Resource Library

This week we'll review the IPv4 Address Classes including subnet masks, examples of Class C, Class B, and Class A subnet masks, and planning IPv4 addresses.

The value of IT certifications has grown considerably over the last decade. Examine the evolution of certification trends, see the top-paying certifications and learn how decision-makers are struggling to hire certified employees.

In support of software-defined networking, Cisco has introduced several products to strengthen networks and meet the increased demand for flexible and cost-efficient solutions. The Cisco SDN solution in the data center is ACI. Outside the data center the primary Cisco solution is DNA.

Cisco IP phones support a variety of different audio codecs. In this post, I will explain some of the differences and explain which versions of CUCM and the Cisco IP phones support the various audio codecs. Audio codecs are responsible for sampling human speech (a s...

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).

While most organizations have not yet fully (or in many cases even partially) adopted cloud computing, the trend is growing in all but the smallest businesses.

Cisco Unified Communications Manager (CUCM) includes a feature called "call throttling" that denies new call attempts when the system is in a state that may lead to delayed dial tone. The Real Time Monitoring Tool (RTMT) will generate a code yellow alert when call t...

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.

This week’s post highlights some of the features and implementation specifics regarding the Datagram Transport Layer Service (DTLS) protocol used in Virtual Private Networks with the Cisco AnyConnect^® SSL client. I’ll provide some background as well as some screenshots and supported CLI commands.

Occasionally I am asked to configure the ability to block calls based on Caller ID. Prior to Cisco Unified Communications Manager (CUCM) v8, the only way to block these calls was to configure voice translation rules and profiles on the gateway receiving the calls. This has changed in CUCM v8 with the introduction of an additional parameter in translation patterns: Route Next Hop By Calling Party Number.