AudioCodes Mediant 2000, User Manual

Page: 385 / 418

Version 5.6 385 November 2008
SIP User's Manual 8. Networking Capabilities
„
Dual IP mode:
The device is assigned two IP addresses for the different traffic types.
One IP address is assigned to a combination of two traffic types (Media and Control,
OAMP and Control, or OAMP and Media), while the other IP address is assigned to
whichever traffic type not included in this combination. For example, a typical scenario
using this mode includes one IP address assigned to Control and OAMP, and another
IP address assigned to Media.
For detailed information on integrating the device into a VLAN and multiple IPs network,
refer to ''Getting Started with VLANS and Multiple IPs'' on page
387 . For detailed
information on configuring the multiple IP parameters, refer to ''Networking Parameters'' on
page
260 .
Notes:
•
A default Gateway is supported only for the Media traffic type; for Control
and OAM traffic, use the 'IP Routing' table (refer to ''Configuring the IP
Routing Table'' on page
62 ).
•
The IP address and subnet mask used in the Single IP Network mode are
used for the OAM traffic type in the Multiple IP Network mode.
8.9.2 IEEE 802.1p/Q (VLANs and Priority)
The Virtual Local Area Network (VLAN) mechanism enables the device to be integrated into
a VLAN-aware environment that includes switches, routers and endpoints. When in VLAN-
enabled mode, each packet is tagged with values that specify its priority (class-of-service /
IEEE 802.1p) and the identifier (traffic type) of the VLAN to which it belongs (Media,
Control, or OAMP / IEEE 802.1Q).
The class-of-service (CoS) mechanism can be utilized to accomplish Ethernet Quality of
Service (QoS). Packets sent by the device to the Ethernet network are divided into five
different-priority classes (Network, Premium Media, Premium Control, Gold, and Bronze).
The priority of each class is determined by a corresponding
ini
file parameter.
Traffic type tagging can be used to implement Layer 2 VLAN security. By discriminating
traffic into separate and independent domains, the information is preserved within the
VLAN. Incoming packets received from an incorrect VLAN are discarded.
The traffic tagging mechanism is as follows:
„
Outgoing packets (from the device to the switch):
All outgoing packets are tagged,
each according to its interface (Control, Media or OAMP). If the device’s native VLAN
ID is identical to one of the other IDs (usually to the OAMP's VLAN ID), this ID (e.g.,
OAMP) is set to zero on outgoing packets (VlanSendNonTaggedOnNative set to 0).
This method is called Priority Tagging (p tag without Q tag). If the parameter
VlanSendNonTaggedOnNative is set to 1, the device sends regular packets (with no
VLAN tag).
„
Incoming packets (from the switch to the device):
The switch sends all packets
intended for the device (according to the switch’s configuration) to the device without
altering them. For packets whose VLAN ID is identical to the switch’s PVID, the switch
removes the tag and sends a packet. The device accepts only packets that have a
VLAN ID identical to one of its interfaces (Control, Media or OAMP). Packets with a
VLAN ID that is 0 or untagged packets are accepted only if the device’s native VLAN
ID is identical to the VLAN ID of one of its interfaces. In this case, the packets are sent
to the relevant interface. All other packets are rejected.