C
HAPTER
2
| Network Planning
Application Notes
– 25 –
ES-3026/3026P
M
AKING
VLAN
C
ONNECTIONS
These switches support VLANs which can be used to organize any group of
network nodes into separate broadcast domains. VLANs confine broadcast
traffic to the originating group, and can eliminate broadcast storms in large
networks. This provides a more secure and cleaner network environment.
VLANs can be based on untagged port groups, or traffic can be explicitly
tagged to identify the VLAN group to which it belongs. Untagged VLANs can
be used for small networks attached to a single switch. However, tagged
VLANs should be used for larger networks, and all the VLANs assigned to
the inter-switch links.
Figure 10: Making VLAN Connections
N
OTE
:
When connecting to a switch that does not support IEEE 802.1Q
VLAN tags, use untagged ports.
A
PPLICATION
N
OTES
1.
Full-duplex operation only applies to point-to-point access (such as
when a switch is attached to a workstation, server, or another switch).
When the switch is connected to a hub, both devices must operate in
half-duplex mode.
2.
Avoid using flow control on a port connected to a hub unless it is
actually required to solve a problem. Otherwise back pressure jamming
signals may degrade overall performance for the segment attached to
the hub.
3.
As a general rule the length of fiber optic cable for a single switched link
should not exceed:
■
1000BASE-SX: 550 m (1805 ft) for multimode fiber.
Finance
Marketing
VLAN 3
Untagged Ports
VLAN
unaware
switch
VLAN
aware
switch
Finance
VLAN 3
R&D
VLAN 2
Testing
R&D
Testing
VLAN 1
VLAN 2
VLAN 4
VLAN 1
Tagged Port
Tagged
Ports
