And redistribution routing path control
First, the route redistribution Overview
Routing redistribution may be provided in a same interconnection network to efficiently support multiple routing protocols, routers perform routing redistribution is referred to as border routers, since they are located on the boundary of two or more autonomous systems.
Distance metrics and manage routing redistribution must be considered, it must be converted during redistribution protocol standard, such that they are compatible. Seeds metric (Seed Metric) is defined when the route raw profile, which is a measure of the initial redistribution external incoming route. Routing protocol default seed measure in the following table:
| EIGRP | Unlimited |
|---|---|
| OSPF | BGP is 1, which is also 20 |
| IS-IS | 0 |
| Redistribution routing and routing protocol into | The default seed metric |
| RIP | Unlimited |
| BGP | The IGP metric |
Consider the question:
1. Route feedback: two-way redistribution is possible to learn from one autonomous system routing information is sent back to the autonomous system.
2. compatible routing information: Metric different routing protocols are different
3. The convergence time inconsistency
Second, the path control Overview
In order to ensure efficient operation of the network and avoid routing redistribution when suboptimal routing or a loop, it is necessary to control routing updates, commonly used methods are passive interface default route, static routing, route map, distribution lists, prefix list, a list of offsets, Cisco IOS IP service level agreement (SLA) and policy routing. When performing routing control, a variety of methods may be combined.
1, route map (Route Map)
Can do complex access control list, the main features include routing control and policy routing.
(1) define the route mapping table following format:
Define a route map: route-map map-tag [permit | deny] [sequence-number]
Matching conditions: macth (matching condition commonly includes the IP address, the interface, measure, tag, type, and routes the packet length, etc.)
If the format is: match ip address abc represents the logical OR condition is satisfied as long as there can be a
If the format is: match ip address a
match ip address b
match ip address c presentation logic, it must meet all the conditions
Definition of behavior: set
| * Set behavior * | *description* |
|---|---|
| set ip next hop | Setting a next-hop packet |
| set interface | Setting a packet Interface |
| set ip default next hop | Set the default next-hop address, routing table for the time when there is no route to the IP address entry |
| set ip tos | The set value of the IP packet TOS |
| set ip precedence | Set the priority of IP packets |
| Set metric | Set the cost of routing |
| set tag | Setting the route tag value |
(2) the routing map has the following characteristics
At the end of a route map A. The default behavior is to "deny any"
Such as the implementation of policy-based routing, it did not match the normal forward
The re-routing time-sharing, no matches were filtered out
B. A route map may comprise a plurality of route map statement is executed from top to bottom, there is no such route map statements Math, all the matches.
C. sequence number specifies the order of conditional execution, do not write the default is 10, does not automatically increment
D.route map does not permit write permit deny by default
E. When you delete a route map, did not write the number to delete the entire route map
2, policy routing
Policy-based routing provides a mechanism for data packet forwarding according to the network administrator defined policies. Policy-Based Routing stronger than traditional routing capabilities, the use of flexible, which allows network administrators not only based on destination address, but also be able to select a forwarding path according to the protocol type, packet size, application or source IP address. Policy is defined by the route map.
PBR
PBR
Policy-based routing provides a mechanism for data packet forwarding according to the network administrator defined policies. Policy-Based Routing stronger than traditional routing capabilities, more flexible, network managers can not only use it according to the destination address and the forwarding path can be selected according to the protocol type, packet size, application or source IP address. Policy is defined by the route map.
Dce line: Dce this end the device must provide a clock frequency, the DTE does not need to, when connected to the serial port, there must be provided a device clock frequency.
VPN: Virtual Private Network
VPN tunnel:
GRE tunnel: do not support encryption
Supports multicast and broadcast (routing protocol)
IPSEK: support encryption
It does not support multicast and broadcast traffic and GRE
PBR experiment:
A school network topology map at right, with Telecom, China Unicom two export lines, the network is divided into living quarters and a teaching area, belonging to lvan10 and vlan20. Through policy-based routing configuration to achieve the following requirements:
1, the dormitory area to access the Internet using a telecommunications outlet, teaching area using Unicom export.
2, any one link fails, can be switched automatically.
3, dormitory area and teaching area are using a router address export PAT.
Experimental Procedure:
1, the external configuration of the network protocol rip2
2, the internal configuration of the network protocol ospf
3. Configure ACL
4, routing policy
5, configure NAT
Configuration one: to achieve the dormitory area to access the Internet using a telecommunications outlet,
China Unicom to use teaching area exports. But can not automatically switch
R1(config)#access-list 10 permit 192.168.10.0 0.0.0.255
R1(config)#access-list 20 permit 192.168.20.0 0.0.0.255
R1(config)#route-map dianxin permit 10
R1(config-route-map)#match int s2/0
R1(config)#route-map liantong permit 20
R1(config-route-map)#match int s2/1
R1(config)#ip nat inside source route-map dianxin int s2/0 overload
R1(config)#ip nat inside source route-map liantong int s2/1 overload
R1(config)#int s2/0
R1(config-if)#ip nat outside
R1(config)#int s2/1
R1(config-if)#ip nat outside
R1(config)#int f0/0
R1(config-if)#ip nat inside
R1(config)#int f1/0
R1(config-if)#ip nat inside
Configuration two: to achieve the dormitory area to access the Internet using a telecommunications outlet,
China Unicom to use teaching area exports. And can realize automatic switch
R1(config)#access-list 10 permit 192.168.10.0 0.0.0.255
R1(config)#access-list 20 permit 192.168.20.0 0.0.0.255
R1(config)#route-map fenliu permit 10
R1(config-route-map)#match ip add 10
R1(config-route-map)#set ip next-hop 50.1.1.2 60.1.1.2
R1(config)#route-map fenliu permit 20
R1(config-route-map)#match ip add 20
R1(config-route-map)#set ip next-hop 60.1.1.2 50.1.1.2
R1(config)#int e1/0
R1(config-if)#ip policy route-map fenliu
R1(config)#int e1/1
R1(config-if)#ip policy route-map fenliu
The hour is late, good night!
