What should the RIP Protocol do when IPv6 comes? (1)

The development of the network is immeasurable. Now we have transitioned from IPv4 to IPv6, So how should we adapt to the routing, especially the RIP Protocol? With the rapid development of the Internet, the network scale expands rapidly, the amount of information is increasing rapidly, and new applications are emerging one after another, the original Network Interconnection protocol version 4 that has been developed for more than 20 years -- IPv4 protocol has insufficient address space due to its inherent defects, low routing efficiency, poor security, low service quality, and lack valid mobile support ), it cannot fundamentally adapt to the needs of network development. in this context, the next generation network standard IPv6 Protocol emerged. this article discusses the RIP of Ripng for IPv6 networks. as the next-generation Internet IP layer technology has become a rule, IPv6 is one of the leading topics in the field of information technology to thoroughly study the simplicity and ease of use protocol Ripng, it has important economic and social significance.

I. Basic working principles of the RIP Protocol

The routing information protocol RIP (RoutingInformationProtocol) is a routing protocol specially designed by the Internal Gateway Protocol Workgroup for the Internet Engineering Task Group IETF, it is an internal gateway dynamic routing protocol based on distance vector algorithm.

Each router running RIP maintains a RIP route table. The content of this route table is 1.

Figure 1RIP route table

The next hop nexthop indicates the address to which the next packet will arrive. The metric) indicates the cost required to deliver the packet from the current router to the destination station ). the maximum valid measurement supported by the RIP Protocol is 15. When the measurement of a route reaches 16, the route is considered invalid and the corresponding destination is considered inaccessible.

The flag indicates whether the route has changed recently for use when an update is triggered. The age is actually a timer used to maintain each route. in RIP, if a route is not refreshed after 180 seconds, the route is considered no longer valid and its measurement is set to 16.

The RIP Router periodically sends a copy of its route table to the neighbor in multicast mode, that is, the <purpose, measurement> group. Each router that receives the message modifies the measurement of the route in the message, add the cost of receiving the route message interface to the measurement of each route. then, judge the route quality based on the measurement size, and put the route with the smallest measurement into the route table. The judgment process is as follows:

1) check whether there are any routes for this purpose in the routing table; 2) Add the route if no route is found; 3) If yes, the route is updated only when the new metric is updated, otherwise, ignore the route.

Figure 2 shows the workflow of the RIP Protocol. As a result, we can clearly see that RIP has such a simple workflow.

Figure 2RIP Workflow

2. When a RIP is started on an interface of the routerrouter, the interface sends a route table information request to the neighbor in the form of multicast, requesting the neighbor to send the route table information to himself; the neighbor RouterB receives the route table information request and sends the entire route table information to respond to the request. After RouterB is started, the router is sent and updated periodically. When RouterB detects route changes, sends a trigger update to the neighbor in multicast mode to notify the neighbor route change.

Ii. Evolution of RIP Protocol in the IPv6 Era

As we all know, today's RIP has evolved from RIP-1 to RIP-2, and now there is a revolutionary IPv6-based Ripng! Studying the evolution of RIP and analyzing the similarities and differences of RIP in various stages of development is of great significance for optimizing and developing the protocol.

RIP-1 only supports subnets in a network with subnets. It is difficult to know the subnet mask outside the network, and thus the subnet and host items cannot be distinguished, in this way, you need to use a strictly hierarchical route: The External router transmits the group to the nearest vro in the network, regardless of which subnet the destination site belongs. followed by a strict hierarchy of routes, this is the requirement for connectivity, that is, every vro in this network should know how to go to any subnet!

Based on the preceding disadvantages, RIP-2 defines an effective RIP improvement solution, and redefines some "must be zero" fields contained in the RIP-1 format.

A new AFI Item 0 xFFFF is added based on security considerations to transmit "verification data". "Route Selection domain" and "Next Hop domain" are added ", allows multiple RIP instances to run on a single vro to specify the destination IP address to which the packets are sent, the "Next Hop domain" attribute allows only one router running another protocol to advertise all the routes, in addition, the router running the RIP Protocol can find the router that runs the Protocol correctly as the next hop to achieve the destination address of all known protocols. The "subnet mask" is added ", to enhance the performance of subnet selection routing, and add a "routing label" to mark external routes.