Lucent Technologies CAJUN P120, Руководство пользователя

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Chapter 1 Overview
4 Cajun P120 User’s Guide
The security commands are available in the Cajun Campus CLI, Legacy CLI or via
the Standalone Manager.
Virtual LANs
A Virtual LAN (VLAN) is a group of LAN stations that communicate as if they were
on the same physical segment even though they are located on any port
throughout the network. The main purpose of VLANs is to confine Multicast and
broadcast traffic to particular parts of the network, reduce potential problems such
as broadcast storms and enhance overall performance. Virtual LANs also simplify
adds, moves, and changes throughout the network, ensuring a higher level of
security.
Cajun P120 allows the network administrator to superimpose a Virtual LAN
structure over the switching fabric by assigning Cajun P120 ports to VLANs.
Initially, all Cajun P120’s ports are assigned the IEEE 802.1Q Default VLAN
(VLAN=1), thus enabling the users to communicate with all other users
immediately after the physical connection is established.
Port-based Vlans
Port-based VLANs are created by assigning the Cajun P120 port to VLANs. All the
stations connected to that port are members of this VLAN. The VLAN value which
can be set per port is 1-3071 (only values 1-255 can be set in Version 1.0). All the
untagged packets are mapped to the Port VLAN.
VLAN/Priority Tagging
Cajun P120 VLANs may span multiple switches. The VLAN information is conveyed
by one switch to the other by tagging. The Cajun P120 uses the standard IEEE
802.1Q tagging format, thus assuring interoperability with third party switches that
support the standard.
Ports that connect to other Cajun P120 switches, to third party switches, or to
stations that are ‘VLAN aware’, should be configured to support tagging.
The priority field in the Tag is also supported, and tagged packets are forwarded to
the line with the priority value.
Full Duplex
The Cajun P120 supports full duplex mode on all ports. When both the Cajun P120
port and the station at the other end of the link are configured to full duplex, then
frames may be transmitted and received simultaneously which doubles the
bandwidth available on the link.