Prognosemetoder – en oversikt - Telenor

fic models, traffic and congestion control mechanisms, resource
allocation and dimensioning methods for IN structured networks
and associated SS No. 7 networks will be recommended
in the new E.7IN series and in revisions of E.723 and E.733.
Signalling traffic issues for B-ISDN are included in the workplan.
Mobile and UPT: Traffic engineering aspects of networks supporting
mobile and UPT services will be covered in the E.750
series of Recommendations to be finalised in the 1994 – 96 time
frame. The first recommendations in the series have already
been published. The series addresses initially circuit-switched
traffic and common channel signalling traffic, whereas packetswitched
connections will be dealt with later on. The teletraffic
engineering problems related to the interchange of messages
required by UPT are addressed. Modelling of the traffic processes
in the user and the control plane, grade of service
requirements, dimensioning methods and measurements methods
will be covered in the E.750 series.
Miscellaneous: Traffic engineering for Public Switched Telephone
Networks (PSTN) requires continuing development to
improve the efficiency of network operation. There is ongoing
work on dimensioning circuit-groups with multi-slot bearer services.
Traffic measurements necessary for SS No. 7, N-ISDN,
B-ISDN, IN and UPT are addressed.
ETSI
The work on traffic control in B-ISDN within ETSI is done by
the Traffic Control and Resource Management (TCR) group
within NA5. This activity goes on in parallel with the corresponding
activity within ITU-T SG 13, the same topics being
discussed aiming at harmonised European positions.
Release of the ETS “Requirements for traffic control and
resource management of VP/VC cross-connected network” (VP
= Virtual Path, VC = Virtual Channel) is scheduled for October
1994, and the ETS “Traffic Control and Congestion Control in
B-ISDN” endorsing the second version of I.371 is expected to
be released in December 1994.
ATM Forum
The ATM Forum is an organisation with the objective of accelerating
the deployment of ATM products and services through
rapid convergence of interoperability specifications and promotion
of industry co-operation. The Traffic Management Group is
responsible for traffic control and network performance issues.
The results so far are included in the ATM Forum User-Network
Interface 3.0 specification and the ATM Forum Broadband
Interconnection Interface (B-ICI) 1.0. The specifications
are based on ITU-T Recommendation I.371, however, on some
points these specifications are more detailed. As an example,
the parameters Sustainable Cell Rate and Burst Tolerance are
defined within the ATM Forum UNI Specification, while they
are still being discussed within ITU-T. Furthermore, reference
traffic loads are defined for use when measuring the performance
of a B-ICI link.
EURESCOM
There are traffic engineering activities in the fields of ATM and
IN within the EURESCOM institute.
Traffic issues in ATM VP cross-connect networks have been
considered in the finalised project P105 “European ATM Network
Studies”, resulting in deliverables on Connection Acceptance
Control (CAC), Network Parameter Control (NPC) and
Dimensioning. The CAC and NPC procedures specified are
based on the declared peak cell rate, and are important input to
the specification of the European ATM Pilot. Within the followup
project P302 “European switched VC-based ATM Network
Studies” (planned for the period September 1993 – November
1995) the activity on resource allocation is aiming at defining
more source traffic descriptors allowing for statistical multiplexing
gain in the network. Guidelines for implementation and
evaluation of the corresponding Usage Parameter Control
(UPC), NPC and CAC procedures will be prepared. Possible
benefits with use of long buffers in the switches and corresponding
buffer management schemes will also be studied.
Due to the planned development of IN and the rapid implementation
of services, the need for appropriate methods and tools
for dimensioning the IN infrastructure is recognised as very
important. The objective of the project P308 “Methods for
Tools to Dimension IN Networks”, planned for the period from
September 93 to mid 95, is to determine general methods in
order to give guidelines to the network operators on how to
dimension the different elements of an IN network (including
the SS no 7 network). The topics include traffic models, congestion
and load control, flow control parameters, dimensioning
methods and performance analysis. The quality of service
aspects include both the delays of the call set-up phase and the
probability of query rejection due to congestion in IN network
elements.
RACE
ISDN Traffic Modelling E.710 ...
ISDN Dimensioning
E. 713
E. 731
E. 732
E. 712
E. 733
E. 73x
E. 73y
Methods E.730 ...
ISDN Traffic Performance E.720 ...
The programme for Research and technology development in
advanced communications in Europe, the RACE programme, is
divided into two main phases, Phase I from 1988 to 1992 and
Phase II from 1992 to 1995. There are a lot of projects within
the RACE programme having activities on traffic engineering
issues. In this survey we will focus on the main projects which,
to the author's knowledge, have influence on the development
of the ATM traffic field.
R1022 ATD: “Technology for ATD” was one of the largest projects
within the RACE I programme with ALCATEL as prime
E. 711
E. 7IN4
E. 721
Circuit-Switched
Packet-Switched
SSno7
ATM
IN
E. 7IN2
E. 74x
E. 722
E. 723
E. 7IN1
E. 743
ISDN Traffic Measurements E.740...
The E.700 series of Recommendations
189