I am attempting to backup NetWare 4.11.  We have a FDDI backbone to which the 
AIX ADSM server attaches directly.  NetWare boxes which use an Ethernet 
connection have no problem.  However, NetWare boxes with FDDI cards lose 
connection to the AIX ADSM server during a backup.  The interruption can last 
several minutes, after which another connection is usually established.  

This happens repeatedly during the incremental.  The ADSM error log on the NW 
server gives the following message, apparantly for each time the connection is 
lost:

12/01/1998 20:56:25 TcpFlush: Error 60     sending data on Tcp/Ip socket 8.
12/01/1998 20:56:25 sessSendVerb:     Error sending Verb, rc: -50
12/01/1998 20:56:25 TcpFlush: Error 32     sending data on Tcp/Ip socket 8.
12/01/1998 20:56:25 ANS1809E Session     is lost; initializing session     
reopen procedure.
12/01/1998 20:56:25 ANS1809E Session is lost; initializing session reopen 
procedure.
12/01/1998 20:56:40 ANS1810E ADSM session has been reestablished.

During the disconnection hiatus, you can't ping from either the NetWare client 
to the AIX server or from the AIX to the NetWare client it can't, but each can 
ping other addresses.

I have tried manipulating the TCPWINDOWSIZE, TCPBUFFSIZE, and LARGECOMMBUFFERS 
parameters to solve the problem, to no avail.

Anybody run into this problem before?  What do these error messages mean?