Cisco Blogs

Cisco Blog > Perspectives

Where to learn ACI

I remember walking through Cisco Live last year in San Francisco and hearing all about ACI and the Cisco DevNet program. To be totally honest, I shrugged it off as just something that was trying to get hyped up and would not have any real impact on what I do.

Well…that has changed over the last year for me. What made it change? I guess a desire to learn and grow. I have also seen how learning to code is becoming very important to any IT position. There is a lot of power in the software layer and learning to harness that power is very important to be able to accomplish our jobs. So, with that in mind I have started to learn Python. Why python? I come from a scripting language background with my years as a Windows admin. I never jumped in with both feet, but I did enough to be dangerous. And learning to write code has always really interested me, I just didn’t have a good reason to do it. Now, with ACI and SDN showing promise and no longer buzz words to me I am going to dive in and learn. Read More »

Tags: , , , , ,

Importance of naming standards in Cisco Unified Communications Manager

In network engineering I have learned that the biggest lie I tell myself is that “I do not need to write this down.” That being said, when you are in the heat of troubleshooting a production issue I really try to design my systems so that I can tell what the heck something does by a label or good name. This does not replace the need for other documentation, but it does help when you are in the heat of troubleshooting a system problem. As I started supporting Unified Communications applications, I discovered there are lots of opportunities to really create a mess when you are configuring things if you do not keep supportability in mind. I want to share with you some tips that I have found helpful in naming objects specifically in Cisco Unified Communications Manager; however, similar concepts can be used for other network components such as Access Control Lists on traditional network equipment too.

When you are starting with a fresh Cisco Unified Communications Manager install, you have a blank slate. This is both good and bad. Good in that you have a lot of flexibility in the system to configure things, but bad because if you don’t put some thought into naming it can get confusing quickly. Spending some time up-front will save you some headaches down the road. Even if you don’t have a fresh Cisco Unified Communications Manager installation, you can start cleaning things up as you provision new services and go back and adapt what is in the other systems when you have time to do so.

Some of the common things you will configure in Cisco Unified Communications Manager will be: Partitions, Calling Search Spaces, Route Groups, Route Lists, Route Patterns, SIP Trunks, Device Pools, etc. First let’s get started with some basic definitions of what some of common objects are. I will also share some examples of how I like to name things to keep them easily sorted so objects of similar function are grouped together in a long list. These are just examples, and your naming convention will have to be something that works for you, your team and your specific environment. Read More »

Tags: , ,

A Tour of Cisco’s Allen Data Center

As a consultant I have seen many different ‘Data Centers’, from Co-location facilities, to in house and well thought out, to a dirty closet that no one was using. Douglas Alger gave us a tour of Cisco’s Data Center in Allen, TX about a month ago. I was expecting to be impressed and I was not disappointed. Cisco has made a commitment to all of their Data Centers at least Leeds Silver certified. The Data Center in Allen, TX is Leeds Gold certified. Also, Cisco tried to use as much off the shelf components as possible so that this model can be replicated to every Data Center.

Outside of the Data Center building

When driving up to the Data Center it was not the usual look of a Data Center. You really have to know where you are going to find it. The building is surrounded by berms 15-20 feet tall. This is doubles as a camouflage for the building, but it’s primary purpose is to deflect tornados from hitting the building directly. If a tornado is heading for the building, the base would have to climb the berms which in turn would cause the tornado to ‘jump’ over the building.

The roof of the Data Center has a high level of wind tolerance, but the building is constructed in several layers. A tornado could take off several of these layers and the Data Center could continue to operate.

There are the typical barriers expected in a secure facility such as fencing, vehicle barriers, cameras, and a bicycle rack. Yeah, a bicycle rack. Part of the Leeds certificate is the ability for alternate modes of transportation to the office. Installing a bicycle rack and shower inside was an easy way to get additional points for the Leeds certification. Read More »

Tags: , , ,

To flow or not to flow?

NetApp’s newest storage operating system, clustered Data ONTAP (cDOT), leverages a backend of Cisco Nexus switches for it’s cluster interconnect network.

When configuring the switch/cluster ports for use with cDOT, the best practice is to turn flow control off as per TR-4182. In fact, that happens to be the recommendation for normal data ports as well. Why is that? Before we get into that, let’s cover the basics…

What is flow control?

Flow control is a mechanism used to help manage the rate of data transfer between two devices. This is done to help prevent a source evice from overwhelming a destination device by sending more packets than the destination can handle. These scenarios can occur if a source device is faster than the destination device (CPU, RAM, NIC, etc). This can also happen if the source is intentionally trying to flood the destination via a malicious Denial of Service (DoS) attack.

Flow control can be enacted for send or receive packets, or both. It can be hardware or software based. It can occur at multiple layers of the OSI model

For a real world analogy to flow control, think of how dams work. A dam will be installed to control the flow of water on a river, usually to create lakes or reservoirs. Dams can be used to adjust the water flow to prevent flooding, depending on rainfall. Network flow control does pretty much the same thing – it prevents data floods. Read More »

Tags: , , , ,

So You Want to be a Network Engineer. Here’s Where You Should Start!

First lets talk about what a Network Engineer is. According to The Free On-line Dictionary of Computing. Retrieved April 27, 2015, from website a Network Engineer is:

“A high-level LAN /WAN technician who plans, implements and supports network solutions between multiple platforms. A network engineer installs and maintains local area network hardware and software, and troubleshoots network usage and computer peripherals.”

Network Engineers can wear many different hats. I believe the more “Traditional” Network Engineers mainly work on devices such as Routers, Switches, Firewalls, Wireless Access Points and Controllers, Load Balancers, Intrusion Detection and Prevention Systems as well as some server maintenance involving virtualization and network management software. Next we should discuss the overview of the differences between Network Engineering and Administration. Keep in mind I am just talking from an industry general view/standpoint. Some companies may not differ between the 2 titles. Engineers and Admins tend to share a lot of responsibility when it comes to maintaining and troubleshooting a network. The dividing line seems to be in the design/installation area with the bulk of this work generally being done by the more “experienced” engineers. Admins usually fall under the NOC (Network Operations Center) which in large companies/agencies is usually staffed 24x7x365. I have also seen the difference broken down into tiers when it comes to troubleshooting escalation. Network Admins usually fall in the Tier 1-2 range with Engineers being considered Tier 3. Read More »

Tags: , , , , ,