Which classful protocols perform an automatic summarization of routes when routers send updates across
major classful network boundaries? (Choose two.)

A.
RIPv1

B.
RIPv2

C.
IGRP

D.
OSPF

E.
EIGRP

F.
BGPv4

Explanation:
The classful routing protocols Routing Information Protocol version1 (RIPv1) and Interior Gateway Routing
Protocol (IGRP) summarize routes at classful network boundaries. RIPv1 is a standard distance vector protocol
that uses hop count as a metric. IGRP is a Cisco Systems proprietary distance vector routing protocol that has
a composite metric based on bandwidth, delay, load, reliability, and maximum transmission unit (MTU).
In classless routing protocols RIPv2, Open Shortest Path First (OSPF), Enhanced IGRP (EIGRP) and Border
Gateway Protocol version 4 (BGPv4), route summarization can be controlled manually at any bit position in the
IP address. Classless routing protocols transmit subnet mask along with the routes, and therefore manual
summarization may be required at times to keep the routing table size in control.
It should be noted that RIPv2 and EIGRP, although classless protocols, will perform automatic summarization
by default unless the no auto-summary command is configured. Once no auto-summary is configured, you can
manually configure summarization on any bit position in the IP address. Since you can override autosummarization in both RIPv2 and EIGRP, RIPv1 and IGRP are better answers to this question.
Objective:
Routing Fundamentals
Sub-Objective:
Compare and contrast interior and exterior routing protocols

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