SIST EN 300 416 V1.2.1:2003

• Abstract:

  Specify the availability objectives for designing, planning and operating digital transmission networks. Reference document: Draft ITU-T Rec. G.827

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.040.20 - Transmission systems
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Ref Project: ETSI EN 300 416 V1.2.1 (1998-08) - Network Aspects (NA); Availability performance of path elements of international digital paths

SIST EN 300 416 V1.2.1:2003 is the Slovenian adoption of ETSI EN 300 416 V1.2.1, a European telecommunications standard from ETSI Network Aspects. It specifies availability performance objectives for path elements of international constant bit rate digital paths, so planners, operators and the organization providing the path can design, assess and run international transmission networks against the same availability model. The document is based on Draft ITU-T Rec. G.827.

What does SIST EN 300 416 V1.2.1:2003 specify?

SIST EN 300 416 V1.2.1:2003 applies to international constant bit rate digital paths at or above 64 kbit/s carried by digital networks. It covers PDH, SDH and other transport networks such as cell-based systems, and it treats the availability model independently of the physical transport technology.

The standard distinguishes two path types:

• type a - between International Switching Centres (ISCs), with an international portion only
• type b - between Customer Premises (CP), with both national and international portions

Clauses 1 to 6 cover scope, normative references, abbreviations, definitions, requirements and measurement methods. Annex A gives examples of path topologies and end-to-end availability derivations, and Annex B is the bibliography.

What are the key requirements of SIST EN 300 416 V1.2.1:2003?

SIST EN 300 416 V1.2.1:2003 sets availability objectives for path elements rather than only for complete end-to-end paths. In practice, this lets a network operator budget availability across the pieces that make up an international route.

Path element categories and length classes

Clause 4 groups path elements by location, length and performance level. The location categories are Inter-Country Path Core Element (ICPCE), International Path Core Element (IPCE) and National Path Element (NPE). This matters because the standard applies different objectives depending on whether the element crosses borders, stays inside one country, or supports the national part of a type b path.

Length is divided into five 500 km classes up to less than 2 500 km. For non-undersea routes, the length is based on actual route length or an air-route distance adjusted by a routing factor, whichever is smaller. That means planners must classify each element consistently before comparing it with the availability objective.

Availability state and performance measures

Clause 4 defines unavailable time using Severely Errored Second (SES) events. A path becomes unavailable after 10 consecutive SES, and it becomes available again after 10 consecutive non-SES. The standard then measures:

• unavailability ratio (UR) - the proportion of time unavailable
• outage intensity (OI) - the number of unavailable periods in the observation period

This is important for maintenance and reporting because short and long outages are counted in a controlled way, using the SES rules from ITU-T G.826 and G.821.

Objectives for 2 048 kbit/s path elements

Clause 5 gives UR and OI objectives for 2 048 kbit/s path elements through formulas and tables. Separate objectives are given for mean values and worst case values, and for Standard and High performance levels. The tables provide coefficients for IPCE, NPE and ICPCE elements, so operators can check both the average network picture and the worst element in the network.

Other bit rates and compliance

For path elements below 2 048 kbit/s, the same requirements apply when they are carried on a 2 048 kbit/s server layer. For bit rates above 2 048 kbit/s, the standard leaves the subject for further study. Clause 5 says compliance is tested according to I-ETS 300 416, and clause 6 allows three measurement approaches, including direct measurement at the element end points and derivation from higher-order or constituent portions.

What terms does SIST EN 300 416 V1.2.1:2003 define?

• Path - a transport entity that carries client network information and ends at a Path End Point (PEP).
• Path element (PE) - a portion of a path created for availability management.
• Inter-Country Path Core Element (ICPCE) - the PE carried on the highest order digital path across the border between two countries.
• International Path Core Element (IPCE) - the PE used in the core network within one country.
• National Path Element (NPE) - the PE used in a terminating country to connect the international portion to the PEP for type b paths.
• Unavailability ratio (UR) - the proportion of time a PE is unavailable during the observation period.
• Outage intensity (OI) - the number of unavailable periods during the observation period.
• Severely Errored Second (SES) - the error state used to detect the start and end of unavailable time.

Who uses SIST EN 300 416 V1.2.1:2003?

Transmission network planners use SIST EN 300 416 V1.2.1:2003 to decide on system reliability, maintenance organization and network protection techniques. The organization responsible for providing a path uses it to judge whether extra end-to-end measures, such as protection switching, are needed to meet quality of service objectives.

Network operators use it when they provide the path core elements that make up an international digital path. It is also relevant for measurement, reporting and availability management in international transmission networks.

What changed in SIST EN 300 416 V1.2.1:2003 from the previous edition?

SIST EN 300 416 V1.2.1:2003 is the second version of former I-ETS 300 416. The foreword states that it was converted into an EN on request of the previous STC TM2 before transfer to NA.

Which standards are used with SIST EN 300 416 V1.2.1:2003?

Clause 2 references ITU-T Recommendation G.826 for SES definition at and above the primary rate, and ITU-T Recommendation G.821 for SES definition below the primary rate down to 64 kbit/s. It also references I-ETS 300 416 as the compliance test document.

The document also names Draft ITU-T Rec. G.827 as its reference document.

What does the SIST EN 300 416 V1.2.1:2003 document contain?

The document contains definitions, availability categories, formulas, objective tables and measurement methods for international digital path elements. Tables 1 to 4 set the UR and OI objectives by element type, performance level and length class.

It also includes figures showing type a and type b path structures, plus Annex A examples for linear and redundant topologies. Annex A shows how to derive end-to-end unavailability and outage intensity from element values, which is useful for design studies, testing and performance calculations.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Omrežni vidiki (NA) – Obseg razpoložljivosti potnih elementov na mednarodnih digitalnih potehNetwork Aspects (NA); Availability performance of path elements of international digital paths33.040.20Prenosni sistemTransmission systemsICS:Ta slovenski standard je istoveten z:EN 300 416 Version 1.2.1SIST EN 300 416 V1.2.1:2003en01-december-2003SIST EN 300 416 V1.2.1:2003SLOVENSKI
STANDARD
EN 300 416 V1.2.1 (1998-08)European Standard (Telecommunications series)Network Aspects (NA);Availability performance of path elementsof international digital pathsSIST EN 300 416 V1.2.1:2003

ETSIEN 300 416 V1.2.1 (1998-08)2ReferenceREN/NA-042140 (3uo00ioo.PDF)Keywordsdigital, path, performance, transmissionETSIPostal addressF-06921 Sophia Antipolis Cedex - FRANCEOffice address650 Route des Lucioles - Sophia AntipolisValbonne - FRANCETel.: [phone]
Fax: [phone]Siret N° 348 623 562 00017 - NAF 742 CAssociation à but non lucratif enregistrée à laSous-Préfecture de Grasse (06) N° 7803/[e-mail]://www.etsi.frhttp://www.etsi.orgCopyright NotificationNo part may be reproduced except as authorized by written permission.The copyright and the foregoing restriction extend to reproduction in all media.© European Telecommunications Standards Institute 1998.All rights reserved.SIST EN 300 416 V1.2.1:2003

ETSIEN 300 416 V1.2.1 (1998-08)3ContentsIntellectual Property Rights.4Foreword.4Introduction.41Scope.52Normative references.53Abbreviations.64Definitions.64.1Definition of paths, path elements and path element categories.64.1.1Path.64.1.2Path element.64.1.3Path element categories.64.1.3.1Network location categories.74.1.3.1.1Inter-country path core element.84.1.3.1.2International path core element.94.1.3.1.3National path element.94.1.3.2Length categories.94.1.3.3Performance level categories.104.2Definition of parameters.104.2.1General.104.2.2Parameters.115Requirements.115.12 048 kbit/s path elements.125.1.1Unavailability ratio.125.1.2Outage intensity.125.2Path elements at bit rates less than 2 048 kbit/s.135.3Path elements at bit rates greater than 2 048 kbit/s.136Measurement methods.13Annex A (informative):Examples of path topologies and end-to-end availabilityperformance derivations.15A.1Path topologies.15A.2End-to-end unavailability.15A.2.1Linear topology.15A.2.2Redundant topology.16A.3End-to-end outage intensity.16A.3.1Linear topology.16A.3.2Redundant topology.17A.4Numerical examples.17A.4.1Assumptions.17A.4.2Calculations.18A.4.2.1End-to-end unavailability for a linear topology.18A.4.2.2End-to-end unavailability for a redundant topology.18A.4.2.3End-to-end outage intensity for a linear topology.18A.4.2.4End-to-end outage intensity for a redundant topology.18Annex B (informative):Bibliography.20History.21SIST EN 300 416 V1.2.1:2003

ETSIEN 300 416 V1.2.1 (1998-08)4Intellectual Property RightsIPRs essential or potentially essential to the present document may have been declared to ETSI. The informationpertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be foundin SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respectof ETSI standards", which is available free of charge from the ETSI Secretariat. Latest updates are available on theETSI Web server (http://www.etsi.fr/ipr or http://www.etsi.org/ipr).Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guaranteecan be given as to the existence of other IPRs not referenced in SR 000 314 (or the updates on the ETSI Web server)which are, or may be, or may become, essential to the present document.ForewordThis European Standard (Telecommunications series) has been produced by ETSI Technical Committee NetworkAspects (NA).The present document specifies the availability performance of path elements for international digital paths.The present document is the second version of the former I-ETS 300 416 which has been converted into an EN onrequest of the previous STC TM2 before its transfer to NA.National transposition datesDate of adoption of this EN:7 August 1998Date of latest announcement of this EN (doa):30 November 1998Date of latest publication of new National Standardor endorsement of this EN (dop/e):31 May 1999Date of withdrawal of any conflicting National Standard (dow):31 May 1999IntroductionThe present document contains availability requirements for a structured approach, based on path elements, to be usedfor planning, designing and operating international transmission networks. The present document should be used:a)by transmission network planners to determine the required actions within the network (e.g. system reliability,maintenance organization, network protection techniques);b)by the organization responsible for the provision of a path to determine whether and which additional end-to-endactions (such as end-to-end protection switching) are necessary to satisfy quality of service objectives;c)by network operators providing path core elements which make up an international digital path, to ensure thatavailability requirements are met.SIST EN 300 416 V1.2.1:2003

ETSIEN 300 416 V1.2.1 (1998-08)51ScopeThe present document is applicable to international constant bit rate digital paths at or above 64 kbit/s supported bydigital networks. International constant bit rate digital paths may be based on the Plesiochronous Digital Hierarchy(PDH), the Synchronous Digital Hierarchy (SDH) or some other transport network such as cell-based. The presentdocument is generic in that it defines parameters and requirements independent of the physical transport networkproviding the paths.Two types of paths are considered; paths between International Switching Centres (ISCs) which consist of aninternational portion only and paths between Customer Premises (CP) which consist of national and internationalportions. These paths are referred to as "type a" and "type b" respectively (see figures 1 and 2).Both the national and international portions are made up of Path Elements (PEs). For the national portion of paths of"type b", the present document specifies availability parameters and requirements for the portion as a whole.Subdivision of requirements to the respective PEs making up the national portion is under the responsibility of thenetwork operator. For the international portion of paths of both types, the present document specifies availabilityparameters and requirements for the PEs making up the international portion.NOTE:The international measurement point is located on the international side of the ISC.The end-to-end availability performance of an international digital path can be calculated from the arrangement of theconstituent PEs and their associated requirements. Annex A gives guidance on evaluating the end-to-end unavailabilityof a path, taking into account the unavailability of each PE.In some countries the network may be subdivided into parts which are under the responsibility of different networkoperators. The partitioning of the requirements between these parts is outside the scope of the present document.Similarly, application of the present document to national paths which do not cross International Borders (IBs) is outsidethe scope of the present document.2Normative referencesReferences may be made to:a)specific versions of publications (identified by date of publication, edition number, version number, etc.), inwhich case, subsequent revisions to the referenced document do not apply; orb)all versions up to and including the identified version (identified by "up to and including" before the versionidentity); orc)all versions subsequent to and including the identified version (identified by "onwards" following the versionidentity); ord)publications without mention of a specific version, in which case the latest version applies.A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the samenumber.[1]ITU-T Recommendation G.826 (1993): "Error performance parameters and objectives forinternational, constant bit rate digital paths at or above the primary rate".[2]ITU-T Recommendation G.821 (1993): "Error performance of an international digital connectionoperating at a bit rate below the primary rate and forming part of an integrated services digitalnetwork".[3]I-ETS 300 416: "Transmission and Multiplexing (TM); Availability performance of path elementsof international digital paths".SIST EN 300 416 V1.2.1:2003

ETSIEN 300 416 V1.2.1 (1998-08)63AbbreviationsFor the purposes of the present document, the following abbreviations apply:CPCustomer PremisesFSFrontier StationIBInternational BorderICPCEInter-Country Path Core ElementIGInternational GatewayIPCEInternational Path Core ElementISCInternational Switching CentreLTLine TerminalMUXMultiplexerNPCENational Path Core ElementNPENational Path ElementPAEPath Access ElementPDHPlesiochronous Digital HierarchyPEPath ElementPEPPath End PointSDHSynchronous Digital HierarchySESSeverely Errored SecondSIEShort Interruption EventTICTerminal International Centre4DefinitionsFor the purposes of the present document, the following definitions apply:4.1Definition of paths, path elements and path elementcategories4.1.1PathA path is a transport entity responsible for the integrity of client network information transfer.Paths are terminated at each end at the Path End Point (PEP). For paths of "type a", the exact location of the PEP is forfurther study, but is on the international side of the ISC. For paths of "type b", the PEP is located at the CP.4.1.2Path elementA PE is a portion of a path resulting from partitioning for the purpose of availability management.NOTE:In the present document, paths are partitioned on the basis of geographical rather than architecturalconsiderations. Therefore, PEs are considered to be logical elements of a path whose boundaries are notnecessarily at the network level (i.e. bit rate) of the path under consideration. For example, on a 2 Mbit/spath, an international boundary may only physically exist at 140 Mbit/s. In such situations, the constituent2 Mbit/s signal at the international boundary can only be observed by using additional equipment whichpassively analyses the embedded signal structure. However, availability performance may still bemonitored using mechanisms at the layer of the supporting path.The physical realization and topology of the PEs are under the responsibility of each network operator.4.1.3Path element categoriesPEs are categorized according to their location in the network, their length and their performance level.SIST EN 300 416 V1.2.1:2003

ETSIEN 300 416 V1.2.1 (1998-08)74.1.3.1Network location categoriesPaths may traverse different portions of networks having significantly different availability performance characteristics.For the purpose of the present document, three different portions are distinguished and accordingly three categories ofPEs are defined:-Inter-Country Path Core Element (ICPCE);-International Path Core Element (IPCE);-National Path Element (NPE).The conceptual location of these path element types is shown in figures 1 and 2.NOTE:The NPE is only applicable to paths of "type b".ISCISCFSFSFSFS
ICPCE
ICPCE(see NOTE)IPCEIPCEIPCEInternational path between ISC (type "a")PEPPEPTerminatingCountryTransitCountry 1TerminatingCountryIBIBIBInternational portionNOTE:This ICPCE crosses two IBs and is typically supported by a satellite or undersea transmission system.PEP:Path End PointICPCE:Inter-Country Path Core ElementISC:International Switching CentreIPCE:International Path Core ElementFS:Frontier StationIB:International BorderFigure 1: Conceptual location of the elements of an international path between ISCsSIST EN 300 416 V1.2.1:2003

ETSIEN 300 416 V1.2.1 (1998-08)8CPCPFSFSFSFS
ICPCE
ICPCE(see NOTE)IPCEIPCEIPCEIBIBIBPEPPEPNational portionNational portionInternational portionTerminatingCountryCountry 1TransitTerminatingCountry
TIC
TICInternational path between customer premises (type "b")NPENPENOTE:This ICPCE crosses two IBs and is typically supported by a satellite or undersea transmission system.PEP:Path End PointICPCE:Inter-Country Path Core ElementTIC:Terminal International CentreIPCE:International Path Core ElementFS:Frontier StationNPE:National Path ElementIB:International BorderCP:Customer PremisesFigure 2: Conceptual location of the elements of an international path between customer premises4.1.3.1.1Inter-country path core elementThe ICPCE is the PE carried on the highest order digital path across the geographical border between two countries.This element is limited by the Frontier Stations (FSs) where the highest order inter-country path may be terminated.When the highest order inter-country path is not terminated in the FS, the ICPCE is limited by the supporting inter-country section access point. An example of an ICPCE is given in figure 3.An ICPCE may be transported on a satellite, terrestrial or undersea cable transmission system. In the case of a satellitetransmission system, the FS is considered to be located in the earth station.SIST EN 300 416 V1.2.1:2003

ETSIEN 300 416 V1.
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