PBB Features
Page 446 7210 SAS M Services Guide
PBB Packet Walkthrough
This section describes the walkthrough for a packet that traverses the B-VPLS and I-VPLS
instances using the example of a unicast frame between two customer stations as depicted in the
following network diagram Figure 62.
Figure 62: PBB Packet Walkthrough
The station with CMAC (customer MAC) X wants to send a unicast frame to CMAC Y through
the PBB-VPLS network. A customer frame arriving at PBB-VPLS U-PE1 is encapsulated with the
PBB header. The local I-VPLS FIB on U-PE1 is consulted to determine the destination BMAC of
OSSG194
N-PEs
VPLS/MPLS
Core
PBB-VPLS
U-PEs
PBB-VPLS
U-PEs
U-PE1
(B1)
CMAC X CMAC Y
Payload
Ethertype
Ethertype
Ethertype
C-VID
S-VID
C-SA X
C-DA Y
Payload
Ethertype
Ethertype
Ethertype
Ethertype
C-VID
S-VID
I-TAG
C-SA X
C-DA Y
B-SA B1
B-DA B2
Payload
Ethertype
Ethertype
Ethertype
C-VID
S-VID
C-SA X
C-DA Y