Bandwidth management – It’s all about visibility

Aug 19, 2022 | Blog

Bandwidth management – The basics

Managing bandwidth is an essential part of your onboard IT services. Fast, stable and reliable connectivity is no longer viewed as a luxury. Instead, it has become a necessary prerequisite for the safe management of large yachts and meeting owner, guest, and crew requirements.

The demand for data, both in volume and bandwidth, has dramatically increased. Inmarsat, a global satellite communication company, predicted that VSAT use on superyachts alone would increase by 42% from 2020 to 2025.

Bandwidth and data are expensive and, unfortunately, not finite – unless you have a generous owner. Therefore, it is essential to see what data is available, what applications are using it, and by who. This is the very essence of bandwidth management.

Your off-vessel connections

An off-vessel connection also referred to as a wide area network (WAN), is the term given to the different connection methods used to connect the yacht to the internet. The most appropriate WAN depends on the yacht’s size, number of users, budget, and location. Examples include a VSAT connection, Fleetbroadband, Marina wifi, 4G/5G and shore ethernet.

40m+ yachts generally have 3 or 4 of these WAN options, which provides redundancy in the case of a connection failure, and increased bandwidth availability. A 40m sailing yacht with an active itinerary needs different WANs than a marina-based 40m motor yacht. Similarly, a heavily chartered yacht needs different WANs from a privately owned vessel.

Local area networks (LAN) and Virtual LAN (VLANs)

On smaller yachts, a single LAN (local area network can be used). This is a single network providing up to 255 IP addresses for up to 255 devices. These devices use a single internet connection, share files, and can be accessed and even controlled by one another. This is not always suitable from a privacy and security perspective, which is one of the reasons we would recommend implementing VLANs.

VLANs (Virtual LANs) are based on multiple subnets. A simple way to understand VLANs is to imagine partitioning the network ports on a switch. If you have a 16-port switch, you could assign eight ports to one VLAN (VLAN1) and eight ports to another VLAN (VLAN 2). VLAN 1 will not see any of VLAN 2’s traffic and vice versa. This is a more effective method of managing the LAN network. The use of VLANs ensures that broadcast traffic is limited within each VLAN; this increases security and optimises network traffic. For example, VLANs could be OWNER, GUEST, CREW, AV, CCTV, TELEPHONE etc.

VLANs are more efficient as you have a less ‘noisy’ network and reduced packet collision, resulting in improved performance. The crew, owner, guest, and AV VLANs can be integrated into the wireless network, allowing the owner or guests to connect to their dedicated VLAN wirelessly.

Bandwidth Management - VLAN

Source: Tech Target

The wireless network – the good and the bad

More and more devices now rely entirely on wireless networks, and the number of access points onboard a yacht has significantly increased. Ten years ago, we would likely find one or two wireless access points; now, we regularly see between 10-20 wireless access points on a 50m yacht. Shipyards often overlook the correct wireless network design and deployment at the build stage, resulting in weak coverage and overlapping. Implementation of a wireless network and security is a precise science that should not be understated.

When an owner’s laptop is requesting a webpage, a number of factors influence the perceived speed that the owner receives that webpage. For example, we can see e.g., 2mbps being delivered by a VSAT airtime provider and 2mbps on the gateway, but the captain’s laptop is only connected at 0.8mbps. This loss can be attributed to other devices’ eating into’ the 2mbps connection, but if no other devices are using the WAN, this loss can simply be attributed to a poor network.

Physically poor cabling, incorrect cable/connectors, and cable interface are some of the many issues that can affect the ‘speed’ of a network. One area that is often mentioned is packet loss. Packet loss occurs when one or more packets of data travelling across a computer network fail to reach their destination. This increases latency due to the additional time needed for retransmission – hence a slower network.

The gateway is the key to effective bandwidth management.

network gateway is a device or node that connects disparate networks by translating communications from one protocol to another. Gateways, such as a Kerio, can offer very clever load balancing algorithms, such as combining the WANs or allocating each device to a specific WAN depending on the bandwidth available.

Let’s run through a scenario. There are 2 WAN connections, both online, VSAT and 4G, and both are connected to the gateway. A 2mbps VSAT and 10mbps 4G service are effectively load-balanced in a 1:5 ratio, so this first user is assigned to the VSAT connection, and the following five users are assigned to the 4G connection. This would be effective for steady speeds but is too ‘clunky’ for variable speeds. If the 4G drops to 50kbps GPRS, the gateway will still assign five users to this connection. More expensive gateways can perform traffic shaping and dynamic load balancing, which ensures users are given the best connection.

A second option is to assign one WAN, for example, 4G, to the owners VLAN, and assign VSAT to the crew VLAN. This is a common solution as it is relatively straightforward to manage the VLAN users. Time schedules can also be assigned to limit personal device use during work hours, so most of the bandwidth is allocated to devices required for work tasks. Social media rules are sometimes added, which will block the websites between 08:00 – 18:00.

Effective bandwidth management becomes even more critical at sea, as the number of active WANs is often limited to a VSAT connection. Solid gateway rules need to be in place, allocating the majority of the VSAT to the owner and guests whilst still providing the crew with internet access so as not to hinder the safe operation of the yacht.

To ensure the owner and guests receive the best internet possible, multiple, flexible WAN connections, an efficient wired and wireless network and a gateway that allows complete visibility and control are essential.