Issue with dot1dTpDiscards (1.3.6.1.2.1.17.4.1.0)

[Michele Bergonzoni]

I'm trying to get dot1dTpDiscards via oid 1.3.6.1.2.1.17.4.1.0

With a lot of small switches, no problem (2960, 3560, etc) but with my 6500 I'm getting increasingly values (while via cli I see no problems):

# snmpget -c public@10 172.20.255.249 1.3.6.1.2.1.17.4.1.0
SNMPv2-SMI::mib-2.17.4.1.0 = Counter32: 271102731

# snmpget -c public@10 172.20.255.249 1.3.6.1.2.1.17.4.1.0
SNMPv2-SMI::mib-2.17.4.1.0 = Counter32: 271102733

172.20.255.249

#sh mac address-table count vla 10
MAC Entries for Vlan 10 :
Dynamic Address Count:                312
Static Address (User-defined) Count:  3
Total MAC Addresses In Use:           315
Total MAC Addresses Available:        98304

Any hint? :)

Thx,

Luca

[AFROJ AHMAD]

Hi Luca,

check the description of the OID:

Object	dot1dTpLearnedEntryDiscards
OID	1.3.6.1.2.1.17.4.1
Type	Counter
Permission	read-only
Status	mandatory
MIB	BRIDGE-MIB ;   -   View Supporting Images
Description	"The total number of Forwarding Database entries, which have been or would have been learned, but have been discarded due to a lack of space to store them in the Forwarding Database. If this counter is increasing, it indicates that the Forwarding Database is regularly becoming full (a condition which has unpleasant performance effects on the subnetwork). If this counter has a significant value but is not presently increasing, it indicates that the problem has been occurring but is not persistent."

Thanks-

Afroz

***Ratings Encourages Contributors ***

[Michele Bergonzoni]

It's always increasing ... but it's in some way false: via cli I see no problem as you can see above. There's a lot of space available ...

It seems a bug, in my opinion ... the strange fact is that I can see this behavior in more 6500 class with different hardware, IOS version and configuration.

[AFROJ AHMAD]

This could be a BUG ,I looked around but I couldn't find  the exact BUG for this issue.

Thanks-

Afroz