User Manual
Publication d ate : January, 2005
Revision A1 38
Mac address aging
There is a field in MAC address table used to put the entry’s Age time which
determines how long a MAC entry can reside in a switch. The age time is refreshed
when a packet with that SA. Usually, the age time is programmable.
Tr ansm issi on sch edul e
In most layer 2 switches, the QoS is supported. QoS in a switch must
associate a transmission schedule to transmit the packet. This function is much to
do with the priorit y level a packet has. With the given priority , the scheduler will do
the proper action on it. The scheduler has many ways to implement, and different
chips may support different schedule algorithms. Most common schedulers are:
FCFS: First Come First Se rvice.
Strictly Priority: All High before Low.
Weighted Round Robin:
Set a weight figure to the packet with a priority level, say 5-7, and next, set
anothe r weight to t he packet with a priori ty level, say 2 -4 and so on. The WRR will
transmit the packet with the weight. So the packet of each priority level can be
allocated a fixed bandwidth.
Band width r ating
Bandwidth rating is the limitation set by administrator, and it can be applied
to those with SLA. Bandwidth rating can be total bandwidth, types of service of a
port with many steps. The switch supports by-port Ingress and Egress total
bandwidth rate control capacity. The bandwidth rate resolution is 0.1 Mbps
(100Kbps) and ranges from 0 to 100Mbps.