Link States (Area 0)

  LS age: 556
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet1)
  Link State ID: 8 (Interface ID)
  Advertising Router: 2.2.2.2
  LS Seq Number: 80000001
  Checksum: 0xCD06
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE08:E390
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:10::
  Prefix Length: 64, Options: None

R1#show ipv6 ospf data link adv-router 3.3.3.3

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Link (Type-8) Link States (Area 0)

  LS age: 661
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet2)
  Link State ID: 8 (Interface ID)
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000001
  Checksum: 0x6209
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE11:C0FE
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:20::
  Prefix Length: 64, Options: None

Link LSAs (Type 8) - R2's Perspective

R2#show ipv6 ospf data link adv-router 1.1.1.1

            OSPFv3 Router with ID (2.2.2.2) (Process ID 1)

                Link (Type-8) Link States (Area 0)

  LS age: 631
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet2)
  Link State ID: 7 (Interface ID)
  Advertising Router: 1.1.1.1
  LS Seq Number: 80000001
  Checksum: 0x128F
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE12:722F
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:10::
  Prefix Length: 64, Options: None

R2#show ipv6 ospf data link adv-router 2.2.2.2

            OSPFv3 Router with ID (2.2.2.2) (Process ID 1)

                Link (Type-8) Link States (Area 0)

  LS age: 586
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet1)
  Link State ID: 7 (Interface ID)
  Advertising Router: 2.2.2.2
  LS Seq Number: 80000001
  Checksum: 0x6224
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE0E:A92
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:30::
  Prefix Length: 64, Options: None

  LS age: 606
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet2)
  Link State ID: 8 (Interface ID)
  Advertising Router: 2.2.2.2
  LS Seq Number: 80000001
  Checksum: 0xCD06
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE08:E390
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:10::
  Prefix Length: 64, Options: None

R2#show ipv6 ospf data link adv-router 3.3.3.3

            OSPFv3 Router with ID (2.2.2.2) (Process ID 1)

                Link (Type-8) Link States (Area 0)

  LS age: 597
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet1)
  Link State ID: 7 (Interface ID)
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000001
  Checksum: 0x9BC1
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE16:D3E5
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:30::
  Prefix Length: 64, Options: None

Link LSAs (Type 8) - R3's Perspective

R3#show ipv6 ospf database link adv-router 1.1.1.1

            OSPFv3 Router with ID (3.3.3.3) (Process ID 1)

                Link (Type-8) Link States (Area 0)

  LS age: 680
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet2)
  Link State ID: 8 (Interface ID)
  Advertising Router: 1.1.1.1
  LS Seq Number: 80000001
  Checksum: 0x59CE
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE1A:6C95
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:20::
  Prefix Length: 64, Options: None

R3#show ipv6 ospf database link adv-router 2.2.2.2

            OSPFv3 Router with ID (3.3.3.3) (Process ID 1)

                Link (Type-8) Link States (Area 0)

  LS age: 617
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet1)
  Link State ID: 7 (Interface ID)
  Advertising Router: 2.2.2.2
  LS Seq Number: 80000001
  Checksum: 0x6224
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE0E:A92
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:30::
  Prefix Length: 64, Options: None

R3#show ipv6 ospf database link adv-router 3.3.3.3

            OSPFv3 Router with ID (3.3.3.3) (Process ID 1)

                Link (Type-8) Link States (Area 0)

  LS age: 627
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet1)
  Link State ID: 7 (Interface ID)
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000001
  Checksum: 0x9BC1
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE16:D3E5
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:30::
  Prefix Length: 64, Options: None

  LS age: 737
  Options: (V6-Bit, E-Bit, R-Bit, DC-Bit)
  LS Type: Link-LSA (Interface: GigabitEthernet2)
  Link State ID: 8 (Interface ID)
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000001
  Checksum: 0x6209
  Length: 56
  Router Priority: 1
  Link Local Address: FE80::5054:FF:FE11:C0FE
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:20::
  Prefix Length: 64, Options: None

• Notice that each router has a different set of type 8 LSAs. How can this be? The Link LSA is only flooded on the interface. It is not flooded area-wide. The link LSA is used to associate an interface ID with a link local address, and prefix address. The prefix address is the IP address that belongs to the interface. This is how a router learns what link local address to use for the next-hop address for routes that are installed in the RIB.

Intra-Area Prefix LSAs (Type 9)

R1#show ipv6 ospf data prefix adv-router 1.1.1.1

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Intra Area Prefix Link States (Area 0)

  LS age: 705
  LS Type: Intra-Area-Prefix-LSA
  Link State ID: 0
  Advertising Router: 1.1.1.1
  LS Seq Number: 80000002
  Checksum: 0x5005
  Length: 56
  Referenced LSA Type: 2001
  Referenced Link State ID: 0
  Referenced Advertising Router: 1.1.1.1
  Number of Prefixes: 2
  Prefix Address: 2001:A:A:10::
  Prefix Length: 64, Options: None, Metric: 64
  Prefix Address: 2001:A:A:20::
  Prefix Length: 64, Options: None, Metric: 64

R1#show ipv6 ospf data prefix adv-router 2.2.2.2

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Intra Area Prefix Link States (Area 0)

  LS age: 623
  LS Type: Intra-Area-Prefix-LSA
  Link State ID: 0
  Advertising Router: 2.2.2.2
  LS Seq Number: 80000003
  Checksum: 0x70BE
  Length: 44
  Referenced LSA Type: 2001
  Referenced Link State ID: 0
  Referenced Advertising Router: 2.2.2.2
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:10::
  Prefix Length: 64, Options: None, Metric: 64

R1#show ipv6 ospf data prefix adv-router 3.3.3.3

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Intra Area Prefix Link States (Area 0)

  LS age: 626
  LS Type: Intra-Area-Prefix-LSA
  Link State ID: 0
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000003
  Checksum: 0x26F0
  Length: 44
  Referenced LSA Type: 2001
  Referenced Link State ID: 0
  Referenced Advertising Router: 3.3.3.3
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:20::
  Prefix Length: 64, Options: None, Metric: 64

  LS age: 626
  LS Type: Intra-Area-Prefix-LSA
  Link State ID: 7168
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000001
  Checksum: 0x5EC6
  Length: 44
  Referenced LSA Type: 2002
  Referenced Link State ID: 7
  Referenced Advertising Router: 3.3.3.3
  Number of Prefixes: 1
  Prefix Address: 2001:A:A:30::
  Prefix Length: 64, Options: None, Metric: 0

• This LSA advertises non-link-local prefix addresses. We actually saw these prefixes in the Link LSA, however that LSA is only flooded on the link. The Intra-Area prefix LSA is flooded area-wide.

• Notice that 2001:A:A:30::/64 has a metric of 0 because it was generated by the DR (pseudonode). The Type 1 LSA includes each attached router’s cost to the pseduonode.

• The referenced LSA type value of 2001 indicates this is referencing a Type 1 LSA, and a value of 2002 indicates that it is referencing a Type 2 LSA.