DB name:ora11gr1
version:11.1.0
TNSLSNR for Linux: Version 11.1.0.6.0

listener status
  Instance "ora11gr1", status READY, has 1 handler(s) for this service...

DB name:ora10gr1
version:10.2.0.3

TNSPING STATUS to 11g database :
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.165.9.70)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = ora11gr1)))
OK (0 msec)

But when i tried to connect to 11g database, it gives error

[oracle@myser1 admin]$ sqlplus strmadmin/strmadmin@ora11gr1.world

SQL*Plus: Release 10.2.0.3.0 - Production on Sat May 16 00:24:34 2009

Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.

ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect
descriptor

ORA-12514: TNS:listener does not currently know of service requested in connect descriptor
 *Cause:  The listener received a request to establish a connection to a
 database or other service. The connect descriptor received by the listener
 specified a service name for a service (usually a database service)
 that either has not yet dynamically registered with the listener or has
 not been statically configured for the listener.  This may be a temporary
 condition such as after the listener has started, but before the database
 instance has registered with the listener.
 *Action:
  - Wait a moment and try to connect a second time.
  - Check which services are currently known by the listener by executing:
    lsnrctl services <listener name>
  - Check that the SERVICE_NAME parameter in the connect descriptor of the
    net service name used specifies a service known by the listener.
  - If an easy connect naming connect identifier was used, check that
    the service name specified is a service known by the listener.
  - Check for an event in the listener.log file.

11g side

LSNRCTL for Linux: Version 11.1.0.6.0

LSNRCTL> services
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=mysrv1)(PORT=1521)))
Services Summary...
Service "PRMRY" has 1 instance(s).
  Instance "ora11gr1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
Service "PRMRY_DGMGRL" has 1 instance(s).
  Instance "ora11gr1", status UNKNOWN, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0
         LOCAL SERVER
Service "PRMRY_XPT" has 1 instance(s).
  Instance "ora11gr1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
Service "ora11gr1XDB" has 1 instance(s).
  Instance "ora11gr1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "D000" established:0 refused:0 current:0 max:1022 state:ready
         DISPATCHER <machine: mysrv1, pid: 27460>
         (ADDRESS=(PROTOCOL=tcp)(HOST=localhost.localdomain)(PORT=47681))

The command completed successfully





TNS Entry, 10g side

ora11gr1.world=(DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.165.9.70)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = ora11gr1)))


[oracle@mysrv1 ~]$ sqlplus strmadmin/strmadmin@ora11gr1

SQL*Plus: Release 11.1.0.6.0 - Production on Sat May 16 00:56:57 2009

Copyright (c) 1982, 2007, Oracle.  All rights reserved.

ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified

#this is When i tnsping 

<msg time='2009-05-16T01:41:02.879+05:30' org_id='oracle' comp_id='tnslsnr'
 type='UNKNOWN' level='16' host_id='mysrv1'
 host_addr='127.0.0.1'>
 <txt>16-MAY-2009 01:41:02 * ping * 0
 </txt>
</msg>

#during  sqlplus strmadmin/strmadmin@ora11gr1.world

<msg time='2009-05-16T01:41:54.389+05:30' org_id='oracle' comp_id='tnslsnr'
 type='UNKNOWN' level='16' host_id='mysrv1'
 host_addr='127.0.0.1'>
 <txt>16-MAY-2009 01:41:54 * (CONNECT_DATA=(SERVICE_NAME=ora11gr1)(CID=(PROGRAM=sqlplus)(HOST=mysrv1)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=17494)) * establish * ora11gr1 * 12514
 </txt>
</msg>
<msg time='2009-05-16T01:41:54.389+05:30' org_id='oracle' comp_id='tnslsnr'
 type='UNKNOWN' level='16' host_id='myserv1'
 host_addr='127.0.0.1'>
 <txt>TNS-12514: TNS:listener does not currently know of service requested in connect descriptor
 </txt>
</msg>

Service "ora11gr1" has 1 instance(s).
  Instance "ora11gr1", status UNKNOWN, has 1 handler(s) for this service...