Systems Network Architecture Switching Services (SNASwitch) may be unable to restart a control-point-to-control-point (CP-CP) session with its primary network node server (NNS) after a failover to the backup NNS.
This failure can only occur when:
The failure described in this field notice is due to an architectural limitation in Cisco IOS. The Bug ID listed above is for reference only. See the Workaround/Solution section below for details on how to avoid the failure condition.
The CP-CP session with the primary NNS fails to restart after a failover to the backup NNS. SNASwitch continues to use the backup NNS after the primary NNS is restored. The failure is indicated by an exception log entry in the pdlog output displayed by the show snasw pdlog EXEC command, as in the following example:
**** EVENT : Link station H#93 activated **** 00000120 - EXCEPTION 512:121 (0) **** Unable to start requested CP-CP sessions with adjacent node Port name = IP LS name = H#93 Adjacent CP name = EBD1.H#93 From ../dcl/ncsxidpi.c 319 :at 7:08:11, 14 October 03
This failure condition can also be verified using the show snasw link detail EXEC CLI command for the link to the primary NNS. The command output will show a value of No for CP-CP session support instead of its normal value of Yes .
When the failure condition occurs, the link to the primary NNS will be activated as a VRN link. Since VRN links do not support CP-CP sessions, the only way to restore the CP-CP session to the primary NNS is to issue a snasw stop EXEC CLI command for the link. This may disrupt any logical-unit-to-logical-unit (LU-LU) sessions currently using that link.
To avoid the failure condition, modify the IOS configuration to prevent SNASwitch from ever allowing a configured link to activate as a VRN link.
Note: Cisco has recently discovered a software problem (CSCsr48604) that may be exposed by this workaround. To avoid the failure condition and the software problem, upgrade to an IOS version with the fix for CSCsr48604 before configuring the workaround shown in the example below.
In the example below, the VRN has been moved to its own snasw port configuration command:
snasw cpname NETA.SNASW snasw port HPRIP hpr-ip Loopback0 <<< VRN removed snasw port HPRIP1 hpr-ip Loopback1 vnname NETA.VRN <<< New port with VRN snasw port DLSWLINK vdlc 802 mac 4000.7700.5555 snasw link HOST151 port HPRIP ip-dest 10.10.10.1 nns <<< Link uses non-VRN port snasw link HOST135 port HPRIP ip-dest 10.10.20.1 <<< Link uses non-VRN port
You must ensure that all APPN nodes specifying this VRN have IP connectivity to the new Loopback1 interface.
To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.
For More Information
If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:
Receive Email Notification For New Field Notices
Product Alert Tool - Set up a profile to receive email updates about reliability, safety, network security, and end-of-sale issues for the Cisco products you specify.