User guide

Chapter 24: Network Configuration Guidelines for VoIP
288 MAXCS ACC 6.7.1 Administration Manual
• The NetFilter driver is installed in the MAXCS server side. For the IPTalk client, the
NetFilter driver will be installed only when the QoS and 802.1p function are enabled
with the IPTalk integrated setting.
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 managed 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 separat-
ed. 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: