Network Assessment…Why?

Get to know what’s beneath your network

By the time you finish reading this post, “Network Assessment…Why?”, you will have learned the physical and software requirements that allow for a successful analogy of your network. From learning peak time bandwidth used, devices attached to the network and switch configurations, optimizing your network security among other factors.

You, as a Network Admin, have the responsibility of testing any network device before putting it into production. The same is true for Network Assessments. They help understand how the data flows throughout your local network and for those with private WAN links, you can also find out speed and data throughput.

I had the opportunity to perform multiple Network Assessments AKA VRAs (VoIP Readiness Assessments.) to help find defective or misconfigured components in the customer’s LAN.

The following is a list of requirements and steps to help you perform the network analysis=

• 1.- What is it and what equipment is affected?
• 2.- Getting the site ready
• 3.- What to expect during and after the test

1.- What is it, and what equipment is affected?

You have to understand that there are different types of network tests performed by the Network Assessment. Here, I detail a few options available:

Data Throughput – The data traversing your network is known as throughput and bandwidth is the pipe that you lease/rent from your service provider. In order to analyze the datagrams, you have to conduct a Vulnerability Assessment (VA), utilizing a customer computer or software application that connects back to a Server, which analyzes the data collected by the endpoints.

The Network Assessment Vulnerability Test consist of Monitoring, Identifying, Assessing, Reporting, and finally Improve, by eliminating or fixing the known issues.

Devices in a network – You have to understand the network topology, including local and remote sites. Here, I walk you through identifying the most common elements responsible for handling your VoIP.

Network Maps – A network map displays all the main characteristics responsible for providing best QoS policies and network performance in a converged network. Starting with Nodes and Switches, IP Routing, Hardware Redundancy, Software Resiliency and Environmentals.

Nodes and Switches – Nodes can be physical or application-based phones as well as any CTI integration with your PBX. Switches are utilized on a packet-switched network helping convergence take place. The Software Version should be equal for all of these devices, equipped with the same service packs and updates.

IP Routing – It is utilized by networks to optimize the traffic flow avoiding undesirable routing loops and minimizing overhead in your network, most commonly used on a multi-location topology. Some of the components include L3 Routing Protocols such as OSPF, EGRP, VRRP, etc.

Hardware Redundancy and Software Resiliency – These are also responsible for processing voice over converged networks whenever they take over the call processing and routing functionalities. You have to assure that the same settings and software levels are the same.

Environmentals – For those rooms running a high or freezing temperature, or any other element that can disrupt the equipment’s performance.

2.- Getting the site ready

As mentioned above, all the devices need to be configured the same across the board. Besides, the equipment in the network, there are other elements that deserve to be mentioned.

Cabling Infrastructure –  Speed and bandwidth are responsible for delivering best performance and QoS. The cabling, as the devices in the network, should have the same capacities. That includes the Patch Panels for Copper and Fiber wiring.

Connectors – Jacks, RJ45 Modular Plugs following the TIA/EIA 568B standard. Others are also to be considered when performing a Network Assessment.

Switch Ports, VLANs, and QoS Settings – These characteristics are to be implemented the same in all systems. This includes Duplex settings, port speeds, VLAN IDs, and QoS Queue sizes and parameters.

DHCP Options – Assure that all devices are registering to the correct DHCP Server with the 802.1Q tags.

Avaya VoIP Considerations

Bandwidth/Codec Selection – Using G.711 CODEC type within the LAN, and G.729 for WAN configurations.

Shuffling / Hairpinning – These should be enabled utilizing direct media between IP Endpoints.

Silence Suppression – This feature needs to be disabled. It conserves bandwidth by not transmitting audio packets during periods of silence.

What to expect during and after the test

A Network Assessment test will simulate calls from one endpoint to another based on desired simultaneous call settings.

For example: For those customers expecting to have 40 calls at the same time, you would want to produce a test with 40 calls. The call amount setting should be easy to configured on your endpoints (Network Assessments Remotes)

Pros and Cons

Pros – Collect the necessary data to optimize those components needing tweaking. You also find those devices utilizing the most network resources.

Cons – By running the test on a production network, you might run into issues, such as bug-down the network, bring down an interface, etc.

As a good practice, you should consult with your customer before starting the test and make them aware and plan for the worse.

3.- Reviewing the Network Assessment Report

Once you have completed the test, you are focusing in the following key aspects=

Voice Jitter / Frame Slips Measurements – This factor is produced by the delay taken by the payload or audio stream when traversing from point A to point B delivering the packets out of sequence.  To remediate this problem, you might want to increase the queue size or Jitter buffer in all systems involved.

Toll quality is an average Jitter less than 20 ms.

Packet Network Delay –  It is measured by the MOS (Mean Opinion Score). The score here depends on the customer expectations. Avaya recommends the maximum network delay between two endpoints to be no greater than 180 ms.

Packet Loss – It is the loss of data between two endpoints. 3% may be acceptable.

 Have you had to fix issues related to QoS in order to optimize your customer’s VoIP Topology?

 

Resources

VoIP Performance Management and Optimization (Networking Technology: IP Communications)