Layer 2 Protocol Tunneling Mode - ZyXEL Communications GS2200-24 User Manual

Chapter 28 Layer 2 Protocol Tunneling
layer 2 protocol packets with a specific MAC address before sending them across
the service provider's network to other edge switches.
Figure 121 Layer 2 Protocol Tunneling Network Scenario
A
B
In the following example, if you enable L2PT for STP, you can have switches A, B,
C and D in the same spanning tree, even though switch A is not directly
connected to switches B, C and D. Topology change information can be
propagated throughout the service provider's network.
To emulate a point-to-point topology between two customer switches at different
sites, such as A and B, you can enable protocol tunneling on edge switches 1 and
2 for PAgP (Port Aggregation Protocol), LACP or UDLD (UniDirectional Link
Detection).
Figure 122 L2PT Network Example
A
STP

28.3.1 Layer 2 Protocol Tunneling Mode

Each port can have two layer 2 protocol tunneling modes, Access and Tunnel.
• The Access port is an ingress port on the service provider's edge device (1 or 2
in Figure 122 on page
Incoming layer 2 protocol packets received on an access port are encapsulated
and forwarded to the tunnel ports.
246
Service Provider's
STP
CDP 1
VTP
1
Service Provider's
Network
246) and connected to a customer switch (A or B).
Network
STP
2
CDP
VTP
STP
STP
2
C
B
D
C
GS2200-24 User's Guide