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one common QoS description for the service

provided at the network level, i.e. the IP level.

The services (e.g. VoIP and VoD) have dis-

tinct QoS descriptions at the application/ser-

vice level (i.e. Voice and Video level). How-

ever, the services are reflected in a common

QoS description at the network level, i.e. IP

level.

• All-in-one:In this case the SLA relates to the
  bundled service, i.e. all services offered to the
  user and their quality are described in a single
  document. This might be the case if one pro-
  vider is responsible for all services delivered
  and controls all networks involved in the ser-
  vice delivery.

In the following the examples of relationships

between SLAs and SLS are elaborated on. The

notation used is given in Table 2.

7.1 One-to-one Relationship

between SLA and SLS

Assume three services – A, B, C, each of them

having a separate SLA. Each of these SLAs

includes QoS descriptions of all service compo-

nents that are enveloped in an SLS. This SLS

gives a full description of the service and rele-

vant QoS parameters for all service components.

In this case, SLS has to include both QoS param-

eters and values for the IP flows carrying the

traffic generated by the application/service (e.g.

IP flows for service A – QoSIPa) and the QoS

parameters related to the application/service

level, (e.g. for service A – QoSa). In this case

the SLAs are separate from each other as illus-

trated in Figure 10.

In Figure 11 is illustrated an example of a ser-

vice delivery with related agreements. The ser-

vice provider (SP) delivers a VoIP service to the

user. In this example, the SP is responsible for

the IP connection used to deliver the VoIP ser-

vice. The user and the SP have set up the SLA,

which covers both business and technical aspects

for the VoIP service delivery/usage. That means

that the SP has to take care of the IP connectivity

(via another SLA made with network operator,

NO12)), and to include the description and QoS-

related aspects in the user-SP SLA. The QoS

description in this SLA (QoSb) covers the rele-

vant parameters for both IP network connectivity

and VoIP level. In order to fulfil SLA User-SP,

two other SLAs should exist, User NP and NP-

SP. In this case a single provider (i.e. SP) con-

trols the process of making agreements and has

an overview/control of mapping service parame-

ters and QoS parameters, but it is still not a triv-

ial problem.

Object Notation

Service A The service name, as given and described in the service

description included in the SLA

QoSa QoS description related to service A at the application/service

level (e.g. VoIP)

QoSIPa QoS description related to service A at the common IP level

(i.e. IP connectivity level)

Table 2 Notation used when
analysing SLA/SLS mapping

Service C

SLS:

QoSc

QoSIPc

Service B

SLS:

QoSb

QoSIPb

Service A

SLS:

QoSa

QoSIPa

Figure 10 One-to-one relationship

Figure 11 One service
delivered and produced by
a single provider

Service Provider (SP)

Network operator (NO)

QoSb

QoSIPb

= SLA

12)Note that the SLA made between SP and NO is not visible to the user and is therefore omitted in Figure 11.