H3C S7500E Series Operation Manual page 313

Operation Manual – IPv4 Routing
H3C S7500E Series Ethernet Switches
VI. LSAck packet
LSAack (Link State Acknowledgment) packets are used to acknowledge received LSU
packets, contents including LSA headers to describe the corresponding LSAs. Multiple
LSAs can be acknowledged in a single Link State Acknowledgment packet. The
following figure gives its format.
Figure 3-14 LSAck packet format
VII. LSA header format
All LSAs have the same header, as shown in the following figure.
Figure 3-15 LSA header format
Major fields:
LS age: Time in seconds elapsed since the LSA was originated. A LSA ages in the
LSDB (added by 1 per second), but does not in transmission.
LS type: Type of the LSA.
Link State ID: The contents of this field depend on the LSA's type
LS sequence number: Used by other routers to judge new and old LSAs.
LS checksum: Checksum of the LSA except the LS age field.
Length: Length in bytes of the LSA, including the LSA header.
VIII. Formats of LSAs
1) Router LSA
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Chapter 3 OSPF Configuration