Configuring Quality Of Service - AudioCodes Mediant 3000 User Manual

User's Manual
13.5

Configuring Quality of Service

The QoS Settings page lets you configure Layer-2 and Layer-3 Quality of Service (QoS).
Differentiated Services (DiffServ) is an architecture providing different types or levels of
service for IP traffic. DiffServ (according to RFC 2474), prioritizes certain traffic types
based on priority, accomplishing a higher-level QoS at the expense of other traffic types.
By prioritizing packets, DiffServ routers can minimize transmission delays for time-sensitive
packets such as VoIP packets.
You can assign different VLAN priorities (IEEE 802.1p) and DiffServ to the following class
of services (CoS):

Network – network control traffic (ICMP, ARP)

Media Premium – RTP packets sent to the LAN

Control Premium – control protocol (SIP) packets sent to the LAN

Gold – HTTP streaming packets sent to the LAN

Bronze – OAMP packets sent to the LAN
The Layer-3 QoS parameters define the values of the DiffServ field in the IP header of the
frames related to a specific service class. The Layer-2 QoS parameters define the values
for the 3 priority bits in the VLAN tag to a specific service class (according to the IEEE
802.1p standard).
The mapping of an application to its CoS and traffic type is shown in the table below:
Application
Debugging interface
Telnet
DHCP
Web server (HTTP)
SNMP GET/SET
Web server (HTTPS)
IPSec IKE
RTP traffic
RTCP traffic
T.38 traffic
SIP
SIP over TLS (SIPS)
Syslog
ICMP
ARP listener
SNMP Traps
DNS client
Version 7.0
Table 13-11: Traffic/Network Types and Priority
Traffic / Network Types
Management
Management
Management
Management
Management
Management
Determined by the service
Media
Media
Media
Control
Control
Management
Management
Determined by the initiator of the
request
Management
Varies according to DNS settings:
Class-of-Service (Priority)
Bronze
Bronze
Network
Bronze
Bronze
Bronze
Determined by the service
Premium media
Premium media
Premium media
Premium control
Premium control
Bronze
Determined by the initiator of the
request
Network
Bronze
Depends on traffic type:
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13. Network
Mediant 3000