Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 322)

292 Multi-Service IronWare Switching Configuration Guide
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Configuring PBB
11
S-Tag DEI Setting
The packet internal drop precedence for an ingress IB endpoint is derived based on ingress PCP
decode table operated on:
1. S-VLAN keep mode is set - The PBB packet's original S-VLAN's PCP value and merged with
S-VLAN's DEI bit if “qos use-dei” is also configured at the ingress IB endpoint.
2. S-VLAN Keep mode is not set - The original packet's I-Tag PCP value and merged with I-Tag's
I-DEI bit if “qos use-dei” is also configured at the ingress IB endpoint.
Depending on the encode PCP policy configured on the egress S-Tagged endpoint, the DEI value
will be derived as following:
1. Encode PCP On - This is the default case where the S-Tag DEI is derived based on the internal
drop precedence and the “qos use-dei” setting configured on the S-Tagged interface.
a. qos use-dei On - The S-Tag DEI setting is based on the internal drop precedence set up at
the ingress
b. qos use-dei Off - The S-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 S-Tagged endpoint, the S-Tag DEI value
will be set as following:
a. S-VLAN keep mode is set - This would be the original PBB packet's S-VLAN DEI bit.
b. S-VLAN keep mode is not set - This would be the original PBB packet's I-Tag I-DEI bit.
NOTE
The above DEI setting applies to both S-Tagged destination endpoint as well as C-Tagged destination
endpoint (CFI setting).
Configuring PBB
This section discusses the limitations and configuration commands required to configure PBB.
Limitations
• Disabling PBB - When PBB is configured, and you want to disable PBB, you will have to remove
all endpoint and b-dest-mac configurations. The alternative is to delete the VPLS instance
before disabling PBB on the instance.
• Ensure the BVLAN configured for the vlan-isid endpoint is already configured as part of the
Layer 2 VLAN for the given interface.
• If PBB is not configured before the endpoint is configured, the user will need to delete all
endpoints before configuring PBB.
• A dual tagged endpoint configuration is not allowed under the PBB configuration.
• Auto-discovery configuration is not allowed under the PBB configuration.
• Multicast configuration is not allowed under the PBB configuration.
• VPLS-MTU configuration is not allowed under the PBB configuration.
• VPLS peer configuration is not allowed under the PBB configuration.