Mac address learning and flooding – H3C Technologies H3C SR8800 User Manual
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PW signaling—The PW signaling protocol is the fundament of VPLS. It is used for creating and
maintaining PWs and automatically discovering VSI peer PE. Currently, there are two PW signaling
protocols: LDP and BGP.
shows a typical VPLS networking scenario.
Figure 35 Network diagram for VPLS
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:
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.
Local MAC address learning of interfaces directly connected to users
This refers to learning source MAC addresses from Layer 2 packets originated by CEs. This
occurs on the corresponding VSI interfaces.
shows the procedure of MAC address learning and flooding on PEs.
CE 3
VPN 1
Site 2
VPN 2
CE 4
PE 1
PE 2
P
AC
PWSignaling
PW
Site 3
Site 1
VPN 1
VPN 2
CE 1
CE 2
MPLS backbone
Forwarder
Tunnel