Cisco Exam 352-001: CCDE Written Exam

Layer 2 Access Edge Design for Host-Only Ports

Question

You are asked to design a large campus network that will be using multicast for data transport.

Which feature should be enabled at the Layer 2 access edge for host-only ports?

Answers

Explanations

Click on the arrows to vote for the correct answer

A. B. C. D.

A.

In a large campus network that uses multicast for data transport, it is important to ensure that multicast traffic is properly managed and controlled. At the Layer 2 access edge, host-only ports are typically used for connecting end-user devices such as computers and printers. To ensure that multicast traffic is properly handled on these ports, a specific feature should be enabled.

The correct answer to this question is A. PortFast.

PortFast is a Cisco IOS feature that is used to enable fast transition of a Layer 2 access port into forwarding state. When a host-only port is configured with PortFast, it bypasses the usual spanning tree protocol (STP) learning and blocking phases and immediately transitions to forwarding state. This ensures that multicast traffic is delivered to end-user devices without delay.

BPDU guard, on the other hand, is used to prevent the introduction of unauthorized switches in the network. When BPDU guard is enabled, the port is disabled if a BPDU packet is received, indicating the presence of an unauthorized switch. While this feature can be useful for security purposes, it is not directly related to multicast traffic management.

PIM-SM (Protocol Independent Multicast - Sparse Mode) is a multicast routing protocol that is used to establish multicast distribution trees in a network. While PIM-SM is important for managing multicast traffic, it is typically implemented at the Layer 3 distribution and core layers of a network, rather than at the Layer 2 access edge.

PIM query interval is a configuration parameter for PIM-SM that determines the frequency at which the multicast router sends queries to the multicast sources. While this parameter can affect multicast traffic performance, it is not directly related to the configuration of host-only ports at the Layer 2 access edge.