4.4.3. Originating LSAs

The process of reoriginating an LSA in IPv6 is the same as in IPv4: the LSA's LS sequence number is incremented, its LS age is set to 0, its LS checksum is calculated, and the LSA is added to the link state database and flooded on the appropriate interfaces.

The list of events causing LSAs to be reoriginated for IPv4 is given in Section 12.4 of [OSPFV2]. The following events and/or actions are added for IPv6:

The state or interface ID of one of the router's interfaces changes. The router may need to (re)originate or flush its link-LSA and one or more router-LSAs and/or intra-area-prefix-LSAs. If the router is the Designated Router, the router may also need to (re)originate and/or flush the network-LSA corresponding to the interface.
The identity of a link's Designated Router changes. The router may need to (re)originate or flush the link's network-LSA and one or more router-LSAs and/or intra-area-prefix-LSAs.
A neighbor transitions to/from "Full" state. The router may need to (re)originate or flush the link's network-LSA and one or more router-LSAs and/or intra-area-prefix-LSAs.
The Interface ID of a neighbor changes. This may cause a new instance of a router-LSA to be originated for the associated area.
A new prefix is added to an attached link, or a prefix is deleted (both through configuration). This causes the router to reoriginate its link-LSA for the link or, if it is the only router attached to the link, causes the router to reoriginate an intra-area-prefix-LSA.
A new link-LSA is received, causing the link's collection of prefixes to change. If the router is the Designated Router for the link, it originates a new intra-area-prefix-LSA.
A new link-LSA is received, causing the logical OR of LSA options advertised by adjacent routers on the link to change. If the router is the Designated Router for the link, it originates a new network-LSA.

The detailed construction of the seven required IPv6 LSA types is supplied by the following subsections. Example network topology and addressing information are shown in Figure 1 and Tables 1-2.

Figure 1: Area 1 with IP Addresses Shown

          ..........................................
          .                                  Area 1.
          .     +                                  .
          .     |                                  .
          .     | 3+---+1                          .
          .  N1 |--|RT1|-----+                     .
          .     |  +---+      \                    .
          .     |              \  ______           .
          .     +               \/       \      1+---+
          .                     *    N3   *------|RT4|------
          .     +               /\_______/       +---+
          .     |              /     |             .
          .     | 3+---+1     /      |             .
          .  N2 |--|RT2|-----+      1|             .
          .     |  +---+           +---+           .
          .     |                  |RT3|----------------
          .     +                  +---+           .
          .                          |2            .
          .                          |             .
          .                   +------------+       .
          .                          N4            .
          ..........................................

Table 1: IPv6 Link Prefixes

Network	IPv6 Prefix
N1	2001:0db8:c001:0200::/56
N2	2001:0db8:c001:0300::/56
N3	2001:0db8:c001:0100::/56
N4	2001:0db8:c001:0400::/56

Table 2: OSPF Interface IDs and Link-Local Addresses

Router	Interface	Interface ID	Link-Local Address
RT1	to N1	1	fe80:0001::RT1
RT1	to N3	2	fe80:0002::RT1
RT2	to N2	1	fe80:0001::RT2
RT2	to N3	2	fe80:0002::RT2
RT3	to N3	1	fe80:0001::RT3
RT3	to N4	2	fe80:0002::RT3
RT4	to N3	1	fe80:0001::RT4