HTTP/1.1 200 OK Date: Tue, 09 Apr 2002 11:08:33 GMT Server: Apache/1.3.20 (Unix) Last-Modified: Tue, 26 Aug 1997 15:41:22 GMT ETag: "2e6b9e-917b-3402f922" Accept-Ranges: bytes Content-Length: 37243 Connection: close Content-Type: text/plain INTERNET-DRAFT EXPIRES: FEB 1998 INTERNET-DRAFT N.S.C Working Group A.Robert INTERNET-DRAFT SITA June 1997 MAPPING OF AIRLINE TRAFFIC OVER IP Status of this Memo Distribution of this memo is unlimited. 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 and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress". To view the entire list of current Internet-Drafts, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Abstract This memo specifies a protocol for the encapsulation of the airline specific protocol over IP. Contents 1. INTRODUCTION 3 2. TERMINOLOGY & ACRONYMS 4 3. LAYERING 6 4. TRAFFIC IDENTIFICATION 7 5. TCP PORT ALLOCATION 7 6. MATIP SESSION ESTABLISHMENT 7 7. OVERALL PACKET FORMAT FOR TYPE A & TYPE B 9 8. MATIP FORMAT FOR TYPE A CONVERSATIONAL TRAFFIC 10 8. 1 Control Packet Format 10 8.1.1 Session Open format (SO) 10 8.1.2 Open Confirm format (OC) 12 SITA [Page 1] I/D Mapping of Airline Traffic over IP June 1997 8.1.3 Session Close (SC) 13 8.2 Data Packet Format 14 9. MATIP FORMAT FOR TYPE A HOST-TO-HOST TRAFFIC 15 9. 1 Control Packet Format 15 9.1.1 Session Open format (SO) 15 9.1.2 Open Confirm format (OC) 17 9.1.3 Session Close (SC) 17 9.2 Data Packet Format 18 10. MATIP FORMAT FOR TYPE B TRAFFIC 19 10.1 Control packet format 19 10.1.1 Session Open format (SO) 19 10.1.2 Open confirm format (OC) 20 10.1.3 Session Close (SC) 21 10.2 Data packet format 21 11. SECURITY 22 12. AUTHOR ADDRESS 22 SITA [Page 2] I/D Mapping of Airline Traffic over IP June 1997 1. Introduction Most airlines are willing to migrate from airline specific protocols to standardized protocols in order to benefit from the lower cost of new technologies, but the migration has been slow done to the following factors: - Applications have not been migrated. - Dumb terminals using airline protocols P1024B (IBM ALC) or P1024C (UNISYS UTS) are still numerous. There are currently many different proprietary solutions based on gateways available to take advantage of low cast networking, but they are not scaleable and cannot interact. In the future, TCP/IP will be more commonly used as a common transport means for traffic types because: - TCP/IP is the standard protocol of UNIX based applications - TCP/IP stacks are inexpensive - TCP/IP is used on intranets. The purpose of this memo is to define the mapping of the airline traffic types over TCP/IP. The airlines implementing it in their systems should have a TCP/IP stack to enable the traffic exchange below : !----! ( ) ! !----------( ) !----! ( ) Type B HOST ( NETWORK ) ( ) ( ) !---o !----! ( )--------! D !---o Type A stations !----!----------( ) !---o !----! ( ) TYPE A HOST ! ! ! ! -------- ! ! -------- Network Messaging System (D) : Gateway TYPE A router SITA [Page 3] I/D Mapping of Airline Traffic over IP June 1997 The different airline traffic flows concerned by this memo are : - TYPE A Host / Terminal - TYPE A Host / TYPE A host - TYPE B Host / Network messaging System In the case of dumb terminals, a conversion is required on the terminal side in order to have an IP connection between the host and the router. However, the IP connection is directly between the central airline host and the intelligent workstation if the latter has a direct connection to the network, a TCP/IP stack and a terminal emulation 2. Terminology & acronyms ALC : Airline Line Control: IBM airline specific protocol (see P1024B) ASCII American Standard Code for Information Interchange ASCU Agent Set Control Unit: Cluster at the user side. AX.25 Airline X.25 : Airline application of the X.25 OSI model (published by IATA) BATAP Type B Application to Application Protocol. Protocol to secure the TYPE B traffic. It was specified by SITA and is now published by IATA (SCR Vol. 3) EBCDIC Extended Binary Coded Decimal Interchange Code Flow ID Traffic Flow identifier used in host to host traffic to differentiate traffic flow types. HLD High Level Designator: Indicates the entry or exit point of a block in the network. SITA [Page 4] I/D Mapping of Airline Traffic over IP June 1997 IA Interchange Address: ASCU identifier in P1024B protocol. IATA International Air Transport Association IP Internet Protocol IPARS International Program Airline Reservation System: IPARS code is used in ALC LSB Least Significant Bit MATIP Mapping of Airline Traffic over Internet Protocol MSB Most Significant Bit OC Open Confirm (MATIP command) OSI Open Standard Interface P1024B SITA implementation of the ALC, the IBM airlines specific protocol. It uses 6- bit padded characters (IPARS) and IA/ TA for physical addressing. P1024C SITA implementation of the UTS, the UNISYS terminal protocol. It uses 7-bit (ASCII) characters and RID/ SID for physical addressing. RFU Reserved for Future Use RID Remote Identifier: ASCU identifier in P1024C protocol. SC Session Close (MATIP command) SID Station Identifier: Terminal identifier in P1024C protocol. SITA [Page 5] I/D Mapping of Airline Traffic over IP June 1997 SITA Societe International de Telecommunications Aeronautiques SO Session Open (MATIP command) TA Terminal Address: Terminal identifier in P1024B protocol. TCP Transport Control Protocol TYPE A Traffic Interactive traffic or host to host TYPE B Traffic Messaging traffic in IATA compliant format with high level of reliability UTS Universal Terminal System by Unisys: (see P1024C) 3. LAYERING MATIP is an end to end protocol. Its purpose is to have a mapping standard between the TCP layer and the airline application without any routing element.. +-------------------------------+ |Airline TYPE A | Airline TYPE B| | Application | Application | +-------------------------------+ | MATIP A | MATIP B | +-------------------------------+ | T.C.P | +-------------------------------+ | I.P | +-------------------------------+ | MEDIA | +-------------------------------+ SITA [Page 6] I/D Mapping of Airline Traffic over IP June 1997 4. TRAFFIC IDENTIFICATION There are two types of traffic: TYPE A traffic: Typically conversational traffic that could be exchanged between a terminal and an airline host or between two airline hosts. TYPE B traffic : For message exchange between an airline host and a TYPE B Message Switching System. In TYPE A conversational traffic, the airline host application recognizes the ASCU thanks to 4 bytes (H1, H2, A1, A2). These bytes are assigned by the host and are unique per ASCU. Thus, a host can dynamically recognize the ASCU independent of IP address. H1 H2 A1 A2 bytes follow one of the three cases below: - A1,A2 only are used and H1H2 is set to 0000. - H1,H2 identify the session and A1A2 the ASCU inside the session. - H1,H2,A1,A2 identify the ASCU. The first two cases are fully compatible with the AX.25 mapping where H1H2 may be equivalent to the HLD of the concentrator, i.e., 2 bytes hexadecimal. The third rule allows more flexibility but is not compatible with AX.25. In TYPE A host to host traffic the identification field is also present and is equal to 3 bytes H1 H2 Flow ID (optional). H1H2 are reserved for remote host identification (independently of the IP address) and must be allocated bilaterally. In Type B traffic, identification of End Systems may be carried out by the use of HLDs, or directly by the pair of IP addresses. 5. TCP PORT ALLOCATION IANA (Internet Assigned Numbers Authority) has allocated the following ports for MATIP TYPE A and TYPE B traffic: MATIP Type A TCP port = 350 MATIP Type B TCP port = 351 Therefore the traffic type A or B is selected according to the TCP port. 6. MATIP SESSION ESTABLISHMENT SITA [Page 7] I/D Mapping of Airline Traffic over IP June 1997 Prior to any exchange between two applications, a unique MATIP session is established above the TCP connection in order to identify the traffic characteristic such as: - Subtype of traffic for TYPE A (Type A host to host or Type A conversational ) - Multiplexing used (for Type A) - Data header - Character set A separate session must be established for each set of parameters (e.g., P1024B, P1024C traffic between two points needs two separate sessions). The establishment of a MATIP session can be initiated by either side. No keep-alive mechanism is defined at MATIP level. Session time out relies on the TCP time-out parameters. There are three commands defined to manage the MATIP session: - Session Open (SO) to open a session. - Open Confirm (OC) to confirm the SO command. - Session close (SC) to close the current session. A MATIP session can be up only if the associated TCP connection is up. However it is not mandatory to close the TCP connection when closing the associated MATIP session. Typical exchange is: TCP session establishment Session Open ---------> <----------- Open confirm data exchange ----------------------> <------------------------- . . . Session Close -----------------> . . . <------------------------- Session Open Open confirm -------------------> data exchange <------------------------- ----------------------> SITA [Page 8] I/D Mapping of Airline Traffic over IP June 1997 The open session command may contain configuration elements. An open session command received on a session already opened (i.e. same IP address and port number) will automatically clear the associated configuration and a new configuration will be set up according to the information contained in the new open session command. As illustrated above, the open and close commands are symmetrical. For type A conversational traffic, the SO and OC commands contain information for the identification of the ASCUs and the session. ASCUs are identified within a session by two or 4 bytes. A flag is set to indicate if the ASCU is identified by 4 bytes (H1H2A1A2) or by 2 bytes (A1A2). In the latter case, H1H2 is reserved for session identification. The SO command is sent to open the MATIP session. In Type A conversational it may contains the list of ASCUs configured in this session. The OC command confirms the SO command. It can refuse or accept it, totally or conditionally. In Type A, it contains the list of the ASCUs either rejected or configured in the session. 7. OVERALL PACKET FORMAT FOR TYPE A & TYPE B The first 4 bytes of the MATIP header follow the following rules. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |C| Cmd | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Ver The `Ver' (Version) field represents the version of the MATIP. It must contain the value 001 otherwise the packet is considered as invalid. C Identifies a CONTROL packet. When set to 1, the packet is a Control packet When set to 0, the packet is a Data packet Cmd This field identifies the control command if the flag C is set to 1. Length SITA [Page 9] I/D Mapping of Airline Traffic over IP June 1997 This byte indicates the number of bytes of the whole command, header included. Notes : Fields identified as optional (Opt) are not transmitted if not used. 8. MATIP FORMAT FOR TYPE A CONVERSATIONAL TRAFFIC 8. 1 Control Packet Format There are 3 control packets to open or close the session at the MATIP level. 8.1.1 Session Open format (SO) To be able to identify the session and before sending any data packets, a Session Open command is sent. It can be initiated by either side. In case of collision, the open session from the side having the lower IP address is ignored. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 1 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0|0 1|0| CD | STYP |0 0 0 0| RFU |MPX|HDR| PRES. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | H1 | H2 | RFU | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | RFU | Nbr of ASCUs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nbr of ASCUs | ASCU list (opt) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ RFU Reserved for future use. Must be set to zero. CD This field specifies the Coding 000 : 5 bits (padded baudot) 010 : 6 bits (IPARS) 100 : 7 bits (ASCII) 110 : 8 bits (EBCDIC) SITA [Page 10] I/D Mapping of Airline Traffic over IP June 1997 xx1 : R.F.U STYP This is the traffic subtype (type being TYPE A). 0001 : TYPE A Conversational MPX This flag specifies the multiplexing used within the TCP session. Possible values are: 00 : Group of ASCU with 4 bytes identification per ASCU (H1H2A1A2) 01 : Group of ASCUs with 2 bytes identification per ASCU (A1A2) 10 : single ASCU inside the TCP session. HDR This field specifies which part of the airline's specific address is placed ahead of the message texts transmitted over the session. Possible values are : 00 : ASCU header = H1+H2+A1+A2 01 : ASCU Header = A1+A2 10 : No Header 11 : Not used The MPX and HDR must be coherent. When ASCUs are multiplexed, the data must contain the ASCU identification. The table below summarizes the allowed combinations : +--------------------------+ | MPX | 00 | 01 | 10 | +--------------------------+ | HDR | | | 00 | Y | Y | Y | | 01 | N | Y | Y | | 10 | N | N | Y | +--------------------------+ PRES This field indicates the presentation format 0001 : P1024B presentation 0010 : P1024C presentation 0011 : 3270 presentation H1 H2 These fields can logically identify the session if MPX is not equal to 00. When this field is not used, it must be set to 0. If used in SITA [Page 11] I/D Mapping of Airline Traffic over IP June 1997 session (MPX <> 0) with HDR=00, H1H2 in data packet must have the same value as set in SO command. Nbr of ASCUs Nbr_of_ASCUs field is mandatory and gives the number of ASCUs per session. A 0 (zero) value means unknown. In this case the ASCU list is not present in the `Open Session' command and must be sent by the other end in the `Open Confirm' command. ASCU LIST Contains the list of identifier for each ASCU. If MPX=00 it has a length of four bytes (H1H2A1A2) for each ASCU, otherwise it is two bytes (A1A2). 8.1.2 Open Confirm format (OC) The OC (Open Confirm) command is a response to an SO (Session Open) command and is used to either refuse the session or accept it conditionally. In case of acceptance, the OC indicates the number and the address of the rejected ASCUs, if any. Alternatively, it indicates the list of ASCUs configured for that MATIP session if the list provided by the SO command was correct or the number of ASCUs configured in the session was unknown (n. of ASCU equals 0). 8.1.2.1 Refuse the connection 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 1| cause | +-+-+-+-+-+-+-+-+ Cause This field indicates the reason for the MATIP session refusal : 0 0 0 0 0 1 : No Traffic Type matching between Sender & Recipient 0 0 0 0 1 0 : Information in SO header incoherent 8.1.2.2 Accept the connection SITA [Page 12] I/D Mapping of Airline Traffic over IP June 1997 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 0 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 R 0 0 0 0 0| Nbr of ASCUs |Nbr of ASCU(opt| ASCU LIST | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ R Flag indicating an error in the ASCU configuration provided in the SO command. NBR of ASCUs If the MPX value is equal to 00 in the SO command, this field is two bytes long. Otherwise, it is one byte. If the R flag is set, the Nbr_of_ASCUs field represents the number of ASCUs in error. Otherwise, it indicates the number of ASCUs configured for that MATIP session. ASCU LIST Depending on the R flag, this field indicates the list of ASCUs (A1A2 or H1H2A1A2) either in error or within the session. 8.1.3 Session Close (SC) The SC (Session Close) command is used to close an existing MATIP session. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Close Cause | +-+-+-+-+-+-+-+-+ Close Cause Indicates the reason for the session closure: SITA [Page 13] I/D Mapping of Airline Traffic over IP June 1997 0 0 0 0 0 0 0 0 : Normal Close 1 0 0 0 0 1 0 0 up to Application dependent 1 1 1 1 1 1 1 1 8.2 Data Packet Format 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |0|0 0 0 0 0 0 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ID (optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Payload | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ID This field is optional and has a different length and format according to the value of HDR, PRES indicated during the session establishment. HDR This field is depending on the PRESENTATION : +------------------------------+-------------------------------+ |HDR | PRES = P1024B and 3270 | PRES = P1024C | +------------------------------+-------------------------------+ |00 |ID = 4 bytes H1-H2-A1-A2 | ID = 5 bytes H1-H2-A1-0x01-A2 | +------------------------------+-------------------------------+ |01 |ID = 2 bytes A1-A2 | ID = 3 bytes A1-0x01-A2 | +------------------------------+-------------------------------+ |10 |ID = 0 bytes | ID = 0 bytes | +------------------------------+-------------------------------+ H1, H2 value must match the value given in the SO command if MPX is different from 0. Payload SITA [Page 14] I/D Mapping of Airline Traffic over IP June 1997 payload begins with the terminal identification : - One byte Terminal identifier (TA) in P1024B - Two bytes SID/DID Terminal identifier in P1024C. 9. MATIP FORMAT FOR TYPE A HOST-TO-HOST TRAFFIC 9. 1 Control Packet Format There are 3 control packets to open or close the session at the MATIP level. 9.1.1 Session Open format (SO) To be able to identify the session and before sending any data packet, a Session Open command is sent. It can be initiated by either side. In case of collision, the open session from the side having the lower IP address is ignored. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 1 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0|0 1|0| CD | STYP |0 0 0 0| RFU |MPX|HDR|0 0 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | H1 | H2 | RFU | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flow ID(opt)| +-+-+-+-+-+-+-+-+ RFU Reserved for future use. Must be set to zero. CD This field specifies the Coding, as defined in section 8.1.1.1. STYP This is the traffic subtype (type being Type A). 0010 : TYPE A IATA Host to Host SITA [Page 15] I/D Mapping of Airline Traffic over IP June 1997 1000 : SITA Host to Host MPX This flag specifies the multiplexing used within the TCP session in TYPE A SITA host to host. Possible values are: 00 : irrelevant 01 : multiple flow inside the TCP connection 10 : single flow inside the TCP connection HDR This field specifies which part of the airline's specific address is placed ahead of the message text transmitted over the session. Possible values are : 00 : used in TYPE A SITA Host to Host Header = H1+H2+Flow ID 01 : used in TYPE A SITA Host to Host Header = Flow ID 10 : No Header (default for IATA host to Host) 11 : Not used The MPX and HDR must be coherent. When flow are multiplexed, the data must contain the flow identification. The table below summarizes the possible combinations: +---------------------+ | MPX | 01 | 10 | +---------------------+ | HDR | | | | 00 | Y | Y | | 01 | Y | Y | | 10 | N | Y | +---------------------+ H1 H2 These fields can be used to identify the session. When this field is not used, it must be set to 0. If HDR=00, H1H2 in data packet must have the same value as set in SO command. Flow ID This field is optional and indicates the Flow ID (range 3F - 4F Hex). SITA [Page 16] I/D Mapping of Airline Traffic over IP June 1997 9.1.2 Open Confirm format (OC) The OC (Open Confirm) command is a response to an SO (Session Open) command and is used to either refuse the session or accept it. 9.1.2.1 Refuse the connection 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 1| cause | +-+-+-+-+-+-+-+-+ Cause This field indicates the reason for the MATIP session refusal 0 0 0 0 0 1 : No Traffic Type matching between Sender & Recipient 0 0 0 0 1 0 : Information in SO header incoherent 9.1.2.2 Accept the connection 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0| +-+-+-+-+-+-+-+-+ 9.1.3 Session Close (SC) The SC (Session Close) command is used to close an existing MATIP session. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Close Cause | +-+-+-+-+-+-+-+-+ SITA [Page 17] I/D Mapping of Airline Traffic over IP June 1997 Close Cause Indicates the reason for the session closure: 0 0 0 0 0 0 0 0 : Normal Close 1 0 0 0 0 1 0 0 up to : Application dependent 1 1 1 1 1 1 1 1 9.2 Data Packet Format 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |0|0 0 0 0 0 0 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ID (optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Payload | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ID This field is optional and has a different length and format according to the value of HDR indicated during the session establishment. HDR +-------------------------------+ |HDR | I.D. | +-------------------------------+ |00 |ID = 3 bytes H1-H2 FLOW ID| +-------------------------------+ |01 |ID = FLOW ID | +-------------------------------+ |10 |ID nor present | +-------------------------------+ SITA [Page 18] I/D Mapping of Airline Traffic over IP June 1997 Payload packet The payload format is transparent to the MATIP layer. It is formatted according to the IATA host to host specifications and agreed bilaterally by the sender and the receiver. 10. MATIP FORMAT FOR TYPE B TRAFFIC 10.1 Control packet format There are 3 control packets used to open or close the session at the MATIP level for exchanging Type B data 10.1.1 Session Open format (SO) Before sending any data packets, it is recommended to check that the systems which are establishing a session are indeed able to communicate (i.e.: Both systems agree on the characteristics of the traffic that will cross the connection). For this purpose, a two way handshake, using the Session commands defined hereafter, is carried out immediately after the establishment of the TCP level connection. Either side can initiate this procedure. In case of collision, the open session from the side having the lower IP address is ignored. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 1 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0|0| C D | PROTEC| BFLAG | Sender HLD | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Recipient HLD | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Length This byte indicates the number of bytes of the whole command, header included. The only possible lengths are : 6 bytes and 10 bytes. CD This field specifies the Coding, as defined in section 8.1.1.1. PROTEC SITA [Page 19] I/D Mapping of Airline Traffic over IP June 1997 Identifies the end to end Messaging Responsibility Transfer protocol used. 0010: BATAP All other values available. BFLAG 0 0 0 0 means that the fields `Sender HLD, Recipient HLD' do not exist in this packet. In this case, the exact length of the packet is 6 Bytes. 0 0 1 0 means that the `Sender HLD, Recipient HLD' are carried respectively in bytes 9,10 and 11,12 of this packet. In this case, the exact length of the packet is 10 Bytes. Sender HLD HLD of the Type B System sending the Open Session. Recipient HLD HLD of the Type B system to which session opening is destined. 10.1.2 Open confirm format (OC) The OC (Open Confirm) command is a response to an SO (Session Open) command and is used to either refuse the session or accept it. 10.1.2.1 Refuse the connection 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause | +-+-+-+-+-+-+-+-+ Length of this packet is 5 Bytes. Cause Indicates the cause of the rejection 0 1 0 0 0 0 0 1 : No Traffic Type matching between Sender & Recipient 0 1 0 0 0 0 1 0 : Information in SO header incoherent 0 1 0 0 0 0 1 1 : Type of Protection mechanism are different 0 1 0 0 0 1 0 0 up to 0 1 1 1 1 1 1 1 : R.F.U SITA [Page 20] I/D Mapping of Airline Traffic over IP June 1997 10.1.2.2 Accept the connection 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0| +-+-+-+-+-+-+-+-+ Length of this packet is 5 Bytes. 10.1.3 Session Close (SC) The SC (Session Close) command is used to close an existing MATIP session. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |1|1 1 1 1 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Close Cause | +-+-+-+-+-+-+-+-+ Close Cause Indicates the reason for the session closure: 0 0 0 0 0 0 0 0 : Normal Close 1 0 0 0 0 1 0 0 up to 1 1 1 1 1 1 1 1 : Application dependent 10.2 Data packet format 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0| Ver |0|0 0 0 0 0 0 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Payload | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Length SITA [Page 21] I/D Mapping of Airline Traffic over IP June 1997 This byte indicate the number of bytes of the whole packet, header included. Payload Type B message formatted according to the IATA standard and conforming to the rules of the accessed Type B service. 11. Security This memo raises no security issues. 12. Author address Alain Robert S.I.T.A. 18, rue Paul Lafargue 92904 PARIS LA DEFENSE 10 FRANCE Phone : 33 1 46411491 Fax : 33 1 46411277 Email : arobert@par1.par.sita.int INTERNET-DRAFT EXP: FEB 1998 INTERNET-DRAFT