H3C Technologies H3C S7500E Series Switches - Manual (Page 163)

4-3
Figure 4-1 Network diagram for VPLS
CE 3
VPN 1
Site 2
VPN 2
CE 4
PE 1
PE 2
P
AC
PW Signaling
PW
Site 3
Site 1
VPN 1
VPN 2
CE 1
CE 2
MPLS backbone
Forwarder
Tunnel
MAC address learning and flooding
VPLS provides reachability by MAC address learning. Each PE maintains a MAC address table.
1) Source MAC address learning
MAC address learning includes two parts:
z
Remote MAC address learning associated with PWs
A PW consists of two unidirectional VC LSPs. A PW is up only when both of the VC LSPs are up.
When the inbound VC LSP learns a new MAC address, the PW needs to map the MAC address to the
outbound VC LSP.
z
Local MAC address learning of interfaces directly connected with users
This refers to learning source MAC addresses from Layer 2 packets originated by CEs. This occurs on
the corresponding VSI interfaces.
Figure 4-2 shows the procedure of MAC address learning and flooding on PEs.