Vlan Trunk - Huawei Quidway S9300 Configuration Manual

3 VLAN Configuration
VLAN Broadcast Attribute
When an interface of a VLAN receives a broadcast packet or a unicast packet whose destination
MAC address does not exist in the MAC address table, this interface broadcasts this packet to
other interfaces in the VLAN.
Disabling MAC Address Learning on VLANs
When a static MAC address table is configured, you can disable MAC address learning to
improve the security of a VLAN. When MAC address learning is enabled on the VLAN, you
can limit the number of MAC addresses in the table to improve forwarding efficiency. In
addition, you need to specify the actions that can be performed when the number of MAC
addresses reaches the upper threshold, such as discard, forward, or alarm (sending traps to the
network management system).

VLAN Trunk

When a VLAN is configured on multiple switches, the interfaces on the switches must be able
to identify and forward the packets of different VLANs. This problem also exists in the package
transmission between the switch and router that support VLAN. The link that can identify and
forward the packets of different VLANs is called a trunk.
The trunk has the following functions:
l
l
The most popular protocol used by the trunk is IEEE 802.1Q, which identifies VLANs through
the VLAN tag.
The trunk refers to a point-to-point (P2P) link between two devices. The interfaces on the trunk
are called the trunk interfaces. One trunk can transmit data flows of multiple VLANs to other
devices.
VLAN Aggregation
To implement inter-VALN communication on switches, you need to configure IP addresses for
the VLANIF interfaces, and thus inter-VLAN routing can be implemented. When many VLANs
are deployed, a great number of IP addresses are occupied. VLAN aggregation can solve the
problem of occupation of excessive IP addresses.
VLAN aggregation means that multiple VLANs are aggregated into a super-VLAN. The VLANs
that form the super-VLAN is called sub-VLANs.
You can create a VLANIF interface for a super-VLAN. Then, you can configure an IP address
only for this interface rather than for each sub-VLAN. All sub-VLANs share the same IP network
segment, which optimizes the use of IP addresses.
3-4
Relay
A trunk can transmit the packets from a VLAN to a switch or router transparently, thus
expanding the VLAN.
Transmission backbone
A trunk can transmit the packets of multiple VLANs.
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Quidway S9300 Terabit Routing Switch
Configuration Guide - Ethernet
Issue 03 (2009-08-20)