Configuring Quality Of Service - AudioCodes Mediant 500 E-SBC User Manual

12.6

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 DiffServ to the following class of services (CoS) and assign VLAN priorities
(IEEE 802.1p) to various values of DiffServ:

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 according to the value of the DiffServ field in the
packet IP header (according to the IEEE 802.1p standard). The DiffServ table lets you
configure up to 64 DiffServ-to-VLAN Priority mapping (Layer 2 class of service). For each
packet sent to the LAN, the VLAN Priority of the packet is set according to the DiffServ
value in the IP header of the packet.
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)
RTP traffic
RTCP traffic
T.38 traffic
SIP
SIP over TLS (SIPS)
Syslog
SNMP Traps
DNS client
NTP
User's Manual
Table 12-13: Traffic/Network Types and Priority
Traffic / Network Types
Management
Management
Management
Management
Management
Management
Media
Media
Media
Control
Control
Management
Management
Varies according to DNS settings:

OAMP

Control
Varies according to the interface
type associated with NTP (see
''Assigning NTP Services to
Application Types'' on page 116):

OAMP
124
Mediant 500 E-SBC
Class-of-Service (Priority)
Bronze
Bronze
Network
Bronze
Bronze
Bronze
Premium media
Premium media
Premium media
Premium control
Premium control
Bronze
Bronze
Depends on traffic type:

Control: Premium Control

Management: Bronze
Depends on traffic type:

Control: Premium control

Management: Bronze
Document #: LTRT-10427