Static Routing and Distance Vector Routing Protocols - CCIE Routing and Switching Exam Certification Guide - page 332

•

Subnet Mask —Contains the subnet mask for the destination. If this field is zero, no
subnet mask has been specified for the entry.

•

Next Hop —Indicates the IP address of the next hop where packets are sent to reach the
destination.

•

Metric —Indicates how many router hops to reach the destination. The metric is between
1 and 15 for a valid route, or 16 for an unreachable or infinite route.

Again, as in version 1, up to 25 occurrences of the last five 32-bit words (20 bytes) are permitted
for up to 25 routes per RIP message. If the AFI specifies an authenticated message, only 24
routing table entries can be specified.

RIPv2 Timers
RIPv2 timers are the same as in version 1. Periodic updates are sent every 30 seconds. The
default invalid timer is 180 seconds, the holddown timer is 180 seconds, and the flush timer is
240 seconds.

RIPv2 Configuration
The RIPv2 protocol is configured just as in RIPv1 by using the global router rip command.
You use a version command to enable use of the RIPv2 protocol. Then, the networks that are
routed with RIP are configured with the network command. Looking again at Figure 7-2, the
routers in this example are configured differently than the example configurations shown for
RIPv1. First, you use the version command. Second, subnetworks can now have different
subnet masks. The serial link is configured with a /30 mask. The Token Ring network is
configured with a /28 mask.

The configuration examples in this section are for Router8, Router9, and Router10, as shown
in Figure 7-4. In these examples, you use VLSMs and authentication is configured.

Example Network Figure 7-4

Router9 Router10

172.16.4.0/30

.1

.1

.2

.1

172.16.2.0/24

172.16.1.0/24

.2

.1

Router8

172.16.3.0/28