Operational Requirements for X.400 Management Domains in the GO-MHS Community June 19, 1992 Robert A. Hagens C=US; ADMD= ; PRMD=INTERNET; DDA.RFC-822=hagens(a)ans.net; | hagens@ans.net | Alf Hansen C=no; ADMD= ; PRMD=uninett; O=sintef; OU=delab; S=Hansen; G=Alf Alf.Hansen@delab.sintef.no $ Revision: 1.13 $ Status of this Memo This document specifies a set of minimal operational requirements that shall be implemented by all Management Domains (MDs) in the Global Open MHS Community (GO-MHS) This document defines the core operational requirements; in some cases, technical detail is handled by reference to other documents. The GO-MHS Community is defined as all organizations which meet the requirements described in this document. This document is an Internet Draft. Internet Drafts are | working documents of the Internet Engineering Task Force | (IETF), its Areas, and its Working Groups. Note that other | groups may also distribute working documents as Internet | Drafts. | Internet Drafts are draft documents valid for a maximum of | six months. Internet Drafts may be updated, replaced, or | obsoleted by other documents at any time. It is not | appropriate to use Internet Drafts as reference material or | to cite them other than as a "working draft" or "work in | progress." | Please check the I-D abstract listing contained in each | Internet Draft directory to learn the current status of this | or any other Internet Draft. | When agreement is reached, it will be submitted to the RFC editor as an informational document. Distribution of this memo is unlimited. Please send comments to the authors or to the discussion group: INTERNET-DRAFT [Page 1] Exp. Date: 12/19/92 ietf-osi-x400ops@cs.wisc.edu C=us; ADMD= ; PRMD=xnren; O=UW-Madison; OU=cs; S=ietf-osi-x400ops Beginning with version 1.9, this document contains change bars which indicated changes that have been made. Change bars only reflect the changes from the previous version. Change bars appear to the right of the text, as in this paragraph. Deleted text is not shown. Pervasive changes are not denoted with change bars. However, they are noted at the beginning of the document. Pervasive changes from version 1.8 to 1.10 are: o~+ The phrase "International Service" has been replaced with "International X.400 Service". o~+ References have been cleaned up. o~+ Section 2.3 has been extensively rewritten Pervasive changes from version 1.10 to 1.13 are: | o~+ The phrase "International X.400 Servce" has been replaced with GO-MHS Community. 9 9INTERNET-DRAFT [Page 2] Exp. Date: 12/19/92 1. Introduction There are several large, operational X.400 services | currently deployed. Many of the organizations in these ser- | vices are connected to the Internet. A number of other | Internet-connected organizations are beginning to operate | internal X.400 services (for example, U.S. government organ- | izations following U.S. GOSIP). The motivation for this | document is to foster a GO-MHS Community that has full | interoperability with the existing E-mail service based on | RFC 822. | The goal of this document is to unite regionally operated | X.400 services on the various continents into one GO-MHS | Community (as seen from an end-user's point of view). Exam- | ples of such regional services are the COSINE MHS Service in | Europe and the XNREN service in the U.S. A successful GO-MHS Community is dependent on decisions at both the national and international level. National X.400 service providers are responsible for the implementation of the minimum requirements defined in this document. In addi- tion to these minimum requirements, national requirements may be defined by each national service provider. This document refers to other documents which should be pub- lished as RFCs. These documents are: o~+ Routing coordination for an X.400 MHS-service within a multi protocol / multi network environment [1]. o~+ X.400 1988 to 1984 downgrading [2]. This document handles issues concerning X.400 1984 and X.400 1988 to 1984 downgrading. Issues concerning pure X.400 1988 are left for further study. We are grateful to Allan Cargille and Lawrence Landweber for their input and guidance on this paper. This paper is also a product of discussions in the IETF X.400 Operations WG and the RARE WG1 (on MHS). 1.1. Terminology This document defines requirements, recommendations and con- ventions. Throughout the document, the following defini- tions apply: a requirement is specified with the word shall. A recommendation is specified with the word should. A con- vention is specified with the word might. Conventions are intended to make life easier for RFC 822 systems that don't follow the host requirements. INTERNET-DRAFT [Page 3] Exp. Date: 12/19/92 1.2. Profiles Different communities have different profile requirements. | The following is a list of such profiles. | o~+ U.S. GOSIP - unspecified version o~+ ENV - 41201 o~+ UK GOSIP for X.400(88) The automatic return of contents when mail is non-delivered | should be requested by RFC 1148bis gateways and should be | supported at the MTA that generates the non-delivery report. | However, it should be noted that this practice causes bil- | ling problems. 2. Architecture of the GO-MHS Community In order to facilitate a coherent deployment of X.400 in the GO-MHS Community it is necessary to define, in general terms, the overall structure and organization of the X.400 service. This section is broken into several parts which discuss management domains, lower layer connectivity issues, and overall routing issues. The GO-MHS Community will operate as a single MHS community, | as defined in [1]. 2.1. Management Domains The X.400 model supports connectivity between communities | with different service requirements; the architectural vehi- cle for this is a Management Domain. Management domains are needed when different administrations have different specific requirements. Two types of management domains are defined by the X.400 model: an Administration Management Domain (ADMD) and a Private Management Domain (PRMD). Throughout the world in various countries there are dif- ferent organizational policies for MDs. All of these poli- cies are legal according to the X.400 standard. Currently, national X.400 service providers are organized as: a) One or several ADMDs. b) One or several PRMDs and with no ADMDs present in the country. c) One or several PRMDs connected to one or several ADMDs. At this stage it is not possible to say which model is the most effective. Thus, the GO-MHS Community shall allow every model. 9 9INTERNET-DRAFT [Page 4] Exp. Date: 12/19/92 2.2. The Well Known Entrypoint (WEP) The X.400 message routing decision process takes as input the destination O/R address and produces as output the name (and perhaps connection information) of the MTA who will take responsibility of delivering the message to the reci- pient. The X.400 store and forward model permits a message to pass through multiple MTAs. However, it is generally accepted that the most efficient path for a message to take is one where a direct connection is made from the originator to the recipient's MTA. Large scale deployment of X.400 in the GO-MHS Community will require a well deployed X.500 infrastructure to support routing. In this environment, a routing decision can be made by searching the X.500 database with a destination O/R address in order to obtain the name of the next hop MTA. This MTA may be a central entry point into an MD, or it may be the destination MTA within an MD. Deployment of X.400 without X.500 will require the use of static tables to store routing information. This table (keyed on O/R addresses), will be used to map a destination O/R address to a next hop MTA. In order to facilitate effi- cient routing, one could build a table that contains infor- mation about every MTA in every MD. However, this table | would be enormous and very dynamic, so this is not feasible | in practice. Therefore, it is necessary to use the concept of a well known entrypoint (WEP). The purpose of a WEP is to act as a default entry point into an MD. The MTA that acts as a WEP for an MD shall be capable of accepting responsibility for all messages that it receives that are destined for well-defined recipients in that MD. The use of a WEP for routing is defined by [1]. WEPs in the | GO-MHS Community shall route according to [1]. 2.3. Lower Layer Stack Incompatibilities A requirement for successful operation of the GO-MHS Commun- ity is that all users can exchange messages. The GO-MHS Com- munity is not dependent on the traditional TCP/IP lower layer protocol suite. A variety of lower layer suites are used as carriers of X.400 messages. For example, consider Figure 1. figure arch.ps height 4i Figure 1: A Deployment Scenario 9 9INTERNET-DRAFT [Page 5] Exp. Date: 12/19/92 PRMD A has three WEPs which collectively provide support for the TP0/CONS/X.25, TP0/RFC1006, and TP4/CLNS stacks[1] Thus, PRMD A is reachable via these stacks. However, since PRMD B only supports the TP0/CONS/X.25 stack, it is not reachable from the TP0/RFC 1006 or the TP4/CLNS stack. PRMD C supports TP0/RFC1006 and TP4/CLNS. Since PRMD B and PRMD C do not share a common stack, how is a message from PRMD C to reach a recipient in PRMD B ? One solution to this problem is to require that PRMD B implement a stack in common with PRMD C. However this may | not be a politically acceptable answer to PRMD B. Another solution is to implement a transport service bridge (TSB) between TP0/RFC 1006 in PRMD C to TP0/CONS in PRMD B. This will solve the problem for PRMD C and B. However, the | lack of coordinated deployment of TSB technology makes this | answer alone unacceptable on an international scale. The solution to this problem is to define a coordinated mechanism that allows PRMD B to advertise to the world that | it has made a bilateral agreement with PRMD A to support | reachability to PRMD B from the TP0/RFC 1006 stack. This solution does not require that every MTA or MD directly support all stacks. However, it is a requirement that if a particular stack is not directly supported by an MD, the MD will need to make bilateral agreements with other MD(s) in order to assure that connectivity from that stack is avail- able. Thus, in the case of Figure 1, PRMD B can make a bilateral agreement with PRMD A which provides for PRMD A to relay messages which arrive on either the TP4/CLNP stack or the TP0/RFC 1006 stack to PRMD B using the TP0/CONS stack. The policies described in [1] define this general purpose solution. It is a requirement that all MDs follow the rules and policies defined by [1]. 3. Description of GO-MHS Community Policies An IMD is a Management Domain in the GO-MHS Community. The policies described in this section constitute a minimum set of common policies for IMDs. They are specified to ensure interoperability between ____________________ 9 [1] Note: it is acceptable for a single WEP to support more than one stack. Three WEPs are shown in this picture for clarity. 9INTERNET-DRAFT [Page 6] Exp. Date: 12/19/92 - all IMDs. - all IMDs and the Internet mail service (SMTP). - all IMDs and other X.400 service providers. Policies defined below are defined in terms of the words: shall, should and might. 3.1. X.400 address registration An O/R address is a descriptive name for a UA that has cer- tain characteristics that help the Service Providers to locate the UA. Every O/R address is an O/R name, but not every O/R name is an O/R address. This is explained in [5], chapter 3.1. Uniqueness of X.400 addresses shall be used to ensure end- user connectivity. Mailboxes shall be addressed according to the description of | O/R names, Form 1, Variant 1 (see [5], chapter 3.3.2). The attributes shall be regarded as a hierarchy of Country name (C) Administration domain name (ADMD) [Private domain name] (PRMD) [Organization name] (O) [Organizational Unit Names] (OUs) [Personal name] (PN) [Domain-defined attributes] (DDAs) Attributes enclosed in square brackets are optional. At least one of PRMD, PN, O an OU names shall be present in an O/R address. In general a subordinate address element shall be unique | within the scope of its immediately superior element. An exception is PRMD, see section 3.1.2. There shall exist registration authorities for each level, or mechanisms shall be available to ensure such uniqueness. 3.1.1. Country (C) The values of the top level element, Country, shall be defined by the set of two letter country codes, or numeric country codes in ISO 3166. 3.1.2. Administration Management Domain (ADMD) This section defines which value should be given to the ADMD attribute. Three values are often proposed: - the real name of (one of) the ADMD(s) INTERNET-DRAFT [Page 7] Exp. Date: 12/19/92 to which the PRMD is attached. - a single space (" ") - a single zero ("0") The 1984 standard does not address this problem. The ENV 41201 (for 1984) proposes the use of a single space when no ADMD exists. The 1988 standard specifies that a single space can be used if it is permitted by the country to designate any ADMD in the country. The Implementor's Guide Version 2 (ISO only) proposes that if a PRMD intends never to be con- nected to an ADMD, it uses "0" as ADMD value. According to the previous document references, three condi- tions must be taken into account: - Has a national decision be taken ? - How many ADMDs are there in the country ? - Is the PRMD connected to an ADMD ? A table has been defined to combine all these conditions and define the value which should be placed into the ADMD field. A general conclusion is that the decision at the national level should be to allow the use of a single space. If the decision has not yet been taken, this document recommends that the country make the decision to allow the use of a single space. In the interim, a country without a national decision should act as if the decision has been made to allow the use of a single space. Therefore, if the national decision is to disallow a " " value for the ADMD, the following table should be used. Number of Number of PRMD ADMDs connections Recommendation ------------------------------------------------- 0 0 prepare for the future 1 0 use "0" 1 1 use the ADMD name more 0 use "0" more 1 use the ADMD name more >1 choose one ------------------------------------------------- If the national decision is to allow a " " value for the ADMD, the following table should be used. 9 9INTERNET-DRAFT [Page 8] Exp. Date: 12/19/92 Number of Number of PRMD ADMDs connections Recommendation ------------------------------------------------- 0 0 prepare for the future 1 0 use "0" 1 1 use " " or ADMD name more 0 use "0" more 1 use " " or ADMD name more >1 use " " or choose one ------------------------------------------------- It is important to note that the semantics of an ADMD value | of single space are not fully understood for routing pur- | poses. 3.1.3. Private Management Domain (PRMD) The PRMD values should be unique within a country. 3.1.4. Organization (O) Organization values shall be unique within the context of the subscribed PRMD or ADMD if there is no PRMD. 3.1.5. Organizational units (OUs) If used, a unique hierarchy of OUs shall be implemented. The | top level OU is unique within the scope of the immediately | superior address element (i.e., Organization, PRMD or ADMD). | A single level of OUs should be used. 3.1.6. Given name, Initials, Surname (G I S) The following elements should be used: Given name (G), Ini- tials (I) and Surname (S). Each Organization can define its own Given-names, Initials, and Surnames to be used within the Organization. In the cases when Surnames are not unique within an O or OU, The Given-name and/or Initial will be used to identify the Originator/Recipient. In the rare cases when more than one user would have the same combination of G, I, S under the same O and/or OUs, each organization is free to find a prac- tical solution, and provide the users with unique O/R addresses. Either one of Given-name or Initials should be used, not | both. Periods shall not be used in Initials. To avoid problems with the mapping of the X.400 addresses into RFC-822 addresses, the following rules might be used. ADMD, PRMD, O, and OU values should consist of characters INTERNET-DRAFT [Page 9] Exp. Date: 12/19/92 drawn from the alphabet (A-Z), digits (0-9), and minus. | Blank or Space characters should be avoided. No distinction | is made between upper and lower case. The last character | must not be a minus sign or period. The first character | should be either a letter or a digit (see [6], [7]). 3.1.7. Domain Defined Attributes (DDAs) The GO-MHS Community shall allow the use of domain defined attributes. Note: support for DDAs is mandatory because all software must upgrade to support DDAs. The following DDAs shall be supported by an IMD: "RFC-822" - defined in [3]. The following DDAs should be supported by an IMD: "COMMON" - defined in [2]. 3.2. X.400 88 -> 84 downgrading The requirements in [2] should be implemented in IMDs. 3.3. X.400 / RFC 822 address mapping All GO-MHS Community end-users shall be reachable from all end-users in the Internet mail service (SMTP), and vice versa. The address mapping issue is split into two parts: 1) Specification of RFC-822 addresses seen from the X.400 world. 2) Specification of X.400 addresses seen from the RFC-822 world. The mapping of X.400 and RFC-822 addresses shall be per- formed according to [3]. 3.3.1. Specification of RFC-822 addresses seen from the X.400 world Two scenarios are described: A. The RFC-822 end-user belongs to an organization with no defined X.400 standard attribute address space. B. The RFC-822 end-user belongs to an organization with a defined X.400 standard attribute address space. Organizations belong to scenario B if their X.400 addresses are registered according to the requirements in section 3.1. 9 9INTERNET-DRAFT [Page 10] Exp. Date: 12/19/92 3.3.1.1. An organization with a defined X.400 address space An RFC-822 address for an Internet mail user in such an organization shall look exactly as a normal X.400 address for X.400 users in the same organization. Example: University of Wisconsin-Madison is registered under C=US; ADMD= ; PRMD=XNREN; with O=UW-Madison and they are using OU=cs to address end-users in the CS-department. The RFC-822 address for Internet mail users in the same department is: user@cs.wisc.edu. An X.400 user in the GO-MHS Community will address the Internet mail user at the CS-department with the X.400 address: C=US; ADMD= ; PRMD=xnren; O=UW-Madison; OU=cs; S=user; This is the same address space as is used for X.400 end- users in the same department. 3.3.1.2. An organization with no defined X.400 address space RFC-822 addresses shall be expressed using X.400 domain defined attributes. The mechanism used to define the RFC- 822 recipient will vary on a per-country basis. For example, in the US, a special PRMD named "Internet" is defined to facilitate the specification of RFC-822 addresses. A X.400 user can address an RFC-822 recipient in the U.S. by constructing an X.400 address such as: C=us; ADMD= ; PRMD=Internet; DD.RFC-822=user(a)some.place.edu; The first part of this address: C=us; ADMD= ; PRMD=Internet; denotes the U.S. portion of the Internet community and not a specific "gateway". The 2nd part: DD.RFC-822=user(a)some.place.edu is the RFC-822 address of the Internet mail user after sub- stitution of non-printable characters according to RFC-1148. The RFC-822 address is placed in an X.400 Domain Defined Attribute of type RFC-822 (DD.RFC-822). INTERNET-DRAFT [Page 11] Exp. Date: 12/19/92 Each country is free to choose its own method of defining the RFC-822 community. For example in Italy, an X.400 user would refer to an RFC-822 user as: C=IT; ADMD=MASTER400; DD.RFC-822=user(a)some.place.it In the UK, an X.400 user would refer to an RFC-822 user as: C=GB; ADMD= ; PRMD=UK.AC; O=MHS-relay; DD.RFC-822=user(a)some.place.uk 3.3.2. Specification of X.400 addresses seen from the RFC- 822 world If an X.400 organization has a defined RFC-822 address space, RFC-822 users will be able to address X.400 reci- pients in RFC-822/Internet terms. This means that the address of the X.400 user, seen from an RFC-822 user, will be on the form: Firstname.Lastname@some.place.edu where the some.place.edu is a registered Internet domain. This implies the necessity of maintaining and distributing address mapping tables to all participating RFC-987 gate- ways. The mapping tables shall be globally consistent. Effective mapping table coordination procedures are needed. The procedures defined in [4] shall be followed. If an organization does not have a defined RFC-822 address space, an escape mapping (defined in [3]) shall be used. In this case, the address of the X.400 user, seen from an RFC- 822 user, will be on the form: "/G=First name/S=Lastname/O=orgname/PRMD=foo/ADMD=bar/C=us/"@ some.gateway.edu Note that [7] specifies that quoted left-hand side addresses | must be supported and that these addresses may be greater | than 80 characters long. This escape mapping shall also be used for X.400 addresses which do not map cleanly to RFC-822 addresses. It is recommended that an organization with no defined RFC- 822 address space, should register RFC-822 domains at SRI- NIC. This will minimize the number of addresses which must use the escape mapping. INTERNET-DRAFT [Page 12] Exp. Date: 12/19/92 If the escape mapping is not used, RFC-822 users will not see the difference between an Internet RFC-822 address and an address in the GO-MHS Community. For example: The X.400 address: C=us; ADMD=ATTMail; PRMD=CDC; O=CPG; S=Lastname; G=Firstname; will from an RFC-822 user look like: Firstname.Lastname@cpg.cdc.com 3.4. Routing policy To facilitate routing in the GO-MHS Community before an X.500 infrastructure is deployed, the following two tables, an MTA table and a Domain table, are defined. These tables are formally defined in [1]. The use of these tables is necessary to solve the routing crisis that is present today. However, this is a temporary solution that will eventually | be replaced by the use of X.500. The MTA table will define the names of well known MTAs (WEPs) and their associated connection data including selec- tor values, NSAP addresses, supported protocol stacks, and supported X.400 protocol version(s). Each entry in the Domain table consists of a sub-tree hierarchy of an X.400 address, followed by a list of MTAs which are willing to accept mail for the address or provide a relay service for it. Each MTA name will be associated with a priority value. Collectively, the list of MTA names in the Domain table make the given address reachable from all protocol stacks. In addition, the list of MTAs may pro- vide redundant paths to the address, so in this case, the priority value indicates the preferred path, or the pre- ferred order in which alternative routes should be tried. The MTA and Domain tables are coordinated by the group | specified in the Community document. The procedures for table information gathering and distribution, are for further study. 3.5. Minimum statistics/accounting | It is important that certain key statistics be kept by each | MTA. This section defines the data which must be kept by | each MTA. There are no constraints on the encoding used to | store the data (i.e., format). MTA managers are free to col- | lect more than the minimum information defined below. This | information is based on work in [8]. | INTERNET-DRAFT [Page 13] Exp. Date: 12/19/92 For each message/report passing the MTA, the following | information is to be collected. | The following fields must be collected. | Date Time Priority Local MTA Name Size The following fields are conditionally collected. | From MTA Name (fm) To MTA Name (tm) Delta Time (dt) Message-id (id) At least one of 'fm' and 'tm' must be present. If one of | 'fm' and 'tm' is not present, 'id' must be present. If both | 'fm' and 'tm' are present, then 'dt' indicates the number of | minutes that the message was delayed in the MTA. If 'id' | cannot be mapped locally because of log file formats, 'id' | is not present and every message creates two lines: one with | 'fm' empty and one with 'tm' empty. In this case, 'date' and | 'time' in the first line represent the date and time the | message entered the MTA. In the second line, they represent | the date and time the message left the MTA. | The following fields are optionally collected. | From Domain (fd) To Domain (td) For route tracing, 'fd' and 'td' are useful. They represent | X.400 OU's, O, PRMD, ADMD and C and may be supplied up to | any level of detail. 4. Community Document This is the community document for the GO-MHS Community. Community: XXX # The XXX service is a MHS community formed by the X.400 # networks in all participating countries. # # The coordination is done by the COSINE-MHS project team. # Another solution must be found at least by the end of 1992. Update: DATE=920302 Address: C=CH;ADMD=ARCOM;PRMD=SWITCH;O=SWITCH; OU=COSINE-MHS;S=Project-Team; Phone: +41 1 2623143 FAX: +41 1 2623151 INTERNET-DRAFT [Page 14] Exp. Date: 12/19/92 Mail: SWITCH Head Office/COSINE-MHS Project Team/Limmatquai 138/ CH-8001 Zurich/Switzerland # Mail-server: C=CH;ADMD=ARCOM;PRMD=SWITCH;O=SWITCH;OU=NIC; S=COSINE-MHS-SERVER; FTP-server: nic.switch.ch; cosine-mhs; 'your email address' # Mandatory-Service: Public-X.25/X.25/TP0 # The public X.25 network. X.25 is supported in most X.400 # applications and mandatory in X.400 anyhow. Mandatory-Service: Internet/TCP/RFC1006 # The Internet, standing for the global TCP/IP network of the # research and development community # RFC1006 is considered a solution to ease migration to OSI. It will # be replaced by TP4/CLNS as soon as a reliable service is available. Optional-Service: RARE-CLNS/CLNS/TP4 # The RARE Connectionless pilot service. Current participants are # NORDUnet, SURFnet, CERN, NSFnet and SWITCH. Optional-Service: NSF-CLNS/CLNS/TP4 # The NSF Connectionless pilot service. Current participants are # NSFnet as well as many regionals. Optional-Service: RARE-IXI/X.25/TP0 # The International X.25 Infrastructure covering most countries in # Europe. The absence of volume tariffs make it a preferred choice. 9 9INTERNET-DRAFT [Page 15] Exp. Date: 12/19/92 References [1] U. Eppenberger, Routing coordination for an X.400 MHS- service within a multi protocol / multi network en- vironment, IETF Internet Draft, "draft-ietf-x400ops- mhs-service-00.txt". [2] S.E. Hardcastle-Kille, X.400 1988 to 1984 downgrading, IETF Internet Draft, "draft-ietf-kille- 88to84downgrade-01.txt". [3] S.E. Hardcastle-Kille, Mapping between X.400(1988) / ISO 10021 and RFC 822, IETF Internet Draft [4] . [5] [6] K. Harrenstien, et al. DOD Internet Host Table Specifi- cation. Request for Comments 952, October 1985. [7] R. Braden. Requirements for Internet Hosts -- Applica- tion and Support. Request for Comments 1123, October 1989. [8] The COSINE MHS Project Team, "Requirements for A Final Format Of Traffic Statistics" 9 9INTERNET-DRAFT [Page 16] Exp. Date: 12/19/92