Specifications

Browser-Based Configuration Pages

NXA-ENET8POE Gigabit PoE Ethernet Switch

QOS

QoS (Quality of Service) is a mechanism which is used to prioritize certain traffic as it is moves through the

switch. Traffic can be classified as High, Medium, Normal or Low priority. This switch features both strict

priority-based and weighted round-robin (WRR) forwarding, with guaranteed bandwidth allocation for the

different QOS classes.

Settings

FIG. 34 QOS - Settings page

QOS - Settings page

QoS Configuration:

Queue Mode:

Select one of the two options:

• Strict priority - Higher priority frames take precedence over lower priority

frames during forwarding. In case of congestion, the lowest priority traffic is

dropped before higher priority frames. Head-of-queue blocking maybe

encountered by using this mode.

• WRR - In this mode, all priorities can be guaranteed a share of the bandwidth

when the system is overloaded. The bandwidth sharing percentage can be

adjusted by specifying the four QOS class with different ratio in WRR

Weight, which appears after WRR is enabled in Queue Mode.

QoS Mode:

Port-Based:

The port-based qos can prioritize each specified port. When QoS Mode is set

to Port-based, the Port Priority Configuration table appears, which allows a

priority to be set for each port.

802.1p:

The 802.1p field is held within the VLAN-tag of a packet. The field is three bits

long so can hold eight values; 0 - 7 inclusive. When QoS Mode is set to

802.1p, the 802.1p Configuration table appears which allows a priority to be

set for each of the eight values.

Note: Because end-stations, like PCs, are not usually VLAN aware, they do

not create VLAN-tagged frames. As a result, this method of prioritization is not

ideal when many PCs are connected to the NXA-ENET8POE.

DSCP:

The Differentiated Services Code Point (DSCP) is a six bit field that is con-

tained within an IP (TCP or UDP) header. Six bits allows the DSCP field to take

any value in the range 0 - 63 inclusive. When QoS Mode is set to DSCP, the

DSCP Configuration table appears which allows a priority to be set for each of

the DSCP values.