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Cisco IGX 8400 Series Switches

Field Notice: *Expired* FN - 27995 - Some Universal Router Modules (URMs) Were Shipped With Defective Bus B Circuitry


Revised April 25, 2008
January 12, 2004

NOTICE:

THIS FIELD NOTICE HAS BEEN EXPIRED AND IS NO LONGER MAINTAINED OR UPDATED BY CISCO.

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE, WARRANTY OR SUPPORT. USE OF THE INFORMATION ON THIS FIELD NOTICE OR MATERIALS LINKED FROM THIS FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.


Products Affected

Product

Top Assembly

Printed Circuit Assembly

Part Number

Rev.

Part Number

Rev.

IGX-URM

800-06260-07

A0 through C0

73-4411-07

A0 through C0

IGX-URM

800-06260-06

A0 through D0

73-4411-06

A0 through C0

  

Serial Numbers

Sequential #

Random #

From 305647 To 305675 From 376552 To 376556 From 376558 To 376560 From 376565 To 376566 From 380354 To 380357 From 407928 To 407973 From 412817 To 412865 From 439068 To 439107 From 442338 To 442387 From C17958 To C18033 From C20212 To C20261 From C20796 To C20843 From C21011 To C21069 From C36638 To C36677 From C53134 To C53180 From C95044 To C95063 From C95146 To C95164 From C95334 To C95353 From C95587 To C95603 From C95746 To C95765 From D01569 To D01616 From D28968 To D28972

305645, 373022, 376547, 380588, 381499, 391576, 405213, 407926, 433107, C32383, C32385,

  

Problem Description

IGX-URM may fail to pass traffic when operating on Bus B.

Background

The IGX8400 supports 4 cell buses for passing data. Most of the cards in the IGX8400 use Cell Bus 1, exclusively, for passing data. Some cards, such as the IGX-URM, IGX-UXM and IGX-UXME use additional cell lane buses two, three and four. In addition to Cell Buses one through four, there is a fifth cell bus, Cell Bus R, used for redundancy when Cell Bus one fails. Cell Buses two through four are not protected by Cell Bus R.

Besides the cell buses, the IGX8400 also has control and clock buses named A and B.

In this irregularity, the Universal Router Module (URM) connections fail when using Bus B. The loss of the B Bus control and clocking causes data to fail to pass to cell buses.

Problem Symptoms

This irregularity results in no traffic leaving the IGX-URM when using the B Bus on the IGX8400. In one instance, pings of 80 bytes or larger were failing.

If connections were added and operational when the IGX8400 was using the A Bus, no problem is detected and traffic from the URM to the rest of the IG8400 cards passes normally. If the IGX8400 subsequently switches to the B Bus, the URM traffic will cease to pass, resulting in loss of connectivity to remote resources, ping failures and session drop outs which cannot be re-established. The loss of connectivity is a silent failure; no alarms or traps are generated.

If connections are added to the IGX-URM while the IGX8400 is using the B Bus, the connections will add normally and appear in the dspcons screens with no failure indication. However, the connections will not pass traffic.

Workaround/Solution

Workaround: If possible, use Bus A. Use the dspbuses command to see if the A bus or B bus is active. If the B Bus is active, issue the cnfbus t command to toggle to the A bus. This workaround is effective until the defective IGX-URM can be replaced.

Solution: Verify that the affected card's serial number listed in this field notice. Request a return materials authorization (RMA) coded "ARFN" (Administrative Request - Field Notice) to replace the IGX-URM.

Verification: Not all the IGX-URMs listed in the serial number section will fail using Bus B.

  • Use the command dspbuses to verify which bus the IGX8400 is using. If it using Bus B, and the IGX-URM is passing traffic successfully, the IGX-URM is not at risk.

  • If the IGX8400 is using Bus A, set a maintenance period to test the Bus B functionality on the IGX-URM.

  • During the maintenance window, use the cnfbus t command to toggle to Bus B. Verify whether the connections using the IGX-URM are still passing traffic.

  • Depending on the application the IGX-URM is being used for, voice, ethernet or both, test by placing phone calls or by pinging remote devices. If the calls or pings pass,then the IGX-URM under test is not at fault. The ping packet size must be 80 bytes or larger.

  • At the end of the test, use the cnfbus t command to toggle back to Bus A if the Bus B test failed. If the Bus B test passed, it is not necessary to toggle back to Bus A.

  • If the IGX-URM failed to pass traffic while using Bus B, replace the IGX-URM using the RMA process.

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:

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