LSA Type Explanation - detailed explanation of lsa-2 (type II LSA network LSA) and lsa-3 (type III LSA network Summary LSA)

Catalog

One 、LSA-2

（1）—— brief introduction ：

（2）—— Header information :

（3）—— Data section :

（4）—— effect :

 （5） How to view ：

  Two 、LSA-3

（1）—— brief introduction ：

（2）—— Header information :

（3）—— Data section :

（4） How to view ：

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One 、LSA-2

（1）—— brief introduction ：

• The Internet LSA（Network LSA）： Every multiple access network Specify router （DR） There will be Networks LSA notice . As discussed earlier ,DR Router Can be seen as a “ false ” node , Or a Virtual router , It is used to describe a multi-channel access network and all routers connected to it . From this point of view , A network LSA Announcements can also describe a logical “ false ” node , Like a router LSA The announcement depicts a physical single router . The Internet LSA The announcement lists all routers connected to it , Include DR The router itself . Like a router LSA equally , The Internet LSA It's just creating this network LSA Flood spread inside the area . Use command show ip ospf database network You can view a network LSA Announcement information . Please note that , And routers LSA Different , The Internet LSA There is no measurement field in .
• produce : DR Generated by router
• Flood boundary : Only flood synchronization within the region

（2）—— Header information :

• LS age : Aging time ,1800--3600 second , among 1800 It's cyclical LSA Refresh time ,3600 yes LSA Maximum aging time
• Options: optional
• LS Type: network
• Link State ID: DR The interface of IP Address
• Advertising Router: This LSA Who made it , Just take this router RID Written here
• LS Seq Number: LSA The serial number of , Use this serial number to determine whose LSA Is the latest ,LSA Every update , Serial number +1
• Checksum: Parity sum , Used to verify the integrity of data transmission
• Length: It contains the total length of header information and data part
• Number of Links: I announced several OSPF link

（3）—— Data section :

• —— Describe each router in this broadcast network RID
• —— Description mask , This mask is mainly for DR The interface of IP Address description

（4）—— effect :

• Describe the topology of this broadcast network

 （5） How to view ：

show ip ospf database network

  Two 、LSA-3

（1）—— brief introduction ：

• produce : ABR Produced （ABR Link two different areas , And one of the areas must be in the backbone area )
• Flood boundary :  Except completely STUB Area , Completely NSSA It can be reached outside the area
• effect :  Announce inter area routing
• Network Summary LSA（Network Summary LSA）： By ABR Router From .ABR The router will send the network Summary LSA To an area , Used to announce the destination address outside the area .

（2）—— Header information :

• Ls age : Aging time ,1800--3600 second , among 1800 It's cyclical LSA Refresh time ,3600 yes LSA Maximum aging time
• Options : optional
• LS Type: summary
• LinkT State ID: Announced inter region routing
• Advertising Router : This LSA Who made it , Just take this router RID Written here
• LS Seq Number : LSA The serial number of , Use this serial number to determine whose LSA Is the latest ,LSA Every update , Serial number +1
• Checksum : Parity sum , Used to verify the integrity of data transmission
• Length : It contains the total length of header information and data part
• Number of Links : I announced several inter area routes

（3）—— Data section :

• ---- Describe the link state ID The mask of inter area routing and this ABR Route to this area cost value

（4） How to view ：

show ip ospf database summary