CCNA 200-301 v1.1 reference — Network Fundamentals
Ethernet switching
MAC address learning and aging, frame switching and flooding decisions, and how to read the MAC address table.
Objective 1.13v1.1 exam target
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MAC learning and forwarding
- A frame arrives: the switch records the source MAC → ingress port in the MAC address table.
- It looks up the destination MAC: known unicast → forward out the listed port only.
- Unknown unicast, broadcast, or multicast without snooping → flood out all ports except the source port.
- Entries age out (default ~300 seconds of silence) and are relearned on the next frame.
Frame forwarding decisions
| Destination MAC | Switch action |
|---|---|
| Known unicast in table | Forward out the single mapped port |
| Unknown unicast | Flood out all ports except ingress |
| Broadcast (ff:ff:ff:ff:ff:ff) | Flood out all ports except ingress |
| Multicast | Floods unless IGMP snooping maps it |
$ show mac address-table dynamic
Vlan Mac Address Type PortsEntries are per-VLAN. 10 001a.2b3c.4d5e DYNAMIC Gi0/5Host learned on Gi0/5 in VLAN 10. 10 00aa.bb01.0201 DYNAMIC Gi0/24Uplink toward the rest of the network.Related resources
Sources
- Cisco CCNA 200-301 v1.1 Exam Topics (official PDF) — reviewed 2026-11-02
- Cisco — LAN Switching Command Reference — reviewed 2026-11-02
Targets CCNA 200-301 v1.1 objectives. Supplemental blocks are labeled beyond exam scope.