Cisco SG500X how to change port assigned VLAN via SNMP

[Matima-serv]

Hello,

I want to change the VLAN assigned to a port on a SG500X using SNMP. The running firmware version is 1.4.9.4 .

What I have done so far:

- definded some VLANs with the web interface
- enabled SNMP and configured communitiy and password for SNMPv2c and configured engine-ID and security name for SNMPv3
- tried SNMPv2c and SNMPv3 requests (get, set, walk) fom the Windows 10 command line tool with the shell tools from snmpsoft.com
- followed the instructions on this thread for vlan snmp management on a catalyst

- worked through the documentation

When I send a snmpwalk request for the "ifDescr" OID (.1.3.6.1.2.1.2.2.1.2) to get the ifIndex referring to the Ports, the first shown ifIndex is 49 for gigabitethernet1/1/1. This works with SNMPv2c and SNMPv3 as well.

All gigabitethernet ports were assigned to a vlan by the web interface and is shown there correctly. When I send a snmpget request with the "vmVlan" OID with the ifIndex of any port (for example port 15 --> ifIndex63: .1.3.6.1.4.1.9.9.68.1.2.2.1.2.63 ) I just get:
- with SNMPv2c:
  %Failed to get value of SNMP variable. Variable does not exist (noSuchName(2))
- with SNMPv3:
  OID=.1.3.6.1.4.1.9.9.68.1.2.2.1.2.63
  Type=<Unknown>
  Value=

Same with snmpset and SNMPv2c, but with SNMPv3 I get:
%Failed to set value to SNMP variable. Not Writable (notWritable(17))

I dont know where else to find a solution for this problem and moreover what exactly the problem is.
May it because not Catalyst systems use another OID?
And shouldnt I get an ifIndex starting from Zero or one from the snmpwalk request?

Hope anyone can help.
Big thanks in advance.

[mipopov]

Hello Matima,

Happy New 2019 Year!

You are correct - Catalysts use different OIDs.

The MIB files for Sx500 switches are here:

https://software.cisco.com/download/home/284099570/type/283415684/release/1.4.1?i=!pp

Hope it helps

Cheers, 

Mike

[Matima-serv]

Hello Mike,

Thank you for your prompt reply!

In the MIB files you linked, I unfortunately found no way to connect a port/interface of the switch with an existing VLAN or rather change a VLAN of a port.

I just found an OID where the individual Indexes (mapped to the ports) return the Indexes of the assigned VLANs.
It is
<.iso.org.dod.internet.mgmt.mib-2.dot1dBridge.qBridgeMIB.qBridgeMIBObjects.dot1qVlan.dot1qPortVlanTable.dot1qPortVlanEntry.dot1qPvid>
or as a number  .1.3.6.1.2.1.17.7.1.4.5.1.1

This one is "readable and writable" so I simply tried to SNMPwrite another (existing) VLAN-Index to

.1.3.6.1.2.1.17.7.1.4.5.1.1.50 for example, which is gigabitethernet1/1/2.
As type of the value I used uint (original value given from SNMPread is GAUGE32 )
The apperaring error message is:
%Failed to set value to SNMP variable. General Error (genErr(5))

If I try to set the VLAN in the SNMPwrite command to the one the port actually has, the CLI shows:
OK

At least something must be right I guess?!?

So further on my question persitsts.
Any more ideas?

Thanks,
Matima