Network SNMP Discovery

Vishal42 · ‎01-23-2023

Hello,

A Question from my Network Discovery issue. Let's say on an IP 10.0.0.1, I had a Cisco 2950 48P Switch configured. Now this is spare and I am configuring a new Cisco 9200 48 P with same IP and same name. Why discovery does not create a new CI and also doesn't updates the old one completely. I often see that , discovery updates the model ID of the older entry and does not creates a new entry for new serial Number. However , i see the new serial number created by discovery in the Serial Number table. So now both serial numbers are available in the Serial Number table and related to the same IP.

Daniel Needles1 · ‎01-23-2023

I ran into similar issues. ServiceNow OOB doesn't support Cisco HSRP or other high availability protocols very well where the name and IP are shared. That is because the Identification rules for Computers and Network Gear both inherit from Hardware (you can see this via CI Class Manager.) To fix this, we created an independent Identification Rules at the Network level that looks for 1) Serial Number and Serial Number Type on the Serial Number Table, 2) Serial Number on the Netgear Table, 3) Name and Serial Number on the Netgear Table and 4) MAC Address and Name on the Networks Adapter table. This effectively added "Serial Number" for the third Identification rule in Hardware and enabled ServiceNow to distinguish between the two HSRP enabled Netgear devices (aka routers, switches, and firewalls.)

View solution in original post

Daniel Needles1 · ‎01-25-2023

Depends on the vendor. If the switch stack reports via SNMP (or whatever protocol is used) a different serial number for each box, then Name + SerialNumber would create one entry per box. In our case that wasn't an issue for the Network team. Their big concern was the hot standby pairs where showing up as one device with unique interfaces "missing" depending on which of the two devices was discovered last. There might be a simple "Identification rule" to get around that, but it wasn't a use case that was a concern for us.

Jens Damhoej · ‎01-24-2023

You need to search for "overloaded CIs" because that is what you are experiencing.

You need to start with asset management (and before that model management) in order to get a correct CMDB.

Vishal42 · ‎01-25-2023

Hello @Jens Damhoej @Possible, because the discovery is not completely updating the old CI identifying it as existing on the basis of name. It just updates the model ID. I believe , checking if the team is using patterns will help solve that issue.