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166
C
HAPTER
6: V
IRTUAL
LAN
S
(VLAN
S
)
Defining New VLANs
If you want to move a port from the Default VLAN to another VLAN, you
must first define information about the new VLAN on your Switch. To do
this, you use the VLAN Setup page of the web interface; see
“Defining
VLAN Information”
on
page 84
.
Untagged and
Tagged VLANs
When setting up VLANs you need to understand when to use untagged
and tagged VLANs. Quite simply, if a port is in a single VLAN it can be
untagged but if the port needs to be a member of multiple VLANs it must
be tagged.
The IEEE 802.1Q standard defines how VLANs operate within an open
packet-switched network. An 802.1Q compliant packet carries additional
information that allows a switch to determine to which VLAN the port
belongs. If a frame is carrying the additional data, it is known as
tagged
.
To carry multiple VLANs across a single physical (backbone) link, each
packet must be tagged with a VLAN identifier so that the switches can
identify which packets belong in which VLANs. Routers interconnect
VLANs, so they must also understand 802.1Q tagging, so that they do
not become bottlenecks for inter-VLAN traffic.
Placing a Port in a
Single VLAN
Once the information for a new VLAN has been defined, you can place a
port in that VLAN. To do this, use the Untagged VLAN listbox on the Port
Setup page of the web interface; see
“Configuring a Port”
on
page 59
.
Placing a Port in
Multiple VLANs
Your Switch supports VLAN tagging, a system that allows traffic for
multiple VLANs to be carried on a single link. Two methods of VLAN
tagging are supported:
802.1Q tagging
and
VLT (Virtual LAN Trunk)
tagging
.
802.1Q Tagging
This method of tagging is defined in the IEEE 802.1Q standard, and
allows a link to carry traffic for any of the VLANs defined on your Switch.
802.1Q tagging can only be used if the devices at both ends of a link
support IEEE 802.1Q.
Summary of Contents for SuperStack II
Page 12: ......
Page 18: ......
Page 42: ......
Page 154: ...154 CHAPTER 4 WORKING WITH THE COMMAND LINE INTERFACE ...
Page 156: ......
Page 162: ...162 CHAPTER 5 PORT TRUNKS ...
Page 169: ...VLANs and Your Switch 169 Figure 32 Forwarding unknown 802 1Q tags ...
Page 173: ...VLAN Configuration for Beginners 173 Figure 34 Simple example Untagged connections using hubs ...
Page 180: ...180 CHAPTER 6 VIRTUAL LANS VLANS ...
Page 188: ...188 CHAPTER 7 FASTIP ...
Page 200: ...200 CHAPTER 9 SPANNING TREE PROTOCOL Figure 49 STP configurations ...
Page 210: ...210 CHAPTER 10 RMON ...
Page 211: ...IV PROBLEM SOLVING Chapter 11 Problem Solving ...
Page 212: ......
Page 224: ...224 CHAPTER 11 PROBLEM SOLVING ...
Page 226: ......