Qos; Ieee 802.1D And 802.1Q - Avaya 4600 Series Administrator's Manual

Server Administration

QoS

QoS
The 4600 Series IP Telephones support both IEEE 802.1D/Q and DiffServ, and in the future may support
other, possibly proprietary, procedures for implementing Quality of Service. In addition, other network-
based QoS initiatives such as UDP port selection do not require support by the telephones, but
nonetheless can contribute to improved QoS for the entire network.

IEEE 802.1D and 802.1Q

IEEE's 802.1Q standard defines a tag that can be added to voice and data packets. Most of the
information associated with this tag deals with Virtual LAN (VLAN) management, but 3 bits are reserved
for identifying packet priority. These 3 bits allow any one of 8 priorities to be assigned to a specific
packet. As defined in the standard, the 8 priorities are, from highest to lowest:
•
7: Network management traffic
•
6: Voice traffic with less than 10ms latency
•
5: Voice traffic with less than 100ms latency
•
4: "Controlled-load" traffic (mission-critical data applications)
•
3: Traffic meriting "extra-effort" by the network for prompt delivery (for example, executives'
e-mail)
•
2: Reserved for future use
•
0: Traffic meriting the network's "best-effort" for prompt delivery (the default priority)
•
1: Background traffic such as bulk data transfers and backups
NOTE:
To support IEEE 802.1D/Q, the 4600 Series IP Telephones can be administered either from the network
via appropriate administration of the DHCP or TFTP servers, or at the telephone itself via dialpad input.
Specific implementation details for local administration are in the Installation Guide, and for remote
administration are in this chapter, in
In summary, four IEEE 802.ID/Q QoS parameters in the telephones can be administered. These
parameters are:
•
L2QVLAN: setting the VLAN ID on which the telephone should operate. For example, what
VLAN ID to use for DHCP Discovery, etc. (up to 4 digits, from 0 to 4094, default is 0).
•
VLANTEST: setting the number of seconds to wait for a DHCPOFFER when using a non--zero
VLAN ID (up to 3 digits, from 0 to 999, default is 60).
•
L2QAUD: setting the 802.1Q audio priority value (between 0 and 7, default is 6)
•
L2QSIG: setting the 802.1Q signaling priority value (between 0 and 7, default is 6)
In the 4600 Series IP Telephone Installation Guide, the Local Administrative Option for specifying
ADDResses also allows you to specify VLAN IDs and VLANTEST values (see also
Considerations
specify values for L2QAUD and L2QSIG.
The 4600 Series IP Telephones can simultaneously support receipt of packets using, or not using, 802.1Q
parameters.
62
Priority 0 is a higher priority than Priority 1.
4600 Series IP Telephone Scripts and Application Files
on page 65). The Local Administrative Option for specifying QoS values allows you to
4600 Series IP Telephone Release 2.1 LAN Administrator's Guide
on page 55.
VLAN
July 2004