Terry's Blog

Data Center Monitoring

2010-09-02T14:16:00Z

I've been doing Data Center (DC) design recently and the customers are interested in what to monitor and why it should be monitored. At first, a DC is just another set of edge devices, albeit servers, connected to a set of access switches. But the traffic patterns and usage in the DC is much different than at user edge ports. Historic traffic patterns were between clients and servers, often called 'north-south'. But with the distribution of applications between web front ends, middleware...(read more)

Top 7 Reasons for Network Automation

2010-08-25T19:44:00Z

I've written in this blog about various reasons for using network automation but it is time to put them together. Counting down… 7. Performance and SLAs The first thing that network management does is performance monitoring. It's conceptually easy, but surprisingly challenging, primarily due to differences in vendors, changes in standards (e.g., 32-bit vs 64-bit counters, different SNMP versions, and bugs in vendor implementations). Once those hurdles are past, the thousands of interfaces...(read more)

Device Naming Conventions

2010-08-09T16:01:00Z

Device naming standards are boring. Why should we even talk about them? When you're in the middle of a network melt-down and you are having problems remembering device names and IP addresses, it isn't boring; it's frustrating. But that's not the right time to be thinking about device naming standards. So let's discuss how device naming standards can help you. Michael Morris, who writes a blog for Network World described a device naming scheme in Naming Conventions . The CCIE Pursuit...(read more)

Automated IOS Updates

2010-08-03T14:30:00Z

You have a lot of switches and routers, more than you care to count. The IOS in each of them is now old and needs updating. You're not looking forward to handling each one with a manual process. What are your options? Well, if you did five of them a day, you could do 25 per week. Ten a day would double that volume. Garnering support from a couple of team mates could get you to 75 to 150 per week. Even still, doing the upgrades is a painful process. How do we make the task less painful? A good...(read more)

The Cost of Network Downtime

2010-07-28T13:13:00Z

I was doing some research on the costs and causes of network downtime and came across a more recent white paper than the information from 2001 that I had previously found. This paper, The Impact of Network Downtime on Business Today , was done in 2007 by Networks First, in conjunction with Warwick Business School. It shows statistics from nine different industries. The cost of an hour of downtime ranged from a low of a few thousand dollars (the study was in British Pounds, so I'm converting to...(read more)

HSRP Preempt Delay

2010-07-23T13:24:00Z

I learned something new at CiscoLive: hsrp preempt delay and why it should be used. In the Resilient Campus Design session, the presenter discussed factors and configurations that make a network more resilient. HSRP is often used in campus networks as a first hop redundancy protocol. If one router or interface of a pair that is servicing a subnet dies, then the backup device/interface takes over. The problem can arise when an HSRP master is rebooted, or the interface is restored after a failure....(read more)

Syslog, SNMP Traps, and UDP Packet Loss

2010-07-19T17:56:00Z

I was recently checking out a product that does syslog correlation and noticed that it had not reported a couple of events that I could see in syslog-ng's log. I use syslog-ng because it is free, easy to install and configure, performs filtering, and forwards to other destinations. I normally have it configured to log everything to the local filesystem and to filter and forward specific events to other systems. It provides a good de-coupling mechanism between the network devices that are sending...(read more)

CCIE Emeritus

2010-07-15T18:00:00Z

Cisco announced the CCIE Emeritus program on June 21, 2010. It is a program that has been requested and discussed a number of times at the CCIE NetVet luncheon/reception with John Chambers for several years. Many of the more senior members of the CCIE community have been moving into jobs that are less about hands-on network operations and more about project management, running companies, and designing networks. An active CCIE must recertify every two years by passing the CCIE qualification written...(read more)

CiscoLive2010

2010-07-12T13:57:00Z

CiscoLive 2010 is the premier event for anyone who uses Cisco products. There is a lot to see and people to talk with at this conference. There are Cisco staff who explain their offerings and future direction. And there are Cisco partners who are showing their products. The attendance this year was a record-breaking 12,500 onsite with another 10,500 virtual, for an attendance of 23,000. John Chambers gave his annual keynote presentation where he talks about what he said last year, what they have...(read more)

CCDE Written Qualification Exam

2010-07-07T19:30:00Z

CiscoLive offers me the chance to renew my CCIE every year by allowing attendees to take a free test. It is a great way to get a $350 rebate on the conference fee, available by entering a discount code from your CiscoLive registration. I always schedule my tests for Monday afternoon, the day that I typically arrive at CiscoLive. By taking the test soon after arrival, I can focus on studying and reading on the flight to the conference, find the testing center, take the test, and then enjoy the remainder...(read more)