15
6. Manage / Configure the Switch
6.1 Introduction of the management functions
This switch is a L2 Management switch. It supports in-band management
function from Http/Telnet/SNMP interfaces. Console is supported for local
command-line settings. It supports network configuration functions, like VLAN,
Trunking, Port Mirror, QoS, spanning tree and software backup/update. Users
can configure these functions for different network applications. The following is
a brief introduction about these functions before the detail operation sections.
1. VLAN (Virtual LAN)
VLAN can divide the switch to several broadcast domains to prevent network
traffic between different user groups. This switch supports 802.1Q tag-based
VLAN and Port-based VLAN. Users with the same VLAN ID can transfer data
to each other. The network traffic will be blocked if they have different VLAN ID.
VLAN Stacking function for 802.1Q tag-based VLAN is supported. It allows two
VLAN tags in a packet for 802.1Q VLAN tunneling application through a central
network.
2. Trunk
If two switches are cascaded together, the bottleneck will happen at the
cascading connection. If more cables could be used for the cascading
connection, it will reduce the bottleneck problem. In normal case, switches will
become unstable because of traffic looping when more than one cable is
connected between them. If the switches support trunk function, they can treat
these cables as one connection between them. The traffic looping will not
happen between these cables and the switches will work stable with bigger
bandwidth between them.
Notes:
About redundant application
The trunk connection supports redundant function. If any trunk cable is broken,
the traffic going through that cable will be transferred to another trunk cable
automatically. For example, if traffic of user port Port 6 is assigned to Port 1 in
a Trunk and Port 1 connection breaks, Port 2 will take over the traffic for Port 6
automatically. (It could be used for redundant application.)
3. Spanning Tree Protocol / Rapid Spanning Tree Protocol
Spanning tree is a protocol to prevent network loop in network topology. If
network loop happens, it will cause switches in the network unstable because
more and more traffic will loop in the network. If network loop happens,
spanning tree protocol will block one connection in the loop automatically. But
it will also cause a period of delay (30 seconds for STP and shorter time for
RSTP) if any network connection is changed because of the network topology
detection operation of the protocol.
Because there could be more than one switch in the network, users can