RIPng

The next generation of routing information protocol (RIPng, used in IPv6) is a kind of IPv6 network protocol and algorithm based on the agreement. In the international network, such as the Internet, have a lot of application in the network routing protocol. Form a network of each autonomy system (AS), has his own routing technology, different autonomous system, routing technology is also different. Autonomous system internal routing protocol called internal gateway protocol (IGP). External gateway protocol (EGP) is a kind of used to in the autonomous system transmission routing information between the agreement. RIPng in the middle scale AS IGP is used AS the agreement. For more complex network environment, RIPng doesn't apply.

RIPng is a Distance Vector (Vector) an algorithm. The agreement of the algorithm used in early 1969, with its to calculate the NCP routing. But the agreement first belong to XEROX network protocol. PUP agreement through the gateway information exchange agreement, and XNS routing information is adopted the agreement updated version, named for routing information protocol (RIP) realize routing information exchange. Berkeley routing protocol to the extent of the same, that is, the ability to deal with RIP IPV4 and other address type of generic address format replaced the XNS address, and routing updates every 30 seconds a. It is for this similarity, RIP applies both to XNS agreement, also suitable for routing type of agreement.

About IPV4 network, routing information agreement refers to the RIP/RIP2, the concrete content can consult relevant specification. This paper mainly expounds RIPng.

About IPV6 network, routing information agreement refers to the RIPng

RIPng message format

RIPng is based on the agreement, and use the UDP port 521 send and receive data reported. RIPng message can be roughly divided into two classes: choose the way

Information and is used in a message request information message. They are using the same format, the first by a fixed Route Table and RTE (Entry Table is a are composed of a routing Table, can have DuoGe.

RIPng working principle

The router usually can't active request to request a message routing, routing request usually just router just start or routers are looking for routing information will request a message for the response. The router in inquires, periodic updates and trigger the response update three cases will receive a response message. According to the response to decide whether it is a message router to local routing table updates. Because a message might be in response to local routing table change to the source of the message, so must be a strict check, to confirm the legitimacy of the message.

As is known to all, based on distance vector routing algorithm is also slow convergence and infinite count produced, which by routing is not the same. RIPng use level division technology, toxic reversal technology, trigger update technology to solve these problems, but the introduction of these technologies, and brought other problems, such as the trigger update technology, if not produce a message of reasonable control, easy to produce the broadcast storm.

The router periodic message broadcast and trigger updates to the network, which a lot of extra load, in order to reduce the number of routing information, RIPng multicast technology can be used to send a message, at the same time update a small random time-delays trigger updates to control a message.

RIPng introduced the working principle of have to mention timer, timer in RIPng plays a very important role, RIPng use to realize the timer routing table updates, message, send. Periodic message broadcast by the timer is realized, in addition to prevent routing table long time not update and failure, every routing table item has two timer and associated the overtime of the routing table, a final will be deleted, in order to prevent the router radio and use have failed routing. The timer used in RIPng basically has the following three: start periodic radio timer. The timer is set to 25 s to 35 s any random number between. The purpose of this set is to avoid all routers on the network at the same time send a message of the random intervals, update can be balanced, thus reduce traffic conflict between the router possibility.

Timer expires. The router to specific XinSu routing the receipt to the XinSu to the expiration of the initial timer. Expires timer is set for 180 s, if a route before the expiration of the timer overtime did not get the update, the relevant message routing is no longer effective, but this is still retained in the routing table, in order to notify the other routers the route have failed.

Garbage collection timer. The router to play for the invalid routing scale the infinity of invalid marked, and will refuse collection timer initialization. At this time, the timer is set for 120 s, in this period of time the routing could still be router periodically, such radio adjacent routers can quickly from the routing table delete from which.

RIPv1 RIPv2 and RIPng comparison

According to the above, we should see RIPng goal is not to create a new agreement, but for RIP necessary modification to make its way to the selected IPv6 requirements, so RIPng basic working principle of is the same with RIP, the main change in address and message format. Following are some RIPv1, RIPv2 and the main difference between RIPng:

1. The address version. RIPv1, RIPv2 is based on IPv4, address domain, and RIPng only 32 bit IPv6, based on the use of all addresses are for 128 bit.

2. The subnet mask and the prefix length. RIPv1 are designed to no subnet network, so no subnet mask concept, this determines the RIPv1 can not be used in communication variable-length subnet address or used for the address. No type CIDR RIPv2 added to choose way, the support of the subnet mask so using subnet MaOu points network routing and subnet routing. IPv6 address prefix have clear meaning, so there is no longer in RIPng subnet mask concept, instead the prefix length. The same is also using the IPv6 address, RIPng also no need to distinguish between network routing, route and host routing subnet.

3. The scope of use agreement. RIPv1, RIPv2 the scope of use is designed not only confined to the TCP/IP protocol suite, still can adapt to the other network protocol suite rules, it's a message routing table are included in the network protocol suite field, but the actual realize the program is rarely used for other than the IP network, so RIPng removing the to the function of support.

4. On the next dance said. RIPv1 no next hop in the information, the receiving end the router IP address as the source of a message to the purpose of network routing next jump. RIPv2 clearly contains the next hop information facilitate select the optimal route and prevent choose road and slow convergence loop. And RIPv2 different, to prevent RTE too long, and at the same time, in order to improve the transmission efficiency of routing information, the RIPng next hop field is as a separate RTE exist.

5. A message length. RIPv1, in a message to the length of the RIPv2 are limited, in each message only carry 25 RTE. And RIPng to a message length, the number of RTE all regulation, the length of a message by the decision of the medium MTU. In the absence of RIPng length, improving the road network processing by the transmission efficiency of information.

6. RIPng use FF02: : 9 this address for multicast update.