incoherence Interface OIDs

[jgervais00]

Hi

Currently, i'm working with 2 Cisco sb SG500X-48P switches stacking.

       Unit            SW version     Boot version    HW version
------------------- ------------------- ------------------- -------------------
         1               1.3.0.62            1.3.0.03               V02
         2               1.3.0.62            1.3.0.03               V02

I observe that the interface OIDs numbers are shifted (i used iReasining LIB Browser), the first interface  gi1/1/1 starts at 49 :

ifDescr.49	gigabitethernet1/1/1	OctetString	X.X.X.X:161
ifDescr.50	gigabitethernet1/1/2	OctetString	X.X.X.X:161
ifDescr.51	gigabitethernet1/1/3	OctetString	X.X.X.X:161
ifDescr.52	gigabitethernet1/1/4	OctetString	X.X.X.X:161

...

ifDescr.95	gigabitethernet1/1/47	OctetString	X.X.X.X:161
ifDescr.96	gigabitethernet1/1/48	OctetString	X.X.X.X:161
ifDescr.107	tengigabitethernet1/1/1	OctetString	X.X.X.X:161
ifDescr.108	tengigabitethernet1/1/2	OctetString	X.X.X.X:161
ifDescr.109	tengigabitethernet1/1/3	OctetString	X.X.X.X:161
ifDescr.110	tengigabitethernet1/1/4	OctetString	X.X.X.X:161
ifDescr.159	gigabitethernet2/1/1	OctetString	X.X.X.X:161
ifDescr.160	gigabitethernet2/1/2	OctetString	X.X.X.X:161

Do you know if it's a configuration problem or a error in the firmware ?

I don't have this problem with 3 cisco sb SGE2010 stacking.

Below, my snmp configuration :

snmp-server server
snmp-server engineID local xxxxxxxxxx
snmp-server location "xxx"
snmp-server contact "xxx"
no snmp-server trap authentication
snmp-server view myview system included
snmp-server filter dns dns included
snmp-server filter dot1dBridge dot1dBridge included
snmp-server filter entityMIB entityMIB included
snmp-server filter if interfaces included
snmp-server filter ifMIB ifMIB included
snmp-server filter interfaces interfaces included
snmp-server filter ip ip included
snmp-server filter lcpu ciscosb included
snmp-server filter lip local.4 included
snmp-server filter ltcp local.6 included
snmp-server filter mon rmon included
snmp-server filter poeMIB powerEthernetMIB included
snmp-server filter snmp snmp included
snmp-server filter sys system included
snmp-server filter tcp tcp included
snmp-server filter tracerouteMIB traceRouteMIB included
snmp-server filter trans transmission included
snmp-server filter udp udp included
snmp-server community xxxxxx rw view Default
snmp-server community xxxxxx ro X.X.X.X view Default
snmp-server host X.X.X.X traps version 2c xxxxxx 

Jeremy.

[Martin Ermel]

I am not sure if I really understand your issue ....
Are you wondering that the first interface does have an ifIndex of 49 (and not 1) ?
If you have 2 non-modular switches of the same hw-type and the same software, the ifIndex should be the same for identical physical interfaces on both devices. But the ifIndex (1.3.6.1.2.1.2.2.1.1) itself is nothing else than a numeration. The meaning of each ifIndex can be found by walking the ifTable (1.3.6.1.2.1.2.2.1).Per definition, it should start with "1" - but it needn't to.
Sometimes the vendors are using a schema like ifIndex 1- 48 for FastEthernet, 49-99 GigInterface, >100 TenGig (as a very simple example...)
The ifIndex can be reassigned with every reboot of a device and can be different from the last one. For non-modular switches this is (typically) not the case, but for modular switches this happens. Imaging a switch with modules in slot 1,2 and 4 and that gets a new module in slot 3 while it is running. After a reboot it is highly possible that the mapping of ifIndices to interface have changed.