[j-nsp] IS-IS now also results in ES-IS adjacencies?

[Pekka Savola]

Hi,

It appears that sometime around 7.3 timeframe, the point-to-point 
links between routers with IS-IS also seemed to start bringing up 
ES-IS adjacencies as well (after IS-IS adjacency has been 
established).

What's the deal?  Why enable it by default on all existing IS-IS 
setups?  AFAICS, it's not useful between routers. Also, the docs seem 
to be a bit of two minds about the usefulness of ES-IS between 
routers:

"ES-IS must not be disabled."

"If ES-IS is explicitly configured and disabled, the interface does not 
send or receive ES-IS packets."

(i.e., if ES-IS must never, under any circumstance be disabled, why is 
there an option for disabling it?)

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings