Routing Policy And Route Redistribution.

When we create a record, we need to choose a routing strategy to determine how to respond to the query.

Therefore, when a client user sends a request, the routing policy will determine to respond to the user request.

About routing policies and route redistribution. SPOTO will analyze these situations, get more IT certification content, and continue to pay attention to us.

Session 1 routing policy

1, ACL access control list, for the data packet, the default deny any

Match odd odd network (172.16.1/3/5/7/9...)

172.16.1.0 0.0.254.0 (1 bit in the reverse mask stands for random, 0 bit represents exact match, just opposite the mask)

Matching even networks (172.16.0/2/4/6/8...)

172.16.0.0 0.0.254.0 (1 bit in the reverse mask stands for random, 0 bit represents exact match, just opposite the mask)

2, ip prefix-list routing prefix list, for routing entries

10.0.0.0/13 ge 16 le 16

13 represents the exact number of bits for the first 13 bits (fixed), and get and le represent the minimum and maximum number of mask entries for the route entry.

Match 8 network routing entries of 10.0-7.0.0/16

Explanation: 10.00000 | 000.0.0, the first 13 bits of the specification (that is, fixed by 10.00000) are changed after the 3 bits, so the result of the change is 8 routes from 000-111, that is, 0-7, followed by ge 16 Le 16 fixed the network with a subnet mask of 255.255.0.0, so it is:

10.0.0.0/16, 10.1.0.0/16, 10.2.0.0/16, 10.3.0.0/16, 10.4.0.0/16, 10.5.0.0/16, 10.6.0.0/16, 10.7.0.0/16 exact match These 8 routes

Class A network (the first bit is fixed to 1, the last 7 bits are freely changed, and the subnet mask must be 255.0.0.0)

0.0.0.0/1 ge 8 le 8

Class B network (the first 2 bits are fixed to 1, the last 7 bits are freely changed, and the subnet mask must be 255.255.0.0)

0.0.0.0/2 ge 16 le 16

Class C network (the first 3 bits are fixed to 1, the last 7 bits are freely changed, and the subnet mask must be 255.255.255.0)

0.0.0.0/3 ge 24 le 24

Default route

0.0.0.0/0

All routing entries except the default route

0.0.0.0/1 le 32

All routing entries any

0.0.0.0/0 le 32

3, route-map routing strategy of a tool, not what routing diagram, the default deny any

You can call ACL and IP prefix-list. The call in ACL and prefix-list represents a match, deny represents a mismatch instead of allowing and deny, and the real permit and deny are in route-map A permit/deny

Exp1:

Route-map FL permit

Match IP address prefix-list 13(IP prefix-list 13 permit 10.0.0.0/13 ge 16 le 16)

Fully grabbed the contents of prelist13, other routes are not crawled

Exp2:

Route-map DMVPN permit

Match IP address prefix-list 6 (IP prefix-list 6 permit 10.6.0.0/16)

Set local-preference 99

Route-map DMVPN permit 20

Write permit 20, which means that LP 99 is only set for prefix-list 6. Other routes are not modified (general-map X permit 20 is required when using set parameters)

Session 2 route redistribution

1, igp redistribute

When OSPF is redistributed into BGP, only the internal route is redistributed by default. If you need to redistribute the external route into BGP, you need to use the parameter match internal external.

2, bgp redistribute

Ibgp cannot be redistributed into the IGP by default. You must use the BGP distribution-internal command.

Ebgp can be redistributed into IGP by default