Analysis of Route redistribution and route optimization

I. Redistribution 1: redistribution means that when an organization runs multiple routing protocols, it must notify the network learned by one routing protocol to the other by the selection protocol, when each endpoint can reach another point, this process is redistribution. Although multiple routing protocols are run in the Organization, each internal routing protocol is considered to be the only internal routing selection protocol in the, OSPF recognizes that OSPF is an external route from the external. 2. Select overnight routes. After redistribution, all networks will be added to the routing selection table and the routing decision is made based on the network status in the table, however, the routing selection protocol only notifies the network that is learned through the process. When routing selection processes do not share information about the network system, it is called night routing (ships in night, SIN ). 3. Default seed measurement values. Default seed measurement values of RIP, IGRP, and VPN are all infinite. They do not enter the route selection table unless the default value is changed; the default IS-IS metric value IS 0, but it can enter the routing table. The default OSPF metric IS two types of LSA value 20, and the routing from bgp is 1; BGP sets MED to the measurement value of IGP. Www.2cto.com 4, when different protocols and different paths exist, use the Management Distance and measurement value for selection: -- add the route with the minimum management distance to the route table in a router with multiple protocols; -- add a route entry with a small measurement value to the selection table in a route entry with multiple paths; -- to re-distribute a route entry, the route entry must be in the corresponding routing selection table, for example, if you want to re-distribute the RIP to the VPC network, the RIP route must be located in the RIP route table. After the route is re-distributed, the default Management Distance from the selected protocol is managed; -- the routes that are redistributed are considered as external routes, and the BGP and VPN are considered as external routes after redistribution. The internal routes are prioritized. Ii. Redistribution may cause selection loops and secondary routes. To avoid these problems, consider using default routes, passive interfaces, and distribution lists, you can use only one-to-one re-distribution method, such as RIP re-distribution to the MongoDB, modify the measurement value, and modify the Management Distance. 3. Control route updates during redistribution to hide the network, prevent loops, control traffic, and ensure security. The methods include: 1. Passive interfaces, the passive interface does not participate in the routing process. In RIP and IGRP, it does not send updates and only listens; this type of interface does not listen or send updates, but does not send HELLO messages. Therefore, they do not establish a neighbor relationship. Router (config-router) # passive-interface ethernet 0/0 configure a passive interface in the routing process mode
2. Static Routing, Which is manually configured, applies to small networks, such as dial-up networks. This type of redistribution static route is also commonly used between BGP and IGP. For example, you can define a static supernetwork to resend the static route to BGP. Static Routing overnetworks are also used when routing protocols that support VLSM are redistributed to those that do not support VLSM. 3. Default route: use the default route when there is no targeted target route. If there is no default route, the group will be lost. IGP commonly uses default routes to connect to the BGP domain, and also uses default routes to connect to large networks. 4. An empty interface is a virtual interface that is used as the logical next hop of a static route. All data streams destined for the network are routed to a black hole. It is often used for redistribution between classless routing and classless routing. 5. distribution list. the distribution list is the access list of the application in the route selection process. It is used to determine which routes will be added to the route table or sent out through update. 6. Routing ing table. route map is a complex access list and can be used for conditional programming. If the match condition is met, the set Modification result is executed. It has the same functions as the distribution list, but it can be more complicated to specify conditions. 4. Configure the re-distribution to enter the target route protocol process mode. First, use redistrubute to specify the source route protocol to be re-distributed, second, configure the default metric value after redistribution: 1. Enter the target routing protocol, that is, the routing protocol to be redistributed to this process by other routing protocols: router (config) # router VPN 100 www.2cto.com
2. Configure the redistribute command to specify the route to be redistributed: router (config-router) # redistribute protocol [process/AS-id] [level-1/level-2/level-1-2] [metric value] [metric-type value] [match internal/external 1/external 2] [tag value] [route-map-tag] [weight value] [subnets] router (config) # router riprouter (config-router) # redistribute OSPF 100 metric 2 redistribution: the Autonomous System number of VPN is 100, and the default Measurement 2 is specified by RIP (the default value is 0 ). Router (config) # router igrp 100 router (config-router) # redistribute rip metric 10000 100 255 1 1500 re-distributing RIP without the AS or process number, when the time is re-allocated to IGRP and ospf, the bandwidth is: bandwidth delay reliability loading mturouter (config) # router ospf 2 router (config-

Router) # redistribute isis level-2 subnets resdistributing ISIS only L2 routes. When it is sent to OSPF, use the SUBNETS parameter to redistribute subnets in the classification network (the default metric is 202 class routes ). Router (config) # router isisrouter (config-router) # redistribute ospf 100 match external 1 metric 10 redistribution OSPF process no. 100 only Class 1 external route redistribution, the configuration metric sent to ISIS is 10 (0 by default) router (config) # router bgp 64512 router (config-router) # tedistribute VPN 64510 weight 10 re-distribution. The autonomous system number of VPN is 64510, send to BGP and set the weight to 10 (1 by default ). 3. Configure the default measurement value) # default-metric value this command will be used for all metric values that are redistributed to the target route (note that metric in the Redistribute command can also be used, however, this metric is used to specify the router (config-router) # default-metric bandwidth delay reliability loading mtu destination route for each protocol when it is IGRP or ix2. For example: router (config) # router VPN 100 router (config-router) # redistriripriprouter (config-router) # redistribute staticrouter (config-rotuer) # default-metric 10000 100 255 1 1500 the same metric from RIP and static route redistribution uses 10000 100 255 1 1500 4. Configure the Management Distance, it is configured when multiple routing protocols have different paths; router (config) # distance VPN internal-distance external-distance when configuring the VPN management distance, the router (config-router) is different from other protocols) # distance value [address mask] [access-list-number/nam E] [ip] configure the Management Distance of other routing protocols; the VALUE is 10--255, Which is retained below 9, and 255 is inaccessible; address and the corresponding anti-subnet mask specify the management distance for the route according to the Route IP address. The ACL applies the corresponding access list to the inbound route update and only specifies the management distance for the qualified route protocol; the IP parameter is used by ISIS to specify the Management Distance for IP routing only. 5. Configure the passive interface. The router (config-router) # passiveinterface interface-type number does not listen in RIP, only receives, and does not listen or send in OSPF and OSPF, configure Static Routing. The router (config) # ip route prefix mask [address/interface] [distance] [tag value] [permanent] www.2cto.com can specify the outbound interface on the point-to-point link, the next hop address must be specified for multi-point or multi-channel access. 7. Configure the default route. router (config) # ip route 0.0.0.0 0.0.0.0 s0 router (config) # ip default-network-number this command generates a default route that will be transmitted through updates. This command is not generated on the configured route, but is generated on the route directly connected to the default network. 8. Control route update by filtering. distribution list: router (config-router) # distribute-list ACL/name in interface-type number router (config-router) # distribute-list ACL/name out interface-name/routeing-process/