Port-Based Vlan - H3C S7500 Series Operation Manual

Operation Manual – VLAN
H3C S7500 Series Ethernet Switches
Figure 1-2 Encapsulation format of traditional Ethernet frames
In Figure 1-2
address, and Type refers to the protocol type of the packet. IEEE 802.1Q protocol
defines that a 4-byte VLAN tag is encapsulated after the destination MAC address and
source MAC address to show the information about VLAN.
DA&SA
Figure 1-3 Format of VLAN tag
As shown in
and VLAN ID.
TPID is a 16-bit field, indicating that this data frame is VLAN-tagged. By default, it
is 0x8100 in H3C series Ethernet switches.
Priority is a 3-bit field, referring to 802.1p priority. Refer to "QoS" part for details.
CFI is a 1-bit field, indicating whether the MAC address is encapsulated in the
standard format in different transmission media. This field is not described in detail
in this chapter.
VLAN ID is a 12-bit field, indicating the ID of the VLAN to which this packet
belongs. It is in the range of 0 to 4,095. Generally, 0 and 4,095 is not used, so the
VLAN ID is in the range of 1 to 4,094.
VLAN ID identifies the VLAN to which a packet belongs. When the switch receives an
un-VLAN-tagged packet, it will encapsulate a VLAN tag with the default VLAN ID of the
inbound port for the packet, and the packet will be assigned to the default VLAN of the
inbound port for transmission. For the details about setting the default VLAN of a port,
refer to the "Port Basic Configuration" part of the H3C S7500 Series Ethernet Switches
– Operation Manual.

1.2 Port-Based VLAN

Port-based VLAN technology introduces the simplest way to classify VLANs. You can
isolate the hosts and divide them into different virtual workgroups through assigning the
ports on the device connecting to hosts to different VLANs.
This way is easy to implement and manage and it is applicable to hosts with relatively
fixed positions.
DA&SA Type
DA refers to the destination MAC address, SA refers to the source MAC
VLAN Tag
TPID Priority CFI
Figure 1-3, a VLAN tag contains four fields, including TPID, priority, CFI,
Data
VL AN ID
1-3
Chapter 1 VLAN Overview
Type