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One of the many useful features of tunneling is to carry non-IP traffic across an IP network, and this is still the case when dealing with IPv6 traffic. This transition mechanism makes use of a configured tunnel to transport IPv6 over a native IPv4 network, which may consist of two sites or more. Unlike the previous transition mechanisms, tunneling is not monolithic; while the basic principles may be similar, the operations are different. The following chart gives a breakdown of the current, major tunneling types in use, particularly in a Cisco environment:
In a recent post, I gave an overall description of a service portfolio and the key components of a portfolio. Here, I will describe how a cloud services provider might implement an ITIL service portfolio. A cloud services provider will regularly have a set of services under development, a set of service in live operation, and a set of services that are retired.
ITIL describes a service portfolio as a collection of the overall set of services managed by a service provider. A service portfolio describes a service provider’s boundaries and promises across all of the customers and market spaces it serves. I like to think of a service portfolio as describing the past, present, and future collection of services offered by a service provider. The figure below shows a high-level view of a service portfolio.
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.
As mentioned in last week’s post, interviews that require ITIL Intermediate level knowledge will most likely be targeted to specific process areas and activities. If I interviewed someone for a job that required ITIL Intermediate level knowledge, in addition to other questions about the specific technical responsibilities of the job, I might ask the following questions:
“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.
Global Knowledge practice director for cloud solutions, Hank Marquis, explains the people, process, and technology aspects of cloud computing.
Here are some secrets, tips, and tricks for virtualizing your datacenter. We want to introduce some best practices for virtualization, while not being too biased towards one virtualization vendor or another. We'll use some common examples of products and tools that work with VMware's vSphere and Microsoft's Hyper-V, but with an eye toward virtualization in general, and not the specifics of any of the capable platforms that could be used). We will assume, however, that bare metal hypervisors, in other words virtualization platforms where the hyper visor is the OS, will be used as opposed to running a hypervisor on top of an existing general-purpose operating system (which is great in a lab, but terrible for data center projects).
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).