Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 490)

TABLE 70 Expected class of service behavior for VPLS tagged mode
VPLS endpoints Incoming packet MPLS cloud Outgoing packet
Outer VLAN Inner VLAN Tunnel/VC
label (Z) Payload tag Outer VLAN Inner VLAN
Dual-tagged
to dual-tagged X Y V or internal
priority Y W or Y Y
Single-tagged
to dual-tagged X N/A X W or X X
Untagged
to dual-tagged N/A N/A 0 W or 0 0
Dual-tagged
to
single-tagged X Y Y W or Y N/A
466 Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide
53-1003031-02
Configuring VPLS instances
3
Legend for Table 70
V = Mapped EXP bits from internal priority (X contributes to internal priority) using the EXP
encode table.
W = Mapped CoS from internal priority (Z contributes to internal priority) using the CoS encode
table.
X = Original outer VLAN CoS.
Y = Original inner VLAN CoS.
Z = Incoming EXP bits as described by the Tunnel / VC label column = V or internal priority.
• The Tunnel/VC label column differentiates the behavior between when qos exp encode
policy is ON (default) or OFF
• The Outgoing Packet Outer VLAN column differentiates the behavior between when qos
pcp encode policy is ON (default) or OFF
QoS for VPLS traffic
By default, packets travelling through an MPLS domain are treated equally from a QoS standpoint,
in a best effort manner. However, when a Layer 2 packet has an internal priority in its 802.1q tag,
or the LSP or VPLS to which the packet is assigned has a configured Class of Service (COS) value,
QoS can be applied to the packet in the MPLS domain. The internal priority or COS value is mapped
to a value in the EXP field of the packet’s MPLS header. The value in the EXP field is then mapped
to an internal forwarding priority, and the packet is sent to the hardware forwarding queue that
corresponds to the internal forwarding priority.
QoS for VPLS traffic at the ingress LER
The following methods can be used to provide QoS to packets entering a VPLS:
• Use the COS value assigned to the tunnel LSP used to reach the VPLS peer.
When a tunnel LSP has a user-configured COS value, all packets in all VPLS travelling through
the tunnel LSP receive the same QoS.