3Com Switch 8800 Advanced Software V5 Configuration Guide

314 CHAPTER 30: OSPF CONFIGURATION
Figure 94 LSR packet format
Major fields:
■ LS type: The type number of the LSA to be requested, type 1 for example
indicates the Router LSA
■ Link State ID: Determined by LSA type
■ Advertising Router: The ID of the router that sent the LSA
LSU packet
LSU (Link State Update) packets are used to send the requested LSAs to peers, and
each packet carries a collection of LSAs. The LSU packet format is shown below.
Figure 95 LSU packet format
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.
Version 3
Router ID
Area ID
Checksum AuType
Packet length
Authentication
Authentication
LS type
Link state ID
...
Advertising router
0715 31
...
Version 4
Router ID
Area ID
Checksum AuType
Packet length
Authentication
Authentication
Number of LSAs
LSA
0715 31
LSA