3Com MSR 50 Series Configuration Manual page 933

Figure 285 Network LSA format
0 7
LS age
LS checksum
Major fields:
Link State ID: The interface address of the DR
■
Network Mask: The mask of the network (a broadcast or NBMA network)
■
Attached Router: The IDs of the routers, which are adjacent to the DR,
■
including the DR itself
3 Summary LSA
Network summary LSAs (type3 LSAs) and ASBR summary LSAs (type4 LSAs) are
originated by ABRs. Other than the difference in the Link State ID field, the format
of type 3 and 4 summary-LSAs is identical.
Figure 286 Summary LSA format
0 7
LS age
LS checksum
0
TOS
Major fields:
Link State ID: For a type3 LSA, it is an IP address outside the area; for a type 4
■
LSA, it is the router ID of an ASBR outside the area.
Network Mask: The network mask for the type 3 LSA; set to 0.0.0.0 for the
■
type4 LSA
metric: The metric to the destination
■
15
Options
Linke state ID
Advertising Router
LS sequence number
Network mask
Attached router
...
15
Options
Linke state ID
Advertising Router
LS sequence number
Network mask
metric
TOS metric
...
Introduction to OSPF 933
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Length
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Length
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