Vlan Tag; Vlan Link Type; Figure 1 Vlan Tag Format - Zte ZXR10 5900 Series User Manual

ZXR10 5900/5200 Series User Manual (Ethernet Switching Volume)
2 Confidential and Proprietary Information of ZTE CORPORATION
Assume ports 1, 2 and 3 belong to the same VLAN, while the other
ports belong to other VLANs, then frames received on port 1 are
broadcast to ports 2 and 3 only while they are not passed to any
other port. When a user in a VLAN moves to a new location, it no
longer belongs to the original VLAN unless the user is assigned to
that VLAN again.

VLAN Tag

It is possible to transmit services of several VLANs over a single
link if a frame carries information about its native VLAN while being
passed through a network. IEEE 802.1Q implements this function
through attaching a VLAN tag to the Ethernet frame.
A VLAN tag is a four-byte long number, and it comes after the
source MAC address and before the length/type field in an Ethernet
frame. Figure 1 shows the VLAN tag format.
F 1 VLAN TAG FORMAT
IGURE
VLAN tag is applied to cross-switch VLANs, when the link between
switches is usually called a trunk. VLAN tag allows VLANs cross
several switches to be created through one or more trunks. When
the ports connecting these switches receive a tagged frame, the
ports can judge which VLAN the frame belongs to based on the
VLAN tag.
Each 802.1Q port is allocated a default VLAN ID, called PVID. Un-
tagged frames received on a port is considered belonging to the
default VLAN, and then broadcasted in that VLAN.
ZXR10 5900/5200 supports IEEE 802.1Q tag.

VLAN Link Type

ZXR10 5900/5200 ports support the following links:
1. Access link
It connects devices (such as workstation) that cannot iden-
tify VLAN tags to the VLAN switch port. It transmits untagged
frames only to a single VLAN.
2. Trunk link