Resource Library

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:

Risk is something we deal with on a daily basis. Living in New Jersey and having the occasional storm, I’ve recently performed my own risk assessment determining the value of certain assets and activities and made a decision on what I was willing to spend to reduce risk to what I perceived as an acceptable level. My management of risk was a rather simple case. Sure, in my revised business continuity plan for my home, I’ll make sure that I have more D cell batteries, have my garage door adjusted so it opens manually again, more food I can heat on a stove and that doesn’t rely on refrigeration, and finally I’ll consider a whole house gas generator that uses natural gas, which has always been available to power critical systems like the sump pump in my basement. What if, however, I was a really large business? One with lots of components and interdependencies that require a tight integration in order to succeed? How and where can a large volume of information necessary to management, business continuity, and disaster recovery be correlated and communicated to those individuals who, because of their roles and responsibilities, need to make the critical decisions regarding the management of risk?

The STP (Spanning Tree Protocol) standard (IEEE 802.1d) was designed when the recovery after an outage could wait a minute or so and be acceptable performance. With Layer 3 switching in LANs, switching began to compete with routers running protocols because they are able to offer faster alternate paths. Rapid Spanning Tree Protocol (RSTP or IEEE 802.1w) brought the ability to take the twenty seconds of waiting for the Max Age counter plus fifteen seconds of Listening plus fifteen seconds of Learning or fifty seconds down to less than one second for point-to-point connected and edge switches and six seconds for root switches.

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.

This short example illustrates basic VLAN operation. Examining VLANs in a large-scale installation can show the full benefits of VLANs. Consider that this is a small portion of a large corporate headquarters with 5,000 devices connected in a 20 building campus.

Depending on the switch vendor, the exact steps will vary on how to set up and configure VLANs on a switch. For the network design shown, the general process for setting up VLANs on the switch is:

We already covered the first three of the twelve advantages of Agile software development. These three advantages focus on team development and refining the process. Advantage #4: Motivated Development Team The positive relationship with a reasonable and satisfied customer is only one of the reasons why many developers prefer to work on Agile projects. The other main contributor is that they tend to value working in self directed teams (which the Agile methods require for success).

Now that the network is installed, each switch has a bridge ID number, and the root switch has been elected, the next step is for each switch to perform a calculation to determine the best link to the root switch. Each switch will do this by comparing the path cost for each link based on the speed. For paths that go through one or more other switches, the link costs are added. The switch compares this aggregate value to the other link costs to determine the best path to the root switch.

There is a reason why the Agile methods are becoming mainstream. They can work! Although every Agile practice is not necessarily appropriate for every organization, each practice has delivered real value to many organizations, and some Agile practices can be used by anyone! This four part series explores twelve ways in which the Agile methods are valuable. I’ll bet that you will find more than a few that could be valuable for you!