# A Framework to Model Bursty Electronic Data Interchange Messages for Queueing Systems +
## 2 Materials and Methods  
Within a supply chain network, many inter-twined applications support EDI message traversal within a B2B network. Figure 1 is a representation of the B2B architecture that we investigated. From the figure, an inbound message can come in from multiple inbound protocols, such as FTP, HTTP, and SAP. Once the messages arrive via the inbound protocol, the message has the potential to pass through six B2B queueing entities (shown in blue) via the B2B rules engine and the B2B dispatcher. The rule engine lists associate rules related to each map associated with a message. The rule indicates steps that a message needs to take along its path. The dispatcher then routes the message based on the rule. Given the many possible protocols, we chose a select few for demonstration purposes. Our research focuses on the \"Translation Service\", coloured green. The \"Translation Service\" transforms a message. For example, an electronic data interchange for administration, commerce and transport (EDIFACT) message could be converted to XML format [33]. Figure 2 is an example of an EDIFACT message that would be transformed into XML. Once transformed, the outbound service then routes the message out of the network. UNB+UNOA:1+01010000253001+00013000093 SCHAZ59+991006:1902+PAV00012101221' UNH+1+INVOIC:0:97A:UN' BGM+381+1060113800026+9' DTM+137:199910060000:102' NAD+BT+VAUXHALL MOTORS LTD:91' RFF+VA:382324067' NAD+SU+2002993:92' RFF+VA:123844750' CUX+2:EUR' PAT+1' DTM+140:19991031:102' LIN+++090346642:IN' QTV+12:54:PC' MOA+203:1960.29' PRI+AAA:3630.1724::NTP:100:C62' RFF+S1:165480' DTM+11:199909280000:102' RFF+ON:X18V00003'  
We briefly explore the content of the message, showing some of the fields used in the lines of the EDIFACT message. 1. UNB Segment: Contains the message header. It forms the envelope of the message. 2. UNH Segment: the message header where the actual message is located. INVOIC indicates that the message is an invoice. The letter \"D\" stands for draft. \"97\" is the year in which a change was made to this message, and \"A\" means that the message is in the first half of the year 1997. Figure 1: Supply chain network architecture. Figure 2: EDIFACT message. 3. BGM Segment: Contains the document message's name, number, and code. Code 9 relates to the initial transmission related to a transaction. 4. DTM Segment: DTM is the date, time and period. Code 137 is when the message was issued. Code 102 is the calendar period: CCYYMMDD. 5. NAD Segment: Contains a name and address. 6. PRI Segment: Price details. The code AAA is the net price, including allowances and charges. As our research is centred around the transactional modelling of queueing systems, it is important to understand the life journey of a message and how frequently it is serviced by queueing entities. As an example, we identified the path that a message takes from start to finish (see Figure 3). We observed that the message first comes into the system from an inbound protocol called SAP (denoted by the green coloured entity). The \"B2B Dispatcher\", coloured purple, picks the message up and passes it through three different queues to be received by the \"Translation Service\", coloured blue. The message splits into several child messages. The \"Translation Service\" transforms the message, passing the message through the relevant queues, whilst a copy of the message is sent to the B2B reporting queue, where the customer can see near real-time the status of their message. The \"B2B Dispatcher\" will then pick the message from the queue and pass it to the outgoing mailbox, coloured orange. Observe that the queueing entities serviced this single message 19 times. When a message is being serviced by the \"Translation Service\", the \"Translation Service\" sends a command message to the CMD Queue (\"Queue 7\") and the data of the message to the Data Queue (\"Queue 8\"). Every message is associated with a CMD and data queue entry. Our research focuses on \"Queue 7\", which is coloured black.