Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 321)

Multi-Service IronWare Switching Configuration Guide 291
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Backbone Edge Bridge (BEB) operation
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NOTE
If the packet ingress is through an untagged endpoint destined to a remote PBB node, the PCP value
of “0” will be used as the I-Tag PCP value in the PBB header.
I-Tag I-DEI Setting
Packets ingress through an S-Tagged endpoint destined to a remote PBB node will have the DEI bit
preserved from the received packet copied unto the PBB header I-Tag I-DEI field.
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 the I-Tag I-DEI value in the PBB header.
NOTE
If the packet ingress is through an untagged endpoint destined to a remote PBB node, the I-Tag I-DEI
value in the PBB header will be “0”.
S-Tag PCP/DEI Setting
When a packet is received from an IB endpoint, there are PCP/DEI in the B-Tag, PCP/DEI in the
I-Tag and optionally PCP/DEI in the S-Tag if S-VLAN keep mode is configured. When this packet is
switched to a local S-Tagged endpoint, the PCP/DEI setting will be set according to the rules
documented in the following sections.
S-Tag PCP Setting
The packet internal priority for an ingress IB endpoint is derived based on the ingress PCP decode
table.
1. S-VLAN keep mode is set - The PBB packet's original S-VLAN's PCP value.
2. S-VLAN Keep mode is not set - The original packet's I-Tag PCP value.
Depending on the encode PCP policy configured on the egress S-Tagged endpoint, the PCP value
will be derived as following:
1. Encode PCP On - This is the default case where the egress S-Tag PCP is derived based on the
packet internal priority operated by the configured PCP encode table.
2. Encode PCP Off - When this is configured on the egress S-Tagged endpoint, the S-Tag PCP value
will be set based on the following:
a. S-VLAN keep mode is set - This would be the original PBB packet's S-VLAN PCP value.
b. S-VLAN keep mode is not set - This would be the original PBB packet's I-Tag PCP value.
NOTE
The above PCP setting applies to both S-Tagged destination endpoint as well as C-Tagged destination
endpoint.