Rip Operation; Rip Versions; Trip - HP MSR Series Configuration Manual

Split horizon—Disables RIP from sending routing information on the interface from which the
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information was learned to prevent routing loops and save bandwidth.
Poison reverse—Enables RIP to set the metric of routes received from a neighbor to 16 and sends
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back these routes to the neighbor so the neighbor can delete such information from its routing table
to prevent routing loops.
Triggered updates—RIP immediately advertises triggered updates for topology changes to reduce
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the possibility of routing loops and to speed up convergence.

RIP operation

RIP works as follows:
1. RIP sends request messages to neighboring routers. Neighboring routers return response
messages containing routing tables.
2. RIP uses the received responses to update the local routing table and sends triggered update
messages to its neighbors. All RIP routers on the network do this to learn latest routing information.
3. RIP periodically sends the local routing table to its neighbors. After a RIP neighbor receives the
message, it updates its routing table, selects optimal routes, and sends an update to other
neighbors. RIP ages routes to keep only valid routes.

RIP versions

There are two RIP versions, RIPv1 and RIPv2.
RIPv1 is a classful routing protocol. It advertises messages through broadcast only. RIPv1 messages do
not carry mask information, so RIPv1 can only recognize natural networks such as Class A, B, and C. For
this reason, RIPv1 does not support non-contiguous subnets.
RIPv2 is a classless routing protocol. It has the following advantages over RIPv1:
Supports route tags to implement flexible route control through routing policies.
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• Supports masks, route summarization, and CIDR.
Supports designated next hops to select the best ones on broadcast networks.
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Supports multicasting route updates so only RIPv2 routers can receive these updates to reduce
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resource consumption.
Supports simple authentication and MD5 authentication to enhance security.
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RIPv2 supports two transmission modes: broadcast and multicast. Multicast is the default mode using
224.0.0.9 as the multicast address. An interface operating in the RIPv2 broadcast mode can also
receive RIPv1 messages.

TRIP

Triggered RIP (TRIP), a RIP extension for WANs, is mainly used in dial-up networks.
Working mechanism
Routing information is sent in triggered updates rather than in periodic broadcasts to reduce route
management cost on WANs.
A routing update message is sent when data in the routing table changes or the next hop is
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unreachable.
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