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How the OpenTravel Alliance is agreeing an XML vocabulary
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multiple industries - airlines, hotels, car rentals, insurance, etc.
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The OpenTravel Alliance has been working on an XML specification (tags,
DTDs, infrastructure etc.) for use across the widely-defined travel industry
since May 1999. Several political, organizational, and technical challenges
had to be overcome to enable it, working with its over 100 member organizations
(airlines, hotel chains, travel agencies, Global Distribution Systems, software
companies, companies with large numbers of ‘managed’ travelers,
etc.), to publish Version 1 of its specification for public review in February
2000. The challenges and the solutions to them are discussed.
Business problem
People who travel think of a typical journey or trip as a compound entity,
involving components from several airlines and other suppliers. The intermediary
that organizes the journey has a similar view. Historically, it has only been
the intermediary (usually a single travel agency, via the Global Distribution
System or GDS that it uses) that has had access to all the data needed to
plan and manage a journey.
As discussed in the OpenTravel Alliance’s
[White Paper], for any one journey there has thus only
been a single distribution channel, consisting of the travel agency and its
GDS. This has presented restrictions, as GDSs offer limited content. Perhaps
because of the lack of channel competition, distribution costs have moreover
risen to the extent where airlines, in particular, wish to reduce the approximately
20% of their revenues that these costs consume.
The Internet and the World-Wide Web offer rapid access to content that
is provided directly by suppliers. There is thus an opportunity for suppliers
to offer journey components directly to travelers, and in particular to the
employees of corporations, and the travel management companies formerly known
as travel agencies working for them. The problem is that these components
are described on the Web in HTML, so they are difficult for a computer to
assemble into a compound journey.
HTML is fine for presenting things to people. But the computers that
are used to plan and manage journeys can only ‘screen scrape’
HTML to capture the information they need – a laborious and error-prone
process that is subject to defeat whenever a supplier changes the presentation
of its services on screen. As observed by many others, XML is a good solution
to this problem.
The schedule
The
OTA was formed
by a small group of airlines, car rental companies, and hotel chains to address
the business problem outlined above. Its ad hoc Board of Directors convened
its first open Advisory Forum in Atlanta, GA, on May 25, 1999. This was followed
by several months during which the bylaws were refined, particularly to allow
better representation of travel agencies and other ‘non-suppliers’.
The Board was filled out through elections held in August 1999. Also in that
month, the Data Interchange Standards Association of Alexandria, VA, was appointed
to manage OTA and provide its Standards Manager. Alan Kotok, formerly of the
GCA, was appointed to this role on October 1.
At the Advisory Forum the Board announced that Version 1 of OTA’s
specification (not ‘standard’ – see below) would be released
before the end of 1999. It was implicit that while the scope was yet to be
defined, the major part of the work was to develop an XML vocabulary for the
broadly-defined travel industry. This combination of loose scope and tight
schedule was, after the politics of representation, the first major challenge.
Other challenges
Cross-industry needs and relationships
OTA structured itself with a minimum management role for the Board,
but a maximum role for the Interoperability Committee that reports to it –
see
Figure 1. In addition to recommending deliverables
and the schedule for them to the Board, a primary role of ‘Interop’
was envisaged as arbitrating on vocabulary issues that were expected to arise
as separate Work Groups (Air, Car, Hotel, Non-Supplier and – a recent
addition – Leisure) defined the tag vocabularies for their sub-industries
– the standard example was ‘Should we talk of Passengers (Air),
Customers (Car), or Guests (Hotel)?

Figure 1
. OTA’s structure
In the event, it turned out that much of the work was done through ad
hoc Task Teams set up by Interop. These drew members from all Work Groups,
with some of the most valuable contributions coming from members who were
not from what would have been expected to be the most relevant Work Groups.
The ease of such contributions was a consequence of the early change to the
original arrangements that opened every Work Group, and Interop, meeting to
any member.
The first area of content to be addressed, that of the Customer Profile,
was deliberately chosen to stretch across all OTA’s Work Groups, so
as to drive evolution of a process that facilitated co-operation across the
entire OTA. This led to the formation of an ad hoc Customer Profile Content
Task Team, whose delivery included:
- Customer elements
- Customer preferences for air, car, hotel, etc., for different types
of journeys (business for employer, business for client, leisure, etc.)
- Customer affiliations
- Access history
- Privacy provisions.
There has been continuing growth in OTA membership, which reached 100
in March 2000 (incidentally delivering the membership fees budgeted for the
first year).
Figure 2 shows the importance of the Non-Supplier
members, who made a substantial contribution to all parts of Version 1 of
the specification.

Figure 2
. Demographic breakdown
The complexity of the work and the size of some of the meetings (27
Non-Suppliers, including several CEOs and CTOs, attended one face-to-face
meeting) strained the resources of DISA’s Standards Manager, who at
one stage was running and documenting daily conference calls, typically lasting
three hours. This challenge was ably met by the incumbent, but it would be
wise for OTA to plan for more resources to be available in the future. Similarly,
DISA’s overall support role for the whole OTA, as the only group drawing
any fees or expenses, should probably grow to embrace such things as facilitating
networking amongst members.
No general-purpose XML infrastructure yet
It was recognized early on that as there was no general-purpose cross-industry
XML infrastructure, OTA would have to build one for itself – or at least
enough to support the demonstration that the Board had made an explicit objective.
This was the most difficult and time-consuming part of the whole process,
leading to the following being addressed by the Technical Architecture Task
Team for Version 1:
- Reference model
- Transport and infrastructure protocols
- Message structure: control and content
- Naming conventions for tags
- Versioning
- Error messaging
- Security and privacy.
Even in the high-pressure course of the Version 1 work, several OTA
staff and members considered the promise of ebXML sufficient to justify attending
the first two meetings and playing a significant role. There is however concern
that ebXML may not deliver what is needed fast enough to avoid continued unilateral
development of infrastructure by OTA and other similar groups. This will consume
effort that could better be applied elsewhere, and will lead to unnecessary
delay and (probably) rework. Further, if ebXML does not deliver an infrastructure
in time for it to be used across all industries it will make it much more
difficult for the travel industry to deal directly with its corporate customers,
as they come from every imaginable industry.
In the event, continued testing and evolution of the infrastructure
and the Customer Profile DTDs made it difficult to keep the two parts of the
Specification and the demonstration (all being developed in parallel) coherent
– a prime cause of Version 1 being published two months late.
Key players doing their own things
Even in May 1999, it was known that some key players in the travel industry
were ‘doing their own things’ with XML – though at that
time the trade press was better at highlighting the companies in such announcements
than the technology they were using.
OTA has been encouraged by early XML adopters such as RezSolutions that
publicly said that it built its own vocabulary etc. because there was nothing
else available, but that it was impatient for the development of a generally-available
specification that it could use instead. Unlike the single-company and bilateral
users of XML, which have generally been able to depend on restricted networks
with implicit security arrangements, OTA has had to address privacy issues
explicitly in its data structures and messages. While it is hoped that some
of the infrastructure products that are being used to front-end GDS and other
mainframes will facilitate migration and avoid the need for long-term support
of multiple vocabularies etc., it remains to be seen how successful this –
and the necessary extension of privacy arrangements to support open use -
will be.
Legacy standards organizations
There are several existing organizations that publish standards for
the travel industry. HEDNA and IATA are extreme examples in the way they have
worked with OTA.
HEDNA was an early supporter. Not only did its then Chair join the
OTA Board, but it made available its existing (non-XML) standards work as
input to OTA. Recently, it has transferred its association management contract
to DISA, which will make future co-operation even easier. IATA (the International
Air Transport Association), by contrast, has not co-operated.
In between, there are ongoing discussions between OTA and
HITIS committee
of the American Hotel and Motel Association. HITIS has had a high-quality
standards effort under way for several years, and has recently embraced XML.
Its area of work overlaps that of OTA, and there is much hope that a way can
be found to combine the efforts.
A major reason why such co-operation is challenging seems to be that
some standards organizations have a very different business model to the cross-industry
groups that have, in the late 1990s, demonstrated the power of rapid, open,
low-cost specification development. If a specification is not only so useful
that it gets used by many powerful organizations but is also made available
early and widely, it becomes a de facto standard. This is why OTA is publishing
a specification.It was pleasing to see
the announcement by GetThere.com that it and the several industry-leading
e-commerce companies (including Ariba, Captura, Concur Technologies, Extensity
and Gelco) involved in the GetThere Application Network are already using
the OTA specification – an announcement made only a month after the
draft publication of Version 1.
Conflict of speed against scope
The schedule for Version 1 was ambitious. It was unattainable, given
the lack of clarity about what had to be developed to provide an infrastructure
to support not only the demonstration, but also to provide a foundation for
what will need to be developed (or adopted from eg. ebXML) later. This was
a major challenge, particularly given the uncompromising nature of some of
the participants in the Technical Architecture Task Team and their commendable
determination to be associated with a high-quality deliverable.
One of the lessons OTA is trying to apply to its work on Version 2 is
to restrict the scope at an early stage, using a Journey and transactions
that edit this as a reference model against which to apply use cases.
Distance
While it should be easy for the travel industry to gather face-to-face,
progress needed to be faster than (say) monthly gatherings would enable –
and everybody but the DISA staff has demanding day jobs, too. So there were
many conference calls, some of them memorably challenging.
Conference calls could be much more productive if there were generally-available
Internet based tools to support them: even a web site listing participants
and showing who was speaking at any time would be a big help. But this would
further highlight the major discrepancy between American Internet access and
that nearly everywhere else in the world. Because of the distances involved
(often, for OTA, across nine time zones), several participants in each call
were at home, or on the road at a hotel. Most of the Americans involved now
have both a voice line and a fast, permanent Internet connection in their
home or hotel, so that during a call they can refer to a document posted to
the OTA website. Most Europeans must however choose between a voice connection
and a slow Internet connection that is so expensive that they disconnect it
when it is not absolutely necessary. This is a major problem not restricted
to OTA (and beyond OTA’s ability to solve!) that will continue to impede
the development of technology in Europe and elsewhere outside North America.
Achievements
Most of the major achievements have been touched on above. In summary,
OTA’s open structure has enabled it to make good use of its diverse
membership – and the size and activity of this is also no small achievement.
Version 1 of the OTA Specification included only the Customer Profile content,
but not only is this the subject of a public demonstration (see
http://www.OpenTravel.org
for both) but it has already been adopted for important real world use. The
home-brew technical infrastructure set out in the Specification seems to go
well beyond what many other XML groups have developed, and it is hoped that
it will be useful to them – better yet, that OTA can get something in
return, fast, through ebXML. Perhaps most important, a brisk style and process
have been adopted that have allowed OTA to meet its objectives within budget.
Plans for the future
The major area of content to address is the multi-component Journey
itself. This involves all the Work Groups, and there is a major danger of
the scope getting out of control. In parallel, individual Work Groups are
likely to tackle ‘internal’ areas. As little infrastructure work
will be done as possible – but if ebXML does not deliver what is needed
fast enough this will also have to be addressed.
Bibliography
| [White Paper] | The OpenTravel Alliance White Paper, Version 2.0,
by Nick Lanyon and Alan Kotok: February 2000, available at http://www.OpenTravel.org |