RIP (Routing Information Protocol, Routing Information Protocol) is an interior gateway protocol (IGP), is a dynamic routing protocol, mainly for smaller networks, such as campus networks and simple regional networks and transmitting routing information within an autonomous system (AS).
This router agreement concerned only with the world around them, only to exchange information with their neighboring routers, the range is limited to 15 hops (15 degrees), the further away, it does not care anymore. RIP is applied to the network layer of the OSI seven layer network model.
For more complex environments and large networks, generally do not use RIP. Management defined from the manufacturers (AD, i.e., priority) are as follows: Priority is defined Huawei 100, priority 120 is defined by Cisco.
RIP is a distance vector protocol (Distance-Vector) algorithm, it exchanges routing information through UDP packets, port number 520. RIP uses a hop count to measure the distance to the destination, the number of hops called the metric. Number of hops in the RIP, a router to its directly connected network is 0, the number of hops up to the router through a network of 1, and so on. To limit convergence time, the RIP predetermined metric is an integer between 0 ~ 15, 16 is greater than or equal to the number of hops is defined as infinite, i.e., the destination network is unreachable. Because of this limitation, RIP is not suitable for large networks. To improve performance, prevent routing loops, RIP supports split horizon (Split Horizon) reversal and toxicity (Poison Reverse) function.
A RIP router has a routing database, the routing database containing routing entries of all reachable destinations. A route entry contains the following information:
• Destination address: IP address of the host or network.
• Next hop: to reach the destination, need to go through the interface IP address of the neighboring router.
• Interface: This router to forward the packet out interface.
• Metric: router to reach the destination.
• Route time: time is updated from the routing entries to now. The time is updated every time a route entry, routing time is set to 0.
• Route Tag (Route Tag): Identifies the route, for flexible control over routing information based on the routing tag in the routing policy. For more information about routing policy, see "Layer -IP Routing Configuration Guide" in the "routing strategy."
RIP process is run as follows:
(1) Start RIP router, the router will send a request to an adjacent packet (Request message), the adjacent routers RIP packet after receiving the request, the response to the request and send the local routing comprises table response message information (response message).
(2) the router receives the response packet, update the local routing table, and sends triggered update to the neighbor router packet routing updates advertised. Adjacent router receives triggered updates, and its neighbor router sends triggered updates. After a series of triggering broadcast, each router can get and keep the new routing information.
(3) the local router periodically transmits routing table to neighboring routers, the neighboring routers in the RIP after receiving the packets, maintenance of the local routes, selecting an optimal route, again their respective neighbors update information, finally make the updated route globally known. Furthermore, RIP uses the aging mechanism out routes by aging process, in order to ensure real and effective routing.
Start rip should be noted:
• If the configuration before starting RIP RIP-related commands in interface view, the configurations take effect only after RIP is enabled.
• RIP is not supported under different segments of the same physical interface to a different RIP processes.
• RIP RIP does not support the multiple processes at the same physical interface.
1. classless routing protocol 2 support variable length subnet mask (VLSM) 3 ways to update the multicast, multicast address:?.?.. 224.0.0.9?4 plaintext (unsecured, you can see the secret capture key) and the encrypted text authentication (MD5 encryption, Cisco private), off by default, need to manually configure authentication update message carrying key neighbor router will compare with their own key, if it receives consistent, otherwise, discard? 5 the routing table lookup mechanism by subcategories - (inquiry by bit, the longest match, exact match, check the 32-bit subnet mask)> 6 major categories of support discontinuous subnets 7 support manual summary,?.?. but enabled by default automatically aggregated and therefore need to turn off auto-summary: no auto-summary
basic concepts of RIP, summary and introduction
Rip import external routes
Network requirements
• Switch B run on two RIP processes: RIP 100 and RIP 200. Switch B exchange routing information through RIP 100 and Switch A, to exchange routing information through RIP 200 and Switch C.
• configuring RIP on Switch B 200 redistribute routes from direct routes and RIP process 100, such that Switch C can learn the routes and 11.1.1.0/24 10.2.1.0/24, but can not learn reach Switch A the route 12.3.1.0/24 and 16.4.1.0/24.
Configure Switch A.
<SwitchA> system-view
[SwitchA] ospf [SwitchA-ospf-1] area 0
[SwitchA-ospf-1-area-0.0.0.0] network 10.5.1.0 0.0.0.255
[SwitchA-ospf-1-area-0.0.0.0] network 10.2.1.0 0.0.0.255
[SwitchA-ospf-1-area-0.0.0.0] quit
Configure Switch B.
<SwitchB> system-view
[SwitchB] ospf
[SwitchB-ospf-1] area 0
[SwitchB-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[SwitchB-ospf-1-area-0.0.0.0] network 10.6.1.0 0.0.0.255
[SwitchB-ospf-1-area-0.0.0.0] quit
Configure Switch C.
<SwitchC> system-view
[SwitchC] ospf
[SwitchC-ospf-1] area 0
[SwitchC-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[SwitchC-ospf-1-area-0.0.0.0] network 10.2.1.0 0.0.0.255
[SwitchC-ospf-1-area-0.0.0.0] quit [SwitchC-ospf-1] quit