# GGSN Traffic & DS PHB Group

Use this dialog to view Universal Mobile Telephone System (UMTS) traffic class mapping with Per Hop Behaviour (PHB) group.

## Procedure

In the Chassis view, right-click the device and select Configure from the popup menu.

The following information appears:

> Traffic Class (cggsnQosUmtsTrafficClass)

> Traffic Class Mapped PHB (cggsnQosUmtsDiffServPhbgroup)

> PDP Per Traffic Class (cggsnQosUmtsPdps)

### Traffic Class (cggsnQosUmtsTrafficClass)

UMTS QoS traffic class.

UMTS TrafficClass values are: signalling(1) conversational(2), streaming(3), interactive(4), background(5)

UMTS QoS uses this parameter to make assumptions about the traffic source, and determine the maximum bit rate, and guaranteed bit rate for this traffic class when performing admission control. The signalling traffic class only applies to UMTS signalling messages.

### Traffic Class Mapped PHB (cggsnQosUmtsDiffServPhbgroup)

PHB which is mapped to the traffic class given by cggsnQosUmtsTrafficClass.

DS architecture is based on number of functional elements, one of which is PHB. PHBs specify queuing, queue management and scheduling characteristics that provide a means of allocating buffer and bandwidth resources at each node among the competing traffic streams.

The various DS PHBs include:

signalling - signallingClass(1)

The signalling class PHB is only used for the UMTS signalling messages. This DS PHB does not apply to any other IP data packets.

expedited forwarding - efClass(2)

The expedited forwarding PHB is used to provide a low loss, low latency, low jitter, assured bandwidth, end-to-end service through DS domains. Such a service appears to endpoints like a point-to-point connection, or a virtual leased line.

assured forwarding - afClass(3-6)

The assured forwarding PHB provides a means for a provider DS domain to offer different levels of delivery assurances for packets received from a customer DS domain.

There are four assured forwarding classes as follows:

- afClass1

- afClass2

- afClass3

- afClass4

afClass1, afClass2, afClass3 and afClass4 are defined, where each AF class is in each DS node and is allocated a certain amount of forwarding resources(buffer space and bandwidth). IP packets are assigned into one or more of these classes, according to the subscribed service. Within each class the packets are marked by a mobile subscriber, or by the provider DS domain, with one of the three possible drop precedence values. In case of congestion, the drop precedence of a packet determines the relative importance of a packet within the class. Packets in one class are forwarded independently of the packets in another class.

best effort - bestEffort(7)

This is the default PHB. The packets of this aggregate are forwarded on an output link whenever the link is not required to satisfy any other PHB.

### PDP Per Traffic Class (cggsnQosUmtsPdps)

Number of PDP contexts associated with each traffic class identified by cggsnQosUmtsTrafficClass.