Nortel Networks 1000ASE-XD Switch User Manual


 
56 Chapter 2 Network configuration
209418-A
Untagged membera port that has been configured as an untagged member
of a specific VLAN. When an untagged frame exits the switch through an
untagged member port, the frame header remains unchanged. When a tagged
frame exits the switch through an untagged member port, the tag is stripped
and the tagged frame is changed to an untagged frame.
Tagged membera port that has been configured as a member of a specific
VLAN. When an untagged frame exits the switch through a tagged member
port, the frame header is modified to include the 32-bit tag associated with the
PVID. When a tagged frame exits the switch through a tagged member port,
the frame header remains unchanged (original VID remains).
User prioritya three-bit field in the header of a tagged frame. The field is
interpreted as a binary number, therefore has a value of 0 - 7. This field allows
the tagged frame to carry the user-priority across bridged LANs where the
individual LAN segments may be unable to signal priority information.
Port prioritythe priority level assigned to untagged frames received on a
port. This value becomes the user priority for the frame. Tagged packets get
their user priority from the value contained in the 802.1Q frame header.
Unregistered packeta tagged frame that contains a VID where the receiving
port is not a member of that VLAN.
The default configuration settings for BayStack 420 switches have all ports set as
untagged members of VLAN 1 with all ports configured as PVID = 1. Every
VLAN is assigned a unique VLAN identifier (VID) that distinguishes it from all
other VLANs. In the default configuration example shown in Figure 12, all
incoming packets are assigned to VLAN 1 by the default port VLAN identifier
(PVID =1). Untagged packets enter and leave the switch unchanged.