ETSI TS 182 018 V2.0.0 (2008-01)

Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Control of Processing Overload; Stage 2 Requirements

DTS/TISPAN-02035-NGN-R2

General Information

• Status: Published
• Publication Date: 27-Jan-2008
• Technical Committee: TISPAN 2 - TISPAN Architecture
• Current Stage: 12 - Completion
• Due Date: 12-Dec-2007
• Completion Date: 28-Jan-2008

Standards Content (Sample)

ETSI TS 182 018 V2.0.0 (2008-01)
Technical Specification


Telecommunications and Internet converged Services and
Protocols for Advanced Networking (TISPAN);
Control of Processing Overload;
Stage 2 Requirements

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2 ETSI TS 182 018 V2.0.0 (2008-01)



Reference
DTS/TISPAN-02035-NGN-R2
Keywords
architecture, control, functional
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3 ETSI TS 182 018 V2.0.0 (2008-01)
Contents
Intellectual Property Rights.4
Foreword.4
1 Scope.5
2 References.5
2.1 Normative references.5
3 Abbreviations.5
4 TISPAN NGN overload control requirements .6
4.1 High level overload control requirements .6
4.2 General requirements for Nearest Neighbour load control.7
4.3 Deployment specific requirements .8
4.4 Application specific requirements.8
Annex A (informative): Comparison between RACS and nearest neighbour overload control .10
History .11

ETSI

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4 ETSI TS 182 018 V2.0.0 (2008-01)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Telecommunications and Internet
converged Services and Protocols for Advanced Networking (TISPAN).
ETSI

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5 ETSI TS 182 018 V2.0.0 (2008-01)
1 Scope
The present document describes the specific TISPAN requirements for controls to manage overload of processing
resources in NGNs. In particular, it addresses overload control between nearest neighbours.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
- if it is accepted that it will be possible to use all future changes of the referenced document for the purposes
of the referring document;
- for informative references.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
For online referenced documents, information sufficient to identify and locate the source shall be provided. Preferably,
the primary source of the referenced document should be cited, in order to ensure traceability. Furthermore, the
reference should, as far as possible, remain valid for the expected life of the document. The reference shall include the
method of access to the referenced document and the full network address, with the same punctuation and use of upper
case and lower case letters.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
[1] ITU-T recommendation E.412: "Network management controls".
[2] ETSI TR 182 015: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Next Generation Networks; Architecture for Control of
Processing Overload".
[3] ETSI ES 282 003: " Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Resource and Admission Control Sub-system (RACS);
Functional Architecture".
[4] ETSI TS 181 005 V2.4.0 (2007-11): "Telecommunications and Internet Converged Services and
Protocols for Advanced Networking (TISPAN); Service and Capability Requirements".
3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
IMS IP Multimedia Subsystem
ISDN Integrated Service Digital Network
NGN Next Generation Network
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6 ETSI TS 182 018 V2.0.0 (2008-01)
PSTN Public Switched Telecommunication Network
QoS Quality of Service
RACS Resource Admission Subsystem
SCF Session Control Function
SIP Session Initiation Protocol
SLA Service Level Agreement
4 TISPAN NGN overload control requirements
4.1 High level overload control requirements
In TS 181 005 [4] we have the following requirements for overload control.
The NGN shall have mechanisms available to control overload that:
1) automatically maximize effective throughput (i.e. admitted service requests/sec) at an overloaded resource;
2) achieve this throughout the duration of an overload event, and irrespective of the overloaded resource's
capacity or of the number of sources of overload;
3) are configurable by the service provider so that, under processing overload, a high proportion of response
times at overloaded resources are low enough so as not to cause customers to prematurely abandon service
requests;
4) should be possible to be applied within a service provider's NGN, and between different service providers'
NGNs;
5) should be possible to be applied within an NGN subsystem (e.g. IMS, PSTN/ISDN emulation) and between
different NGN subsystems.
NOTE: As a general rule, an NGN's call, session and command processing resources can experience prolonged
processing overload under the appropriate circumstances (e.g. partial, or full, server failure, high rates of
incoming service requests). Consequently, it needs to be equipped with some form of overload detection
and control (including expansive controls such as load balancing and resource replication), in order to
keep response times just low enough under such processing overload to preclude customers abandoning
their service requests prematurely.
Many pieces of equipment will have internal load control, which aims to meet the ideal behaviour described in
ITU-T recommendation E.412 [1] and shown graphically in figure 1. The object of these internal controls is to bound
the system response time by rejecting some of the workload (because rejecting workload requires less effort than
accepting it). As the load increases requests are rejected, but because the rejected requests still consume some
processing resource, the rate at which requests can be accepted falls. As a consequence, such internal load control can
only protect the physical host against overload to a limited extent. Severe overloads will reduce the rate at which useful
work can be done, and very severe overloads may cause the system to operate incorrectly or with unacceptably long
response times.

ETSI

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Figure 1: hedoo Typical overload behaviour in a host with internal load control.
By deploying a distributed overload control, in which systems suppress some ser
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