Extreme networks Summit1 Manuale Utente

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5-8
S
UMMIT
 S
WITCH
 I
NSTALLATION
 
AND
 U
SER
 G
UIDE
V
IRTUAL
 LAN
S
 (VLAN
S
)
 an
:
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