S
UMMIT
S
WITCH
I
NSTALLATION
AND
U
SER
G
UIDE
5-5
T
YPES
OF
VLAN
S
Figure 5-3
illustrates two VLANs spanning two Switches. On Switch 1, ports 1-4 are
part of VLAN
Accounting
; ports 5 - 8 are part of VLAN
Engineering
. On Switch 2, ports
1-4 are part of VLAN
Accounting
; ports 5 - 8 are part of VLAN
Engineering
. VLAN
Accounting
spans Switch 1 and Switch 2 by way of a connection between Switch 1 port 2
and Switch 2 port 4. VLAN
Engineering
spans Switch 1 and Switch 2 by way of a
connection between Switch 1 port 5 and Switch 2 port 8.
Figure 5-3: Two port-based VLANs spanning two Switches
Using these steps, you can create multiple VLANs that span multiple Switches, in a
daisy-chained fashion. Each Switch must have a dedicated port for each VLAN. Each
dedicated port must be connected to a port that is a member its VLAN on the next
Switch.
T
AGGED
VLAN
S
Tagging
is a process that inserts a marker (called a
tag
) into the Ethernet frame. The tag
contains the identiÞcation number of a speciÞc VLAN, called the
VLAN ID
.
The use of 802.1Q tagged packets may lead to the appearance of packets
slightly bigger than the current IEEE 802.3/Ethernet maximum of 1518 bytes.
This may affect packet error counters in other devices, and may also lead to
connectivity problems if non-802.1Q bridges or routers are placed in the path.
Accounting
Engineering
SUMMIT.BK Page 5 Thursday, September 25, 1997 12:33 PM
