interface IP address of the DR; and that of Network Summarization LSA stands for the IP
address of the network or subnet advertised; and etc.
3)
Advertising Router:
Router ID of the router advertising this LSA.
5.
LSU Packet
When one router receives an LSR, it would send an LSU packet to inform the other the
complete LSA information. The router receiving the LSA update will re-encapsulate this LSA
and then flood it.
Figure 10-45 LSU Packet
1)
LSA Quantity:
The quantity of LSA included in the LSU.
2)
LSA:
A complete description of LSA.
6.
LSAck Packet
When receiving a LSU, the router will send to the router forwarding the LSU packet a LSAck
packet including the LSA header it receives to confirm whether the data received is correct.
7.
LSA
OSPF protocol defines area and multiple router types. Via various sorts of LSA, different types
of router complete routing update caused by network changes. OSPF protocol defines 11
types of LSA, which all have the same LSA header. As shown below, every LSA is unique in the
network, and could be identified uniquely by the key field of LSA header.
Figure 10-46 LSA Header
1)
Age:
The time passed since the LSA is generated. When the age goes over the threshold
value set by the router system, which is one hour, and the router doesn’t receive an LSA
update, it will delete this LSA.
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