Managing Wireless Uploads on Returning Patrol Cars

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Introduction

In the quest for ever-increasing amounts of video evidence by law enforcement, the methods of moving that video from the point of capture to the department network becomes a larger and more difficult task. The transition from standard definition (480p) to high definition (720p) creates a 225% increase in file size. With in-car video systems, like WatchGuard Video’s 4RE, there are multiple video streams that further increase the amount of data that is acquired and subsequently moved.

Overview

MikroTik CAPsMAN is a managed wireless solution for large locations. This document describes the technical requirements for using MikroTik CAPsMAN in large deployment scenarios. Those scenarios are defined as departments that have 15 or more concurrent vehicle connections (i.e., 15 vehicles uploading at one time) and at least four access points. Maintaining a four-vehicles-per-access-point ratio is key to achieving optimum performance on wireless uploads.

The target audience for this document is WatchGuard customers that need more efficient management of their wireless uploads.

The objectives of this document are (1) to explain the benefits of a managed wireless solution and (2) to describe the requirements and configuration of the managed wireless solution.

Summary of Key Points

Here are several key messages addressed in this document.

  1. Authentication with the vehicle’s MikroTik Groove radio happens at the CAPsMAN router not the access point. This allows a vehicle driving through a parking lot to move seamlessly between access points.
  2. Commercially advertised wireless speeds are based on single devices and allow for “acceptable” data packet loss. We don’t allow for data loss, and we plan for multiple vehicles uploading at the same time. Therefore, speeds are slower than those advertised.
  3. Additional configuration time is required when compared to a basic access point installation.
  4. CAPsMAN is a MikroTik product and only works on MikroTik routers and access points.

Installation

Large locations usually have complex issues that smaller locations don’t have. This could be a parking structure or a limited-access area that requires a vehicle to pass multiple access points before parking. CAPsMAN addresses these by centrally managing all connections instead of the individual access points. This allows for load balancing and seamless handoffs between access points.

Installation requires the addition of a MikroTik router and a switch (to connect the router, server, and all access points) to isolate the wireless network from the agency network. The technician then configures the router and adds the access points to the system. Once the access points are online, they can be configured individually or as a group from CAPsMAN to optimize both the frequency and signal strength.

Benefits of a Managed Wireless Solution

With a properly configured managed wireless solution, an agency sees the following benefits:

  1. Quicker server connection and upload initiation when the vehicle passes multiple access points.
  2. Improved load balancing and load management per access point.
  3. Better analytics of network load, both per access point and combined.
  4. Centralized management of access points’ signal frequency and radio strength (instead of individual).

Potential Downsides of a Managed Wireless Solution

While there are many benefits, there are some downsides to this solution:

  1. Added cost of additional routers and switches to control the access points.
  2. Additional time to configure and document the wireless network properly.

Candidacy for a Managed Wireless Solution

Implementing a centralized wireless network is a complex setup and can take a full day to configure and tune properly. To determine if your agency is a good match, you need to understand the technical differences of how a managed solution works versus individual access points.

An agency is a good candidate if:

  1. There is enough system load to offset the cost and time needed to implement this solution. This is defined as 15 concurrent vehicles uploading across a minimum of four access points.
  2. The space that needs to be covered is either densely populated, a parking garage, or a scenario that requires a vehicle to drive past one or more access points to get to assigned parking.
  3. They are using MikroTik SXT access points exclusively for wireless uploading. MikroTik Grooves are strongly recommended in the cars.

An agency is not a good candidate if:

  1. If they connect the managed wireless solution into their existing internal network infrastructure. The managed solution must be completely isolated and directly connected into the non-routing network card on the server. This is required as the CAPsMAN router functions as a DHCP server on that network.
  2. If you are using non-MikroTik devices to connect to the wireless network (Ubiquiti, Cradlepoint, Sierra, etc.), extra consideration for configuration time might be needed. Additional vendor/IT support may be required.

Recommended Configuration

Requirements

  • MikroTik PowerBox Pro
  • Up to 32 MikroTik SXT access points per PowerBox Pro (minimum is four)
  • Layer 2 or 3 gigabit network switch with enough ports to connect all access points, PowerBox Pro, and server
    • PoE is preferred or you will need a power outlet for the PoE injector for each access point
  • Infrastructure planning (including):
    • Cabling (copper or fiber) from server room to access point locations
    • Installation: Department IT, outside vendor, or WatchGuard-supplied vendor
    • Environmental analysis of parking locations

Cost Analysis

Cost comparison using 10 access points, a single controller, and 24-port PoE switch to connect all devices. This does not include the time and cost to install and configure the equipment. If you do not have a dedicated Aruba or Cisco person, that service would have to be outsourced at a substantial cost per hour.

  Aruba Cisco MikroTik
Controller $1,570 $2,990 $250
10 Access Points $3,100 $8,440 $2,500
24-Port Gigabit Switch $1,407 $665 $450
       
Total Cost $6,077 $12,095 $3,200

Case Study 1

An agency had four Cisco access points that were not keeping up with the amount of video they were uploading. The customer performed USB transfers daily on several vehicles. This customer did not have analytics from this old system, but during analysis, WatchGuard rarely saw more than 70 to 75 Mbps coming into the server during a shift change.

After implementing a new wireless solution, the agency now has four access points configured with five more available for future expansion. Since implementation, they have not had to do a USB transfer due to upload speeds. We’ve seen numbers more than 150 Mbps into the server regularly with spikes over 200 Mbps during several shift changes.

The graphs below show the average throughput for different time increments. This is a screenshot from within the CAPsMAN software.

Case Study 2

An agency replaced 22 Cisco access points with eight MikroTik access points in a parking garage environment. After load balancing and performance tuning of the system, all vehicles are regularly uploading without any backlog.

Performance tuning for this environment included turning down the signal strength on the access points to significantly lower the noise floor that the wireless had to compete with. Frequency optimization per access point also played a large role in the performance tuning in this scenario as we could minimize the signal interference between access points. The initial surge on the 1 Day Average graph is the vehicles that had a backlog of events that needed to upload due to the previous system’s inefficiency. Several parking spots in the parking garage went from 5 to 8 Mbps upload speeds to 30 to 35 Mbps. This allowed those vehicles to get back on the road much faster after a shift change.

The graph below shows an initial surge after the transition to CAPsMAN and then a leveling off over time. This surge was caused by vehicles that previously had problems with uploading being able to transfer all events faster and eventually get caught up.

Questions?

Contact us to see if a managed wireless solution is right for you.