SDU setting being ignored?

From: Rich Jesse <>
Date: Wed, 28 Jan 2009 15:50:02 -0600 (CST)
Message-ID: <>

Hey all,

Yes, I'm traveling down the dark path of Oracle traffic over a WAN. Naturally, I want to test changing the SDU to optimize it. Client is 32-bit WinXP, server is AIX 5.3TL8 and both are using v10. Oracle.

To test, I added these entries to $OH/network/admin/listener.ora on the server:


  (SID_LIST = (SID_DESC = (SDU = 8192)(SID_NAME = mydb)))

I then started the MYDBWAN listener, so as not to affect connections to the default listener:

lsnrctl start mydbwan

On the client's %OH%\network\admin\tnsnames.ora, I added:


I enabled a net trace in the client's sqlnet.ora. When connecting to MYDBWAN from SQL*Plus, the trace has:

[28-JAN-2009 13:01:15:966] nsc2addr:

[28-JAN-2009 13:01:15:966] nttbnd2addr: entry
[28-JAN-2009 13:01:15:966] nttgetport: entry
[28-JAN-2009 13:01:15:966] nttgetport: port resolved to 1526
[28-JAN-2009 13:01:15:976] nsopen: lcl[0]=0xf4ffefff, lcl[1]=0x102000,
gbl[0]=0xfabf, gbl[1]=0x0, tdu=32767, sdu=2048

Still only 2048! I've tried changing "SERVICE_NAME" to "SID" in the tnsnames.ora, selecting different values for SDU on both client and server, and bouncing the listener in between each change. But I can't confirm that SQL*Net's using a non-default SDU value.

I've searched the Oracle Net Admin Guide, Metalink, and the List archives, but no luck. I think the last time I messed with this was in the Fatcity days...

Thoughts anyone?


Received on Wed Jan 28 2009 - 15:50:02 CST

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