3Com Switch 8800 Advanced Software V5 Configuration Guide

316 CHAPTER 30: OSPF CONFIGURATION
Formats of LSAs
1 Router LSA
Figure 98 Router LSA format
Major fields:
■ Link State ID: The ID of the router that originated the LSA.
■ V (Virtual Link): Set to 1 if the router that originated the LSA is a virtual link
endpoint.
■ E (External): Set to 1 if the router that originated the LSA is an ASBR.
■ B (Border): Set to 1 if the router that originated the LSA is an ABR.
■ # links: The number of router links (interfaces) to the area, described in the
LSA.
■ Link ID: Determined by Link type.
■ Link Data: Determined by Link type.
■ Type: Link type. A value of 1 indicates a point-to-point link to a remote router;
a value of 2 indicates a link to a transit network; a value of 3 indicates a link to
a stub network; a value of 4 indicates a virtual link.
■ #TOS: The number of different TOS metrics given for this link.
■ metric: The cost of using this router link.
■ TOS: IP Type of Service that this metric refers to.
■ TOS metric: TOS-specific metric information.
2 Network LSA
A Network LSA is originated by the DR on a broadcast or NBMA network. The LSA
describes all routers attached to the network.
...
0 # links
Link ID
Link data
Type
TOS
Link ID
Link data
...
V 0E B
#TOS metric
0 TOS metric
LS age
Linke state ID
Advertising Router
Options 1
LS sequence number
LS checksum Length
0 7 15 31