H3C Technologies H3C S3100 Series Switches - Manual (Page 613)

Operation Manual – VLAN VPN
H3C S3100-52P Ethernet Switch Chapter 1 VLAN-VPN Configuration
2-2
Netw ork B
ensures the data portion of the packet is consistent with that before the packet
enters the tunnel. So, a tunnel here acts as a local link for user devices. It enables
Layer 2 protocol packets to travel across a logical LAN.
Netw ork A
Netw ork
Netw ork B Netw ork A
Netw ork
Netw ork B Netw ork A
Netw ork
User network
Receiving/sending device
Netw ork A
Netw ork
Netw ork B
Operator’s network
Receiving/sending device
Netw ork B Netw ork A
Netw ork
Netw ork B Netw ork A
Netw ork
Netw ork B Netw ork A
Netw ork
User network
Receiving/sending device
Netw ork A
Netw ork
Netw ork B
Operator’s network
Receiving/sending device
y
Figure 2-1
BPDU Tunnel network hierarch
Figure 2-2 and Figure 2-3 show the structure of a BPDU packet before and after it enter
a BPDU tunnel.
BPDU Data FCS
Destination MAC address
(Protocol-specific MAC)
Source MAC
address
BPDU Data FCS
Destination MAC address
(Protocol-specific MAC)
Source MAC
address
Figure 2-2
The structure of a BPDU packet before it enters a BPDU tunnel
BPDU Data FCS
Destination MAC address
(Recognizable by user)
Source MAC
address
BPDU Data FCS
Destination MAC address
(Recognizable by user)
Source MAC
address
Figure 2-3
The structure of a BPDU packet after it enters a BPDU tunnel
2.2 BPDU Tunnel Configuration
You can establish BPDU tunnels between S3100-52P Ethernet switch for the packets
of the following protocols:
z
ALCP (link aggregation control protocol)
z
NDP (neighbor discovery protocol)
z
Proprietary protocols, including CDP and VTP