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4.4.3.3. Network-LSAs

The LS type of a network-LSA is set to the value 0x2002. Network-LSAs have area flooding scope. A network-LSA is originated for every broadcast or NBMA link with an elected Designated Router that is fully adjacent with at least one other router on the link. The network-LSA is originated by the link's Designated Router and lists all routers on the link with which it is fully adjacent.

The procedure for originating network-LSAs in IPv6 is the same as the IPv4 procedure documented in Section 12.4.2 of [OSPFV2], with the following exceptions:

  • An IPv6 network-LSA's Link State ID is set to the Interface ID of the Designated Router on the link.

  • IPv6 network-LSAs do not contain a Network Mask. All addressing information formerly contained in the IPv4 network-LSA has now been consigned to intra-Area-Prefix-LSAs originated by the link's Designated Router.

  • The Options field in the network-LSA is set to the logical OR of the Options fields contained within the link's associated link-LSAs corresponding to fully adjacent neighbors. In this way, the network link exhibits a capability when at least one fully adjacent neighbor on the link requests that the capability be advertised.

As an example, assuming that Router RT4 has been elected the Designated Router of Network N3 in Figure 1, the following network-LSA is originated:

; Network-LSA for Network N3

LS age = 0                     ; newly (re)originated
LS type = 0x2002               ; network-LSA
Link State ID = 1              ; RT4's Interface ID on N3
Advertising Router = 192.0.2.4 ; RT4's Router ID
Options = (V6-bit|E-bit|R-bit)
       Attached Router = 192.0.2.4    ; Router ID
       Attached Router = 192.0.2.1    ; Router ID
       Attached Router = 192.0.2.2    ; Router ID
       Attached Router = 192.0.2.3    ; Router ID
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