Cisco Tech Days – Don’t Miss Out

Want to get the inside scoop on network technology straight from the network experts? Cisco is hosting its Tech Days series throughout the month of May and into June in several cities throughout the country. I’ve attended the sessions in the past and found them to be very useful. Viewing demos, hearing about product roadmaps and features from the horse’s mouth is very helpful.


The hot topics this year include borderless networking, virtualization and collaboration technologies. Find out how the newest innovations can help you develop strategies and deploy solutions to make your network more efficient and effective.

Get the full details here for all the locations and dates. If you’ll be attending the event on May 26th in McLean, VA or the June 9th event in San Francisco, CA let me know. It would be great to meet up and discuss some of these latest networking trends.

Routers in Space…Extending the Internet into the Universe???

Managing a network on Earth is no easy feat. How about in space? This may sound far fetched, but the concept may be becoming a reality. Internet technology is now being made available from a space-based platform.


Cisco is testing an IP router aboard a satellite in Earth orbit (22,300 miles above the Earth). The aim is to extend IP access to places that aren’t served by traditional phone and wireless networks.


As part of its Internet Routing in Space (IRIS) program, Cisco is testing the router to demonstrate to the Department of Defense (DoD) that the technology can be used to enhance military communications.


Here is a picture of the Intelsat 14 satellite with reflectors deployed for testing. Check out more pictures here.

According to Cisco, IRIS shifts much more of the intelligence to the orbiting router – with potentially dramatic benefits. The long-term goal is to route voice, data and video traffic between satellites over a single IP network in ways that are more efficient, flexible and cost effective than is possible over today's fragmented satellite communications networks.


After testing is completed in April, the IRIS project will be switched over for commercial use.

This is a very interesting development from my perspective. My company has been helping the government manage LAN, WAN, satellite and a range of networks for some time. Perhaps its time to take it to the next level….

A Tip for Managing Wired Networks

Earlier in the week, I posted three tips for managing wireless networks. Thought I would also share a tip for managing wired networks to round things out for the week. Here is a response to a question I often get from customers.

How can I tell when a Cisco device configuration has been altered or accessed?
You can be notified of any configuration changes or attempts by enabling the CiscoConfigManEvent trap. This feature sends you a trap whenever a user exits the configuration session. Simply point the trap to your network management system to see when somebody accesses a Cisco configuration session.

For dopplerVUE Users
You can forward traps as an email for 24x7 instant access to changes on network devices. To read more about this trap and how to configure it, please reference the following Cisco article.

Five Ways to Get IT Training Cost-Effectively

In these tough economic times, keeping up-to-date and sharp with the latest high-tech skills can be very beneficial for the health of your career. Here are five creative ways to get training cost-effectively according to Network World.

1. Share the cost with your employer
One option is to offer to split the cost of training with your employer. It would cost the company more to bring in a new person than to train you in the skills they need. The solution serves both parties well.

2. Train yourself
You can gain a wealth of knowledge from self-study from online courses, books, videos and webcasts. Another resource for IT pros looking to learn is CBT Nuggets, which offers fee-based and free training products online.

3. Build your own learning environment
Building a home lab can help progress your career and be done cost-effectively (in some cases). Finding used parts and complimentary software can help with Microsoft and Cisco self-training. Check Microsoft for free trials of their products online and open source tools. Two open source projects worth reviewing include Dynamips, for simulating Cisco networks, and Olive for simulating Juniper networks.

4. Practice your skills
Use your knowledge and skills to help friends, family, charities or small businesses at low or no-cost to gain valuable experience. The effort can pay dividends on your resume and help you learn about new technologies without investing in training. This can also serve as the start of your own business.

5. Look for training discounts
Many training vendors are offering significant discounts because of the recession. It may be worth the time to do a little research to find some cost-effective training. Many vendors offer educational content at events and online as part of their marketing efforts. Keep an eye out for specific opportunities at your favorite vendors’ websites and for upcoming low cost or complimentary technology tradeshows.

Getting A Handle On Dropped Packets – 4 Key Troubleshooting Tips

In today’s net-centric environment, organizations often depend on the network for voice over IP, video conferencing and webcasts. Network problems caused by packet loss can create noticeable performance issues.

Is packet loss a problem your organization is experiencing? Could it be contributing to larger problems? One thing’s for sure, almost every network experiences packet loss to one degree or another. Dropped packets can originate in almost any part of the network path, from bad cables to flakey applications. Here are a few common causes and what you can do to fix them:

1 . Find the source. First, understand where the packet loss is occurring. The command line tracer tool helps determine the exact location. Then, learn the extent of the problem by using the “Netstat –s –p tcp” command. This will display the total segments sent and total segments retransmitted. (Check out this site for more information on how to use command line tools)

2. It's probably the cables. More often than not, it’s this simple. Check that nothing has been placed on top of the cable and that the connections are tight. Test by replacing the potentially bad cable with a known good one. Frequently, very long cables will only show excessive problems when they are processing a heavy load.

3. Check for duplex mismatches. Many systems auto negotiate the duplex speed, however errors do occur. Consider manually setting it to a known level and see if the problem goes away.

4. Unleash the routers! If your routers are overwhelmed, they will drop packets. Check for excessive utilization across each link and make sure the system overall is not saturated. Not all routers drop packets at the same traffic level. Some Cisco routers can begin dropping packets at a CPU load of 50%; on other models this may not occur until 95% or more.

Tip for dopplerVUE users: The Locator view lets you sort all interfaces by packet loss so you can isolate the location of dropped packets instantly.

Network Troubleshooting: IP SLA+ WMI = Better Web Services

Why is the network so slow? I’m sure you’ve never heard this complaint before :) Diagnosing the problem isn’t always easy with so many possible culprits. You can start by running down the network troubleshooting checklist:
The DNS service?
The web server?
The WAN link?

IP SLA and WMI information is critical to diagnosing potential network problems. For most Cisco devices, IP SLA can give you performance information for the connectivity layers of a net-centric service like a web application or VoIP. In Microsoft environments, WMI can do the same for the application/server/desktop layer. Combining WMI with IP SLA provides performance information about both layers and gives an end-to-end view of your web application or other net-centered service to most efficiently troubleshoot any issues.

Using IP SLA to Access the User Experience
IP SLA (Internet Protocol Service Level Agreements) is embedded in the Cisco IOS (Internet Operating System) for most Cisco routers and switches. IP SLA operations can measure delay (round trip time), jitter, packet loss, connectivity, voice quality scores, and many other key metrics for monitoring and troubleshooting network elements.

Additionally, threshold levels can be set for most metrics. When a metric crosses a threshold level, IP SLA sends an SNMP trap to the specified IP addresses.

You can configure an IP SLA HTTP operation to monitor the overall user experience for the “connectivity layer” of a web application (or any other net-centered application such as email, VoIP or videoconferencing). This operation uses a synthetic web transaction to measure the total round trip time (RTT) to perform a DNS query, establish a TCP connection to the HTTP service, and retrieve the web site’s home page. By configuring the HTTP operation on the LAN switch closest to users, the total RTT (or latency) is an accurate measure of the users’ experience (as opposed to measuring RTT from a central network management server).

Next, configure an IP SLA ICMP Echo operation to monitor RTT between the switch on the user LAN and the switch to which the web server is connected. This way, if the HTTP operation indicates the web transaction is slow or unresponsive, you can check the WAN RTT between the switches to see whether the problem is related to the WAN link or something on the web server.

Watching the Applications and Servers: Adding WMI
WMI (Windows Management Instrumentation) is an instrumentation tool similar to IP SLA that Microsoft has created for its products. WMI provides thousands of performance metrics for applications such as MS Exchange and MS SQL Server, as well as for server hardware and operating system components.

Microsoft has a built-in performance administration tool for monitoring WMI data for applications and servers. Using the tool you can view each server’s CPU utilization, physical memory and free disk space. Each of these sub systems is critical to the server’s performance regardless of the application running. Lack of memory, CPU cycles and low disk space are common causes of slowdowns on a server. You’ll have to go into each server to view the individual performance counters or you can use network management software to simplify the process by collecting any of the thousands of available WMI counters from across multiple servers.

Getting the End-To-End View
An end-to-end view of the network will really help you troubleshoot network problems much faster and avoid the common complaints you often hear. To get an end-to-end view consider network management software such as dopplerVUE that integrates fault and performance data from a variety of sources, including SNMP, syslog, WMI and IP SLA, you can integrate metrics from both layers of a web service into a single end-to-end dashboard view. Using dopplerVUE’s drag-and-drop interface, you can quickly create an integrated view of both layers of the service without having to shift between tools or viewers (screenshot below).

Implementing a Bandwidth Monitoring Program: Getting Started

Nearly every network engineer I work with is either looking for a way to monitor their bandwidth or ways to improve how they monitor their bandwidth usage. So, popularity wins out this week and the next couple of posts will be a series on implementing bandwidth monitoring.

Why monitor bandwidth usage?
We each have our reasons, here are some of mine:

1. When the network slows, lots of people call and complain, and I don’t like that

2. Need to have data supporting when an upgrade to the T1 line is necessary and validation that we are getting the service we have paid for

3. Helps to understand what servers are being used heavily and when the load should be split into multiple servers

4. Lets me identify high bandwidth consumers and adjust the network topology keeping the key users close to their end systems

5. Allows me to locate end users who are downloading high volumes of data and request they stop during sensitive times (executive webcasts etc…)

Getting started: SNMP enable your network
To effectively monitor bandwidth usage it requires that you have a method of accessing the bandwidth consumption statistics for each device. SNMP is the industry standard and works with all major brands of networking devices, server and workstation operating systems. It uses a software agent installed on each device and a collector type system to aggregate and report the data. With SNMP you will be able to collect bandwidth data such as utilization % for each interface, total packets, discards and more. Here is a screenshot of a typical interface display for an SNMP enabled device:



















To retrieve this information on a device, you will need to set a community string (aka password) that your monitoring system will use when retrieving the bandwidth statistics. At the bottom of this article are the steps to enable SNMP on Windows and Cisco devices.

For more overview information check out these website links:
http://www.dopplervue.com/bandwidth.php and the tutorial at http://www.dopplervue.com/tutorials_show.php?what=Managing_Bandwidth.

The next blog post will discuss monitoring systems that can gather this data, what to do with the information, alerts and rules that can be set and common reports that you will want to use for bandwidth monitoring.

Enabling SNMP on a Windows System

Windows 2003 and XP
1. In the Control Panel, click Add Remove Programs.
2. In the left pane, click Add/Remove Windows Components.
3. Select the Management and Monitoring Tools checkbox and click Details.
4. Select the Simple Network Management Protocol checkbox, click OK, and then click Next.
5. If prompted, insert the Windows 2003 or XP disc to finish the setup.

Windows Vista
1.In the Control Panel, click Programs and Features.
2. In the left pane, click Turn Windows features on or off.
3. Select the SNMP Feature checkbox and and click OK.

On a Windows system, you must configure security for the SNMP service by adding a community name(s) and permissions to a list of communities that can send it SNMP requests. This is known as a "community string":
1. In the Control Panel, click Administrative Tools, and then click Services.
2. Right-click the SNMP Service, click Properties, and then select the Security tab.
3. In the Accepted Community Names pane, click Add.
4. You may accept the default community rights, and then enter a community name (case sensitive). Click Add.
5. Select Accept SNMP packets from any host, and then click OK.
This ensures all SNMP packets from all SNMP hosts belonging to any community listed in Accepted community names are processed. No SNMP packets are rejected on the basis of the host name or IP address of the source host or the list of acceptable hosts.
6. Ensure the SNMP Service is selected and click Restart the Service to initiate the changes.

Enabling SNMP on Cisco Devices
Log in to the router and enter configuration mode: Router#configure terminal

1. Enable SNMP on the router (note that "public" and "private" are for example purposes):
Router(config)#snmp-server community public RO
Router(config)#snmp-server community private RW
Router(config)#exit