3Com 2500 manual For example, two IP VLANs can be configured for ports 1-10 as follows

About VLANs 2-7

Data received on...	Is flooded on...	Because...
XNS - port 1	VLAN 1	XNS data does not match any defined VLAN
		in the system.
IP - port 2	VLAN 2	IP data received matches IP VLAN 2 for
		source ports 1 - 10.
IP - port 12	VLAN 1	IP data received on source port 12 does not
		match any defined source port for IP VLAN,
		so the Default VLAN is used.

Overlapped IP The LANplex system also gives you the ability to assign network layer VLANs information to IP VLANs. This capability allows network administrators to

manage their VLANs by subnet. Flooding decisions are made by first matching the incoming frame using the protocol (IP) and then matching it with layer 3 subnet information. If received data is IP but does not match any defined IP subnet VLAN, it is flooded within all IP VLANs using the relevant switch port.

For example, two IP VLANs can be configured for ports 1-10 as follows:

IP VLAN 1 - Subnet 158.101.112.0, ports 1-10

IP VLAN 2 - Subnet 158.101.113.0, ports 1-10

This example shows how flooding decisions are made using overlapping IP VLANs (assuming a 12-port switch):

		Network
Index	VLAN	Address/Mask	Ports
1	Default	none	1	- 12
2	IP	158.103.122.0/	1	- 6
		255.255.255.0
3	IP	158.103.123.0/	6	- 12
		255.255.255.0