Amber Witherspoon wrote:

>     I suppose we can classify the two models. The old one could be called
>     the "Hub" model, where starports only grow if there is trade volume to
>     support them, while the new model is the "Interdependent" model and it
>     assumes that planets will specialize in goods and trade for the ones
>     they don't produce.

>     While both are accurate, I see more advantages to the hub model. Now,
>     I do have ideas for combining the two (Primary routes being based on
>     starport class within 4 parsecs, as the original 77 table, secondary
>     routes being based on trade code within 2 parsecs), but what are your
>     ideas?

In My Very Own Highly Variant and Very Non-Canon Traveller Universe (tm), I do both :-)

If a planet(*) generates a lot of trade, then inevitably a lot of ships will start calling
there, and equally inevitably the infrastructure around the planet will grow up to support
these ships. Infrastructure includes HighPoints, traffic control, refuelling stations, fuel
refineries, chandleries, repair yards, scrapyards, pawnbrokers, loan sharks, and everything
which would naturally come along with these - hotels, restaurants, brothels, entertainment
facilities, offices, shops, tourist traps, you name it. Very likely some military infrastructure
will start to show up too. Over time the classification of the starport (by which term I include
both deep-orbit, planetary-orbit, and ground facilities) of the system will start to climb.
This is what one might call the 'bottom-up' model (and of course it assumes that nothing
derails this sort of natural growth - a war, an isolationist planetary government, etc).

* "Planet" here might be a Jumpspace hub for a few systems which are a J-1 or J-2 from it,
but are otherwise inconvenient to get to or from. See below for a little more on this.

At the same time, sometimes governments of large polities (e.g. the Regency and the Sword
Worlds) will get together and agree to open a "trade route". Usually this will involve
building a "trade nexus" - a set of infrastructure in a system which can support "many"
ships (thousands?) loading and off-loading at the same time, with all the ancillary bits
and pieces - all the above, plus customs offices, quarantine, bio checks, etc, etc, etc.

In RL a trade nexus here on Earth might be Port Elizabeth, Rotterdam, Singapore, etc. It's
the sort of major investment that costs zillions of credits and is expected to be paying off
for decades, or more likely centuries. These tend not to get built if you think that you might
be fighting a war with any of the trading partners in the next few decades. (Realistically,
these don't get built from scratch - existing facilities get massively upgraded over many
years.) This is what one might call the 'top-down' model.

My model of trade, which I am sure bears no relation to canon, is that 95%+ of all trade is
carried by bulk carriers owned by mega-corps and kilo-corps (to coin a phrase). These ships
run on regular schedules - A to B and back, or A to B to C to D and back to A. They tend to
be J-1, with some proportion J-2, a much smaller proportion J-3, and so on.

On occasion a bulk carrier may have space for 'opportunistic' cargo, so their supercargoes
will fill them up with stuff that they think might turn a profit somewhere along the run -
booze, luxury items, gourmet food (Python Whiffets, anyone? :-) ), fashion clothing, shiny
beads, high-TL technology items, low-TL arts and craft items, etc, etc.

The Free Traders will carry pretty much anything for a credit, and so if, for example, some
bulk carrier is unloading the shiny beads it hopefully carried into the system because it needs
the room for 'real' cargo, then some Free Trader may snap these up at a discount. Maybe they
know that there is a demand for these in system X, two Jumps away but off the main trade routes.
Maybe they are just buying them in hope.

Anyway, that's my model. I'm not a gearhead, and I care less for canon than I do the 'feel' of
the Universe. Hope this is useful to someone.

Jonathan