Medium Access Control (MAC) and Physical Layer (PHY) - CISE

4-June-07 P1901_PRO_016_r0
6.2.2 OVLAN Fields
OVLAN fields are intended for OVLAN The OVLAN is a sort of Virtual LAN (VLAN), which functions
independtly of IEEE 802.1Q. Jointly with IEEE 802.1Q functionality it provides a two-layer Virtual LAN
functionality between BPL nodes. OVLAN functionality is described in Clause 7.4).
The OVLAN fields are the following:
- OVLANV - 1 bit. Valid OVLAN
- OVLANID - 12 bits. OVLAN Identifier
The OVLAN fields have the following meaning:
- When OVLANV is equal to 0, the OVLANID is not used and the packet is not carrying OVLAN
information.
- When OVLANV is equal to 1, the OVLANID is equal to the tag, and the tag is used with the same sense as
in IEEE 802.1Q. The only difference is the following:
o The tag equal to 0 is a possible tag
o The tag equal to 0xFFF is a tag that must be accepted by all the filters.
As in IEEE 802.1Q where the TCI has priority information, the OVLAN word has two fields to know the priority of
this packet:
- PCF: Pre-classified Packet
- PCP: Pre-classified Packet Priority
If PCF is set to 1, the priority of this packet is equal to PCP value. The 802.1p or any other rule is not applied to
decide the priority. Priority assignment is described in clause 8.
In the case of nodes that do not perform OVLAN filtering, the OVLAN field will not be modified if the packet was
received through a BPL interface. If the packet was received through other interfaces, the node will add the
OVLAN fields with OVLANV = 1b0 and PCF = 1b0.
6.2.3 BPL service class
The OVLAN word has two fields that store the poweline service class of this packet. BPL service class is used in
parallel to IEEE 802.1Q priority. The fields are:
- PCF: Pre-classified Packet
- PCP: Pre-classified Packet Service class
Submission page 168 UPA-OPERA