Blade ICE G8124-E Manuale Utente

BMD00220, October 2010

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In a routed environment, routers communicate with one another to keep track of available routes. 
Routers can learn about available routes dynamically using the Routing Information Protocol (RIP). 
BLADEOS software supports RIP version 1 (RIPv1) and RIP version 2 (RIPv2) for exchanging 
TCP/IPv4 route information with other routers. 

BLADEOS 6.5 does not support IPv6 for RIP.

RIP is known as a distance vector protocol. The vector is the network number and next hop, and the 
distance is the metric associated with the network number. RIP identifies network reachability 
based on metric, and metric is defined as hop count. One hop is considered to be the distance from 
one switch to the next, which typically is 1. 

When a switch receives a routing update that contains a new or changed destination network entry, 
the switch adds 1 to the metric value indicated in the update and enters the network in the routing 
table. The IPv4 address of the sender is used as the next hop.

RIP includes a number of other stability features that are common to many routing protocols. For 
example, RIP implements the split horizon and hold-down mechanisms to prevent incorrect routing 
information from being propagated. 

RIP prevents routing loops from continuing indefinitely by implementing a limit on the number of 
hops allowed in a path from the source to a destination. The maximum number of hops in a path 
is 15. The network destination network is considered unreachable if increasing the metric value 
by 1 causes the metric to be 16 (that is infinity). This limits the maximum diameter of a RIP 
network to less than 16 hops.

RIP is often used in stub networks and in small autonomous systems that do not have many 
redundant paths.