Alcatel-Lucent 7750 SR - MAC Flush Additions for PBB VPLS; Figure 70: MC-EP with B-VPLS Failure Scenario

Page 468 7750 SR OS Services Guide
MAC Flush Additions for PBB VPLS
The scenario depicted in Figure 70 is used to define the blackholing problem in PBB-VPLS using
MC-EP.
Figure 70: MC-EP with B-VPLS Failure Scenario
In topology displayed in Figure 70, PE A and PE B are regular VPLS PEs participating in the blue
VPLS mesh deployed in the metro and respectively WAN region. As the traffic flows between CEs
with CMAC X and CMAC Y, the FIB entries in blue are installed. A failure of the active PW1 will
result in the activation of PW4 between PE3 and PE2 in this example. An LDP flush-all-but-mine
will be sent from PE3 to PE2 to clear the BVPLS FIBs. The traffic between CMAC X and CMAC
Y will be blackholed as long as the entries in red from the VPLS and I-VPLS FIBs along the path
are not removed. This may take as long as 300 seconds, the usual aging timer used for MAC
entries in a VPLS FIB.
A MAC flush is required in the I-VPLS space from PBB PEs to PEA and PEB to avoid
blackholing in the regular VPLS space.
In the case of a regular VPLS the following procedure is used:
• PE3 sends a flush-all-from-me towards its local blue IVPLS mesh to PE3 and PEA when
its MC-Endpoint becomes disabled
• PE3 sends a flush-all-but-mine on the active PW4 to PE2 which is then propagated by PE2
(propagate-mac-flush must be on) to PEB in the WAN IVPLS mesh.
OSSG319
WANMetro Region
Resilient Inter-domain Handoff
VPLS
(Mesh)
VPLS
(Mesh)
PE3
PEA
PEB
CMAC X
CMAC Y
PE3’
PE1
PE2
MC
EP
B
B
B
B
PW1
PW4
Standby PWs
X
-
>SAP2
Y
-
>PWtoPE3
X
-
>PWtoPE1
Y
-
>SAP1
X
-
>PWtoA
Y
-
>BM1
-
>PW1
X
-
>BM3
-
>PW1
Y
-
>PWtoB
X
-
>PWtoA
Y
-
>PWtoPE3
X
-
>PWtoPE1
Y
-
>PWtoB