Ah, but the line isn't referring to literal boundaries. (Ok, it might)
Message:At that point the Centauri were aggressors to 12 other species.
Babylon 5's treatment of space is similar to Era 10.
In E10, in general, travel is limited to the wormhole routes Foster has opened. There are limited "train tracks" into and out of systems, and you can't get directly from Bogus Blue to BG-Weatherstorm without taking multiple wormholes. Yes, the Skia can Trip, but it's much more dangerous. Anything goes wrong with your Crystal or Empath, and you're stuck in real-space between systems hoping to get somewhere before the MRD is gone.
In B5, in general, travel is limited to the hyperspace routes originally laid down by ancient races. The jumpgates in use are all copies of the original tech, and gate pairs have tightbeam beacons delineating "train tracks." There are limited ways in and out of systems, and you can't get directly from Earth to Babylon 5. It's a three-jump route. Ships that can generate their own jump points still follow the gate beacon routes because hyperspace is full of turbulence, heavy gravity wells, and, at the point in the show timeline that episode takes place, ships that wander off the beacon routes basically are almost never heard again (destroyed by Shadows). Varied species do have Explorer-Class ships to attempt to discover new systems, but the attrition rate is high. There's an entire episode where the A-plot is largely about what I've discussed. An Earth Explorer ship is damaged in hyperspace, drifting off somewhere, and the search vessels are forming a "chain." A squadron of Starfuries moves off beacon until the beacon signal fades to a certain threshold, a Starfury holds position pinging a repeater signal, and the rest of the squad moves on.
Hyperspace in B5 was DANGEROUS.
But, for purposes of tactics in both Era 10 and Babylon 5, all the action happens around planetary "islands" and no one is actually worried about the open "ocean" of three-dimensional space... Just control the choke points.
Londo could literally HAVE described 12 different "fronts," if we assume the Centauri have one major jump route into each of their neighbor's controlled areas. Then, of course, you have to take the system at the other side of the gate and hold it while traveling across system in real space to the next gate in the chain on the other side of the system.
Either way, "12 fronts" is a thematically appropriate line and an accurate representation of how that universe works.
It should be noted that after the first couple of episodes editing cheats for time, but jumpgates are always placed far away from other things. You're talking about a reactor powerful enough to rip holes between dimensions here (and hitting the backwash energy or edge of an opening jump point will absolutely destroy a ship as will being anywhere near an exploding gate), so Babylon 5's jump gate is quite far out from the station. In the pilot ships emerged BACKWARDS firing deceleration burns and it would take half an hour to slow down and approach. The backwards was dropped because network suits couldn't understand the damn concept and complained it looked funny. The passage of time is covered with a cut to an establishing shot.
Cuz, you know, B5 was largely thought out ahead of time, unlike most franchises. Classic Trek holds up better than most others (because the main designer was an aeronautics engineer with military experience), but... You never have to worry about fuel in Star Wars until Episode VIII when you have only 12 hours of fuel left, except for the shuttles that can cross the galaxy twice, but, when your ships run out of fuel and you have to ditch your cruisers and carriers and bail to a planet in shuttles and fighters Laura Dern can still jump the cruiser with no fuel into hyperspace in the middle of an enemy flotilla, which damages everything and is very pretty VFX but makes no sense at all and directly contradicts the last 90 minutes of story logic. Also Porgs. Fugging Porgs. Fugging Porgs made me say "Fug you, Chewie!" three times in that film, which is why I am no longer a Star Wars fan, and you never see my opinionated self comment on any Star Wars series, because who cares about that franchise anymore?
Yours,
IronMike
25-Nov-2022