Routing policy in republishing

Default RIP and OSPF If the agreement is reissued at two points , Because of their different priorities , So the first one ASBR After the re release of the device , Will affect other ASBR Routing table of the device . So that the route may be returned to the source protocol , Routing feedback occurs

Due to the seed metric problem of republishing Technology , Will inevitably lead to poor route selection ; We can only rely on the routing strategy to consider interference in routing

Control layer flow ： The routing protocol transmits the traffic generated by the routing information
Data layer traffic ： When the device accesses the target network segment , Data traffic generated

Routing strategy
In the process of controlling the flow of the layer , Intercept flow , Then modify the traffic and forward it or not ; The final implementation affects the generation of router routing table , The effect of interference in route selection

1、 Grab traffic
1、ACL list

2、IP-prefix ---- The prefix list
View prefix list information ：
display ip-prefix aa

Insert rules according to serial number ：
ip ip-prefix aa index 15 permit 192.168.3.0 24

Delete the rule in the prefix list ：
undo ip ip-prefix aa index 15

Crawl mask length is 24 To 28 Between ：
ip ip-prefix aa permit 192.168.3.0 24 less-equal 28

Match all host routes ：
ip ip-prefix aa permit 0.0.0.0 0 greater-equal 32

Match the default ：
ip ip-prefix aa permit 0.0.0.0 0 less-equal 32

Matching rules for prefix list ：
From top to bottom , One by one matching , Once matched, the action will be executed according to the corresponding rules , Don't match down any more . The end implicitly rejects all rules

2、 Routing strategy
1、RIP Of merticin and merticout ---- Offset list ---- Only for distance vector protocol design and Application
1. Grab traffic
ip ip-prefix aa permit 23.0.0.0 24
2. Call... On the interface
rip metricin ip-prefix aa 10

2、filter-policy ---- Filtering strategy
1. Grab traffic
ip ip-prefix bb deny 34.0.0.0 24
ip ip-perfix bb permit 0.0.0.0 0 less-equal 32
2. Called in the process
filter-policy ip-prefix bb import G 0/0/0

3、route-policy ---- Routing strategy
1. Grab traffic
rule permit source 1.1.1.0 0
rule permit source 2.2.2.0 0
ip ip-prefix aa permit 3.3.3.0 24
ip ip-prefix bb permit 4.4.4.0 24
2. Configure routing policies
route-policy aa deny node 10
if-match acl 2000
Be careful ： One rule , If there are multiple apply perhaps if-match, Then these needs are met at the same time , Satisfy " And " Relationship .

route-policy aa permit node 50 ---- Allow all
1、 No, if-match ---- Match all
2、 No, apply ---- Just follow the big action

3、 Call the routing policy during republishing
import-route rip route-policy aa
Matching rules of routing policy ：
From top to bottom , One by one matching , Once matched, the action will be executed according to the corresponding rules , Don't match down any more . The end implicitly rejects all rules

ROUTE-POLICY Configuration Guide for
1、 Even if a traffic needs to be rejected , When capturing traffic , Permission must also be used , Then reject in the routing policy
2、 In one rule , If there is no flow matching , Then it means that all ; If there is no APPLY, Only follow the big action . therefore , The big action is allowed, and the empty table means that all .