Brocade Communications Systems Layer 3 Routing Configuration ICX 6650 - Manual (Page 159)

Brocade ICX 6650 Layer 3 Routing Configuration Guide 141
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Chapter
3
RIP (IPv4)
Table 27 lists the the Routing Information Protocol (RIP) for IPv4 features Brocade ICX 6650
devices support. These features are supported in the full Layer 3 software image.
RIP overview
Routing Information Protocol (RIP) is an IP route exchange protocol that uses a distance vector (a
number representing a distance) to measure the cost of a given route. The cost is a distance
vector because the cost often is equivalent to the number of router hops between the Brocade
Layer 3 Switch and the destination network.
A Brocade Layer 3 Switch can receive multiple paths to a destination. The software evaluates the
paths, selects the best path, and saves the path in the IP route table as the route to the
destination. Typically, the best path is the path with the fewest hops. A hop is another router
through which packets must travel to reach the destination. If the Brocade Layer 3 Switch receives
a RIP update from another router that contains a path with fewer hops than the path stored in the
Brocade Layer 3 Switch route table, the Layer 3 Switch replaces the older route with the newer one.
The Layer 3 Switch then includes the new path in the updates it sends to other RIP routers,
including Brocade Layer 3 Switches.
RIP routers, including the Brocade Layer 3 Switch, also can modify a route cost, generally by adding
to it, to bias the selection of a route for a given destination. In this case, the actual number of router
hops may be the same, but the route has an administratively higher cost and is thus less likely to
be used than other, lower-cost routes.
A RIP route can have a maximum cost of 15. Any destination with a higher cost is considered
unreachable. Although limiting to larger networks, the low maximum hop count prevents endless
loops in the network.
TABLE 27 Supported RIP features
Feature Brocade ICX 6650
RIP V1 and V2 Yes
Route learning and advertising Yes
Route redistribution into RIP Yes
Route metrics Yes
Route loop prevention:
•
Poison reverse
•
Split horizon
Yes
RIP route advertisement suppression on a
VRRP or VRRP-E backup interface Yes
Route filters Yes
CPU utilization statistics for RIP Yes