Service Egress QoS Policy
204 Quality of Service Guide
A combination of two access networks can be possible. If PBB encapsulation is used, the 
configuration used for DE in SAP and SDP policies applies to both BVID and ITAG DE bits. 
When both fields are used the BVID takes precedence. 
IEEE 802.1ah Use Case
Figure 17 illustrates an example of a PBB topology where the DE feature can be used. The 
processing requirements highlighted in the 802.1ad use case apply to the 802.1ah BVID, 
format and etype, these being identical with the 802.1ad STAG. In addition the DE bit from 
the 802.1ah ITAG header may need to be processed following the same rules as for the related 
field in the BVID/STAG: for example, the DE bit from the BVID header represents the QoS 
associated with the “Ethernet Tunnel” while the DE bit from the ITAG represent the service 
QoS. 
Figure 17: DE Aware PBB Topology 
In this example, the BVID is not used for a part of the network leaving only I-DEI bit from 
the ITAG as the only option for a dedicated DE field. If both are included, then the QoS 
information from the BVID is to be used.
DSCP/Prec Egress Remarking
DSCP/prec marking can be performed on egress for all services and with respect to the profile 
of the packet.
The following commands can be used to remark the DSCP/prec values at a SAP egress:
sap-egress <policy-id> create
fc <fc-name> create
dscp {dscp <dscp-name>|
in-profile {<dscp-name> 
out-profile <dscp-name>
[exceed-profile <dscp-name>]}
prec {<ip-prec-value>|
UNI
Fig_27
PBBN
(CE aware using
802.1 a/b/d &/or
802.1afITAG)
MPLS
7x50 PE2
I-SAP
CE
MPLS
SDP
B-VPLS
CE
7x50 PE1
B-VPLS
SDPB-SAP
PBB PE