ZyXEL Communications ES3500 Series Access, Tunnel, Access, Tunnel

Chapter 29 Layer 2 Protocol Tunneling

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 138 L2PT Network Example

				B
A
STP			STP
		STP
					D
1	Service Provider's		2
		Network		C

29.1.1 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 138 on page 243) and connected to a customer switch (A or B). Incoming layer-2 protocol packets received on an access port are encapsulated and forwarded to the tunnel ports.

•The Tunnel port is an egress port at the edge of the service provider's network and connected to another service provider’s switch. Incoming encapsulated layer-2 protocol packets received on a tunnel port are decapsulated and sent to an access port.

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ES3500 Series User’s Guide