OSPFv2 LSA Message Format

OSPFv2 Protocol LSA Header

  • OSPFv2 Router LSA
  • OSPFv2 Network LSA
  • OSPFv2 Network/ASBR Summary LSA
  • OSPFv2 Autonomous System External LSA
  • OSPFv2 Not-So-Stubby Area External LSA

OSPFv2 Protocol LSA Header

┃ 16bit    |  8bit  | 8bit ┃
┏----------+--------+------┓
┃ Age      | Option | Type ┃
┠----------+--------+------┨
┃ Link State ID            ┃
┠--------------------------┨
┃ Advertising Router       ┃
┠--------------------------┨
┃ Sequence                 ┃
┠----------+---------------┨
┃ Checksum | Length        ┃
┗----------+---------------┛
Type LSA Type Command
1 Router LSA show ip ospf database router
2 Network LSA show ip ospf database network
3 Network Summary LSA show ip ospf database summary
4 ASBR Summary LSA show ip ospf database asbr-summary
5 AS External LSA show ip ospf database external
6 Group Membership LSA
7 NSSA External LSA show ip ospf database nssa-external
8 External Attributes LSA show ip ospf database
9 Opaque LSA (link链路本地范围 )
10 Opaque LSA (area本地区域范围)
11 Opaque LSA (AS范围)

OSPFv2 Router LSA

┃ 8bit      | 8bit          | 8bit   | 8bit   ┃
┏---------------------------+--------+--------┓
┃ Age                       | Option | Type=1 ┃
┠---------------------------+--------+--------┨
┃ Link State ID                               ┃
┠---------------------------------------------┨
┃ Advertising Router                          ┃
┠---------------------------------------------┨
┃ Sequence                                    ┃
┠---------------------------+-----------------┨
┃ Checksum                  | Length          ┃
┠-----------+---------------+-----------------┨
┃00000|V|E|B| 0x00          | Number of Links ┃
┠-----------+---------------+-----------------┨
┃ Link ID                                     ┃
┠---------------------------------------------┨
┃ Link Data                                   ┃
┠-----------+---------------+-----------------┨
┃ Link Type | Number of Tos | Metric          ┃
┠-----------+---------------+-----------------┨
┃ Tos       | 0x00          | Tos Metric      ┃
┠-----------+---------------+-----------------┨
┃                    ...                      ┃
┠---------------------------------------------┨
┃ Link ID                                     ┃
┠---------------------------------------------┨
┃ Link Data                                   ┃
┗---------------------------------------------┛
Link Type Link connected to: Link ID Value Link Data Value
1 another Router (point-to-point) neighboring router’s ID 和网络相连的始发路由器接口的ipaddr
2 a Transit Network designated router’s interface’s IP addr 和网络相连的始发路由器接口的ipaddr
3 a Stub Network IP网络/子网地址 网络ip addr / subnet mask
4 virtual link neighboring router’s ID 始发路由器接口的mib-ii ifindex值

OSPFv2 Network LSA

┃ 16bit    |  8bit  | 8bit ┃
┏----------+--------+------┓
┃ Age      | Option |Type=2┃
┠----------+--------+------┨
┃ Link State ID            ┃
┠--------------------------┨
┃ Advertising Router       ┃
┠--------------------------┨
┃ Sequence                 ┃
┠----------+---------------┨
┃ Checksum | Length        ┃
┠----------+---------------┨
┃ Network Mask             ┃
┠--------------------------┨
┃ Attached Router          ┃
┠--------------------------┨
┃           ...            ┃
┠--------------------------┨
┃ Attached Router          ┃
┗--------------------------┛

OSPFv2 Network/ASBR Summary LSA

┃ 8bit | 8bit | 8bit   | 8bit     ┃
┏-------------+--------+----------┓
┃ Age         | Option | Type=3/4 ┃
┠-------------+--------+----------┨
┃ Link State ID                   ┃
┠---------------------------------┨
┃ Advertising Router              ┃
┠---------------------------------┨
┃ Sequence                        ┃
┠-------------+-------------------┨
┃ Checksum    | Length            ┃
┠-------------+-------------------┨
┃ Network Mask                    ┃
┠------+--------------------------┨
┃ 0x00 | Metric                   ┃
┠------+--------------------------┨
┃ Tos  | Tos Metric               ┃
┠------+--------------------------┨
┃               ...               ┃
┠------+--------------------------┨
┃ 0x00 | Metric                   ┃
┗---------------------------------┛

OSPFv2 Autonomous System External LSA

┃ 8bit    | 8bit | 8bit   | 8bit   ┃
┏----------------+--------+--------┓
┃ Age            | Option | Type=5 ┃
┠----------------+--------+--------┨
┃ Link State ID                    ┃
┠----------------------------------┨
┃ Advertising Router               ┃
┠----------------------------------┨
┃ Sequence                         ┃
┠----------------+-----------------┨
┃ Checksum       | Length          ┃
┠----------------+-----------------┨
┃ Network Mask                     ┃
┠-+-------+------------------------┨
┃E|0000000| Metric                 ┃
┠-+-------+------------------------┨
┃ Forwarding Address               ┃
┠----------------------------------┨
┃ External Route Tag               ┃
┠-+-------+------------------------┨
┃E|  Tos  | Metric                 ┃
┠-+-------+------------------------┨
┃ Forwarding Address               ┃
┠----------------------------------┨
┃ External Route Tag               ┃
┠----------------------------------┨
┃                ...               ┃
┠----------------------------------┨
┃ Network Mask                     ┃
┠-+-------+------------------------┨
┃E|0000000| Metric                 ┃
┠-+-------+------------------------┨
┃ Forwarding Address               ┃
┠----------------------------------┨
┃ External Route Tag               ┃
┗----------------------------------┛
E:External Metric bit:0(E1)/1(E2)

OSPFv2 Not-So-Stubby Area External LSA

┃ 8bit    | 8bit | 8bit   | 8bit   ┃
┏----------------+--------+--------┓
┃ Age            | Option | Type=5 ┃
┠----------------+--------+--------┨
┃ Link State ID                    ┃
┠----------------------------------┨
┃ Advertising Router               ┃
┠----------------------------------┨
┃ Sequence                         ┃
┠----------------+-----------------┨
┃ Checksum       | Length          ┃
┠----------------+-----------------┨
┃ Network Mask                     ┃
┠-+-------+------------------------┨
┃E|  Tos  | Metric                 ┃
┠-+-------+------------------------┨
┃ Forwarding Address               ┃
┠----------------------------------┨
┃ External Route Tag               ┃
┠----------------------------------┨
┃                ...               ┃
┠----------------------------------┨
┃ Network Mask                     ┃
┠-+-------+------------------------┨
┃E|  Tos  | Metric                 ┃
┠-+-------+------------------------┨
┃ Forwarding Address               ┃
┠----------------------------------┨
┃ External Route Tag               ┃
┗----------------------------------┛
E:External Metric bit:0(E1)/1(E2)