The National Transportation Communications for Intelligent Transportation System (ITS) Protocol, or NTCIP, is a protocol that allows traffic devices to communicate with each other. Prior to the development of NTCIP, ITS devices and systems from different manufacturers were unable to communicate without a costly and time-consuming integration effort. Devices that support NTCIP are considered NTCIP “conformant”, which is a requirement in many bids or RFPs. Often times, the device must also meet the specific requirements, making the device “compliant.” Let’s explore the differences and what it means to be conformant and compliant.
Conformance vs. Compliance
It’s important to understand that conformance and compliance are not interchangeable terms. Whether a device is conformant or non-conformant is determined by how it relates to the NCTIP standard. Conforming to the NTCIP protocol requires meeting a list of minimum standards.
Compliance relates to the specifications within the bid or the RFP. Typically included in a bid or an RFP is a detailed list of NTCIP functions that the given device should have the ability to perform. The device must be able to support all of the requirements in order for it to claim compliance.
It is possible for a device to be NTCIP conformant and not be compliant with an RFP or bid. For example, a sign may have the ability to store 50 messages and 50 events. It meets the list of mandatory NTCIP requirements and is conformant to the NTCIP standard. However, if a bid specifies 250 messages and 250 events, the device is not compliant with the bid.
The number and scope of options within NTCIP is virtually limitless. The PRL, or Protocol Requirements List, is a means of standardizing the requested options. Essentially it’s a checklist within a standard. The objective of the PRL is to clarify the list of features that are required by the specifying organization. When creating a bid, an organization can use the PRL to specify which features they want the device to support. Vendors can then consult the standard PRL to determine if their device is compliant with the bid. The PRL lets both the specifying organization and vendor agree on what compliance means.
An additional method to communicate compliance is through a Protocol Information Conformance Statement, or PICS. PICS are created by the manufacturer and are a checklist that indicates which options are supported by a particular device. It clearly lists the functionality of the product using the PRL and can be used to verify conformance to the standard and compliance with the specifications.
For more information on NTCIP conformance and compliance, PRLs and PICS, visit our previous posts, What Is NTCIP?, NTCIP Protocol Requirements, and Creating a Better NTCIP Specification With the PRL.
The NTCIP protocol is an industry wide standard data communications protocol, designed to facilitate interoperability and interchangeability between computers and electronic traffic control equipment from different manufacturers.
Each layer of the protocol provides an increasing level of detail as to how information should be transferred and received. It explains the logical progression of the process, what to do with the information and in what order to do it.
5 Levels of NTCIP Protocol
NTCIP defines both the method of transferring information and also the functionality of the field device, answering questions such as: what communications hardware is to be supported? How is the data to be packetized, sent, and verified? What optional functions must the field device support, such as sign display colors, camera labels, and weather station sensors?
There are five defined levels that makeup NTCIP. These include: information level, application level, transport level, subnetwork level, and plant level.
- Information Level defines the meaning of the data and represents the functionality of the system.
- Application Level defines the rules for exchanging data. It is responsible for the sequence of statements in order to form a complete thought or sentence.
- Transport Level defines the rules and procedures for exchanging the application data, including any necessary routing, assembly or reassembly of a message and network management functions.
- Subnetwork Level defines the rules and procedures for exchanging data between two devices over a chosen communications media.
- Plant Level The Plant Level is shown in the NTCIP Framework only as a means of providing a point of reference to those learning about NTCIP. It includes the communications infrastructure over which NTCIP communications standards are to be used.
Mastering NTCIP takes effort and there are not a wide range of classes or books to choose from when it comes to learning the protocol. Having an understanding of programming languages and the basics of networking are the best places to start.
There are some online resources you can leverage to gain a working knowledge of NTCIP. These include the NTCIP 9001 “Guide” for detailed deployment and NTCIP procurement information, the NTCIP Forums, which provide a channel for both technical and non-technical people to discuss the NTCIP and the Library Table, which has links to the status information, drafts, and jointly approved standards.
All NTCIP standards are published on the NTCIP website and webinars that define both the standard itself, testing to the standard, and individual standards for specific devices are often available.
Automatic vehicle location (AVL) systems typically use the cellular data network to transmit information. Determining which cellular technology to use for your AVL system is an important decision in the planning process. The newest cellular technology available to AVL systems is Long-Term Evolution (LTE), also referred to as 4G. There is no question that LTE modems are faster and can carry more data, but the improvements come with increased costs. 3G systems are still widely used and, depending on the nature of your application and its expected life cycle, it may make more sense to choose 3G rather than LTE.
Making the Decision—Where to Start
When you are trying to decide which cellular system to specify, it’s best to start by analyzing how your AVL system will be using the data. If your primary goal is to track vehicles and obtain engine information, then a 3G connection is all you need. If the vehicles are accessing websites or pulling down data, then a faster connection such as LTE may make sense.
Network Life Span Considerations
Some organizations fear that the 3G networks will eventually be retired and that 3G devices will no longer work. But, is this a valid fear? Upgrading to LTE from 3G may seem like a way to “future proof” your company’s devices, but it’s only a temporary fix. The next generation of networks that will replace LTE is already being developed and at some time in the future 5G will replace 4G.
Additionally, even if the retirement of the 3G network is officially announced, it will be years before the system is deactivated. For example, when the 2G system was decommissioned, users received three years’ notice and were provided ample time to plan for a transition.
Using Wi-Fi Through the Cellular Modem
In seeking ways to lower cellular network costs, some service-related companies decided to utilize in-vehicle Wi-Fi modems as a way to allow field workers with tablets to use Wi-Fi inside the vehicle. While this sounded like an excellent idea, in reality, many times it did not work. The worker would be inside the customer’s house, need to look up a part number, and try to access the Wi-Fi in the vehicle. It was not uncommon that they had to go back outside to access the network, thus decreasing their productivity. With the additional concerns about data security, this solution has diminished in acceptance by many organizations. However, if employees spend most of the day near the vehicle, a Wi-Fi solution could make sense. It’s important to evaluate how employees will utilize the data when making a decision.
Cellular Contract Considerations
When exploring cellular options, it’s important to know who “owns” the cellular contract. Many companies include the cellular solution with their AVL solution. Often, a business entity will have a corporate agreement that enables the business to receive volume pricing on wireless services through its preferred provider. In these situations, it may be in the customer’s best interest to utilize its preferred carrier, rather than the wireless service provided by the AVL provider. The additional volume generated via the AVL system could drive the customer’s overall cellular prices even lower. When selecting an AVL provider, it is important that the customer specify if it will provide the wireless service itself, or if the vendor has the option to include the wireless service in its pricing plan.
- Many AVL systems use cellular data to transmit information
- The newest cellular technology that AVL systems are using is LTE
- There is no question that LTE modems and data are better
- But the improvements come with increase cost
- 3G systems are still widely used and depending on the nature of your application it may make more sense to use 3G vs. LTE
- Don’t assume that you need the latest and greatest just because that tis what’s available
Network Lifespan Considerations
- The fear many companies have is that the 3G networks will eventually be depreciated and that their devices will stop working
- Choosing LTE over 3G can be a way to “future proof” the device but it’s only a temporary fix
- The next generation of networks that will replace LTE are being developed
- So you’re only buying a few years
- Even if the 3G network is officially depreciated it will be years before the system is turned off
- When the 2G system was decommissioned there were three years of notices
Where to Start
- The best thing to do is start with what you need the system to do
- Get a very clear understanding of how your AVL system will be using the data
- If your primary goal is to track vehicles and obtain engine information then a 3G connection is all you would need
- If the vehicles will be accessing websites or pulling down data then a faster connection may make sense
- If you are looking to do more with the data it might be worth exploring the LTE option
- When exploring cellular options, it’s important to know who “owns” the cellular contract?
- Will the contract be a direct sales to your organization or will it go through a third-party provider?
- Many states have existing cellular agreements so it’s good to check and see what your direct options are
- If a lower rate has been pre-negotiated you could take advantage of the discount
- Another item to consider is the security of your cellular network
- If you are working with a third party provider it is important to secure the network and make sure the data is protected
- This could be at the carrier level or specific security changes on your devices
- Locking the devices down will prevent un-intended use and data overages