Backup & Recovery :: Multiple Channels In RMAN?

I am working to configure on both the nodes of RAC server, but getting error invalid username and password even password is right.. And the remote_login_passwordfile is set to exclusive.

RMAN> run {
2> ALLOCATE CHANNEL ch1 DEVICE TYPE DISK CONNECT 'sys/sys@node1';
3> ALLOCATE CHANNEL ch2 DEVICE TYPE DISK CONNECT 'sys/sys@node2';
4> backup datafile 1;
5> }

using target database control file instead of recovery catalog
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-12001: could not open channel ch1
RMAN-10008: could not create channel context
RMAN-10003: unable to connect to target database
ORA-01017: invalid username/password; logon denied

and when trying to connect with sqlplus i'm getting below error

CCLCLMP1 /oravl01/oracle/11.1.0.7/network/admin > sqlplus sys/sys@node2 as sysdba

SQL*Plus: Release 11.1.0.7.0 - Production on Fri May 4 12:11:59 2012

Copyright (c) 1982, 2008, Oracle. All rights reserved.

ERROR:
ORA-24313: user already authenticated