Bulk Device Configuration with Ansible

Like most computer systems, network devices like routers and switches can also be managed through Ansible. Ansible has a modular design that enables it to deal with a large variety of devices. It already ships with a number of modules, and in cases where no specific module is available users can still leverage general usage modules like RAW, SHELL or COMMAND.

Every action executed by Ansible modules must be previously defined in “playbooks”. Actions defined in a playbook will be executed through SSH, dispensing any additional piece of software on client side such as a software agent.

The use of SSH makes Ansible compatible with a larger range of devices and its adoption way simpler.

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Adding a Netflow Listener to Cacti

This article explains how to add new Netflow listeners to Cacti. By default, Cacti is not able to show Netflow reports. So, to follow the steps in this article, the Flowview plugin have to be installed on Cacti.

1. Configure Cacti server to receive and store the netflow files adding the lines shown below, one line for each router:

vi /etc/flow-tools/flow-capture.conf

-V 5 -w /var/flow/ABC-Router -n 275 -N 3 -E500M 0/0/3001
-V 5 -w /var/flow/DEF-Router -n 275 -N 3 -E500M 0/0/3002
-V 5 -w /var/flow/GHI-Router -n 275 -N 3 -E500M 0/0/3003
-V 5 -w /var/flow/JKL-Router -n 275 -N 3 -E500M 0/0/3004
-V 5 -w /var/flow/MNO-Router -n 275 -N 3 -E500M 0/0/3005
-V 5 -w /var/flow/PQR-Router -n 275 -N 3 -E500M 0/0/3006
-V 5 -w /var/flow/STU-Router -n 275 -N 3 -E500M 0/0/3007
-V 5 -w /var/flow/VWX-Router -n 275 -N 3 -E500M 0/0/3008
-V 5 -w /var/flow/XYZ-Router -n 275 -N 3 -E500M 0/0/3009

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Traffic Classification and Marking on Cisco IOS

In this article I will show how to mark IP packets to prioritize multimedia and critical applications following a QoS policy that will be later enforced inside the ISP cloud.

1. The QoS service offered by the ISP allows for control of how traffic is prioritized and bandwidth is reserved, with three queues available as shown in the figure below.

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