Vlan Policies - Extreme Networks EPICenter Guide Manual

VLAN Policies

A VLAN policy identifies traffic originating from the member ports of one or more VLANs, and assigns
that traffic to a QoS profile. The Policy System implements VLAN QoS for all the traffic flows from the
specified VLANs, on the devices you have defined in your policy scope.
Figure 76 shows the effects of a VLAN Policy that has been specified for VLAN A, and scoped on
switches A and B. The policy specifies that traffic originating from ports that are members of VLAN A
should use QoS profile QP2. Thus, this policy affects traffic originating from the ports associated with
client 1 on switch A, clients 5 and 6 on switch B, and the link between switches A and B. Traffic
originating from client 2 on switch A is not affected, since it originates on a port that is not a member of
VLAN A. In addition, traffic originating from client 4 on switch C is also not affected, even though it is
a member of VLAN A, because switch C was not included in the policy scope.
Figure 76: VLAN policy
Switch A
VLAN A
Client 1
VLAN A
Like Source Port QoS, VLAN QoS rules are implemented only in the devices included in the policy
scope that have the specified VLAN. To enforce QoS settings across switch/VLAN boundaries you
must use 802.1Q tagging—specifically through explicit packet marking using 802.1p or DiffServ. If the
switch ports used for output use 802.1Q tagging, the QoS profile assignment will be carried via the
802.1p priority bits to the next switch. On i-series chipset devices, you can also enable DiffServ
examination and replacement to observe and carry the QoS setting with the packet between switches.
The use of 802.1p priority bits is enabled when you enable VLAN tagging, which you can do through
the EPICenter VLAN Manager applet. DiffServ examination must be enabled using the ExtremeWare
EPICenter Concepts and Solutions Guide
Client 2
Switch C
VLAN B
VLAN B
VLAN B
QP2
(802.1p tag)
QP2
Switch B
VLAN A
QP2
Policy scope
VLAN A
Client 5
Client 3
VLAN B
QP2
VLAN A
QP2
Client 4
VLAN A
(802.1p tag)
VLAN A
QP2
QP2
VLAN A
Client 6
Policy Types
XM_019
169