SNMP OID changeover on virtual interface

[MartinZapa]

Dear forum,
I have weighty problem with monitoring virtual interfaces on cisco ATM boxes and IP routers. For example interface ATM1/0.50 has had this value: IF-MIB::ifDescr.27 = STRING: ATM1/0.50-atm subif. After incident on line (DOWN/UP) is value changed to: IF-MIB::ifDescr.22 = STRING: ATM1/0.50-atm subif. So if I have in zabbix Item OID field IF-MIB::ifOperStatus.27 is it serious problem. Similar problem is coming up on IP router when I add or remove virtual interface. Interface string is also changed. Please is some solution of this problem? For example item definition by interface name?
Thank you verry much for any solution.

Best regards,
Martin

[Alexei]

This is not currently supported by ZABBIX. Major SNMP related improvements are expected in 1.6.

[elmerfud]

I've encountered this problem as well. It's nice to hear that we can expect some improvements with SNMP. Hopefully a method of dealing with migrating OID indexes will be on of them.

In the interim for my needs I've managed to kludge together some PHP that understands how to remap the OID indexes based on ifDescr text. The way I handle it is likely overkill for most situations, but the script knows about the host, items, triggers, etc... So with a click I can scan the device for index changes and dump out an XML file to import in to Zabbix which updates the needed values.

It's all very alpha right now, but the basic idea is to not only solve the moving index issues, but also to allow our OSS to enable/disable monitoring on interfaces with minimal intervention.

[Markus]

Some network devices provide a feature called "ifIndex persistence". The following link describes this for Cisco's IOS: http://www.cisco.com/warp/public/477...rsistence.html

What's equally annoying is that in many devices the ifIndex numbering is calculated through some formula involving slot/module/interfaces numbers and not by increasing numbers. This makes it very difficult to have generic templates for routers and switches.

Example for Alcatel SR 7750:


.2.1 = STRING: "system, Loopback IP interface"
.2.2 = STRING: "i1/1/1, IP interface"
.2.3 = STRING: "i1/1/2, IP interface"
.2.4 = STRING: "i1/1/10.1, IP interface"
.2.18907136 = STRING: "1/1/1, 1-Gig Ethernet SFP"
.2.18939904 = STRING: "1/1/2, 1-Gig Ethernet SFP"
...
.2.100696064 = STRING: "A/1, 10/100 Ethernet TX"
.2.117473280 = STRING: "B/1, 10/100 Ethernet TX"

Markus