Alcatel-Lucent 1643 AMS User's Operation Manual page 424

Traffic provisioning
ID (12 bits)
Concerning their structure there is no difference between a VLAN tag (C-tag) and a
CID tag (S-tag). A distinction between both types of tags can be made by means of the
value in the TPID field, the "Ethertype". In the IEEE 802.1ad VLAN tagging mode
(provider bridge tagging mode), the Ethertype can be provisioned per virtual switch.
The value of the Ethertype depends on the mode of operation:
• In the transparent tagging modes (VPN tagging modes), the value of the Ethertype
is 0xFFFF, and cannot be changed.
• In the IEEE 802.1Q VLAN tagging mode, the value of the Ethertype is 0x8100,
and cannot be changed.
• In the IEEE 802.1ad VLAN tagging mode (provider bridge tagging mode), the
value of the Ethertype can be flexibly chosen in the range 0x0601 { 0xFFFF, but
unequal to 0x8100. The recommended value for the Ethertype in the provider
bridge tagging mode is 0x9100.
Comparison of different tagging schemes
The next figure summarizes the possible tagging schemes:
• No tagging
• Single tagging (IEEE 802.1Q VLAN tagging)
• Double tagging (VPN tagging, IEEE 802.1ad VLAN tagging)
No tagging
Single tagging
Bytes: 12
Double tagging
....................................................................................................................................................................................................................................
8-72
Identification - customer identification which can be configured
in the range [0 { 4093].
Bytes: 12 7
(min.)
IPG Preamble SFD
1
7 6
(min.)
IPG Preamble SFD DA
6 6
DA SA
Alcatel-Lucent - Proprietary
1 6 6 2
DA SA L / T
6 4 2
SA VLAN L / T
4 4 2
CID VLAN L / T
See notice on first page
46 - 1500 4
Data FCS
46 - 1500 4
Data FCS
46 - 1500 4
Data FCS
Tagging modes
365-312-807R7.2
Issue 4, May 2007