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Cisco Bug: CSCvi06412 - ASIC programming error among port-channel members leading to intermittent drops in VLAN 1

Last Modified

Aug 13, 2019

Products (1)

  • Cisco Unified Computing System

Known Affected Releases

3.1(2f)A

Description (partial)

Symptom:
A server part of UCS Mini in VLAN 1 is having intermittent access issues to only a few hosts in the same VLAN but works for others in the same VLAN

Conditions:
Problem happens when one or both of the backplane ports between the FI and the server's adapter are not programmed correctly for VLAN 1

To find this, use 'show hardware internal libsdk mtc vlan svi-bd-front-port valid-only' NX-OS command. Example:

Here, the focus is on Eth1/6 and Eth1/7
	- These are part of the same port-channel and allow VLAN 1
	- Eth1/6 is front port 9 and Eth1/7 is front port 10
	- Ethernet interface ID to front port ID mapping can be found from 'show hardware internal mtc-usd info driver-info' (NX-OS command)
	
UCS-A(nxos)# sh hard internal libsdk mtc vlan svi-bd-front-port valid-only
MAC SA index: router mac index 0-3
Egr Cbl Drop: 0: dont drop, 1:drop
QinQ type   : 0:no qtag, 1:one qtag; 2: two qtag
Customer ID : Qtag insert into packet

. .... .... . . . .... .. .... [[[[[[   F R O N T   P O R T   01-04   ]]]]]]
                               [[[[[[   F R O N T   P O R T   05-08   ]]]]]]
                               [[[[[[   F R O N T   P O R T   09-12   ]]]]]]
                               [[[[[[   . . . . . . . . . .   . . .   ]]]]]]
                               [[[[[[   F R O N T   P O R T   45-48   ]]]]]]
                               |N E       |N E       |N E       |N E       |
                               |A G     C |A G     C |A G     C |A G     C |
              M                |T R     U |T R     U |T R     U |T R     U |
              A                |    Q   S |    Q   S |    Q   S |    Q   S |
              C         F      |O C I   T |O C I   T |O C I   T |O C I   T |
            C   N       T      |U B N   O |U B N   O |U B N   O |U B N   O |
            E S O       A   T  |T L Q   M |T L Q   M |T L Q   M |T L Q   M |
              A         G  ME  |        E |        E |        E |        E |
            M   S          UN  |S D T   R |S D T   R |S D T   R |S D T   R |
V           O I T       M  LA  |I R Y     |I R Y     |I R Y     |I R Y     |
L ****      D D A FTAG  O  TNI |D O P   I |D O P   I |D O P   I |D O P   I |
D VLAN  BD  E X T BASE  D  ITD |E P E   D |E P E   D |E P E   D |E P E   D |
- ---- ---- - - - ---- -- ---- +- - - ----+- - - ----+- - - ----+- - - ----+
1    1    3 1 0 0 1023  0    0
                     PORT 01-04|0 0 0    1|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 05-08|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 09-12|0 0 1    1|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 13-16|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 17-20|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 21-24|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 25-28|0 1 0    1|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 29-32|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 33-36|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 37-40|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 41-44|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 45-48|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|

- The 2nd column indicates the VLAN ID					 
- Focusing on the following line from the above output:
					 
PORT 09-12|0 0 1    1|0 1 0 4095|0 1 0 4095|0 1 0 4095|
 
Port 9:  0 0 1    1		(correct programming)
Port 10: 0 1 0 4095		(wrong - we expect to see the VLAN value in the last column instead of 4095)


<< after recovering >>

UCS-A(nxos)# sh hard internal libsdk mtc vlan svi-bd-front-port valid-only
MAC SA index: router mac index 0-3
Egr Cbl Drop: 0: dont drop, 1:drop
QinQ type   : 0:no qtag, 1:one qtag; 2: two qtag
Customer ID : Qtag insert into packet

. .... .... . . . .... .. .... [[[[[[   F R O N T   P O R T   01-04   ]]]]]]
                               [[[[[[   F R O N T   P O R T   05-08   ]]]]]]
                               [[[[[[   F R O N T   P O R T   09-12   ]]]]]]
                               [[[[[[   . . . . . . . . . .   . . .   ]]]]]]
                               [[[[[[   F R O N T   P O R T   45-48   ]]]]]]
                               |N E       |N E       |N E       |N E       |
                               |A G     C |A G     C |A G     C |A G     C |
              M                |T R     U |T R     U |T R     U |T R     U |
              A                |    Q   S |    Q   S |    Q   S |    Q   S |
              C         F      |O C I   T |O C I   T |O C I   T |O C I   T |
            C   N       T      |U B N   O |U B N   O |U B N   O |U B N   O |
            E S O       A   T  |T L Q   M |T L Q   M |T L Q   M |T L Q   M |
              A         G  ME  |        E |        E |        E |        E |
            M   S          UN  |S D T   R |S D T   R |S D T   R |S D T   R |
V           O I T       M  LA  |I R Y     |I R Y     |I R Y     |I R Y     |
L ****      D D A FTAG  O  TNI |D O P   I |D O P   I |D O P   I |D O P   I |
D VLAN  BD  E X T BASE  D  ITD |E P E   D |E P E   D |E P E   D |E P E   D |
- ---- ---- - - - ---- -- ---- +- - - ----+- - - ----+- - - ----+- - - ----+
1    1    3 1 0 0 1023  0    0
                     PORT 01-04|0 0 0    1|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 05-08|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 09-12|0 0 1    1|0 0 1    1|0 1 0 4095|0 1 0 4095|
                     PORT 13-16|0 1 0 4095|0 1 0 4095|0 1 0    1|0 1 0    1|
                     PORT 17-20|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 21-24|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 25-28|0 1 0    1|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 29-32|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 33-36|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 37-40|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 41-44|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|
                     PORT 45-48|0 1 0 4095|0 1 0 4095|0 1 0 4095|0 1 0 4095|

Now both port 9 and 10 show '0 0 1    1'
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