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Every second of every day, data is being sent and received. Billions of data packets are processed by your company’s network every day. In fact, you received dozens of packets just to read this article, but the vast majority of us have no idea how this works. People have no clue as to what goes on behind the scenes to ensure data actually gets to the right device.
Data center return on investment – which is measured by time to cost savings, time to revenue, time to break even, etc. – has proven more elusive than expected. But that doesn’t mean it isn’t attainable. To understand the genesis of the bad and ugly parts of data center ROI, we need to recognize the good parts and appreciate why so many companies are putting their faith in new and unfamiliar technologies.
In 2013, Cisco released their Software Defined Networking (SDN) solution for the data center known as Cisco Application Centric Infrastructure (ACI). For many years, the networking industry has been asking for an approach to configuring networking devices more efficiently than having to individually configure each and every router and switch.
Cisco Internetwork Operating System (IOS) has been around since a little after the inception of Cisco Systems as a company. In 1984, Len and Sandy Bosack from Stanford University founded Cisco Systems with a small commercial gateway server. The first Cisco router that I touched was an Advanced Gateway Server (AGS), which was the first marketed product of the company. After this came the Mid-Range Gateway Server (MGS), the Compact Gateway Server (CGS) and later the Integrated Gateway Server (IGS) and AGS+. The first version of IOS that I touched was 8.2(7). The operating system was based on a Unix-based system and was designed as a monolithic operating system, meaning that processes are stacked and interrelated.
Accessing cloud-based resources, whether they be IaaS/PaaS/SaaS-based, is very convenient. With a browser and Internet connection, you are up and running. No driving to your work office, no need to log into the corporate network. Just open up your web browser and go. This convenience, however, comes with a security risk. All of your business work is conducted over an insecure communication network. Unlike your office network, where the network link between you and the data center is under corporate control and is physically secure, the cloud access link is over the Internet.
That depends on their configurations. For example: While it makes very good sense to include redundant physical links in a network, connecting switches in loops, without taking the appropriate measures, will cause havoc on a network. Without the correct measures, a switch floods broadcast frames out all of its ports, causing serious problems for the network devices. The main problem is a broadcast storm where broadcast frames are flooded through every switch until all available bandwidth is used and all network devices have more inbound frames than they can process.
As we discussed previously, Cisco created the Nexus Operating System (NX-OS) to power its next-generation data-center switching platform. While this new OS shares many similarities to the original IOS, there are some definite differences that you need to be aware of as you begin using it.
The biggest difference between Ethernet II and 802.3 is the fields of their Ethernet headers. Ethernet II is much more popular - find out why in this post.
“Twisted Pair” is another way to identify a network cabling solution that’s also called Unshielded Twisted Pair (UTP) and was invented by Alexander Graham Bell in 1881. Indoor business telephone applications use them in 25-pair bundles. In homes, they were down to four wires, but in networking we use them in 8-wire cables. By twisting the pairs at different rates (twists per foot), cable manufacturers can reduce the electromagnetic pulses coming from the cable while improving the cable’s ability to reject common electronic noise from the environment.
Anyone who’s managed switches over the years knows that the Spanning-tree protocol (STP) is both the best and worst thing to ever happen to the data center at layer 2 of the OSI model. On the plus side, the Spanning-tree protocol is what first allowed us to create redundant paths within our switching infrastructure, making our data center much more resilient to outages than ever before. Anyone who’s experienced a “broadcast storm” knows the full value of Spanning-tree in the traditional switching environment. We’ve also seen many improvements in Spanning-tree over the years to make it work faster and more efficiently (i.e. Rapid Spanning-tree, Bridge Assurance, and many others).