Maximum Network Size - Hirschmann Power MICE User Manual

RIP

6.2 Maximum Network Size

The biggest problem with RIP is that routers only know their neighbors
directly. This results in long convergence times and the count-to-infinity
problem. Infinity refers to the inaccessibility of a destination, and it is
designated by hop count 16 in RIP. If the above example did not contain
the parallel path via routers D, E and F, then routers A and B would keep
sending their routing tables until the metric reached a value of 16. Then the
routers recognize that the destination is inaccessible.
Using the "split horizon" approach eliminates this looping problem between
two neighboring routers. Split horizon has two operating modes.
Simple split horizon
Simple split horizon with
poison reverse
Thus the hop count 16 specifies the maximum size of a network with RIP as
the routing procedure. The longest paths may use up to 15 routers.
68
Omits the entries known by a neighbor when sending the
routing table to this neighbor.
Sends the routing table to a neighbor with the entries known
by this neighbor, but denotes these entries with the infinity
metric (=16).
6.2 Maximum Network Size
Release 4.2 08/08
Routing L3E