Introduction To Mac Address Table; Chapter 1 Mac Address Table Management; Introduction To Mac Address Learning - H3C S5100-SI Series Operation Manual

Operation Manual – MAC Address Table Management
H3C S5100-SI/EI Series Ethernet Switches

Chapter 1 MAC Address Table Management

Note:
This chapter describes the management of static, dynamic, and blackhole MAC
address entries. For information about the management of multicast MAC address
entries, refer to the part related to multicast protocol.
1.1 Overview

1.1.1 Introduction to MAC Address Table

An Ethernet switch is mainly used to forward packets at the data link layer, that is,
transmit the packets to the corresponding ports according to the destination MAC
address of the packets. To forward packets quickly, a switch maintains a MAC address
table, which is a Layer 2 address table recording the MAC address-to-forwarding port
association. Each entry in a MAC address table contains the following fields:
Destination MAC address
ID of the VLAN which a port belongs to
Forwarding egress port numbers on the local switch
When forwarding a packet, an Ethernet switch adopts one of the two forwarding
methods based upon the MAC address table entries.
Unicast forwarding: If the destination MAC address carried in the packet is
included in a MAC address table entry, the switch forwards the packet through the
forwarding egress port in the entry.
Broadcast forwarding: If the destination MAC address carried in the packet is not
included in the MAC address table, the switch broadcasts the packet to all ports
except the one receiving the packet.

1.1.2 Introduction to MAC Address Learning

MAC address table entries can be updated and maintained through the following two
ways:
Manual configuration
MAC address learning
1-1
Chapter 1 MAC Address Table
Management