Vlan Exception Flooding - 3Com LANPLEX 2500 EXTENDEDPLEX®2500 EXTENDED User Manual

2-6 C 2: VLAN
HAPTER
VLAN Exception
Flooding
LAN ® S
S ON THE PLEX YSTEM
This example shows how flooding decisions are made according to VLANs
set up by protocol (assuming an 18-port switch):
Data received on... Is flooded on...
IP - port 1 VLAN 2
IPX - port 11 VLAN 3
XNS - port 1 VLAN 1
If data arrives on a switch port for a certain protocol and VLANs for that
protocol are defined in the system but not on that switch port, the default
VLAN defines the flooding domain for that data. This case is called VLAN
exception flooding.
This example shows how the VLAN exception flooding decision is made
(assuming an 18-port switch):
Index VLAN
1 Default
2 IP
3 IPX
Because...
IP data received matches IP VLAN on the
source port.
IPX data received matches IPX VLAN on the
source port.
XNS data received matches no protocol
VLAN, so the Default VLAN is used.
Index VLAN
1 Default
2 IP
Ports
1 - 18
1 - 12
11 - 16
Ports
1 - 18
1 - 10