Network SNMP Discovery

[Vishal42]

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. 

[SiD2]

Hi @Vishal42 

@Daniel Needles1 replied here [the post that has an attachment] in this thread with some suggestion to customize the identifiers and seems that suits you, try see if that might work.

[Daniel Needles1]

Per my other response, if you are OOB, you are inheriting the Hardware IRE Identification Rules and matching by Name.  Our work around was to duplicate the rules at the Network Gear level and add Serial Number to the Name (300) match.  That will allow ServiceNow to deal with Cisco HSRP and other hot standby approaches where the IP Address and Name are shared between two routers, switches, or firewalls.  

[Vishal42]

Hello @Daniel Needles1  I believe
1. For every new Hardware ,using the IRE you gave , possibly every new serial number should get added in CMDB using 300 priority as it will check for Name + Serial Number.

2, Priority currently is to improve the discovery coverage because , another device configured on the same IP and name is getting identified as existing but it does not updates all of the info and just model ID. If it updates everything - my old serial number is lost in CMDB.
If it updates only model ID then , it is misleading because New Model ID is not related to the older serial number. 

Hope discovery patterns help on this.

[Daniel Needles1 · Accepted solution]

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.)

[Vishal42]

Hello @Daniel Needles1 Thank you for your solution. Does this also add the new CI in CI Name + Serial Number format where there is a stack of switch? 
Also , if there is a stack of 4 switch , is it ok if one gets actively discovered and rest 3 are not OR all the switches in the stack should show as Most recent discovered on the any same date.