UDP is NOT the answer to increasing throughput.

We have ADSM V3 backing up NT, Unix, Novell, And VMS platforms. Our current 
throughout ranges from 1.9 Mb/sec to 150kb/sec. 
The network is not bottleneck. 
Parallel FTP stream testing slows our system is capable of 3 Mb/sec (5 parallel 
stream).
We are currently using IBM9672-R25, Interlink TCPAccess 4.1,  Interlink 3762 
FDDI controller, and 100 Mb lans to the client with a sustainable rate of about 
2.5 Mb/sec.
We are migrating to the IBM OSA adapter and have found a sustainable rate to be 
about 4.5 Mb/sec. Getting the throughput up requires multiple streams from 
mulitple clients. 
Tracing at the TCP/IP level shows the client is slower than the 9672 when the 
9672 is not under heavy load and database operations limit the real throughput.
ADSM in this shop appears to be CPU bound.
The traces also indicate the sliding window feature of TCP/IP is not being used 
by ADSM and is in use by FTP (FTP loads the communications systems much more 
than ADSM, ADSM loads the CPU/IO subsystem much more than FTP - as both should).

I need to find out how to get ADSM to be more efficent using the CPU 
(database/overhead stuff) so ADSM has the cycles to keep the communications 
pipe full. Both the client and server do not keep the communications pipe full 
even when the systems are under light load (40% cpu) and ADSM is setup with 
basically unlimited access to the system resourses. Yes, use of the 
communications pipe could be better, changing to UDP will ONLY increase the 
number of problems and decrease total throughput (unless the network is perfect 
(lossless)).
Any suggestions on improving the database throughput and increasing the 
efficency of ADSM are welcome.
thanks
Oscar 
Thiokol Inc.
schuloh AT thiokol DOT com


>>> Johann Zeiser <johann.zeiser AT BRZ.GV DOT AT> 12/04 6:51 AM >>>
Hi


>No,  We have no plans to extend our client/server socket drivers beyond
>TCP.
>   We depend on the reliable connection over TCP.

>   Watch this space for developments in ADSM MVS ESCON attach support
>    for SP2(AIX), NT and other platforms. >Thanks, Bob La Brie  ADSM
Development

And how can i get an ACCEPTABLE throughput, soon ??

Which developments ? Are there any developments ?


regards
johann Zeiser
email: johann.zeiser AT brz.gv DOT at 






>>Hi
>>(especially ADSM-Server(OS/390) Developers)

>>ADSM cannot use UDP (but only TCP). Will ADSM soon be able to use UDP?

>>Because for ADSM OS/390 Servers:
>>* CLIOS is no longer available (and could only be used on DIRECT
>>connected   nodes)
>>* MPC+ (Multi Path Channel) is IBM's new strategy
>>* MPC+ has an acceptable throuput only with UDP         (i heard)


>>Or how can i get an ACCEPTABLE throughput over my  EXISTING
>>ESCON's-(S/390 to SP/2-RS/6000) ?
>>(now i have a throughput of 2MB/sec with CLAW but it's a 17MB/sec ESCON
>>-> that's very poor
 >>(it's like: IBM sells a big truck, but you can only transport as much
>>as you can also with a simple car))

>>regards
>>Johann Zeiser
>>email: johann.zeiser AT brz.gv DOT at