Seminar on ITU-T hot topics for Standardization (Mar del Plata, Argentina, 2 September 2009) Interoperability technical means, services, classes and parameters of QoS A. Koucheryavy, ZNIIS General Director Advisor, ITU-T SG11 Vice Chairman Content ITU-T activities
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Seminar on ITU-T hot topics for Standardization (Mar del Plata, Argentina, 2 September 2009)Interoperability technical means, services, classes and parameters of QoS
A. Koucheryavy, ZNIIS
General Director Advisor,
ITU-T SG11 Vice Chairman
Resolution 76 “Studies related to conformance and interoperability testing, assistance to developing countries, and a possible future ITU mark program” was approved at the World Telecommunication Standard Assembly (Johannesburg, 2008).
“The interoperability of international telecommunication networks was the main reason to create ITU in the year 1865 (International Telegraph Union), and that this remains one of the main goals in the ITU strategic plan”.
What is the
Recommendation Y.101 “Global Information Infrastructure terminology: Terms and definitions” Interoperability is the ability of two or more systems or applications to exchange information and to mutually use the information that has been exchanged”. This Recommendation was approved at March 2000. It’s so long ago from today point of view.
We will consider further interoperability issues for the technical means, services and QoS context on the base of the last searching and developing progress and Study Group 11 ITU-T activities. The main focus for interoperability issues will be interoperability supporting by testing procedures.
The NGN concept is the real implementation plan for network modernization today. The full NGN definition could be found in the Recommendation Y.2001. The NGN concept includes the some QoS guarantees levels in according with Y.1540 and Y.1541 and very widely services set, in principle unlimited. Both of them points request to consider interoperability as a complex definition, including technical means, services and QoS interoperability, not only systems or applications.
The conformance testing goal is the specification profiles verification. The network testing goal is the correct, integrity and reliability services for users.
The table 1 ETR 101 667 defines the users of both methodologies. The conformance testing methodology users are the vendors at first place and Administrations and operators optionally, the network testing methodology users are the Administrations and operators only.
The methodology of the model network using for network testing was proposed at ITU-T in 2004 (Q.39xx series).
The model network is the network, which simulates the capabilities similar to those available in present telecommunication networks, has a similar architecture and functionality and users, the same telecommunication technical means.
ZNIIS Model Network (2004, Softswitch) 1016 tests – 8.1% unsuccessful tests
Plug Test ETSI (Slovenia, 2008, IMS)
410 tests – 18% unsuccessful tests.
(Joint ITU-T/ETSI meeting, Moscow, ZNIIS, 10 April, 2009).
Q.3900 – Model Network Architecture
Q.3901 – NGN (Softswitches)
Q.3903 – Data base
Q.3904 – NGN (IMS) (draft)
Q.3905 – IPTV
Q.3906.1 – Broadband access (wired) (draft)
Q.3906.2 - Broadband access (WiFi) (draft)
Q.3906.3 - Broadband access (WiMax) (draft)
The ITU –T recommendations on the services interoperability testing are absent today. Furthermore, the service scenarios for important NGN services are absent too. It’s very complicated problem today, but during ITU-T study period 2009-2012 the key recommendations set for service interoperability testing should be developed.
The detailed requirements for the services implementation should be developed. It could be include:
The testing scenarios, list and types of tests for NGN TS1 basic call and supplementary services, NGN TS1 streaming services and NGN TS1 multimedia services should be developed as separately ITU-T Recommendations.
Q.3915 – TS1 (draft)
Q.3916 – Testing scenarios, list and types of tests for NGN (TS1) basic call and supplementary services,
Q.3917 - Testing scenarios, list and types of tests for streaming services (TS1),
Q.3918 - Testing scenarios, list and types of tests for multimedia services (TS1).
The many networks are realized NGN concept. At first, of course, it’s the basic IP network. Furthermore, it could be WiFi (based on Ethernet technology), IPTV and so on.
The some QoS mechanisms were developed for QoS supporting at IP-based networks. The recommendation Y.1291 which was approved in 2004 determine four standardized approaches for QoS supporting: Integrated services (IntServ), Differentiated services (DiffServ), MultiProtocol Label Switching (MPLS), IPCablecom Dynamic QoS.
The service level agreement (SLA) concept and the wireless broadband access technologies development (WiFi and WiMax) are shown, that DiffServ mechanism could be using for QoS supporting in the heterogeneous NGN networks. If we can see the IEEE 802.11e or QoS requests at the pooling-based services for WiMax, we will found that the QoS classes based on DiffServ concept.
There are three PHB classes:
EF PHB is targeted to applications which require strict guarantees of end-to-end delay. The EF PHB applications request the QoS level, which compare with the QoS level for unloaded network.
AF PHB has been designed for a range applications which require different QoS guarantees. There are four classes of PHB identification codes within the AF PHB group. Within each class there are three distinct DiffServ Code Points (DSCP) with different packet drop precedence.
The mapping between Y.1541 QoS classes and DiffServ mechanism are determined in the recommendation Y.1291. The EF are corresponding with Y.1541 classes 0 and 1, AF – classes 2, 3 and 4 respectively, and Best Effort – class 5.
The mapping between VLAN (Virtual LAN in accordance with IEEE 802.1) and DiffServ DSCP are recommended in the Y.2112.
The traffic flows types are really complicated for NGN. They are
self-similar as usually. The self-similar traffic generation at the model network is a real problem today. We will consider IPTV traffic further.
The IPTV traffic measurements was made at ZNIIS model network. The actual traffic of movies named Ohotnik, likely thriller performed on DVD was analyzed for differences times fragments and for differences aggregation period in processing of measuring data.
The minimum observation movies fragment is the 60s. The fragment includes 6863 frames, each of frame has the length 1356 bytes
Wavelet transform for Poisson traffic
Wavelet transform for measured traffic (fragment 60s)
Q.3919 – The types of traffic flows which should be generated for voice, data and video on the Model Network for testing QoS parameters.
Q.3920 – The types and list of tests for QoS testing on Model networks for traffic-unloaded conditions.
Q.3921 - The types and list of tests for QoS testing on Model networks for traffic-loaded conditions.
Q.3922 - The types and list of tests for QoS testing for intra-domain connectivity.
Q.3923 - The types and list of tests for QoS testing for inter-domain connectivity.
COM 11-C33-E, SG11 meeting, 19-23 January, 2009, Geneva.
ETSI TS 186 008-1, October, 2007
IMS/NGN Performance Benchmark Part 1:
IMS/NGN Performance Benchmark Part 2:
Subsystem Configurations and Benchmarks
IMS/NGN Performance Benchmark Part 3:
Traffic Sets and Traffic Profiles
Benchmark Part 4:
Delay objectives for various IMS transactions
Q. Bench-PES NGN A
Q. Bench-PES NGN B
Q. Bench-PES NGN C
Benchmark Part 1:
Benchmark Part 2:
Subsystem Configurations and Benchmarks
Benchmark Part 3:
Traffic Sets and Traffic Profiles
The six QoS classes from 0 to 5 are defined at the table 2/Y.1541 “Guidance for IP QoS classes” Recommendation Y.1541.
The “0” QoS class contents real-time, jitter sensitive, high interaction applications. It could be VoIP and VTC (Video Teleconference). The same applications (VoIP, VTC) is the base for ”1” QoS class, named “Real-time, jitter sensitive, interactive” as we see, the difference is only between “high interactive” and “interactive”.
Q. Perf-obj test VS IP
objectives Tests for IP-based Voice services