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TS Virtual Ports and VLAN Tagging
Unlike ordinary Token Ring ports, Translational Switch (TS) ports can function as trunk ports, which means they can carry traffic belonging to all of the 63 VLANs it is possible to configure in the switch over the same physical cable connection.
Frames from different VLANs are distinguished by means of standard IEEE 802.1Q frame tags. A frame tag consists of a
To identify the VLAN to which the frame belongs, the TCI field makes use of a 12- bit VLAN identifier that uniquely identifies the BRF. It also contains a 3 bit priority field (described in “FC Modification” on page 31).
Each TS port can be assigned to several CRFs, but there can be only one TS port per BRF/VLAN. A virtual port is created for each CRF to which the TS port is assigned. All virtual ports but one must be tagged (that is a single virtual port can be left untagged).
Note that a TS port with a single untagged virtual port is functionally equivalent to an ordinary Token Ring port. This is also the default configuration, with the virtual port in
Virtual Port Restriction
A TS port can have only one virtual port in each VLAN. Otherwise it would not be possible to distinguish frames from two virtual ports in the same VLAN, since they would have the same VLAN identifier.
Ring Number Restriction
All CRFs in which a TS port has virtual ports must have the same ring number. The ring number is a
Configuration |
