Routing Information Protocol

The Acquisition Advice Agreement (RIP) is a distance-vector acquisition protocol, which employs the hop calculation as a acquisition metric. RIP prevents acquisition loops by implementing a absolute on the amount of hops accustomed in a aisle from the antecedent to a destination. The best amount of hops accustomed for RIP is 15. This hop limit, however, aswell banned the admeasurement of networks that RIP can support. A hop calculation of 16 is advised an absolute ambit and acclimated to bemoan inaccessible, inoperable, or contrarily abominable routes in the alternative process.

RIP accouterments the breach horizon, avenue contagion and holddown mechanisms to anticipate incorrect acquisition advice from getting propagated. These are some of the adherence appearance of RIP. It is aswell accessible to use the so alleged RMTI1 (Routing Advice Agreement with Metric-based Topology Investigation) algorithm to cope with the count-to-infinity problem. With its help, it is accessible to ascertain every accessible bend with a actual baby ciphering effort.

Originally anniversary RIP router transmitted abounding updates every 30 seconds. In the aboriginal deployments, acquisition tables were baby abundant that the cartage was not significant. As networks grew in size, however, it became axiomatic there could be a massive cartage access every 30 seconds, even if the routers had been initialized at accidental times. It was thought, as a aftereffect of accidental initialization, the acquisition updates would advance out in time, but this was not accurate in practice. Sally Floyd and Van Jacobson showed in 19942 that, after slight randomization of the amend timer, the timers synchronized over time. In a lot of accepted networking environments, RIP is not the adopted best for acquisition as its time to assemble and scalability are poor compared to EIGRP, OSPF, or IS-IS (the closing two getting link-state acquisition protocols), and (without RMTI) a hop absolute acutely banned the admeasurement of arrangement it can be acclimated in. However, it is simple to configure, because RIP does not crave any ambit on a router clashing added protocols (see actuality for an action of basal RIP simulation visualizing RIP agreement and exchanging of Request and Response to ascertain new routes).

RIP uses the User Datagram Agreement (UDP) as its carriage protocol, and is assigned the aloof anchorage amount 520.3

Versions

There are three versions of the Acquisition Advice Protocol: RIPv1, RIPv2, and RIPng.

editRIP adaptation 1

The aboriginal blueprint of RIP, authentic in RFC 1058,4 uses classful routing. The alternate acquisition updates do not backpack subnet information, defective abutment for capricious breadth subnet masks (VLSM). This limitation makes it absurd to accept different-sized subnets central of the aforementioned arrangement class. In added words, all subnets in a arrangement chic accept to accept the aforementioned size. There is aswell no abutment for router authentication, authoritative RIP accessible to assorted attacks.

editRIP adaptation 2

Due to the deficiencies of the aboriginal RIP specification, RIP adaptation 2 (RIPv2) was developed in 19935 and endure connected in 1998.6 It included the adeptness to backpack subnet information, appropriately acknowledging Classless Inter-Domain Acquisition (CIDR). To advance astern compatibility, the hop calculation absolute of 15 remained. RIPv2 has accessories to absolutely interoperate with the beforehand blueprint if all Accept to Be Zero agreement fields in the RIPv1 letters are appropriately specified. In addition, a affinity about-face feature6 allows aerial interoperability adjustments.

In an accomplishment to abstain accidental amount on hosts that do not participate in routing, RIPv2 multicasts the absolute acquisition table to all adjoining routers at the abode 224.0.0.9, as against to RIPv1 which uses broadcast. Unicast acclamation is still accustomed for appropriate applications.

(MD5) affidavit for RIP was alien in 1997.78

RIPv2 is Internet Standard STD56 (which is RFC 2453).

Route tags were aswell added in RIP adaptation 2. This functionality allows for routes to be acclaimed from centralized routes to alien redistributed routes from EGP protocols.

editRIPng

RIPng (RIP next generation), authentic in RFC 2080,9 is an addendum of RIPv2 for abutment of IPv6, the next bearing Internet Protocol. The capital differences amid RIPv2 and RIPng are:

Support of IPv6 networking.

While RIPv2 supports RIPv1 updates authentication, RIPng does not. IPv6 routers were, at the time, declared to use IPsec for authentication.

RIPv2 allows adhering approximate tags to routes, RIPng does not;

RIPv2 encodes the next-hop into anniversary avenue entries, RIPng requires specific encoding of the next hop for a set of avenue entries.

RIPng sends updates on UDP anchorage 521 application the multicast accumulation FF02::9.

Limitations

Without application RMTI, Hop calculation can not beat 15, in the case that it exceeds this limitation, it will be advised invalid.

Most RIP networks are flat. There is no abstraction of areas or boundaries in RIP networks.

Variable Length Subnet Masks were not accurate by RIP adaptation 1.

Without application RMTI, RIP has apathetic aggregation and calculation to beyond problems.

Implementations

Cisco IOS, software acclimated in Cisco routers (supports adaptation 1, adaptation 2 and RIPng)

Cisco NX-OS software acclimated in Cisco Nexus abstracts centermost switches (supports RIPv1 and RIPv2)

Junos software acclimated in Juniper routers, switches, and firewalls (supports RIPv1 and RIPv2)

routed[10] and route6d, included in a lot of BSD Unix systems

Routing and Remote Access, a Windows Server feature, contains RIP support

Quagga, a chargeless accessible antecedent acquisition software apartment based on GNU Zebra

BIRD, a chargeless accessible antecedent acquisition software suite

OpenBSD, includes a RIP implementation

Similar protocols

IGRP: Cisco's proprietary Interior Gateway Acquisition Agreement (IGRP) was a somewhat added able agreement than RIP. It belongs to the aforementioned basal ancestors of distance-vector acquisition protocols. Cisco has accomplished abutment and administration of IGRP in their router software. It was replaced by the Enhanced Interior Gateway Acquisition Agreement (EIGRP) which is a absolutely new design. While EIGRP still uses a distance-vector model, it relates to IGRP alone in application the aforementioned acquisition metrics. IGRP supports assorted metrics for anniversary route, including bandwidth, delay, load, MTU, and reliability.