Extreme Networks Summit1 - Manual (Page 94)

5-8 S UMMIT S WITCH I NSTALLATION AND U SER G UIDE
V IRTUAL LAN S (VLAN S )
In Figure 5-4 and Figure 5-5 :
• The trunk port on each switch carries traffic for both VLAN Marketing and VLAN
Sales.
• The trunk port on each switch is tagged.
• The server connected to port 1 on Switch 1 has a NIC that supports 802.1Q tagging.
• The server connected to port 1 on Switch 1 is a member of both VLAN Marketing
and VLAN Sales.
• All other stations use untagged traffic.
As data passes out of the switch, the switch determines if the destination port requires
the frames to be tagged or untagged. All traffic coming from and going to the server is
tagged. Traffic coming from and going to the trunk ports is tagged. The traffic that
comes from and goes to the other stations on this network is not tagged.
M IXING P ORT -B ASED AND T AGGED VLAN S
You can configure the Summit using a combination of port-based and tagged VLANs. A
given port can be a member of multiple VLANs, with the stipulation that only one of its
VLANs uses untagged traffic. In other words, a port can simultaneously be a member of
one port-based VLAN and multiple tag-based VLANs.
For the purposes of VLAN classification, packets arriving on a port with an
802.1Q tag containing a VLANid of zero are treated as untagged.
G ENERIC VLAN R EGISTRATION P ROTOCOL
The Generic VLAN Registration Protocol (GVRP) allows a LAN device to signal other
neighboring devices that it wishes to receive packets for one or more VLANs. The
GVRP protocol is defined as part of the IEEE 802.1Q Virtual LANs draft standard. The
main purpose of the protocol is to allow switches to automatically discover some of the
VLAN information that would otherwise have to be manually configured in each
switch. GVRP can also be run by network servers. These servers are usually configured
to join several VLANs, and then signal the network switches of the VLANs of which
they want to be part.
Summit.bk : 5VLAN.FM Page 8 Thursday, June 18, 1998 9:27 AM