Recently Mark Leary, wrote a blog about the “Top Ten IOS Services You Should Be Using Now!” In the blog he talks about some of the key high-value IOS services that can go unnoticed and unused by network operators.

Plixer International can help you put a number of these services to work for you by providing the best network analysis and reporting tools available on the market today.

We have talked for a long time about the benefits of using Cisco IPSLA as a proactive method of reliably measuring network performance. Raul Duran wrote a series of blogs talking about the use of IPSLA operations, and believes that IPSLA should be a part of every Network Administrator’s toolbox. Using our SNMP Performance and Trending tool, data can be retrieved and trended, enabling users to graph performance over time.

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Cisco IOS IP Service Level Agreements (SLAs) help network administrators ensure that a high level of voice and data communication quality is maintained. Cisco IP SLA operations are a proactive method of reliably measuring network performance. IP SLA data can be retrieved and trended with an SNMP Performance trender to enable users to graph performance over time. Cisco IP SLA and SNMP should be in the tool belt of every network administrator. Pair these technologies with a NetFlow analyzer and you’ve got a great setup to help troubleshoot most network problems.

The purpose of this blog is to outline some of the IP SLA configuration changes in newer versions of Cisco’s IOS.

We’ve written a 4-part blog in the past that focuses on the following IP SLA operations:

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As most of you know, IP SLA and Cisco NetFlow are both free features on your Cisco routers. If you are looking to somehow get a higher level status report on both, here is an idea.  Why not put both in your maps.

Notice that there are two links between devices that refresh every few minutes. One link represents utilization from NetFlow and the other link represents the MOS (Mean Option Score) on the link which is helpful with VoIP traffic monitoring. The second link can be based on any SNMP value (errors, latency, jitter, etc.) and is done using the Denika plugin.

This feature is 100% web based to configure and view in our Application Performance Dashboard ‘MyView’ and can be a nice addition to your network traffic monitoring needs. Within the maps, you can click on the links to bring up a trend of the interface. This is especially useful when the link changes color based on utilization and you want to drill in for details.

Call us if you need help setting this up.

Cisco IP SLA is useful in so many ways, it’s not even funny.  There is no doubt that IP SLA can be useful for long term performance trends and in documenting how well, or how bad your network is behaving.

Cisco IP SLA is a lot more than just a monitor for ping, jitter, and packet loss over TCP and UDP.  There are so many great tools to use, it’s amazing!  Using IP SLA, we can retrieve measurement metrics like round-trip time, packet loss, network jitter, and connectivity.

Current monitor types for IP SLA include jitter, FTP, DNS, DHCP, DLSW, ICMP, UDP, TCP, HTTP, and LDP.  Cisco also has a few more types in the pipe.  Soon we’ll see H.323, SIP, RTP, RADIUS and video.

I’m sure we can all agree that a key for successful troubleshooting is using the right tools for the job.  The job being to detect the problem as quickly and as efficiently as possible right? Right…  We don’t have all day to sit and stare at a screen to catch a blip, and this is where the value of setting up IP SLA thresholds and notifications comes in.

IP SLAs can generate SNMP traps upon the violation of a threshold.  Because these are traps, we’re going to need to import MIBs to the log manager so that it can decode the OIDs properly.  You will want to download the CISCO-SYSLOG-MIB, and the CISCO-RTTMON-MIB.

We can generate events for each violation, whether they be consecutive violations, X of Y violations (to generate a trap), or averaged violations.

If the situation deems necessary, we can configure an IP SLA monitor to activate a second IP SLA operation to gather additional data.  IP SLA reaction configurations are done using the ”ip sla monitor reaction-configuration” command via the terminal console.( or ip sla reaction-configuration for those of you whose IOS doesn’t like the word “monitor”).

To tie it all together, using router thresholds and notifications can be a useful tool in troubleshooting a large variety of the “hard to track problems.”  Using thresholds and notifications benefit us in troubleshooting problems that happen intermittently, or at odd times.  For detailed instructions on how to set these up, Cisco has a white paper on the exact commands to use.  Check it out: IP SLAs –Proactive Thresholding Monitoring.

Also check out the 4 part blog on Cisco IP SLA Configuration.

Do like the Shat… Use Cisco IP SLA.

Raul J Duran

Hello Everyone,

If you would like to see other blogs on how to setup IP SLAs check out these links.
IP SLA – Jitter – 1 of 4
IP SLA – ICMP Echo – 2 of 4
IP SLA – TCP Connect – 3 of 4

We’ve arrived at the fourth and final part of this series.  In this blog, we’re talking about the Cisco HTTP IP SLA operation and some ways that it can be useful.

The HTTP IP SLA operation is a very useful tool in the verification of performance of Web servers, Proxy servers, or any other HTTP server.

There are 3 measurements that will provide a total round trip time measurement for the HTTP operation:

• DNS lookup:  How much time it takes to complete a domain name lookup.
• TCP Connect:  How much time it takes to complete a TCP connection to the HTTP server.
• HTTP transaction time:  How long it took to send a request and get a response from the HTTP server.

A good use for this monitor is to confirm that performance stays within the acceptable limits of an SLA and also to gauge your user’s perceptions as to how fast the connection is.   
The HTTP IP SLA operation can also be used to monitor proxy servers.  One is example is with a VRRP deployment where there is an HTTP proxy server involved.  If the HTTP IP SLA operation reports a failed connection to the proxy server, a failover process can be initiated automatically so that a secondary router continues to forward all HTTP requests to the proxy server. 

The DNS lookup time is an important factor to a good overall user experience. 

“How MySpace is hurting your network”, a Networkworld.com article,  explains how social networking sites like MySpace and Facebook  may exponentially increase the number of DNS lookups, impacting the performance of your network.  You may want to check out your netflow analyzer to see whether too many users are checking out these sites.

Cisco IP SLAs can make a huge difference in how well network administrators can increase efficiency of their network.  Pair Cisco IP SLAs with Netflow, good SNMP and Netflow Analyzing applications and you’ll have a winning combination of tools to make sure your network is well tuned.

Thanks for reading this series, good luck and have fun setting up the IP SLAs!

Sincerely,
Raul Duran

Hello Everyone,

If you would like to see other blogs on how to setup IP SLAs check out these links.

IP SLA – Jitter – 1 of 4
IP SLA – ICMP Echo – 2 of 4
IP SLA – HTTP – 4 of 4

This week we are focusing on the Cisco IP SLA TCP Connect operation.  One can consider this to be a ping over TCP.  The TCP Connect operation can be useful in several ways.  Administrators can set it up to baseline existing performance, and also to monitor changes in performance due to configuration changes. 

Some companies use this monitor for their own verification of outsourced service provider SLAs.  This information can then be used to negotiate more cost effective SLAs with their service providers.

The TCP Connect operation is also a great alternative to measure response times when ICMP ping is blocked.

If you would like detailed instructions on setting up the Cisco TCP Connect IP SLA operation, check out our white paper on how to set it up.

Check out the next and final part of the series – HTTP IP SLAs.

Raul

Hello Everyone,

If you would like to see other blogs on how to setup IP SLAs check out these links.

IP SLA – Jitter – 1 of 4
IP SLA – TCP Connect – 3 of 4
IP SLA – HTTP – 4 of 4

In my first blog, we covered the Cisco Jitter IP SLA Operation and how to set it up.  This week the focus will be on the ICMP Echo Operation. 

The ICMP Echo IP SLA Operation measures end-to-end response time between a Cisco router and any device with an IP Address. The response time is computed by measuring the time taken between sending an ICMP Echo request and receiving an Echo reply.

The ICMP Echo operation can be useful in several ways.  Administrators can set it up to baseline existing performance, and also to monitor changes in performance due to configuration changes. 

This operation is easy to set up, and the information made available makes this a great tool for any administrator. 

Check out our whitepaper for detailed instructions on how to set it up.

Check out Part 3 of the series focusing on TCP Connect IP SLA.

Raul

Hello Everyone,

If you would like to see other blogs on how to setup IP SLAs check out these links.

IP SLA  – ICMP Echo – 2 of 4
IP SLA – TCP Connect – 3 of 4
IP SLA - HTTP - 4 of 4 

I’m going to be putting together a four part series on some common Cisco IP SLA monitor configurations.  Cisco IP SLAs are great ways to get statistics on different types of communications between routers.  They’re relatively simple to set up, and reports can be generated by an SNMP trender.

focus on the Jitter monitor.  You can get a ton of information from the Jitter monitor, starting with latency, Packet Loss, and Jitter.  If the router’s clocks are synchronized you can also get the latencies for each way.  By adding a VoIP codec to the monitor, the router can generate the Mean Opinion Score (MOS), and the Impairment/calculated planning impairment factor (ICPIF) score.

Check out Plixer’s white paper on setting up the Jitter operation.  It will walk you through setting up a Jitter monitor, how to trend the statistics, and generate reports.

If you plan on using the jitter operation to monitor VoIP, pay special attention to make sure that you are using the codec that matches the actual codec being used.

It is also important to have realistic expectations on MOS values pertaining to each codec.  Although Cisco’s scale is 1-5 in their documentation, production environments will not see a 5.  The chart below will help in determining how well your communications are doing.

Cisco VoIP Codec White Paper

Scrutinizer Netflow Analyzer has a My View page that contains gadgets that can integrate with third party applications.  One of these applications is Denika which can trend the IP SLA statistics.  If you have Scrutinizer and Denika ask us about a custom VoIP gadget to display VoIP IP SLA Statistics.

Check out Part 2 of the IP SLA series.

Raul