AltiGen MAXCS 7.0 Update 1 ACM Administration - Manual (Page 316)

Chapter 25: Network Configuration Guidelines for VoIP
300 MaxCS 7.5 Administration Manual
Ethernet II Framing Header
The Ethernet II framing header is defined as follows, with 802.1Q VLAN tag and 802.1p priority bits:
For 802.1Q VLAN-tagged Ethernet frame, the Tag Protocol Identifier (TPID) or Ethernet Type is set to 0x8100.
The next 16 bits defines the VLAN and QoS bits:
• Priority Code Point (PCP): a 3-bit field which refers to the IEEE 802.1p priority. It indicates the frame
priority level from 0 (lowest) to 7 (highest), which can be used to prioritize different classes of traffic (voice,
video, data, and so on).
• Canonical Format Indicator (CFI): a 1-bit field. If the value of this field is 1, the MAC address is in non-
canonical format. If the value is 0, the MAC address is in canonical format. It is always set to zero for
Ethernet switches.
• VLAN Identifier (VID): a 12-bit field specifying the VLAN to which the frame belongs. A value of 0 means
that the frame doesn't belong to any VLAN; in this case the 802.1Q tag specifies only a priority and is
referred to as a priority tag. A value of hex FFF is reserved for implementation use. All other values may
be used as VLAN identifiers, allowing up to 4094 VLANs.
Only port-based VLAN is supported in MAXCS, which means the VLAN is assigned in the switch port and man-
aged in the switch internally. The end device, like the MAXCS NIC and IP phone ARM MAC port, does not
need to tag the packet with VLAN so there is no software implementation on the end device. MAXCS can use
two NICs and connects them to the switch ports with a different VLAN assigned so the network traffic can be
separated. However inside the IP phone, the firmware programs the Ethernet switch to assign and manage
the different ports with different VLAN IDs. The IP phone user can configure the IP phone port with voice VLAN
ID and PC port with data VLAN ID. Different VLANs use a different IP network. Below is a typical VLAN setup:
The NIC in both the MAXCS server and the IPTalk client (used with MaxCommunicator/MaxAgent) must
support 802.1p. To see if the NIC supports the 802.1p feature, open the NIC’s Properties dialog box and select
the Advanced tab. See if the "QoS Packet Tagging" property is in the Property list. (Different NICs have
different properties and may display a different property name for the 802.1p feature.) If the NIC supports the
802.1p feature, the default value is Disabled and you can change this value to enable 802.1p as seen in the
following figure: