Brocade TurboIron 24X Series Configuration Guide - Manual (Page 406)

372 Brocade TurboIron 24X Series Configuration Guide
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VLAN overview
Dynamic, static, and excluded port membership
When you add ports to a protocol VLAN, IP subnet VLAN, IPX network VLAN, or AppleTalk cable
VLAN, you can add them dynamically or statically:
• Dynamic ports
• Static ports
You also can explicitly exclude ports.
Dynamic ports
Dynamic ports are added to a VLAN when you create the VLAN. However, if a dynamically added
port does not receive any traffic for the VLAN protocol within ten minutes, the port is removed from
the VLAN. However, the port remains a candidate for port membership. Thus, if the port receives
traffic for the VLAN protocol, the device adds the port back to the VLAN.
After the port is added back to the VLAN, the port can remain an active member of the VLAN up to
20 minutes without receiving traffic for the VLAN protocol. If the port ages out, it remains a
candidate for VLAN membership and is added back to the VLAN when the VLAN receives protocol
traffic. At this point, the port can remain in the VLAN up to 20 minutes without receiving traffic for
the VLAN protocol, and so on.
Unless you explicitly add a port statically or exclude a port, the port is a dynamic port and thus can
be an active member of the VLAN, depending on the traffic it receives.
NOTE
You cannot configure dynamic ports in an AppleTalk cable VLAN. The ports in an AppleTalk cable
VLAN must be static. However, ports in an AppleTalk protocol VLAN can be dynamic or static.
Figure 41 shows an example of a VLAN with dynamic ports. Dynamic ports not only join and leave
the VLAN according to traffic, but also allow some broadcast packets of the specific protocol to
“leak” through the VLAN. Refer to
“Broadcast leaks” on page 374.
FIGURE 41 VLAN with dynamic ports—all ports are active when you create the VLAN
A = active port
C = candidate port
When you add ports dynamically,
all the ports are added when you add
the VLAN.
A A A A
A A A A