Vlan Interface - H3C S3100 8C SI Operation Manual

Operation Manual – VLAN
H3C S3100 Series Ethernet Switches
II. MAC address learning mechanism of VLANs
Switches forward packets according to the destination MAC addresses of the packets.
So that switches maintain a table called MAC address forwarding table to record the
source MAC addresses of the received packets and the corresponding ports receiving
the packets for consequent packet forwarding. The process of recording is called MAC
address learning.
After VLANs are configured on a switch, the MAC address learning of the switch has
the following two modes.
Shared VLAN Learning (SVL): the switch records all the MAC address entries
learnt by ports in all VLANs to a shared MAC address forwarding table. Packets
received on any port of any VLAN are forwarded according to this table.
Independent VLAN Learning (IVL): the switch maintains an independent MAC
address forwarding table for each VLAN. The source MAC address of a packet
received on a port of a VLAN is recorded to the MAC address forwarding table of
this VLAN only, and packets received on a port of a VLAN are forwarded
according to the VLAN's own MAC address forwarding table.
Currently, the H3C S3100 series Ethernet switches adopt the IVL mode only. For more
information about the MAC address forwarding table, refer to the "MAC Address
Forwarding Table Management" part of the manual.

1.1.4 VLAN Interface

Hosts in different VLANs cannot communicate with each other directly unless routers or
Layer 3 switches are used to do Layer 3 forwarding. The S3100 series Ethernet
switches support VLAN interfaces configuration to forward packets in Layer 3.
VLAN interface is a virtual interface in Layer 3 mode, used to realize the layer 3
communication between different VLANs, and does not exist on a switch as a physical
entity. Each VLAN has a VLAN interface, which can forward packets of the local VLAN
to the destination IP addresses at the network layer. Normally, since VLANs can isolate
broadcast domains, each VLAN corresponds to an IP network segment. And a VLAN
interface serves as the gateway of the segment to forward packets in Layer 3 based on
IP addresses.
Note:
An S3100 series switch can be configured with a single VLAN interface only, and the
VLAN must be the management VLAN. For details about the management VLAN, refer
to the "Management VLAN Configuration" part of this manual.
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Chapter 1 VLAN Overview