Cisco: How to configure simple IP SLA monitor

By On December 16, 2008 · 12 Comments

Before we begin let’s see what is this SLA term, for those of us who are not very familiar with the Service Provider terms. IP Service Level Agreements (SLAs) enable customers to assure new business-critical IP applications, as well as IP services that utilize data, voice, and video, in an IP network. With Cisco IOS IP SLAs, users can verify service guarantees, increase network reliability by validating network performance, pro actively identify network issues assure an easy way to deploy new IP services. Cisco IOS IP SLAs use active monitoring, enabling the measurement of network performance and health.

For the following how-to please have a quick look into the topology. As you can see I have a basic routing topology, imported from another tutorial from FirstDigest, and let’s assume that we want to monitor the line between R1 and TEST-RT. For this we will configure a very simple IP SLA monitor, based on icmp echo packets, which will measure our RTT (Round Trip Time) or latency and provide us with valuable informations. For example in case of VoIP problems we can check the latency and in case of a value bigger than 200 ms (220 ms maximum accepted for the voice service to function properly) we will know from where are the problems generated.  Of course IP SLA can have more complex configuration under Cisco IOS (e.g. http or ftp transfer to check if the service provider assure us the bandwidth specified in the contract).

One personal advice from my experience. Even if all the data and information provided by IOS IP SLA monitor can be checked with “show…” commands, I would advice you to get a third party software that can interpret this data for you and draw nice graphs or store them in an archive for you. This kind of software are MRTG, Weathermap, Nagios, RRDtool and others (I put here only the free ones).

Please check the how-to by clicking the image below:

IP SLA monitor

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  • Pingback: Cisco: How to configure simple IP SLA monitor « Binary Insanity

  • Tolga

    It would be great if you had put here the MIB OID’s to use in the management softwares you have mentioned (MRTG etc).

    I am still looking for the required OID # for “Number of failures” displayed with the “show ip sla monitor statistics”

    Br;

  • http://www.firstdigest.com Calin

    Hello Tolga!

    I’ll try to find this information for you ASAP and I’ll post it here and send you an e-mail. I think I have the OID somewhere in the documentation, but I’ll have to look for it.

    Cheers,
    Calin

  • http://www.firstdigest.com Calin

    Hello Tolga again!

    I don’t know if you will come back here to read the answer for your OID question but here it is. I could not find exactly the number of failures OID ( I don’t know if it exist…) but to help you somehow you can use two other objects to get your results in case of a failure:
    rttMonCtrlOperTimeoutOccurred (OID: 1.3.6.1.4.1.9.9.42.1.2.9.1.6)
    rttMonCtrlOperConnectionLostOccurred (OID: 1.3.6.1.4.1.9.9.42.1.2.9.1.5)
    More you can read here: http://tools.cisco.com/Support/SNMP/do/BrowseOID.do?local=en&translate=Translate&objectInput=1.3.6.1.4.1.9.9.42.1.2.9.1.5
    or you can see an example how to configure this here: http://blog.ioshints.info/2007/01/log-ip-sla-failures.html

    I hope I helped you somehow!

    Cheers!

  • Tolga

    Hi Calin;

    I am very pleased with your diligence efforts.

    I have tested the OID’s you have posted and it seems I can get the proper response for the rttMonCtrlOperTimeoutOccurred. However rttMonCtrlOperConnectionLostOccurred seems to return 2 (false) in all cases I have created in my test lab.
    Anyway thanks for everything.

    BR;

    Tolga

  • Mohammad khalil

    Hi
    i need help with something
    its regard to IP sla
    i configured IP sla on a router and i want to receive a mail when the RTT value exceeds specified threshold can this be done ??
    thanks in advance

  • http://www.firstdigest.com Calin

    Hello Mohammad Khalil,

    I did not tried yet this behavior, but I’ll check and return here with a response to you. Just let me some days, because I have a lot of work to do!

    Cheers,
    Calin

  • Pingback: Cisco: How-to get notifications for IP SLA monitor using EEM | FirstDigest

  • http://www.firstdigest.com Calin

    Hi Mohammad,

    As I promised I tried to find an answer to your question, and I came up with a new post. Please check it here:
    http://www.firstdigest.com/2009/02/cisco-how-to-get-notifications-for-ip-sla-monitor-using-eem/
    I hope you will be satisfied with my tutorial!

    Cheers,
    Calin

  • HAT

    Hello,

    How can you download IP SLA Monitor in Solarwind site? I got to the download page, but I couldn’t type phone number in phone box which is required to proceed with the download.

    Please help me download the software. The link is here: http://www.solarwinds.com/register/registration.aspx?Program=896&c=70150000000EQ0I

    Thanks

  • http://www.firstdigest.com Calin

    Hi HAT,

    I don’t know how you cannot type in the phone number…I had no problems with is as you can see in this photos. Maybe is your browser…I was using Firefox when I downloaded the software.
    Anyway in case that you cannot get it from their download page, you can have it here. I hope they don’t mind that I put it on my website as download.

    Good luck!

  • Aqdas

    hi,
    Had a question about MIB for ip sla. I have configured a test router with a bunch of ip sla’s. I was looking at the RTT-MON mib from Cisco and i’m compleletly confused. What will be the Basic MIB I will use for lets say icmp-echo, just to get the statistics off the router onto Orion. I know about the free monitor tool but it does  not have any advance options and the manager is not in the budget rite now.
     
    thanks.