Cisco Certified Network Associate (CCNA) Practice Exam

Disable ads (and more) with a membership for a one time $2.99 payment

Study for the Cisco Certified Network Associate (CCNA) exam with our comprehensive quiz featuring multiple-choice questions and detailed explanations. Prepare effectively and enhance your understanding of networking concepts!

Practice this question and more.

Which command is used to lower the default MTU size for a PPPoE configuration?

ip mtu 1500
ip mtu 1492
mtu 1492
set mtu 1492

The correct answer is: ip mtu 1492

The command used to lower the default Maximum Transmission Unit (MTU) size for a Point-to-Point Protocol over Ethernet (PPPoE) configuration is "ip mtu 1492." This command is particularly relevant in PPPoE environments because the standard Ethernet MTU is 1500 bytes. However, PPPoE introduces a slight overhead due to the additional header it adds to each packet, which effectively reduces the available MTU size for the data being sent. By setting the MTU size to 1492, you account for this overhead (8 bytes) and ensure that the packets transmitted do not get fragmented, which can lead to performance issues and connection problems. This is crucial for maintaining efficient and reliable network communication over PPPoE connections. The other options either do not apply in the context of PPPoE or are incorrectly formatted for the purpose of configuring the MTU. The "ip mtu" command itself is necessary to specify the MTU size on a specific interface, while "mtu" alone is often used for layer two interfaces but may not always be recognized in all Cisco devices or contexts.