Catalog

1 class Lsa：

Transnet type :

P2P type ：

stubnet type ：

virtual type

2 class Lsa：

3 class Lsa：

5 class Lsa：

4 class Lsa:

7 class Lsa：

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   stay Hcia Stage , We introduced OSPF frequently-used LSA The main types are 1、2、3、4、5、7 common 6 Kind of LSA.

      Today we mainly focus on OSPF Of 1 class 、2 class 、3 class LSA To comb . To this end, we set up OSPF The network is shown in the figure below ：

    Area 0 For broadcast type ,R1 Of G0 mouth ( Hereinafter referred to as interface 1) and R2 Of G0 mouth ( Hereinafter referred to as interface 2) Announce to area 0 in .R2 Of S0 mouth ( Hereinafter referred to as serial port 1)  and R4 Of S0 mouth ( Hereinafter referred to as serial port 2) Announce to area 1 in . Area 1 by p2p Network type . The specific configuration will not be repeated .

      We are R2 Routers , see lsdb Here's the picture .( The order is :[R2]display  ospf  lsdb)

1 class Lsa：

(1) It mainly describes the link information of the direct interface with the route ;

(2) Each router will generate one 1 class Lsa entry ;

(3)1 class Lsa There are four types of , Respectively p2p、stubnet、transnet、virtual;

(4)Lsa The meaning of internal elements :

      We can see that , stay 2.2.2.2 Of lsdb in , contain 3 Kind of 1 class Lsa.

Transnet type :

among :

      type： Express Lsa The type of ,router Express 1 class Lsa;

       Ls id： It means that we should lsa The name of ;

       adv rtr： Indicates that the lsa The router ;

       Ls age： Indicates aging time , For the initial 0,3600 For aging ;

       Len： Express Lsa Message length ;

     seq： Serial number , For comparison Lsa New and old ;

     Checksum： The checksum

     Link count： The amount of link information

            Link id： Information representing the pseudo node

            Data： Indicates that it is connected to the pseudo node IP

            link type： describe 1 class Lsa The type of ,transnet Expressed as broadcast or NBMA type

            Metric： Cost value

P2P type ：

  among ,Lsa The header information is the same , No more narratives ：

         Link id： Indicates neighbor information ;

         Data： Represents the interface between itself and its neighbors ;

         Link type： describe 1 class Lsa The type of ,p2p Indicates that the network type is P2P,

         Metric： Indicates the cost value of the link .

stubnet type ：

          Link id： The routing network number directly connected to itself ;

         Data： A mask representing the network number ;

         Link type： Expressed as node information ;

         Metric： Indicates the cost value of the link .

virtual type

The virtual link is configured as :

[ Area ]vlink-peer  To the end router id

      To generate a link type by virtual A class of lsa. Its link id Represents the end-to-end route of the virtual link router id,data Represents the interface to the virtual link .

2 class Lsa：

(1) Mainly on the radio or NBMA In the network type , Information used to describe pseudo nodes ;

(2)Lsa The internal elements are shown in the figure below ：

       type： Express lsa type ,network Expressed as 2 class Lsa;

        Attached router： Indicates neighbor routing

3 class Lsa：

(1) It's mainly about... In different areas 1 class Lsa and 2 class Lsa convert , So that it can be transmitted in different areas .

(2) Only ABR Route can be converted , And 3 class Lsa Flooding in this area .

(3)3 class Lsa The meaning of each element ：

Compared with the above figure ：

 

Last article , We talked about it. OSPF In the agreement 1 class ,2 class ,3 class Lsa, These three categories Lsa Mainly transmitted OSPF Link information in the protocol , However , In our daily life , It's impossible for all routers to run ospf agreement , This involves the concept of external routing , Is to be non ospf Routing information of the protocol , Announce the advance ospf Agreement . The specific configuration is ：

[ospf process ]import-router  static( Routing protocol , Here is the static route )

​

      Let's set up a brief Topology .

        Above picture , There were 3 individual area Area ,R4 For external routing ,R3 Of G0 The mouth did not announce OSPF in , But in R3 Add a static route , To find R4 Of loopback0 mouth .

        stay R3 On , Introduce... Through the external routing just learned , Introduce this static route to ospf in .

      R5 Of loopback0 There is no announcement into ospf in , But a direct external route .

        according to Hcia Learned configuration commands , After we configure the network in the figure above , Introduce external routes into ospf in , stay R1 Check out ospf Of lsdb Information ：

We found that , There are two new types of lsa entry , Namely sum-asbr,external. That's what we're talking about today 4 class ,5 class Lsa.

5 class Lsa：

(1) When an external route is introduced to ospf In the agreement , A router that connects external routes ( For example R3 Router ) Will be set to asbr route , And send the 1 strip 1 class Lsa Information , Tell the neighbors , I am for asbr, Then , Send external routing information , With 5 class Lsa In the form of , Forward .

(2)5 class Lsa Is in ospf Forwarding in the whole region .

(3)5 class Lsa Elements

        type： Express Lsa type ,External Expressed as 5 class Lsa;

       Ls id： Indicates the network number of the routing information ;

       adv rtr： Indicates the advertiser's router-id:

       E type：asbr Reach the target network cost The type of calculation , The default is 2, Indicates that only asbr To the target network cost value ; Can be changed to 1, In addition to calculating the above cost value , And then + Arrive by oneself asbr Of cost value .

       Forwarding  address： Used to do ospf Link optimization , If Fa by 0.0.0.0, Then the route to the outside will pass through adv rtr. If Fa There are specific ip, Then route to the outside , Will pass Fa Address to external routing .

4 class Lsa:

(1)4 class lsa Yes. asbr Sent 1 class Lsa Transformed from , The main function is to tell other areas that I can find 5 class Lsa The link state information contained .

(2)4 class Lsa By Abr Produced , And in ospf Flood in this area . That's why area0 and area1 One of them 4 class lsa, And only 5 class Lsa It's a separate one .

(3)4 class Lsa Elements ：

    type： Express Lsa The type of ,sum-asbr It means that we should Lsa by 4 class Lsa;

    Ls id： Express asbr Route name for ;

    adv rtr： It means you can go to asbr Route name for , stay abr Routers , Will be converted again , For example, above ,R1 Know what you're looking for Asbr Can pass R2 Router , meanwhile R1 Through to 4 class Lsa To update , Tell the area 2 The routing , I can find asbr.

    Other elements and others Lsa identical .

7 class Lsa：

(1)7 class Lsa yes Nssa The area is used to generate when introducing external routes Lsa;

(2)7 class Lsa Flood only in this area ;

(3)7 class Lsa When passing to other areas ,abr Will 7 class Lsa Convert to 5 class Lsa, Flooding in other areas .

(4)7 class Lsa Elements ：

      type： Express Lsa type ,nssa by 7 class lsa

      Ls  id： Indicates the network number that announces the routing information ;

     Adv  rtr： Indicates the advertiser ;

    The rest is related to 5 class Lsa Exactly the same ,7 class lsa It is to solve the problem of introducing external routing into special areas , It can be simply understood as nssa Regional 7 Class is equivalent to the... Of a normal region 5 class .

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