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Quality of Service (QoS, IEEE802.1p)

The Quality of Service (QoS) feature provides internal queues to support different classifications of traffic. High
priority packet streams experience less delay inside managed Ethernet switches, which support lower latencies
for certain delay-sensitive traffic. EtherWAN's Managed Ethernet Switch can classify packets according to the
Port ID, MAC address, IEEE802.1p priority tag, DiffServ, and/or IP TOS.

Ring Coupling

Sometimes there might not only be one single ring in an industrial network. Industrial networks may be
composed of numerous rings, as well as interconnected networks among these individual rings. The network
among these rings can also provide network redundancy via the Coupling method. Thus, all the switches do
not have to be confined and connected in one ring, since a single large ring that contains numerous switches
can be broken into smaller, more manageable ring networks to ensure network efficiency and performance.

Rapid Spanning Tree Protocol (RSTP, IEEE802.1w)

RSTP provides significantly faster spanning tree convergence after a topology change, by introducing new
convergence behaviors and bridge port roles. RSTP was designed to be backward-compatible with standard
STP.

RMON

The switch supports the following RMON MIB groups defined in RFC 1757:
a. The RMON Statistics Group, which maintains utilization and error statistics for the switch port being

   monitored.
b. The RMON History Group, which gathers and stores periodic statistical samples from the previous

   statistics group.
c. The RMON Alarm Group, which allows a network administrator to define alarm thresholds for any MIB

   variable. An alarm can be triggered when the value of a specific MIB variable exceeds or falls below a
   threshold.
d. The RMON Event Group, which allows a network administrator to define actions based on alarms.
   SNMP Traps are generated when RMON Alarms are triggered.

Store-and-Forward

Store-and-forward switching is Cisco’s primary LAN switching method. The store-and-forward method provides
efficient and error-free transport instead of fast transport. In this mode, the complete data frame is received
on the switch’s buffer and a CRC is run. If the CRC passes, the switch looks up the destination hardware address
in the MAC filter table, finds the correct outgoing interface, and sends the frame toward its destination.

Ethernet Switch Glossary  11  www.EtherWAN.com
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