1, LSA : LS of the type , Link State ID , Advertising, Router can only represent a LSA
(. 1) Advertising, Router : This generates LSA router Router ID .
(2) a class 2 categories: network or router ID generated
(3) 3 categories: the ABR produced
2, LSA old and new comparison
(1) will first compare the sequence number ( Sequence Number ), more preferably greater sequence number
(2) If the same serial number, compares the check value ( Checksum ), more preferably greater
(3) If the check value are the same, it would be more LSA Age time is equal to MAX-age period ( 3600S )
(4) If the age time is not equal to MAX-age time, compares their difference, if the difference of> 15 minutes ( 900S ), more preferably less
(5) If the age time is not equal to MAX-age time, compares their difference, if the difference <15 minutes ( 900S ), the same description is the LSA , wherein an ignore
3. Under what circumstances LSA updates?
(1) 1800 maturity will be updated
(2) trigger an update (interface address conversion, interface cost transformation, delete interfaces, or delete announcements)
4, OSPF can not be deleted is not self-generated LSA (this LSA who produce and who deleted)
5, in addition to Hello external messages, other OSPF packet carries LSA information
6, command: bandwidth-Reference // modify the reference bandwidth
. 7, Stub network indicates only the segment data entry, for example, a Loopback interfaces is a Stub segment.
8, 
point type of interface will generate two types of a class of the LSA : are P2P (topology), the Stub (route)
9, in addition to Hello external messages, other OSPF packet carries LSA information
10, LS Age : This field indicates the LSA time has to survive in seconds.
11, LS of the type : This field identifies the LSA format and function. Common LSA types there are five.
12 is, Link State ID : This field is the LSA identity of the link portion described. E.g. Router ID and the like.
13 is, Advertising, Router : This field is generated in this LSA router Router ID .
14, the LS Sequence Number : This field is used to detect the old and repeated the LSA .
15, point to point interface type will generate two types of a class of the LSA : P 2P and STUB
16, [int] OSPF cost 100 // overhead manually modify the interface
. 17, are P2P network produces only one type of Point-to-Point and SutbNet the Router LSA
18, an Ethernet network, generates a class ' TransNet , SutbNet the Router LAS and 2 classes the Network the LSA .
19, P2P computing network, the cost value
(1) ends not in the same network segment
Therefore, from R1 to 12.1.1.1 overhead is 96
(2) ends at the same network
Therefore, from R1 to 10.1.1.2 overhead is 48
20, calculated the cost of Ethernet
From RTA to RTC overhead value . 5 ( Nl can be seen as the DR )