Once the booking request has been sent, and once the feedback has been received by the client system, the system will keep up to date the client back-end using tracking messages.

In this case is the TOWeRS system that will contact the client one sending tracking messages to the requested URLs. If the response mode has been set to xml then the tracking message has the following structure:

<?xml version="1.0" encoding="UTF-8"?>
<envelope>
    <header>
        <version>1.6.1</version>
        <timestamp>20030423170100</timestamp>
    </header>
    <query type="track" product="hotel">
        <supplier code="789012">NetStorming srl</supplier>
        <invoiced by="netstorming"/>
        <booking code="789012"/>
        <status code="cnf"/>
        <checkin date="2003-09-05"/>
        <checkout date="2003-09-13"/>
        <city code="vce"/>
        <hotel code="2860" agreement="LCL.3186" c_type="2"/>
        <reference code="BOOK2005 000001" hcn="A-1234-000"/>
        <deadline date="2005-09-04"/>
        <details>
            <room type="dbl" extrabed="true" cot="true">
                <pax leader="true" title="MR" initial="G" surname="ROSSI"/>
                <pax title="MS" initial="M" surname="ROSSI"/>
                <pax title="MR" initial="G" surname="ROSSI" age=5"/>
                <prices>
                    <roomprice nett="120.00"/>
                    <extrabedprice nett="40.25"/>
                    <cotprice nett="10.00"/>
                </prices>
            </room>
        </details>
        <userdetails login="username" pwd="xxxxxxxx" /> 
 </query>
</envelope>

The type attribute has been set to the track value. The heading does not contain any user or password details in order to avoid that, if the wrong URL is passed, those data are not shared with some third parts. There are more tags here compared with availability response and booking request.

The supplier tag reports the name of the supplier of the hotel and the referece number in code attribute: it has to been reported in the voucher unless retrieved from the TOWeRS system.

The invoiced tag reports, in its by attribute, the code of the office that will issue the invoice bound to the referred booking; the current existing office codes will be listed in a specific document.

The booking tag reports in its code attribute the booking number in the TOWeRS system. Those references must be used later to cancel the booking. The status tag reports the status value in its code attribute. Possible values for status are:

• pnd for pending;
• cnf for confirmed;
• cxl for cancelled;
• rej for rejected

The deadline tag reports, in its date attribute, the day within you won't be charged.

Tag prices are usually present only with cnf status. In other statuses those details could not be present yet or they could have been already removed.

The userdetails tag reports, if provided in the availability request, the data of the created user in login and pwd attributes.

Please note that the reference tag can optionally contain a new attribute, hcn, wich reports the Hotel Confirmation Number (if available).