Diffserv - Avaya 4600 Series Administrator's Manual

Server Administration
L2QAUD: 802.1Q VoIP (voice) user RTP traffic priority value (between 0 and 7, default
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is 6).
L2QSIG: 802.1Q VoIP (voice) user Call Control Signaling traffic priority value (between 0
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and 7, default is 6).
VLANSEP: enables VLAN separation when set to 1 (the default); disables VLAN
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separation when set to 0. If the value is zero, broadcasts are transmitted. Can only be
administered using DHCP/TFTP, not by a manual procedure.
PHY2VLAN: VLAN ID to be used for tagged (data) frames received on the secondary
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Ethernet interface when VLAN separation is enabled (up to 4 digits, from 0 to 4094, default
is 0). Can only be administered using DHCP/TFTP, not by a manual procedure.
PHY2PRIO: Layer 2 (data) priority value to be used for tagged frames received on
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the secondary Ethernet interface when VLAN separation is enabled (1 digit, 0 (zero)
through 7, default is 0). Can only be administered using DHCP/TFTP, not by a manual
procedure.
In the 4600 Series IP Telephone Installation Guide, the Local Administrative Option ADDR also
allows you to specify VLAN IDs and VLANTEST values. The Local Administrative Option QoS
allows you to specify values for L2Q, L2QAUD, and L2QSIG.
The 4600 Series IP Telephones can simultaneously support receipt of packets using, or not
using, 802.1Q parameters.
For additional information on VLAN administration, see

DIFFSERV

IETF RFCs 2474 and 2475 define "services" basically as different ways to treat a network's
different traffic subsets at the Internet Protocol (IP) layer, Layer 3. For example, some packets
might be routed to expedite delivery and minimize delay, with other packets routed to minimize
loss or cost. Redefining an octet in the Layer 3 headers for IP versions 4, or IPv4 and 6, or IPv6
provides the differentiation between these services (Differentiated Services). IPv4 calls this
octet a Type of Service (TOS) octet while IPv6 calls this octet a Traffic Class. 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). The DSCP
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 DSCP-compliant routers ignore them.
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 represented by xxx000, where "x" represents one bit. These Code Selector Codepoints are
considered prioritized, with the larger numeric values having a higher relative order.
DSCP-compliant routers should give the associated packets of larger-valued DSCPs a
"probability of timely forwarding" greater than a packet with a lower-valued DSCP. In addition to
the eight Class Selector Codepoints, a network can define its own DSCPs by defining
86 4600 Series IP Telephone LAN Administrator Guide
VLAN Considerations on page 91.