Information Technology Reference
In-Depth Information
Output for
show ip rip database
and
show ip route
on Router8 (Continued)
Example 7-9
C 192.168.199.0/24 is directly connected, Loopback4
192.168.1.0/30 is subnetted, 1 subnets
C 192.168.1.0 is directly connected, Serial1
router8#
RIPv1 Summary
The characteristics of RIPv1 are summarized as follows:
•
Distance vector protocol.
•
Uses UDP port 520.
•
Classful protocol (no support for VLSM or CIDR).
•
Metric is router hop count.
•
Maximum hop count is 15; unreachable routes have a metric of 16.
•
Periodic route updates broadcast every 30 seconds.
•
25 routes per RIP message.
•
Implements split horizon with poison reverse.
•
Implements triggered updates.
•
No support for authentication.
•
Administrative distance for RIP is 120.
RIPv2
RIPv2 was first described in RFC 1388 and RFC 1723 (1994); the current RFC is 2453, written
in November 1998. Although current environments use advanced routing protocols, such as
OSPF and EIGRP, there still are networks that use RIP. The need for VLSMs and other
requirements prompted the definition of RIPv2.
RIPv2 improves upon RIPv1, as it has the capability to use VLSM and supports route authen-
tication and multicasts route updates. RIPv2 also supports CIDR. Updates are still sent every
30 seconds and the 15-hop limit is retained; triggered updates are also still used. RIPv2 uses
UDP port 520; the RIP process is responsible for checking the version number. Loop prevention
strategies of poison reverse and counting to infinity are retained. On Cisco routes, RIPv2 has
the same administrative distance as RIPv1, which is 120. Finally, RIPv2 uses the IP address
224.0.0.9 when multicasting route updates to other RIP routers.
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