Diffserv - Avaya 4600 Series Administrator's Manual

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
Priority 0 is a higher priority than Priority 1.
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
Manual, and for remote administration are in this Chapter, in ''4600 Series IP Telephone Scripts
and Application Files'' on page 4-14 In summary, three IEEE 802.1D/Q QoS parameters in the
telephones can be administered. These parameters are:
L2Q: setting the 802.1Q framing parameter ON or OFF
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)
The 4600 Series IP Telephones can simultaneously support receipt of packets using, or not using,
802.1Q parameters.
WARNING:
If you turn VLAN framing on (L2Q=1) using the TFTP-based upgrade script
(46xxupgrade.scr), and you set your VLAN ID (L2QVLAN) to something other than
your default VLAN ID, the IP address you are using for the telephone will probably be
wrong for the new VLAN. See ''Administering Options for the 4600 Series IP
Telephones'' for more information.

DIFFSERV

As defined in IETF RFCs 2474 and 2475, "services" are basically ways of treating different subsets
of a network's traffic in different ways at the Internet Protocol (IP) layer, Layer 3. For example,
some packets might be routed in such a way as to expedite delivery (minimize delay), while others
are routed to minimize loss, minimize cost, etc. The differentiation between these services (that is,
Differentiated Services) is provided by a redefinition of an octet in the Layer 3 headers for IP
versions 4 and 6, also termed IPv4 and IPv6, respectively. This octet is called a Type of Service
(TOS) octet in IPv4 and a Traffic Class octet in IPv6, but in both cases the octet is interpreted
differently than it was originally defined. With Differentiated Services, bits 0 through 5 of the octet
identify a Differentiated Services Code Point (DSCP) that identifies a procedure to be used to
handle that packet on a per-hop basis. Bits 6 and 7 of the octet are currently unused, and are
ignored by DSCP-compliant routers.
With DiffServ, the default DSCP is all zeroes, and represents "no special handling". RFC 2474 also
defines eight "Class Selector Codepoints", which are the eight DSCP encodings that can be
Server Administration
4
QoS
4-17