[c-nsp] SRB1 BGP bug?

[Justin Shore]

I'm on the tail end of a maintenance window for our 7600s running SRB1. 
  The window required me to completely reboot both boxes to fix an IPSec 
SPA problem.  I started with the secondary 7600, killing off one OSPF 
connection to our old ISP core.  Then I killed off iBGP sessions one by 
one.  Finally I set the overload bit in IS-IS to make sure all the IS-IS 
neighbors ignored the routes from that box.  I then removed all the 
'crypto engine' config lines, wrote the config and reloaded.  The box 
came up ok.  I made all my crypto config changes, removed the overload 
bit from IS-IS, re-enabled all the iBGP peers and finally brought up the 
1 OSPF peer.  Everything worked fine; no problems so far.

I did the same thing to the primary 7600 next including shutting down 
each of the iBGP peers and writing the config (both important).  When I 
reloaded that 7600 I noticed that the load didn't drop as quickly as it 
should have when it came back up.  It usually takes 6.5 minutes to boot 
and another 3-5 minutes for the load drop to normal levels as it loads 
all the BGP routes.  Of course I had all BGP peers shutdown and our IGP 
takes only a few seconds to load; I should have had nominal load at 
6.5-7 minutes.  As it turns out the 7600 loaded up 4 of the 5 my iBGP 
peers *even though they were admin down in the config*.  It takes almost 
5 minutes for the BGP scanner and RIB update processes to settle down; 
that's why the load didn't drop when expected.  I verified that the all 
5 iBGP peers were shut in the config and that 4 of the peers were in 
fact up with prefixes received.

When I unshut all 5 iBGP peers each peer dropped with an:

BGP-5-ADJCHANGE: neighbor a.b.c.d Down Capability changed

and came back up 15-30 seconds later like normal.  Can anyone tell me 
why the 7600 would connect to 4 of my 5 normally-used BGP peers when 
they were admin down in the config?  I actually have 8 peers configured 
but 3 are legacy config that I haven't removed yet and are always admin 
down.  Perplexing.  Both 7600s have single Sup720-3BXLs and are running 
SRB1.

Thanks
  Justin