SNMP Trap retransmissions

[Ricky S]

Hi everyone,

I have been trying to configure my Cisco 1941 ISR to send traps to my NMS. There is a setting to configure timeout for TRAP message retransmissions but it doesn't state anywhere how many times a trap message is retransmitted. Does anyone know the default as to how many times a TRAP message is retransmitted for a particular event?

Please advise.

[Vasileios Bouloukos MSc, ITIL, CCIE · Accepted solution]

Hi Ricky,

The TRAP message is retranmitted when the Trap timeout expires. The default value is 30 sec.

Read the next link by cisco.com for additional details and config example

Before the Cisco IOS software tries to send a trap, it looks for a route to the destination address. If there is no known route, the trap is saved in a retransmission queue. Theserver trap-timeout command determines the number of seconds between retransmission attempts.

Examples

The following example sets an interval of 20 seconds to try resending trap messages on the retransmission queue:

snmp-server trap-timeout 20

http://www.cisco.com/en/US/docs/ios/12_1/configfun/command/reference/frd3001.html#wp1023262

Hope that helps!

Vasilis

[Ricky S]

Hi Vasilis, thanks for your reply and clearing it up for me. Cheers!

[Ricky S]

Hi Vasilis,

I ran a debug snmp packets and noticed the router continuously keeps transmitting a same trap over and over again even though I have a route and connectivity with the NMS.

I notice the same cellular trap goes out every few seconds. Any ideas?

[Vasileios Bouloukos MSc, ITIL, CCIE]

Hi Ricky,

it is very possible that this event is triggered again and again and so you have these traps every few seconds (there are not retransmission of the same event).

You can check the number of total outut snmp traps with the show snmp coomand.

If you do not need to send these traps you can remove these extra tabs

For example, issue these commands to make a Cisco IOS Software device report only configuration, Border Gateway Protocol (BGP)traps to Network Management System 10.10.10.10,:

snmp-server host 10.10.10.10 public config bgp 
snmp-server enable traps config 
snmp-server enable traps bgp 

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094a05.shtml

Hope that helps!

Vasilis