Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 320)

290 Multi-Service IronWare Switching Configuration Guide
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Backbone Edge Bridge (BEB) operation
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NOTE
If a packet ingress through a C-Tagged endpoint is destined to a remote PBB node, the C-Tag PCP
value will be used the same way as described above.
The Internal priority setting is based on the original packet's PCP value operated by the port's PCP
decode table, as explained in the Multi-Service IronWare Traffic Management Configuration Guide.
The forced-PBB-PCP configuration option has no effect on the regular Layer 2 traffic using the same
B-VID.
For pass through PBB packets (BEB acting as a BCB case), the B-Tag PCP value is not modified at all.
The existing “priority” configuration on the B-VLAN operates independently from the forced-PBB-PCP.
It governs on the PCP setting of the regular Layer 2 traffic as well as pass through PBB traffic.
B-Tag DEI Setting
The B-Tag DEI setting has the following options:
1. Encode PCP On - This is the default case where the B-Tag DEI is derived based on the internal
drop precedence and the qos use-dei setting configured on the egress IB interface.
a. “qos use-dei” On - The B-Tag DEI setting is based on the internal drop precedence set up at
the ingress.
b. “qos use-dei” Off - The B-Tag DEI setting is set to “0” regardless of what the internal drop
precedence may be.
2. Encode PCP Off - When this is configured on the egress IB endpoint interface, the B-Tag DEI
value will always be “0”.
NOTE
There is no force option for the DEI setting.
NOTE
If the packet ingress is through a C-Tagged endpoint destined to a remote PBB node, the C-Tag CFI
value will be used as described above.
NOTE
Internal drop precedence on the ingress is derived based on the original packet's PCP value
operated by the PCP decode table and optionally merged with the packet's DEI/CFI bit if the “qos
use-dei” is set on the ingress port.
I-Tag PCP Setting
I-Tag PCP is always taken from the PCP value that is received from the ingress. In most cases this is
the SVLAN PCP value.
NOTE
If the packet ingress is through a C-Tagged endpoint destined to a remote PBB node, the C-Tag PCP
value will be used as the I-Tag PCP value in the PBB header.