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

4-June-07 P1901_PRO_016_r0
The Packet Format has the following fields:
- EXT – 16 bits. Reserved for extensions
- PB – 48 bits. Previous Bridge ID
Figure 64 Packet format
- OVLAN – 32 bits with the following information:
o PCF – 1 bit. Pre-classified Packet
o PCP – 3 bit. Pre-classified Packet Priority
o OVLANV - 1 bit.Valid OVLAN
o OVLANID - 12 bits. OVLAN Identifier
- DA – 48 bits. Destination MAC Address. The DA field identifies which station(s) should receive the
frame.
- SA – 48 bits. Source MAC Address. The SA identifies the sending station.
- TPID – 16 bits. Optional field. Defined value of 8100 in hex. When a frame has the EtherType equal to
8100, this frame carries the tag IEEE 802.1Q/802.1p, otherwise it will be filled with 0x0000.
- TCI – 16 bits. Optional field. VLAN Tag Control Information field including user priority, Canonical
format indicator and VLAN ID. This field is always present, even if the TPID is not 0x8100.
- Len – 16 bits. IEEE Std 802.3-style Length/Type Field
- Data – From 42 to 1500 bytes. The Data Payload of this packet.
- PLW – From 0 to 3 bytes. Because the packet has to be 32 bit aligned, there are from 0 to 3 bytes of no
valid data at the end of this packet. This field is called Padding Last Word.
The incoming IEEE std 802.3 packet may have TCI field or not, but the TCI field is always present in the IEEE
1901 packet format.
6.2.1 Maximum and Minimum Packet length
The maximum length of one packet is equal to 1536 octets.
The minimum length of one packet is equal to 76 octets.
Submission page 167 UPA-OPERA