Planning for GMS

Planning for GMS. 1

Equipment. 1

Tablets. 1

Laptops. 2

WiFi Access Points. 3

Staffing. 4

Venue WiFi infrastructure. 4

General Network Requirements. 4

Additional Requirements for the Cloud Mode 5

Additional Requirements for the Local Mode 5

Adopting GMS involves some planning and investment before the start of the season.   WiFi access should be one of the criteria considered while selecting an event site.  Depending on the available budget, there are many options.  This section discusses key selection guidelines. 

Equipment

Tablets

Tablet Selection Criteria:

• Android or Amazon/Kindle Fire.  Apple iOS is currently not supported.  Perhaps if there is a demand.
• Battery life should last 8 hours.  Typical sub $100 devices may not have this capacity.
• A suitable case should be available to protect against accidental drops.
• Back camera  (Front camera is optional)
• Dual band WiFi (2.4 & 5 GHz).  The 2.4 GHz band can get crowded at very large events.
• 6" screen or larger
• Bluetooth & NFC are optional (enables the sharing feature)
• Buying refurbished tablets from eBay may be a good idea.

Some of the tablets that are available now (in 2016) for less than $150 are listed below.  Click on product name for more info.

Cost	Click on name for product details	Notes
$50	Amazon Fire, 8" Display, Wi-Fi, 16 GB	Recommended.   Pretty good value.
$35	Amazon Fire v7, 7" Display, Wi-Fi, 8 GB See below for comments..	least expensive with 5 GHz WiFi.  Get the latest version from Amazon.
$120	Nexus 7 2013 Asus/Google  7"	5 GHz, Refurbished
$130	ASUS - ZenPad 8.0 - 8"	has 5 GHz

The Amazon Fire tablets have been tested with GMS, and the 8" with 16 GB is quite a good deal.  I would not recommend the Amazon Fire 7" as a tablet for regular home use, but it is great for GMS.  The tablet is slow for browsing the web or most games.  Its screen isn't great for hi def pictures or movies.  But GMS is very small & efficient, it does not place many demands on the tablet.  The camera resolution isn't great, but quite adequate for taking pictures of robots.  A few times during the year, this tablet even goes on sale for less.  Most districts buy a set of tablets and use then exclusively for GMS. The Fire is good for this type of usage.

Estimating tablet count

To estimate the number of tablets that should be acquired, first decide on the roles that will use GMS.  GMS supports the following roles on tablets, in order of popularity:

• Robot Inspector, including LRI (RI)
• Queue Manager (QM)
• Game Announcer (GA)
• Match Observer Judge (MO)
• Judge, includes Judge Assistant
• Referee (Ref)
• First Tech Advisor (FTA)

An event with about 60 participating teams typically assigns about 10 Robot Inspectors (including the LRI) during the peak period, the Inspection time just before the matches start.  This number decreases as the event progresses and there is less need for RIs.  Other roles also need different numbers of volunteers at different event phases.  Not all Referees need to be given a tablet.  Also, some Judges may not want to use GMS.  A sample table is listed below.  Enter your own estimates and calculate the tablet count that suits your situation.

Phase	RI	QM	MO	Judge	Ref	GA	FTA	Spare	Total
Inspection evening	10						1	1	12
Practice phase	8	5		12	1		1	1	28
Qualification phase	5	5	2	12	1	1	1	1	28
Elimination / Playoffs	7	5		12	2	1	1		28
Max tablet total throughout the event									28

If used carefully, tablets have a life of at least 4 years.

Laptops

Selection criteria:

• Screen: 15 in or larger
• Memory: 4 GB or more
• CPU: Intel Core 2 Duo - AMD A4,   or better
• WiFi: Dual band, otherwise get a 5 GHz WiFi adapter, like this

Estimating laptop count

GMS needs between 1 to 3 laptops, depending on how GMS is being used.  They can be assigned as follows.  Note that GMS can be operated in Local mode or Cloud mode, as described in this note.

Laptop Usage	Count
No laptop is required if the Cloud Mode is used.  GMA can support Robot Inspection, Queuing, Match Observing and Match Announcing without a laptop.  However, a Backup laptop is strongly recommended.  This mode requires the venue to have Internet access via WiFi.	0
The Local Mode does not require Internet access.  One laptop can support Robot Inspection, Queuing, Match Observing and Match Announcing.  This laptop can be placed at the Inspection station and used by the LRI/Inspection Manager.	1
Judging needs a dedicated laptop placed in the Judge's room.  This laptop can be used to also support Robot Inspection, Queuing, Match Observing and Match Announcing, but sharing is not recommended due to security and accessibility reasons.	1
Pit Administration needs a laptop, if that function is used.  This laptop can also function as the Backup laptop for Inspection and other functions.	1
A Backup laptop is optional in both Cloud and Local modes.  It allows for many optional conveniences like Password resets, uploading match schedules, printing reports, etc. It can be shared with Pit Administration.	1
Add up the total number of laptops needed.

WiFi Access Points

GMS lives on WiFi.  A WiFi network will have to be set up only if the event site does not already have one.  It is also needed for the "Disaster Recovery" plan.  This requires WiFi Access Point devices.  

Selection criteria:

• Dual band: 5 GHz and 2.4 GHz
• Built-in router  (DD-WRT compatibility would be nice)

Estimating WiFi AP device count

The number of devices depends on the event venue layout.  A technical write up is here.

Add an AP for Team access, if desired.

Remember to buy 200' CAT 6 Ethernet cables to connect the APs.  About $16 from Amazon.

Staffing

Each event should have at least one volunteer dedicated to setting up and operating GMS.  Their roles and responsibilities are described in the GMS Roles page.

Venue WiFi infrastructure

It is convenient to use the venue WiFi system, if it exists.  Most event sites, especially schools, will have WiFi available.  The advantages of using this WiFi is that no set-up/tear-down is necessary.  The coverage is usually good and Internet access is will be available.  Disadvantages are there may be various network restrictions, the risk of kids trying to connect to a GMS server, and that wired access may not be available for the laptop.  Adequate testing and early conversations with the network administrator will minimize surprises on the day of the event.  The advantages will usually win over the disadvantages.

The venue network requirements are listed below.  There are some differences for the Local Mode and Cloud Mode and those requirements are listed separately.

General Network Requirements

• The contact information for the venue IT staff must be kept handy.  They may need to make configuration changes before or during an event.  Though their presence is not required during the event, they should be reachable for questions. 
• Schools often have open access for guests and a separate private SSID for Staff.  Try to get access to the Staff's WiFi network SSID and password.  This will make things a lot easier.  It avoids the risk of students poking at GMS, provides Internet access, and will be less congested.  With enough notice, the Event Manager can usually make this happen.  The password can be programmed into GMS and will not be revealed to the volunteers.
• The venue may be spread with the arena far away from the pits.  WiFi communications must work between all points.  A professionally installed WiFi system at the venue will provide excellent and reliable service.
• WiFi dead zones should be identified so that users can be notified.
• Some public WiFi installations require the users to accept Terms & Conditions before WiFi access is granted.  This has to be done periodically on each tablet via a browser.  The time between these authentications should preferably be more than 8 hours.  Otherwise, GMS communications will appear to fail inexplicably and the users will be upset.
• GMS does not support Proxy servers for outbound Internet access.
• GMS uses about 100 Kbits/sec throughput on the average.  This is fairly low.  The traffic will be bursty and latency is not a concern. 

Additional Requirements for the Cloud Mode

The GMS server is set up and operated by the GMS Administrator in Cloud mode.  This greatly simplifies the use of GMS.

• Internet access is required to the GMS Cloud server
• GMS Cloud Server, http://c.pejaver.com, TCP port 4433
• The port number can be changed on request.
• Access to other URLs is not required.
• In the Cloud Mode, the laptop is usually the Pit Admin station or the Backup.  Having a wired connection for it is nice but optional.

Additional Requirements for the Local Mode

The Local mode can be used if the Cloud mode is not possible. 

• The venue may block routing between WiFi clients for security reasons.  This will prevent tablets' access to the GMS laptop. Pre-event testing may reveal this issue.
• Routing between WiFi clients may be blocked for other reasons.  For example, DHCP addresses may be assigned in /24 subnet blocks.  Routing may be allowed within a subnet, but not supported across subnets.  In this case, GMS will work on some clients but not others.  It will be hard to test for such situations and the venue IT person should be consulted.  Though this is really a venue WiFi configuration error, the IT guys will be reluctant to correct it.
• Having a wired connection for the laptop will reduce WiFi traffic by 50%.  This can be beneficial at large events.  Given enough notice, the venue IT staff can usually lay out an Ethernet cable to the Inspections Station.
• Though optional, Internet access enables getting match info from FIRST :
• FIRST API server, https://frc-api.usfirst.org, TCP port 443,
• FIRST Web server, http://www.usfirst.org, TCP ports 80 & 443
• Though optional, Internet access enables posting event updates to teams.
• GMS Team Server, ftp://ftp.pejaver.com, FTP ports: TCP 20, 21