Figure 113: Tcn Triggered Pbb Flush-All-But-Mine Procedure - Alcatel-Lucent 7750 SR Manual

PBB Features
There are a number of advantages to this approach. Firstly, the PBB-TLV presence indicates this is
a PBB MAC Flush. As a result, all PEs containing only the B-VPLS instance will automatically
propagate the LDP MAC withdraw in the B-VPLS context respecting the split-horizon and active
link topology. There is no flushing of the B-VPLS FIBs throughout the core PEs. Subsequently,
the receiving PBB VPLS PEs will use the BMAC and ISID list information to identify the specific
I-VPLS FIBs and the CMAC entries pointing to the source BMAC included in the PBB TLV.
An example of processing steps involved in PBB MAC Flush is depicted in
when a Topology Change Notification (TCN) is received on PBB PE 2 from a QinQ access in the
I-VPLS domain.
The received TCN may be related to one or more I-VPLS domains. This will generate a MAC
Flush in the local I-VPLS instance(s) and if configured, it will originate a PBB MAC flush-all-
but-mine throughout the related B-VPLS context(s) represented by the white circles 1-8 in our
example.
A PBB-TLV is added by PE2 to the regular LDP MAC flush-all-but-mine. BMAC2, the source
BMAC associated with B-VPLS on PE2 is carried inside the PBB TLV to indicate who "mine" is.
The ISID list identifying the I-VPLS affected by the TCN is also included if the number of
affected I-VPLS is 100 or less. No ISID list is included in the PBB-TLV if more than 100 ISIDs
are affected. If no ISID list is included, then the receiving PBB PE will flush all the local I-VPLS
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Figure 113: TCN Triggered PBB Flush-ALl-but-mine Procedure

Figure 113
7750 SR OS Services Guide
for the case