ZXR10 2600 Product Description
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4.3.2.2
Flow Direction of VLAN Data Packet
In consideration of the network security and convenient management, the VLAN
technology is adopted in the current network deployment. The following describes the
flow direction of data packets in the VLAN. The VLAN processing procedure is as
follows:
•
Data frame inbound: The switch classifies inbound data frames according to their
VLAN identification (VID): data frames without VID into one category and those with
the same VID into another category. The switch forwards or discards a data packet
according to the VID. Meanwhile, the switch can assign a VID to a frame without
any labeling or a frame labeled as priority.
•
VLAN tag: If a data frame has no VID, the switch will assign a VID to it and insert it
into the frame header. This process is called “Label VLAN”. The switch handles
packet forwarding and fills the VLAN of the data frame or the identification field of
the priority information through this process. The administrator can set the priority to
select the type of VLAN and the VID. The default setting of the switch includes the
IP subnet information, the network protocol, the MAC address, and the inbound port
of the data frame.
•
Filtering: The process verifies whether the destination address and the source
address are in the same VLAN.
•
Forwarding: The switch either forwards a data frame or discards it according to the
information of the VLAN database.
•
Learning: The switch checks the source address of the data frame and VLAN
classification information and records them in the forwarding database.
The port mode of ZXR10 2600 series is divided into access mode and trunk mode. The
port mode determines the data output form, namely, whether the VLAN data packet is
output directly or output with the Tag removed after the switch makes a forwarding
decision.
As far as the encapsulation of data packets is concerned, ZXR10 2600 series are the
same as most Ethernet switches. That is, when an untagged data packet reaches a port,
the switch encapsulates a tag for the packet according to the PVID of the port and then
determines the VID according to the tag. Finally the switch searches the destination site
of the data packet in the same VLAN. If the destination MAC address is found, the data
packet will reach the destination. If the destination MAC address is not determined or
found, the data packet will be broadcast in the same VLAN or directly discarded.
