Planex FMG-24K, Руководство пользователя

Страница: 74 / 263

12.Class of Service Configuration
Class of Service (CoS) allows you to specify which data packets have greater
precedence when traffic is buffered in the switch due to congestion. This switch
supports CoS with four priority queues for each port. Data packets in a port’s
high-priority queue will be transmitted before those in the lower-priority queues.
You can set the default priority for each interface, and configure the mapping of
frame priority tags to the switch’s priority queues.
Setting the Default Priority for Interfaces
You can specify the default port priority for each interface on the switch. All
untagged packets entering the switch are tagged with the specified default port
priority, and then sorted into the appropriate priority queue at the output port.
Command Usage
> This switch provides four priority queues for each port. It uses Weighted Round
Robin to prevent head-of-queue blockage.
> The default priority applies if the incoming frame is an untagged frame received
from a VLAN trunk or a static-access port. This priority does not apply to IEEE
802.1Q VLAN tagged frames. If the incoming frame is an IEEE 802.1Q VLAN
tagged frame, the IEEE 802.1p User Priority bits will be used.
> If the output port is an untagged member of the associated VLAN,
these frames are stripped of all VLAN tags prior to transmission.
Command Attributes
> Default Priority – The priority that is assigned to untagged frames received on
the specified port. (Range: 0 - 7, Default: 0)
> Number of Egress Traffic Classes – The number of queue buffers provided for
each port.
73