cancel
Showing results for 
Search instead for 
Did you mean: 
cancel

NACK is present on the CyBus

1274
Views
0
Helpful
0
Comments

Core Issue

When the Versatile Interface Processor (VIP) tries to write to an invalid address in the packet memory (MEMD), the Route Switch Processor (RSP) places a Negative Acknowledgement (NACK) message on the CyBus for that slot. This is usually a software problem, but can also be a hardware problem. In this example, the VIP writes four bytes to an invalid address, so the RSP places a NACK on the CyBus for that slot:

%RSP-3-ERROR: CyBus0 error 10 
%RSP-3-ERROR: command/address mismatch
%RSP-3-ERROR: bus command write 4bytes (0xE)
%RSP-3-ERROR: address offset (bits 3:1) 0
%RSP-3-ERROR: virtual address (bits 23:17) 000000
%VIP2-1-MSG: slot5 Nevada Error Interrupt Register = 0x1
%VIP2-1-MSG: slot5 CYASIC Error Interrupt register 0x20000003
%VIP2-1-MSG: slot5 Missing ACK on CyBus access
%VIP2-1-MSG: slot5 NACK present on CyBus access

However, the RSP also places a NACK on a VIP for trying to write bad parity to the MEMD, as shown in this example:

CYASIC Error Interrupt register 0x1B 
Parity Error in data from Packet Bus
Parity Error internal to CYA
Missing ACK on CyBus access
NACK present on CyBus access

Resolution

To resolve this issue, perform these steps:

  1. Check the errors above the NACK for hardware related errors. If hardware related errors are absent, the error is likely software related.

    For more information, refer to the VIP Crashes Due to Software section of Troubleshooting Versatile Interface Processor (VIP) Crashes.

  2. If a parity error is indicated, and the card recovers, a primary cache or Processor Memory Parity Error (PMPE) may be a transient error. If this is the first instance of a PMPE, you can usually ignore it. However if the same VIP experiences a second, or subsequent PMPE, you should replace the VIP. Replacing the DRAM itself can also resolve the issue.
  3. When a NACK appears on all slots, as shown in this example, it is a hardware error. In this case, the arbiter is faulty and the card cage must be replaced:

    Jan 1 23:55:21: %FEIP2-1-MSG: slot0 Nevada Error Interrupt Register =0x1

    Jan 1 23:55:21: %FEIP2-1-MSG: slot0 CYASIC Error Interrupt register0x20000001

    Jan 1 23:55:21: %FEIP2-1-MSG: slot0 NACK present on CyBus access

    Jan 1 23:55:21: %FEIP2-1-MSG: slot0 CYASIC Other Interrupt register 0x0

    Jan 1 23:55:21: %FEIP2-1-MSG: slot0 CYBUS Error register 0x8001A00,

    PKTBus Error register 0x0

    Jan 1 23:55:21: %VIP2-1-MSG: slot2 Nevada Error Interrupt Register = 0x1

    Jan 1 23:55:21: %VIP2-1-MSG: slot2 CYASIC Error Interrupt register 0x20000001

    Jan 1 23:55:21: %VIP2-1-MSG: slot2 NACK present on CyBus access

    Jan 1 23:55:21: %VIP2-1-MSG: slot2 CYASIC Other Interrupt register 0x0

    Jan 1 23:55:21: %VIP2-1-MSG: slot2 CYBUS Error register 0x800006A,

    PKT Bus Error register 0x0

    Jan 1 23:55:21: %VIP2-1-MSG: slot5 Nevada Error Interrupt Register = 0x1

    Jan 1 23:55:21: %VIP2-1-MSG: slot5 CYASIC Error Interrupt register 0x20200001

    Jan 1 23:55:21: %VIP2-1-MSG: slot5 NACK present on CyBus access

    Jan 1 23:55:21: %VIP2-1-MSG: slot5 CYASIC Other Interrupt register 0x200000

    Jan 1 23:55:21: %VIP2-1-MSG: slot5 CYBUS Error register 0x800006C,

    PKT Bus Error register 0x0

When hardware replacement is indicated, choose from one of these options:

  • If you have a hardware support contract directly with Cisco for this part, use the Service Order Submit Tool to request a replacement part directly.
  • For warranty service, contact the Cisco Technical Assistance Center (TAC) directly at 1-800-553-2447,  or online by using the TAC Service Request Tool.
  • If your product is not covered by contract or warranty, contact your Cisco partner or reseller to request a replacement part for the hardware component that is causing the issue.
CreatePlease to create content
Content for Community-Ad
July's Community Spotlight Awards