Correct Answer: D. The MAC addresses of devices communicating on active ports and static MAC addresses configured by the administrator.
A MAC address table, commonly implemented as a Content Addressable Memory (CAM) table, is maintained by Ethernet switches to support efficient Layer 2 frame forwarding.
The table contains MAC addresses associated with switch interfaces and VLANs. Entries can be dynamically learned or statically configured.
Dynamic MAC Address Entries:
When a switch receives an Ethernet frame, it examines the source MAC address and associates that address with the receiving interface and VLAN. Dynamically learned entries normally expire after an aging period when no corresponding traffic is observed.
Static MAC Address Entries:
Administrators can manually configure MAC address entries to associate specific MAC addresses with designated interfaces and VLANs. These entries do not follow ordinary dynamic aging procedures.
The Cisco IOS command used to examine the table is:
show mac address-table
Why the other options are incorrect:
A. IP-to-MAC mappings belong to ARP tables for IPv4, not ordinary Layer 2 MAC address tables.
B. Standard MAC address tables store Layer 2 addresses rather than both Layer 2 and Layer 3 addresses.
C. MAC address tables do not dynamically maintain host Layer 3 addresses for every active switch port.
Therefore, Option D correctly identifies both dynamically learned and statically configured MAC address information.
[References:, Cisco Certified Support Technician Networking (100-150) — Network Infrastructure, Ethernet Switching and MAC Address Learning., Cisco IOS XE CDP, LLDP, MAC, and UDLD Configuration Guide — Configure MAC., Cisco Catalyst Switching Documentation — MAC Address Table Creation, Dynamic and Static MAC Address Entries., , , ]
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