3Com 4800G Series, Configuration Manual

Page: 288 / 1246

288 C
HAPTER
28: OSPF C
ONFIGURATION
Formats of LSAs
1 Router LSA
Figure 88 Router LSA format
Major fields:
■
Link State ID: 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: 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: Number of different TOS metrics given for this link.
■
metric: Cost of using this router link.
■
TOS: IP Type of Service that this metric refers to.
■
TOS metric: TOS-specific metric information.
■
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 0 E 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