Cisco IGX 8400 Series Switches

December 28, 1998

Products Affected

Problem Description

D-Channel Compression connection bandwidth cannot be configured to less than 100%. This feature is implemented by adding a connection on a UVM Model D as type "td" (Transparent D-channel), which can be altered from the default of 100%. At 100% utilization, the "td" connection produces a load of 381 packets per second. Configuring the channel utilization to less than 100% does not alter the load for the "td" connection as expected.

Problem Symptoms

Perform the following steps to observe the symptoms:

1. addcon slot.port.chan farendnode slot.port.chan td

2. cnfchutl slot.port.chan 100

3. vt farendnode

4. cnfchutl slot.port.chan 100

5. dcct slot.port.chan (service or higher login)

6. The following screen appears:

   nodename     TN    Service         IGX 8420  9.1.03   Dec. 19 1998 20:46 GMT
   
   Slot: 9   Chan: 5                LCON# 9  &3186D17E        VC# 9  &319376AC
   
   Alloc     : 1   Bundled   : 0    MS Cmax,SM: 0,0     mir  : 0,0
   Exists    : 1   Never rtd : 0    COS       : 0       peak : 0,0
   Master    : 1   No DC fnd : 0    Hops      : 1       Cmax : 0,0
   Local     : 0   Failed    : 0    Src dc    : 10      %Utl : 0,0
   Pref only : 0   Down,pend : 0,0  Snk dc    : 10      FSTsts    : 0
   No rt fnd : 0   Cur route : CUR  Frst Pt,oe: 3,3     Route wait: 1138820
   Path fail : 0   BW needed : No   Bndl Sz,oe: 0,0     Cdt reason: None
   Derouted  : 0   baddr type: 0    Group num : 0       MS PLU,SM : 381,381
   RrtReq L,G: 0,0 acc dev vx: 0    VC count  : 1       MS CLU,SM : 381,381
   Route cdt : 0   Max cost  : 100  VC index  : 9       Line rstr : NONE
                                                        RR Group #: 0
   Path:  2/1 8                                         Prev LCON : 65535
   Pref:  0                                             Next LCON : 2
   

   Note the red underlined text showing the packet load units (PLUs) and cell load units (CLUs). The values should show "381,381" for CLU and PLU value for both the Master-to-Slave (MS) and Slave-to-Master (SM) directions.

7. cnfchutl slot.port.chan 50

8. bye

9. cnfchutl slot.port.chan 50

10. dcct slot.port.chan

11. The PLU and CLU values are changed to "191,191". If the values are still "381, 381", the problem per bug id CSCdk64543 is being exhibited.

    nodename     TN    Service         IGX 8420  9.1.03   Dec. 19 1998 20:46 GMT
    
    Slot: 9   Chan: 5                LCON# 9  &3186D17E        VC# 9  &319376AC
    
    Alloc     : 1   Bundled   : 0    MS Cmax,SM: 0,0     mir  : 0,0
    Exists    : 1   Never rtd : 0    COS       : 0       peak : 0,0
    Master    : 1   No DC fnd : 0    Hops      : 1       Cmax : 0,0
    Local     : 0   Failed    : 0    Src dc    : 10      %Utl : 0,0
    Pref only : 0   Down,pend : 0,0  Snk dc    : 10      FSTsts    : 0
    No rt fnd : 0   Cur route : CUR  Frst Pt,oe: 3,3     Route wait: 1138820
    Path fail : 0   BW needed : No   Bndl Sz,oe: 0,0     Cdt reason: None
    Derouted  : 0   baddr type: 0    Group num : 0       MS PLU,SM : 191,191
    RrtReq L,G: 0,0 acc dev vx: 0    VC count  : 1       MS CLU,SM : 191,191
    Route cdt : 0   Max cost  : 100  VC index  : 9       Line rstr : NONE
                                                         RR Group #: 0
    Path:  2/1 8                                         Prev LCON : 65535
    Pref:  0                                             Next LCON : 2
    

Background

Connections on the UVM can be assigned less load by reducing the utilization. The less load a channel uses, the more connections can be routed over fixed bandwidth resources. Utilization can be altered on a channel-by-channel basis by using the cnfchutl command.

Workaround/Solution

There is no workaround.

Since this problem is exhibited in 9.1.06 software and earlier 9.1 versions, upgrade the software to the latest 9.1 release. Release 9.1.07 and later releases contain the fix for this issue.

DDTS

To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.

View CSCdk64543 (registered customers only)

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:

• Open a service request on Cisco.com
• By email
• By telephone

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