In our earlier article 4 Stages of Big Data Exploitation in Container Terminals, we had a look at the needs for automated terminals and saw how big data could be applied in a terminal. In this piece, we are going to describe things that must be considered when creating network infrastructure, the basic and essential element of various equipment and data transmission and reception in an automated terminal that uses big data.

Three basic attributes of network creation for industrial sites

There are things that one must take note of for developing a network for an industrial site. Basically, a network must have reliability, real-time responsiveness, and stability.

• Reliability is about making sure that data or a signal sent to a device has properly reached it. If data sent to industrial equipment gets lost, something unexpected can result from the specific operation.
• Real-time responsiveness implies that in conducting control or real-time monitoring between devices, response to data is delivered within a specified period of time. Since equipment used on industrial sites has huge size and weight, its status check and safety cannot be assured without real-time performance.
• Stability implies that in case network infrastructure runs into problems, it must have a way to bypass them. If an industrial site suffers its IT service to stop for some reason, it will immediately lead to loss for a company and furthermore, the afore-mentioned reliability and real-time responsiveness cannot be guaranteed, either.

Considering such potential issues, the industry is developing standard protocols such as Ethernet/IP, Profinet, and Modbus. In order to realize automation in ports and terminals, it is required to apply these protocols to the wired network for parts related to control and monitoring.

Reason that Wi-Fi is most frequently used in creating a wireless network in ports and terminals

Port and terminal environment cannot be created with the above wired network alone. It’s because a yard characteristically covers a large area and has its various equipment move freely. While it is required to introduce a wireless network in a terminal, it is not easy to successfully apply a wireless network. Currently, various wireless network services such as 3G, Wide Band, Narrow band, and Wi-Fi are available, but consideration of traffic volume and financial cost finds Wi-Fi network the most frequently used. If not for financial consideration, using a licensed bandwidth provides the best service quality, but it comes with continued financial burden. Among unlicensed bandwidths, Wide Band and Narrow Band technologies are available, but with narrow bandwidth available for transmission, they have difficulty in transmitting needed traffic. So, Wi-Fi network should be the most suitable under current circumstances with its economy and technology.

Things to consider when applying Wi-Fi to ports

When we apply such Wi-Fi network to a port, there are things that we must consider in addition to the characteristics of wired network mentioned earlier.

First, it’s coverage. While this is a basic thing about using wireless network, it is the first thing that has to be considered for ports that are composed of iron such as equipment and containers, because of the characteristics of radio wave (which does not travel through but bounces off iron). So, a network design must anticipate various situations while considering the stacking and movement of containers. Using recently developed Wireless Mesh network technology can further boost Wi-Fi coverage.

Second, it’s interference. Using unlicensed bandwidth cannot do away with the issue. It’s because one cannot assert one’s exclusive area in a bandwidth that anyone can use. Interference is the issue that is the most difficult to overcome in a Wi-Fi environment. It’s because you don’t know who is using which bandwidth of frequency, which is invisible. It is also because customs, national agencies, and outside companies, which a terminal cannot manage, may use the same bandwidth. A problem like that cannot be easily discovered with an ordinary type of Wi-Fi tool and its occurrence is unpredictable. To solve such a problem, consultation with neighboring organizations must precede the creation of a Wi-Fi network, and if a problem has occurred, it can be checked using a Wi-Fi spectrum analyzer.

Third, it is roaming. When ITV, which has wireless clients, roams a wide area, it is out of the question for a single access point (AP) to cover a radius of minimum 100m. So, a number of APs are installed, considering its coverage. As they move between access points, clients repeatedly experience connection, disconnection, and reconnection. And in case roaming does not work properly, network disconnection will repeat continuously. Indeed, when this problem occurred, people had to stop their work occasionally, which adversely influenced the operation. The problem should be solved by testing the compatibility between AP infrastructure and wireless LAN client module, which must be considered before one decides to get the network. Or, it is important to see whether wireless LAN infrastructure supports fast roaming technology, which is provided by each wireless LAN vendor.

We have so far reviewed the characteristics of network which are required in a terminal environment. We believe that considering the above-mentioned basic characteristics could reduce problems that occur in a terminal network environment.

In addition, a document on applying wireless LAN on industrial sites, created by Cisco and Rockwell, is available at the URL below.

http://www.cisco.com/c/en/us/td/docs/solutions/Verticals/CPwE/NovCVD/CPwE_WLAN_CVD.pdf