why haven't ethernet connectors changed?

[streiner at cluebyfour.org (Justin M. Streiner)]

On Thu, 20 Dec 2012, Michael Thomas wrote:

> I was looking at a Raspberry Pi board and was struck with how large the 
> ethernet
> connector is in comparison to the board as a whole. It strikes me: ethernet
> connectors haven't changed that I'm aware in pretty much 25 years. Every 
> other
> cable has changed several times in that time frame. I imaging that if anybody
> cared, ethernet cables could be many times smaller. Looking at wiring 
> closets,
> etc, it seems like it might be a big win for density too.

I've you've ever seen a truly 'dense' wiring closet, they are plenty dense 
already - dense enough that unplugging a single patch cable in a rack 
jammed full of switches is already a bit of a chore.

> So why, oh why, nanog the omniscient do we still use rj45's?

Inertia, for one thing.  By that, I mean:
1. There hasn't been any real incentive to make the connectors smaller.
2. The installed base of copper Ethernet ports dwarfs pretty much anything 
except maybe POTS lines, and even there, different countries sometimes 
adopted their own standards.  The costs of having to make physical changes 
to even a small portion of the installed cable plant would be 
unjustifiably prohibitive.

There could also be some valid technical reasons:
1. The conductors really can't get any thinner.  In fact, with Cat6A, 
they're somewhat thicker than Cat5E.
2. I would also think that the conductors/pins really can't get much 
closer together inside the connector shell, without cross-talk becoming 
more of a problem.  I don't have any technical data to back this up at the 
moment, but it seems reasonable.
3. If assertions 1 and 2 are true, then the cable really can't get any 
thinner either.  Again, if you look at Cat6A cable (especially shielded 
Cat6A), it is significantly thicker than Cat5E.

jms