Web Management Guide

Chapter 1 | Introduction
Description of Software Features
– 41 –
STP-compliant mode if they detect STP protocol messages from attached
devices.
◆ Multiple Spanning Tree Protocol (MSTP, IEEE 802.1s) – This protocol is a direct
extension of RSTP. It can provide an independent spanning tree for different
VLANs. It simplifies network management, provides for even faster
convergence than RSTP by limiting the size of each region, and prevents VLAN
members from being segmented from the rest of the group (as sometimes
occurs with IEEE 802.1D STP).
Virtual LANs The switch supports up to 4094 VLANs. A Virtual LAN is a collection of network
nodes that share the same collision domain regardless of their physical location or
connection point in the network. The switch supports tagged VLANs based on the
IEEE 802.1Q standard. Members of VLAN groups can be manually assigned to a
specific set of VLANs. This allows the switch to restrict traffic to the VLAN groups to
which a user has been assigned. By segmenting your network into VLANs, you can:
◆ Eliminate broadcast storms which severely degrade performance in a flat
network.
◆ Simplify network management for node changes/moves by remotely
configuring VLAN membership for any port, rather than having to manually
change the network connection.
◆ Provide data security by restricting all traffic to the originating VLAN, except
where a connection is explicitly defined via the switch's routing service.
Traffic Prioritization This switch prioritizes each packet based on the required level of service, using
eight priority queues with strict priority, Weighted Round Robin (WRR), or a
combination of strict and weighted queuing. It uses IEEE 802.1p and 802.1Q tags to
prioritize incoming traffic based on input from the end-station application. These
functions can
be used to provide independent priorities for delay-sensitive data and
best-effort data.
This switch also supports several common methods of prioritizing layer 3/4 traffic
to meet application requirements. Traffic can be prioritized based on the priority
bits in the IP frame’s Type of Service (ToS) octet using DSCP, or IP Precedence or
TCP/UDP port numbers. When these services are enabled, the priorities are
mapped to a Class of Service value by the switch, and the traffic then sent to the
corresponding output queue.
Quality of Service Differentiated Services (DiffServ) provides policy-based management mechanisms
used for prioritizing network resources to meet the requirements of specific traffic
types on a per-hop basis. Each packet is classified upon entry into the network
based on access lists, IP Precedence or DSCP values, or VLAN lists. Using access lists
allows you select traffic based on Layer 2, Layer 3, or Layer 4 information contained