Resource Library

Multicast Sparse Mode and its derivatives are supported in the Nexus OS. This white paper explains how it has been implemented in the Nexus platform to provide optimum performance in both virtual PortChannel and FabricPath environments.

Cisco provides a wide array of connectivity and isolation tools within the datacenter. This white paper addresses Virtual Routing and Forwarding (VRF), which is a Layer 3 isolation mechanism for routing protocols.

Moving data from one networked device to another requires several different functions. Each function has its own protocol or protocols that define how it is accomplished. Also, the process of delivering data from one device to another can vary. The main factor in data delivery is determining whether the two devices are directly connected or remotely connected.

Moving data from one networked device to another requires several different functions. Each function has its own protocol or protocols that define how it is accomplished. Also, the process of delivering data from one device to another can vary. The main factor in data delivery is determining whether the two devices are directly connected or remotely connected.

The process of learning how to subnet IP addresses begins with understanding binary numbers and decimal conversions along with the basic structure of IPv4 addresses. This paper focuses on the mathematics of binary numbering and IP address structure.

While the Internet uses IP addresses assigned by an Internet authority such as the American Registry for Internet Numbers (ARIN), there are too few of these numbers to uniquely identify the millions of computers and computing devices in the world. Therefore, most enterprises use private addresses which allow them to identify the aforementioned computers. Of course, these IP numbers cannot be allowed on the Internet because all private networks use the same ones so there would be vast overlapping of addresses, and the addresses are not compliant anyway. Therefore, it is necessary to change the identity of a private host to a legal public host. This process is called Network Address Translation (NAT) and may be implemented on Cisco firewall products and Cisco routers. The firewall device(s) at the Internet demarcation point is by far the more popular way to implement NAT, but routers are used in small offices or small-to-medium-sized networks in which a separate firewalling solution is not possible or affordable. The focus of this paper is on the router-based NAT solution.

Cisco Access Control Lists (ACLs) are used in nearly all product lines for several purposes, including filtering packets (data traffic) as it crosses from an inbound port to an outbound port on a router or switch, defining classes of traffic, and restricting access to devices or services. Knowing how to design, configure, and troubleshoot ACLs is required for all network engineers working within a Cisco network.

In the spring of 2013, Cisco announced major updates to their Cisco Certified Network Associate (CCNA) curricula, including a new version of the CCNA Routing and Switching exam (200-120 CCNA). This paper provides a review of the CCNA Routing and Switching exam's critical concepts, as an aid to students preparing to pass the latest version of the CCNA Routing and Switching exam.

In this report, I've reviewed the 15 most popular certifications according to our more than 12,000 North American respondents to our annual IT Skills and Salary Survey. For each certification, you'll find a brief description, the average salary, and some insight into why it is popular.

You know you need to invest in training, but how do you get the best return on investment (ROI) from your training dollars? To help you make smart training decisions, we've put together this guide, which illustrates some alternative and little-known payment options, the types of discounts and promotions available with training and a suggested list of courses that give you excellent value.