9i shared servers (dispatcher) hung

People could not connect via shared server - hung. So tried stopping the dispatchers and restarting them. I did:
alter system shutdown immediate 'D000' ; alter system shutdown immediate 'D001' ;

In alert log I see the following.
idle dispatcher 'D000' terminated, pid = (13, 1)

I do not see d001 stopping. If do a lsnrctl services it still shows d001.

If do:
ALTER SYSTEM SET DISPATCHERS=''(address=(host=10.20.7.11)(proto =tcp))(dispatchers=2)'';

Then lsnrctl services shows d000, d001 and d002.

I ended up bouncing the database. I had to do a shutdown abort since shutdown immediate hung - probably due to dispatcher d001 getting stuck.  Any ideas on why a dispatcher would get stuck?      

Jeffrey Beckstrom
Database Administrator
Greater Cleveland Regional Transit Authority 1240 W. 6th Street
Cleveland, Ohio 44113

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