1、DEUTSCHE NORM November 1995 Frame-relay-Dienste Teil 1 : Allgemeine Beschreibung Englische Fassung ETS 300399-1 : 1995 I ETS 300399-1 ICs 33.040.10 Deskriptoren: Telekommunikation, ISDN, bermittlungsprozedur, Frame-relay-Dienst, Allgemeines Frame-relay-services - Part 1 : General description; Englis
2、h version ETS 300399-1 : 1995 Die Europische Telekommunikationsnorm ETS 300399-1 : 1995 hat den Status einer Deutschen Norm. Nationales Vorwort Die vorliegende Norm ist auf der Grundlage der vom Europischen Institut fr Telekommunika- tionsnormen (ETSI) herausgegebenen Europischen Telekommunikationsn
3、orm ETS 300399-1, Ausgabe Mrz 1995, “Frame relay services - Part 1: General description“, verffentlicht worden. Diese Norm enthlt unter Bercksichtigung des DIN-Prsidialbeschlusses 1 311 983 den englischen Originattext der vom Technischen Unterkomitee NA 2 des ETSI erarbeiteten ETS 300399-1. Fachlich
4、 zustndig in Deutschland ist das Unterkomitee 722.1 “Netzkonzepte“ der Deutschen Elektrotechnischen Kommission im DIN und VDE (DKE). Fortsetzung 41 Seiten ETS-Original Deutsche Elektrotechnische Kommission im DIN und VDE (DKE) DIN Deutsches Institut fur Normung e.V. . Jede Art der Vervielfalligung,
5、auch auszugsweise. Ref. NL DIN ETS 300399-1: 1995-11 PreisgK 15 Vertr.-NI: 1715 nur mit Genehmigung des DIN Deutsches Institut fur Normung eV, Berlin, gestattet. Alleinverkauf der Normen durch Beuth Verlag GmbH, 10772 Berlin DIN1 DIN ETS 300399-II 95 2794442 0528320 555 = k:“ N I CAT I o N STANDARD
6、ETS 300 399-1 March 1995 Source: ETSI TC-NA Reference: DE/NA-023216-1 UDC: 621.395 Key words: ISDN, frame relay, stage 1 Frame relay services; Part 1 : General description ETSI European Telecommunications Standards Institute ETSI Secretariat Postal address: 06921 Sophia Antipolis Cedex - FRANCE Offi
7、ce address: Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE Tel.: + 33 92 94 42 O0 - Fax: + 33 93 65 47 16 European Telecommunications Standards Institute 1995. All. rights reserved. No part may be reproduced except as authorised by written permission. The copyright and the foregoing restr
8、iction on reproduction extend to all media in which the information may be embodied. Page 2 ETS 300 399-1 : March 1995 Whilst every care has been taken in the preparation and publication of this document, errors in content, typographical or otherwise, may occur. If you have comments concerning its a
9、ccuracy, please write to “ETSI Editing and Standards Approval Dept.“ at the address shown on the title page. DIN Frame relay bearer service; Service d ef i nit i on “ . Part 3: “Part 3: Integrated Services Digital Network (ISDN); Frame relay data transmission service; Service definition“. Part 4: “P
10、art 4: Broadband Integrated Services Digital Network (B-ISDN); Frame relay bearer service; Service definition“. TransDosition dates I Date of latest announcement of this ETS (doa): 30 June 1995 Date of latest publication of new National Standard or endorsement of this ETS (dop/e): 31 December 1995 I
11、 Date of withdrawal of anv conflictina National Standard idow): 31 December 1995 I Introduction The purpose of this ETS is to describe the frame relay service. The definition and description of this service forms the basis to define the network capabilities required for the support of the service. T
12、he prose description begins with clause 5, the static description begins with clause 11. No dynamic description is provided. DIM1 DIN ETS 300399-1 95 m 2794442 0528127 70T m Page 8 ETS 300 399-1 : March 1995 Blank page DIN1 DIN ETS 300399-1 95 2794442 0528128 846 = Page 9 ETS 300 399-1 : March 1995
13、1 Scope This European Telecommunication Standard (ETS) specifies the general aspects of the frame relay service that is common to all frame relay services independent of the network on which the service is offered. This ETS is applicable for all network-specific frame relay service definitions. This
14、 ETS should be complemented with standards for the network-specific part of the frame relay service. 2 Normative references This ETS incorporates by dated and undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the pub
15、lications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this ETS only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. ll CCITT Recommendation
16、E. 164: “Numbering plan for the ISDN era“ I21 CCITT Recommendation 1.233.1 : “ISDN frame relaying bearer service“. i31 i41 i51 i61 71 i81 i91 i1 01 (1 21 ITU-T Recommendation 1.500: “General structure of the ISDN Interworking Recommendations“. CCITT Recommendation Q.922: “ISDN data link layer specif
17、ication for frame mode bearer services“. ITU-T Recommendation Q.933: “Layer 3 signalling specification for frame mode bearer service“. ITU-T Recommendation X.25: “Interface between data terminal equipment (DTE) and data circuit-terminating equipment (DCE) for terminals operating in the packet mode a
18、nd connected to public data networks by dedicated ci r cu it “ . ITU-T Recommendation X.31: “Support of packet mode terminal equipment by an ISDN“. CCITT Recommendation X. 121 : “International numbering plan for public data networks“. ITU-T Recommendation X. 1 34: “Portion boundaries and packet laye
19、r reference events: basis for defining packet-switched performance parameters“. ITU-T Recommendation X. 140: “General quality of service parameters for communication via public data networks“. CCITT Recommendation X.200: “Reference Model of Open Systems Interconnection for CCITT applications“. ITU-T
20、 Recommendation X.21 O: “Open Systems Interconnection layer service definition conventions“. ITU-T Recommendation X.2 1 3: “Information technology - Network service definition for Open Systems Interconnection“. DIN1 DIN ETS 300399-1 95 m 2794442 0528329 782 m Page 10 ETS 300 399-1 : March 1995 141 C
21、CITT Recommendation X.300: “General principles for interworking between public networks and between public networks and other networks for the provision of data transmission services“. i1 51 Addendum 1 to IS0 8348 (1 987): “Connectionless mode transmission“. i1 61 IS0 8473: “Information processing s
22、ystems - Data communications - Protocol for providing the connectionless-mode network service“. 3 Definitions For the purposes of this ETS, the following definitions apply: access rate: The data rate of the physical connection at the user-network interface. The speed of the physical connection deter
23、mines how much data (maximum rate) the end-user can inject into the network. Forward Explicit Congestion Notification (FECN): See CCITT Recommendation Q.922 41 for the full definition. Backward Explicit Congestion Notification (BECN): See CCITT Recommendation Q.922 41 for the full definition. Consol
24、idated Link Layer Management Message (CLLM): See CCITT Recommendation 0.922 141 for the full definition. Committed Burst size (Bc): The maximum committed amount of data a user may offer to the network during a time interval T,. B, is negotiated at virtual circuit establishment. Committed rate measur
25、ement interval (TC): The time interval during which the user is allowed to send only the committed amount of data (Bc) and the excess amount of data (BE). T, is computed. Committed Information Rate (CIR): The information transfer rate which the network is committed to transfer under normal condition
26、s. The rate is averaged over a minimum increment of time T,. CIR is negotiated at virtual circuit establishment. congestion management: This includes: network engineering; Operation, Administration and Maintenance (OAM) procedures to detect the onset of congestion; and real time mechanisms to preven
27、t or recover from congestion. Congestion management includes, but is not limited to; congestion control, congestion avoidance and congestion recovery, as defined below: - congestion control: this refers to real-time mechanisms to prevent and recover from congestion during periods of coincidental pea
28、k traffic demands or network overload conditions (e.g. resource failures). Congestion control includes both congestion avoidance and congestion recovery mechanisms; - congestion avoidance: congestion avoidance procedures refer to procedures initiated at or prior to the onset of mild congestion in or
29、der to prevent congestion from becoming severe. Congestion avoidance procedures operate around and within the regions of mild congestion and severe congestion; - congestion recovery: congestion recovery procedures refer to procedures initiated to prevent congestion from severely degrading the end-us
30、er perceived Quality of Service (QoS) delivered by the network. These procedures are typically initiated when the network has begun to discard frames due to congestion. Congestion recovery procedures operate around and within the region of severe congestion. core service: See CCITT Recommendation 0.
31、922 41, annex A for the full definition. DIN1 DIN ETS 300379-1 95 = 2794442 0528330 4T4 Page 11 ETS 300 399-1: March 1995 C-plane: The C-plane refers to the data exchanged across a user-network interface for establishment, release, monitoring, etc. of virtual circuits that are carried out outside th
32、e virtual circuits data transmission. delivered duplicated frames: A frame D received by a particular destination user is defined to be a duplicated frame if both of the following conditions are true: - frame D was not generated by the source user; - frame D is exactly the same as a frame that was p
33、reviously delivered to that destination. delivered errored frames: A delivered frame is defined to be an errored frame when the values of one or more of the bits in the frame is in error, or when some, but not all, bits in the frame are lost bits or extra bits (.e. bits which were not present in the
34、 original signal) have been inserted (see ITU-T Recommendation X. 140 1 O). delivered out-of-sequence frames: Consider a sequence of frames F, F, F, . , F, and assume that F, is transmitted first, F, second, . , F, last. A delivered frame Fi is defined to be out-of-sequence if it arrives at the dest
35、ination after any of the frames F(,+,), F(,+2), . , F,. discard eligibility indicator: This indicates that a frame should be discarded in preference to other frames in a congestion situation, when frames need to be discarded to ensure safe network operation and to maintain the committed level of ser
36、vice within the network. egress node: The node that supports the destination user-network interface. Excess Burst size (BE): The maximum allowed amount of data by which a user can exceed B, during a time interval TC. This data (BE) is delivered in general with a lower probability than B,. BE is nego
37、tiated at virtual circuit establishment. fairness: An attempt by the network to maintain the committed call parameters which the end-user negotiated at call Set-up time. An example of this would be first discarding the frames in excess of the CIR and refusing to allow new call Set-ups to occur prior
38、 to discarding committed data traffic. information integrity: Information integrity is preserved when for all frames delivered by the network no transmission errors have been detected. ingress node: The node that supports the source user-network interface. lost frames: A transmitted frame is declare
39、d to be a lost frame when the frame is not delivered to the intended destination user within a specified timeout period, and the network is responsible for the non-delivery (see ITU-T Recommendation X. 140 l O). misdelivered frames: A misdelivered frame is a frame transferred from a source to a dest
40、ination user other than the intended destination user. It is considered inconsequential whether the information is correct or incorrect in content (see ITU-T Recommendation X. 140 I 01). offered load: Refers to the frames offered to the network, by an end-user, to be delivered to the selected destin
41、ation. The information rate offered to the network could exceed the negotiated class of service parameters. DIN1 DIN ETS 300399-L 95 m 2794442 0528131 330 m Page 12 ETS 300 399-1: March 1995 residual error rate: The residual error rate is defined for frame relay services and the corresponding layer
42、services. The layer services corresponding to the frame relay services are characterized by the exchange of Service Data Units (SDUs). For frame relay, SDUs are exchanged at the functional boundary between the core functions of CCITT Recommendation Q.922 I41 and the end-to-end protocol implemented a
43、bove them. The network participates in this exchange by means of FPDUs. The residual error rate for the frame relay layer service is defined as: Total correctSDUs delivered Total offered SDUs Rfr = 1 - The residual error rate for frame relay is defined as: Total CorrectSDUs delivered Total offered F
44、PDUs Rfr = 1- statistical guarantee on traffic parameters: The QoS level for committed traffic characterized by the CIR, B, and T, parameters may be guaranteed with a certain probability. The 00s level for excess traffic characterized by the supplementary parameter BE may also be guaranteed with a c
45、ertain probability. The values of these probabilities are network dependent. These statistical guarantees may only be verified over an observation period which is: - sufficiently long with respect to T,; - constraining for the network; and - significant for the user. As an example, the “busy hour“ (
46、in terms of traffic load) of the network may be used for this purpose. throughput: Throughput for a virtual circuit (see ITU-T Recommendation X. 134 91, figure 1 /X. 139) is the number of data bits contained in the SDU of the frame successfully transferred in one direction across the virtual circuit
47、 per unit time. Successful transfer means that, for each frame, no transmission errors have been detected. transit delay: Transit delay is defined only between pairs of section boundaries. Transit delay of a Frame relay Protocol Data Unit (FPDU) starts at the time t, at whichthe first bit of the FPD
48、U crosses the first boundary, and ends at the time t2 at which the last bit of the FPDU crosses the second boundary: transit delay = tp - t, Transit delay for a virtual circuit is equal to the summation of the section delays. n national national c - one or more one or more one or more optional optio
49、nal optional C C C 3 C ._ C .- .- C .- - v Page 13 ETS 300 399-1 : March 1995 - DTE - n I Figure 1 ; International reference frame relay connection section boundary portion boundary O U-plane: The U-plane refers to the data exchanged across a user-network interface for the data transfer on one or more virtual circuits. virtual circuit: The term “virtual circuit“ refers to a layer 2 virtual circuit, .e. a frame relay virtual circuit. 4 Symbols and abbreviations For the purpose of this ETC, the following symbols and abbreviations apply: BECN B
