SIST ETS 300 275 E1:2003

• Abstract:

  Direct interconnection of MANs by means of dedicated links.

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 35.110 - Networking
• 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 ETS 300 275 ed.1 (1994-03) - Network Aspects (NA); Metropolitan Area Network (MAN); Interconnection of MANs

SIST ETS 300 275 E1:2003 is the Slovenian adoption of ETS 300 275 Edition 1 from ETSI. It specifies direct interconnection of Metropolitan Area Networks (MANs) by means of dedicated links, using the MSS Interconnection Protocol (MIP) for connectionless service. The document is for people who need to design, configure, manage, or test interconnection between MAN Switching Systems (MSSs) within one operator domain or between different operators.

What does SIST ETS 300 275 E1:2003 specify?

SIST ETS 300 275 E1:2003 specifies the direct interconnection of MANs by dedicated links and the interface behavior needed to carry traffic between MSSs. It focuses on MAN-to-MAN interconnection, not on interworking with other network types.

The standard is limited to the connectionless service defined for MANs, even though MAN interconnection is intended to support multiple service types in principle. It also limits the protocol description to encapsulation at the IMI/INI interface, with no routeing protocol, no congestion procedure, and no explicit operator selection.

The document is organized into clauses on scope, references, abbreviations and definitions, interface characteristics, architecture, addressing, protocol reference model, and MIP specification. It has one normative annex.

Annex	What it covers
A	Encoding of the address_type and address subfields for Destination Address and Source Address

What are the key requirements of SIST ETS 300 275 E1:2003?

SIST ETS 300 275 E1:2003 defines the interconnection model, the protocol used on the MSS-to-MSS link, the addressing basis, and the conformance checks that implementations must support. The practical point is that a conforming system has to move IMPDUs transparently between MSSs while preserving order, using the specified layer-2 structures and validations.

Interconnection model and interfaces

Clause 4 says that the interface characteristics support the connectionless service and guarantee transparent transfer of Initial MAC Protocol Data Units (IMPDUs) between source and destination MSSs. The sequence order of IMPDUs is preserved, which matters when end users expect data to arrive in the same order it was sent.

Clause 5 defines the direct interconnection architecture. The Transit Network (TN) is reduced to a dedicated link, and the standard distinguishes the Inter MSS Interface (IMI) for MSSs in the same network operator domain from the Inter Network operator Interface (INI) for MSSs in different domains. In practice, the same interconnection concept is used in both cases, but the management and addressing context differs.

Protocol location and functional blocks

Clause 5 places the interconnection functions in the Transit Access Termination (TAT), with a Transit Access Function (TAF) block and a Relay Functions (RF) block. The TAF carries the transport-related part based on MIP, while the RF handles receiving, forwarding, address lookup, and discard actions.

This matters because implementers need to know where each job belongs inside the MSS. The standard also says the management functions for IMI and INI are in the MAN Interconnection Management Functions (MIMF) within the MSS Management Functions (MMF), including protocol-layer management for TAF, operational management for RF, and traffic statistics.

Addressing and forwarding

Clause 6 uses E.164-based addressing for end users and for forwarding MIP_IMPDUs between MSSs. Both individual and group addresses are supported, and forwarding relies on the hierarchical E.164 number.

That means the MSS must be able to look up addresses and decide where to send traffic next. Annex A gives the encoding of the address_type and address subfields, so implementers need to align their address tables and validation logic with that encoding.

MIP and encapsulation

Clause 8 states that the MSS Interconnection Protocol (MIP) supports Connectionless Broadband Data Service (CBDS) over dedicated links between MSSs. The specification is restricted to encapsulation, and the MIP is based on the DQDB protocol with the MIP_IM sublayer replacing the DQDB IM sublayer.

The MIP_IM sublayer provides transparent transfer of the part of the IMPDU covered by CRC32, with no retransmission of lost or corrupted data units. In practice, that means the interconnection behaves like a transport path for PDUs rather than a recovery protocol.

PDU structure and field behavior

Clause 8.2 defines the MIP_IMPDU format, including the header, user information, and trailer. Important fields include BEtag, BAsize, DA, SA, PI, PAD Length, QOS, CIB, HEL, Bridging, Header Extension, and Length.

Several fields have fixed meanings that affect implementation directly:

• PI values 44 to 47 identify an encapsulating MIP_IMPDU.
• BAsize and Length carry the same length information.
• QOS, CIB, and Bridging have default or reserved behavior that receivers check.
• HEL indicates how many 32-bit words are used by the header extension.

For engineers and testers, this is the core format to encode, decode, and validate.

Encapsulation and primitives

Clause 8.3 describes how the Mapping Entity strips the Common PDU Trailer from an IMPDU, encapsulates the remaining data into a MIP_IMPDU, and reconstructs the IMPDU on reception. It also defines the MIP_IM_UNITDATA.request and MIP_IM_UNITDATA.indication primitives and their parameters.

This is important because it tells you what information crosses the internal service boundary: source address, destination address, protocol identifier, header extension, data, and QOS. The document also allows pipelining, so part of a packet may move onward before all slots have arrived.

Validation and error handling

Clause 8.3.4 lists mandatory and optional error conditions. Mandatory stopping conditions include a mismatch between header and trailer BEtag, invalid address encoding, size errors, source or destination address mismatches in specified cases, and a mismatch between Length and BAsize.

Optional stopping conditions cover non-zero reserved fields, invalid pad length, unsupported QOS or CIB settings, invalid HEL values, a non-zero Bridging field, and a length mismatch against the received octet count. Clause 8.4 turns these rules into a Protocol Implementation Conformance Statement (PICS) checklist, which is the basis for vendor claims and conformance testing.

What terms does SIST ETS 300 275 E1:2003 define?

• Metropolitan Area Network (MAN) - A MAN is the network type used in this standard, based on a shared medium and a restricted geographical area.
• MAN Switching System (MSS) - An MSS is the switching node that forms the basis of MAN interconnection by coupling MANs together.
• MSS Interconnection Protocol (MIP) - MIP is the protocol used at the IMI/INI interface to carry CBDS traffic between MSSs.
• MIP_IM - MIP_IM is the sublayer that carries the MIP_IMPDU and replaces the IM sublayer of DQDB in this application.
• Transit Access Termination (TAT) - TAT is the set of functions in an MSS that terminates the transit link at the Z reference point.
• Inter MSS Interface (IMI) - IMI is the direct interface between two MSSs in the same network operator domain.
• Inter Network operator Interface (INI) - INI is the direct interface between two MSSs belonging to different network operators.
• MAN Interconnection Management Functions (MIMF) - MIMF manages the interconnection functions, including TAF management, RF operational management, and traffic statistics.

Who uses SIST ETS 300 275 E1:2003?

SIST ETS 300 275 E1:2003 is used by network operators that connect MANs through dedicated links. It is also used by equipment vendors and system integrators who implement MSSs, TAT functions, address handling, and MIP_IMPDU processing.

Test labs and quality teams use it for conformance checking, especially the PICS-related fields and validation rules in Clause 8. Engineers involved in operations use it to manage addressing tables, statistics, and interconnection behavior across IMI and INI links.

Which standards are used with SIST ETS 300 275 E1:2003?

Reference	What it contributes
ETS 300 211	MAN principles and architecture, including MSS concepts and reference points
ETS 300 217	Connectionless Broadband Data Service (CBDS), the service model used here
ETS 300 212	DQDB media access control and physical layer specification, which MIP is based on
ETS 300 268	PICS structure and definitions for MAN protocols
CCITT Recommendation E.164	Numbering plan and the E.164-based address model used for forwarding
CCITT Recommendation M.3010	Telecommunication Management Network (TMN) principles used for management context
ETS 300 273	MAC layer management functions, referenced for TAF management
DE/NA-052104	ATM-based MSS interconnection, noted as a separate interconnection approach
ISO/IEC 8802-6	DQDB subnetwork specification, used for the encapsulation basis

What does the SIST ETS 300 275 E1:2003 document contain?

The document contains architectural figures for direct MSS interconnection, including the general model, example topologies, the reference configuration, the TAT functional model, and the protocol reference model. It also contains the detailed MIP_IMPDU format figure and the encapsulation figure showing how an IMPDU is wrapped and unwrapped.

Clause 8 includes the service description, field-by-field PDU behavior, the Mapping Entity interaction, and the mandatory and optional error conditions. Table 1 is a PICS proforma for implementation claims, and Annex A contains the address encoding tables for Destination Address and Source Address.

SLOVENSKI STANDARD
01-december-2003
Omrežni vidiki (NA) – Velemestno omrežje (MAN) – Medsebojno povezovanje
omrežij MAN
Network Aspects (NA); Metropolitan Area Network (MAN); Interconnection of MANs
Ta slovenski standard je istoveten z: ETS 300 275 Edition 1
ICS:
35.110 Omreževanje Networking
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 275
TELECOMMUNICATION March 1994
STANDARD
Source: ETSI TC-NA Reference: DE/NA-053401
ICS: 33.080
MAN, interconnection
Key words:
Network Aspects (NA);
Metropolitan Area Network (MAN)
Interconnection of MANs
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - [e-mail]
X.400: Internet:
Tel.: [phone] - Fax: [phone]
Copyright Notification: No 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 1994. All rights reserved.
New presentation - see History box

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ETS 300 275: March 1994
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 accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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Contents
Foreword .5
Introduction.5
1 Scope .7
2 Normative references.7
3 Abbreviations and definitions .8
3.1 Abbreviations .8
3.2 Definitions .9
4 MAN interconnection interface characteristics.10
5 General architecture.10
5.1 Architectural model for MSS interconnection.10
5.2 Reference configuration.13
5.3 TAT functional model.13
5.4 Management functions .14
6 Addressing aspects.15
7 Protocol reference model for MSS interconnection.15
8 MSS Interconnection Protocol (MIP) specification .16
8.1 Service provided by the MIP_IM sublayer.16
8.2 MIP_IM Protocol Data Unit (PDU) structure and encoding.16
8.2.1 Reserved .17
8.2.2 Beginning-End tag (BEtag).17
8.2.3 Buffer Allocation size (BAsize) .18
8.2.4 Destination Address (DA).18
8.2.5 Source Address (SA).18
8.2.6 Protocol Identification (PI) .18
8.2.7 PAD Length .18
8.2.8 Quality of Service (QOS).18
8.2.9 CRC Indication Bit (CIB).18
8.2.10 Header Extension Length (HEL) .18
8.2.11 Bridging .18
8.2.12 Header Extension.19
8.2.13 HE Post-Pad.19
8.2.14 User Information.19
8.2.15 Reserved .19
8.2.16 Beginning-End tag (BEtag).19
8.2.17 Length .19
8.3 Encapsulation mechanism specification.19
8.3.1 Introduction.19
8.3.2 Mapping Entity functionalities.19
8.3.2.1 Transfer of PDUs from MSS towards IMI / INI .20
8.3.2.2 Transfer of PDUs from IMI / INI towards MSS .20
8.3.3 Interaction between Mapping Entity and MIP_IM sublayer.21
8.3.4 Error conditions .22
8.3.4.1 Mandatory error condition.22
8.3.4.2 Optional error conditions.22
8.4 Protocol Implementation Conformance Statement (PICS) proforma for the
MIP_IMPDU format and validation.23

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Annex A (normative): Encoding of the 'address_type' and 'address' subfields . 24
History. 25

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ETS 300 275: March 1994
Foreword
This European Telecommunication Standard (ETS) has been prepared by the Network Aspects (NA)
Technical Committee of the European Telecommunications Standards Institute (ETSI).
Introduction
The purpose of Metropolitan Area Network (MAN) interconnection is to enable users connected to
different MANs using the same bearer service to communicate with each other.
MANs are based upon a shared medium access and cover a restricted geographical area.
In order to cover larger areas, MAN interconnection is needed.
As described in ETS 300 211 [1], a MAN is composed of one MSS (MAN Switching System) and one or
more access facilities connected to the MSS. Since interconnection of MANs is achieved by the coupling
of MSSs, in this ETS the term "MAN interconnection" is synonymous to "MSS interconnection".
The Protocol Implementation Conformance Statement (PICS) proforma for the protocol specified in this
ETS can be found in ETS 300 268 [4], with the exceptions specified in Clause 8.
The reference for the PICS proforma structure and definitions is ETS 300 268 [4] Clause 4.

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1 Scope
This European Telecommunication Standard (ETS) describes the direct interconnection between
European Metropolitan Area Networks (MANs), as defined in European MAN ETSs, by means of
dedicated links.
Interworking between MANs and other networks is outside the scope of this ETS.
Although MAN interconnection is intended to cover all services as defined in ETS 300 211 [1] (i.e.
connectionless, isochronous and connection-oriented non-isochronous), this ETS is restricted to the
connectionless service, as defined in ETS 300 217 [2].
Interconnection within a network operator domain and between different network operator domains is
specified.
This ETS provides the general principles and functional requirements and specifies the corresponding
interfaces for interconnection of MANs, assuming ETS 300 211 [1] as a basis.
The protocol at the interfaces between MAN Switching Systems (MSSs) is the MSS Interconnection
Protocol (MIP), specified in this ETS and based on Distributed Queue Dual Bus (DQDB) protocol as
specified in ETS 300 212 [3].
The interconnection of MSSs via Asynchronous Transfer Mode (ATM) links is specified in DE/NA-2104:
"Interconnection of MSSs based on an ATM interface".
This ETS defines the reference configuration, functional blocks, and their corresponding Protocol
Reference Models (PRMs), related to MAN direct interconnection.
Neither routeing protocol, nor congestion procedures are specified.
The scope of this ETS is presently limited to the case where there is no need for an explicit operator
selection.
2 Normative references
This ETS incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications 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.
[1] ETS 300 211 (1992): "Network Aspects (NA); Metropolitan Area Network (MAN)
Principles and Architecture".
[2] ETS 300 217 (1992): "Network Aspects (NA); Connectionless Broadband Data
Service (CBDS)".
[3] ETS 300 212 (1992): "Network Aspects (NA); Metropolitan Area Network (MAN)
Media access control layer and physical layer specification".
[4] ETS 300 268: "Network Aspects (NA); Metropolitan Area Network (MAN)
Protocol Implementation Conformance Statement".
[5] CCITT Recommendation E.164 (1991): "Numbering plan interworking for the
ISDN era".
[6] CCITT Recommendation M.3010 (1992): "Principles for a Telecommunications
Management Network".
[7] ETS 300 273: "Network Aspects (NA); Metropolitan Area Network (MAN)
Medium Access Control (MAC) layer management".

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ETS 300 275: March 1994
[8] DE/NA-052104: "Interconnection of MSSs based on an ATM interface".
[9] ISO/IEC 8802-6: "Distributed Queue Dual Bus (DQDB) Subnetwork of a
Metropolitan Area Network".
3 Abbreviations and definitions
3.1 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
AF1 Access Facility 1
AF2 Access Facility 2
ATM Asynchronous Transfer Mode
BAsize Buffer Allocation size
BEtag Beginning End tag
BT Bit sublayer
CBDS Connectionless Broadband Data Service
CEQ Customer EQuipment
CIB CRC Indicator Bit
DA Destination Address
DM Derived MAC sublayer
DQDB Distributed Queue Dual Bus
HE Header Extension
HEL Header Extension Length
IM Initial MAC sublayer
IMI Inter MSS Interface
IMPDU Initial MAC Protocol Data Unit
IMSI Inter MAN System Interface
INI Inter Network operator Interface
MAN Metropolitan Area Network
MIP MSS Interconnection Protocol
MMF MSS Management Function
MIMF MAN Interconnection Management Functions
MSS MAN Switching System
NE Network Entity
PDU Protocol Data Unit
PI Protocol Identification
PICS Protocol Implementation Conformance Statement
PL Physical Layer
PRM Protocol Reference Model
QOS Quality Of Service
RF Relay Function
SA Source Address
SLT Slot sublayer
SM Segment sublayer
SV Service sublayer
TAF Transit Access Functions
TAT Transit Access Termination
TC Transmission Convergence sublayer
TM Transmission sublayer
TMN Telecommunication Management Network
TN Transit Network
UMI User MAN Interface
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ETS 300 275: March 1994
3.2 Definitions
For the purposes of this ETS, the following definitions apply:
Metropolitan Area Network (MAN): see ETS 300 211 [1].
Inter MSS Interface (IMI): interface between two MSSs within the same network operator domain.
MAN Switching System (MSS): see ETS 300 211 [1].
Inter Network operator Interface (INI): interface between two MSSs, belonging to different network
operators.
Transit Access Termination (TAT): the collection of functions residing in the MSS, for terminating the
transit link at the Z reference point and for the interconnection with other MSSs.
M
Transit Network (TN): a network which provides transmission, switching and maintenance functions to
allow the MSS interconnection. It can be implemented through point-to-point links, digital cross connect,
B-ISDN transit node, etc. For further details see ETS 300 211 [1].
Network operator domain: the area (not strictly geographical) which a single network operator is
responsible for; inside this area the MAN Network Entities (NEs) are managed according to the
Telecommunication Management Network (TMN) architectural model.
Dedicated link: is a semi-permanent or permanent point-to-point connection, which may be offered by
digital cross connect.
Telecommunication Management Network (TMN): see CCITT Recommendation M.3010 [6].
Relay Functions (RF) block: contains the relay functionality.
Transit Access Functions (TAF) block: contains functions to receive and transmit information over a
medium. It is based on the MIP specified in this document which is based on the DQDB protocol as
specified in ETS 300 212 [3].
MAN Interconnection Management Functions (MIMF) functional component: it includes both protocol
layer management functions for the TAF block and management functions related to operational aspects
of the RF block; it also contains functionality to gather statistics for traffic exchanged between MSSs.
MSS Management Functions (MMFs) block: contains the functions related to the management of MSS
local resources and optionally the connected Access Facility 1 (AF1) and Access Facility 2 (AF2)
resources.
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ETS 300 275: March 1994
4 MAN interconnection interface characteristics
MAN Interconnection interface characteristics support the service described in ETS 300 217 [2].
The transparent transfer of Initial MAC Protocol Data Units (IMPDUs) (see ETS 300 212 [3]) between
source and destination MSSs is guaranteed.
The definition of these interface characteristics encompasses the two cases of MSSs belonging to the
same or different network operators.
Two techniques are allowed to forward/receive the PDUs across the IMI/INI interfaces:
- encapsulation of the IMPDU defined at the Y reference point within the MIP_IMPDU defined at the
M
Z reference point; or
M
- non-encapsulation of the IMPDU.
The following requirements for the use of encapsulation / non-encapsulation apply:
- for the interconnection of MSSs belonging to different network operator domain encapsulation is
always used for both group and individually addressed PDUs;
- for the interconnection of the MSSs within the same network operator domain encapsulation and/or
non-encapsulation may be used, depending on the choice of the network operator.
This ETS specifies the encapsulation technique only.
IMPDU sequence order is preserved between MSSs to maintain the sequence order between end users.
The protocol elements for interconnection of MSSs reside inside the OSI layer 2.
5 General architecture
5.1 Architectural model for MSS interconnection
In this ETS, the TN, as mentioned in ETS 300 211 [1], is reduced to a dedicated link.
The general architectural model for MSS interconnection is depicted in figure 1. For the support of CBDS
data transport between source and destination CEQ, configurations involving several directly
interconnected MSSs are possible as shown in figure 1.
The coexistence between the interfaces described in this ETS and the interfaces for the interconnection
between MSSs via a TN including switching functionalities is not precluded and is therefore also shown in
figure 1.
However the description of the interfaces between MSSs and TN which include switching functionalities is
outside the scope of this ETS.
In figure 1, the TN is not indicated in those cases where the TN is reduced to a dedicated link.
For direct MSS interconnection two interfaces are envisaged:
- the IMI is located between two MSSs that are directly connected, within the same network operator
1)
domain ;
- the Inter Network operator Interface (INI) is located between two MSSs belonging to different
network operators. The MSSs are directly connected. This interface provides functions and
requirements in order to assure the connectivity of MANs belonging to different network operators,
1)
while taking into account different management systems .

1)
In ETS 300 211 [1] the IMI (and INI) are referred to as IMSI.

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ETS 300 275: March 1994
Examples of topologies for direct interconnection of MSSs are shown in figure 2.
TMN TMN TMN
X X
Q Q Q
NETWORK
OPERATOR
MSS
MSS
DOMAIN
Z
M
MSS
IMI Z
INI
M
MSS
TN
MSS
MSS
Z
M
Y
M
Z
M
MSS
AF
MSS TN
AF
AF
T
T M
M
CEQ CEQ
CEQ
NOTE: The TN is only indicated in this figure whenever it contains switching functionality;
when it is reduced to a dedicated link it is omitted.
Figure 1: General architectural model for MSS interconnection

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ETS 300 275: March 1994
Network Operator Domain 1 Network Operator Domain 2
MSS MSS
IMI
MSS
IMI
INI
MSS MSS MSS
2a: Fully meshed interconnection of MSSs
Network Operator Domain 1 Network Operator Domain 2
MSS MSS
IMI
MSS
IMI
INI
MSS MSS MSS
2b: Non-meshed interconnections of MSSs
Network Operator Domain 1
Network Operator Domain 2
MSS MSS
IMI
MSS
IMI
INI
MSS MSS MSS
2c: Meshed within, non-meshed outside an operator domain
Figure 2: Direct connections between MSSs

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ETS 300 275: March 1994
5.2 Reference configuration
The reference configuration for direct connection of MSSs is derived from the general reference
configuration as defined in ETS 300 211 [1] and is depicted in figure 3.
The TN which is reduced to a dedicated link is not indicated.
The interface between MSSs is referred to as the IMI or INI, for the interconnection between MSSs
belonging to the same or different network operators, respectively, and is located at the Z reference
M
point.
A detailed description of other reference points and functional blocks in figure 3 is given in ETS 300 211
[1].
Taking into account the MSS functional configuration described in ETS 300 211 [1], functions related to
ensure interworking with other MSSs are provided in the TAT.
(IMI or INI)
AF MSS MSS
CEQ CEQ
AF
T Y Z T
Y
M M M
M M
Figure 3: Reference configuration for MSS interconnec
...