OFFSHORE BANDWIDTH BOOST TECHNICAL WHITEPAPER

Transcription

1 OFFSHORE BANDWIDTH BOOST TECHNICAL WHITEPAPER

2 Page: 2 Executive Summary Costly, outdated technology has restricted those wanting to communicate to and from offshore supply vessels. Innovations from MCP enable the same mobile and data reach at sea as onshore, with vastly reduced need for expensive satellite communications. This whitepaper explains how ship-owners, crew and ICT-departments benefits from technology that reduces costs and yields new opportunities. Introduction MCP solutions facilitate first class mobile telephony coverage, while ensuring that crewmembers can access the internet. The solutions boast features that radically improve the data network, both by optimising throughput over satellite, as well as bundling it with additional data links, creating a bandwidth boost. MCP provides mobile base stations on-board. Connection is made via the ships satellite link to public networks on shore (figure 1). The solution meets the demands of the merchant marine and offshore markets for full GSM functionality. It is also designed to provide value, take up the minimum of space and require minimal maintenance. Installation can be configured to cover the entire ship or selected areas, giving an optimal communications solution customised to individual vessel requirements. The system complements VSAT and offers streamlined reporting, which reduces administrative time and costs. Crew and passengers that utilise MCP s solution are conveniently billed by their own service provider. Alternatively, they can be provided with CrewSIM cards. Repeater solution MCP s repeater solutions provide land mobile coverage as far as 50 nautical miles (nm) out at sea, while improving the reach of oil rig base-stations (figure 2). The repeater is connected to the MCP indoor mobile network, which gives those inside the vessel increased access to land mobile networks. It is also connected to the GSM modem as part of the multiple data link bundling, giving extended range of operation for this data connection boost service. The repeater is automatically turned on and off according to the location of the ship, avoiding intrusive network interference when the vessel enters EEZ zones of countries that the repeater is not approved for. MCP also provides the installation of wireless Internet, securing effective coverage for on-board locations. MCP bandwidth boosters MCP solutions optimise the on-board data network. Both corporate and welfare networks can be tuned and given different priorities and configurations. MCP benefits: Reliable phone service while at sea 2G, EDGE and 3G support Compression technologies save money and resources Works seamlessly with all major cell phone carriers. Customer Console provide up-to-date information check incoming and outgoing call statistics, minutes used, data usage, customer service requests, and vessel locations Easily installed without disrupting ship operations. No maintenance required. MCP monitors and operates networks remotely along with any regulatory and legal challenges. MCP provides several bandwidth booster services, addressing all aspects of ship-to-shore data network issues, encompassing typical VSAT data link (1) characteristics, as well as seamlessly adding multiple other data links (2) when available, and finally deploying IP traffic control (3) blocking bandwidth eaters.

3 Page: 3 Figure 1: CellAtSea mobile system and repeater Figure 2: MCP GSM and repeater GSM signals availability

4 Page: 4 1. VSAT data link optimisation MCP offers Data Compression and TCP tuning, Adaptive Forward Error Correction (FEC), Packet Order Correction (POC), and various Quality of Service (QoS) and Priority adjustments. Data Compression MCP s data compression saves 10-20% bandwidth on GSM data, 30-50% on mobile data, and between 20 and 50% bandwidth on mixed IP traffic. The selected compression method is suitable to combine with FEC. TCP tuning and POC TCP protocol has a congestion avoidance mechanism based on acknowledging packets received, back to the transmitter. In long latency systems like satellite links the round trip time is high, typically >500ms, due to the physical distance data has to travel. Thus the acknowledge packets sent frequently arrive too late, which TCP interprets as network congestion. TCP will then quickly reduce the transmission rate to unblock congestion, before slowly building the rate up again. This results in low utilisation of the actual satellite link bandwidth. The MCP system adjusts TCP window sizes indicating how long to wait for acknowledge packets (acks), as well as providing selective acknowledgements over the satellite link - a feature that causes most acks to return quickly on the local end of the satellite link. In addition, the system provides POC, rearranging received packets into the correct order before providing them to the data network, streamlining the data and compensating for satellite link characteristics. Adaptive FEC Forward Error Correction (FEC) ensures good communication even when packet losses are in the 1-10% range. By deploying link layer FEC, correcting the data before they are delivered to the transport layer, high bandwidth savings can be experienced. One also avoids transport level protocol retransmissions for any protocol and application over IP. Link layer FEC has a maximum effect at high bandwidth utilisation and at high capacity links. This can be illustrated in Figure 3 where a given satellite link offers 2Mbps DL and the data network is trying to utilise all of that capacity. It is not uncommon to experience 1% packet loss on satellite links, but even if the loss is as low as 0.1% this causes a severe drop of throughput down to 0.75Mbps. When FEC is used it restores the data rate up to 1.8Mbps, with an example level of FEC redundancy packets of 1 for 8 normal IP packets. Through the addition of more redundancy packets, for example 2 to 8, one can maintain reasonable throughput even at packet losses of 5%. Further from Figure 3, if the satellite link offers only 512kbps DL, FEC is less relevant. But if packet loss is higher than 0.3%, FEC again starts to become useful. The addition of FEC error correction packets means less real data packets are submitted. As demonstrated by the example in Figure 3, for FEC at 1:8 levels this means 10% of the total bandwidth of 2Mbps. Link layer FEC is most effective by packet loss statistically spread. This is more typical for satellite links. FEC is not as effective at burst loss of multiple packets, which is more typical for network congestions. The effects of FEC has been studied e.g. in [1], which suggests adapting the level of error correction packets to the level of packet loss. Adaptive FEC ensures that overhead from having FEC enabled is limited at low packet loss rates. At higher packet loss FEC overhead increases, but the recovery of packets increases even more, avoiding further retransmissions and the triggering of the TCP congestion avoidance mechanism, which would result in lower speed. Combining data compression and FEC services yields positive cross-effects, although these two services may be deployed separately. Satellite link monitoring Through real-time monitoring of satellite connections ship-owners always have an overview of the quality of the VSAT provider service (Figure 4). This ensures that the quality is in accordance to the agreed SLA with the VSAT provider.

5 Page: 5 % Packet loss Figure 3: Throughput as function of packet loss Figure 4: Satellite link quality monitoring console per ship

6 Page: 6 2. Multiple Data Link Bundling Bandwidth needs are always increasing and VSAT bandwidth upgrades are costly. MCP offers an alternative way - bundling multiple data links together with the VSAT (Figure 5). When a ship is in position to communicate with land-based or oil rig-based mobile data networks (2G/3G/4G), or at harbour in the proximity of a WLAN access point, the MCP Multiple Data Link Bundling feature gives seamless network-access resulting in an additional bandwidth boost. MCP default configures this feature for flat priority between the different data links, except for 2G GPRS data link, which is used only as backup. This means all data links are used as available, including VSAT. Data links are selected in a round-robin way, per created IP session. There are options to customise the bundling configuration based on low latency, priority, overflow, persistence, least used, weighted balance, or enforcing. The further away from the coast or oil rig, the less added speed will be provided on top of the VSAT link, as the land mobile network s signal strength diminishes. A descriptive usage scenario of the MCP mobile system, including the MCP Mobile Data Link Bundling feature, is available from MCP. com. Data link monitoring Some mobile subscriptions have data volume limitations. The MCP Multiple Data Link Bundling mechanism can be configured to automatically monitor data consumption and switch off the related data connection when volume limits are exceeded, to minimise cost and maximise speed. Figure 5: MCP bandwidth boosters and multiple data link bundling

7 Page: 7 3. IP traffic filters The final booster is IP traffic filtering, helping prevent the usage of bandwidth eaters, such as streaming, gaming, and downloads (Figure 6). This system monitors traffic as well as filtering and is highly configurable, adapting to the needs of the customer. Traditional Wi-Fi management systems optimise bandwidth usage by white and black-listing webpages and apps. However, services like Skype and YouTube are using port hopping and other technical tricks to avoid blacklisting. MCP s IP traffic control system is based on dynamic context based policy management. The IP traffic can be restricted based on white-list, black-list, content, address, or port. Filtering can be set on user/group basis. Filtering examples Some streaming protocols like RTP, which is frequently used by mobile phones, limit their bandwidth usage to a given fraction of the total available bandwidth. Other streaming services need 500Kbps and HD streaming requires between 1.5 Mbps and 8 Mbps to buffer data faster than showing the content. Thus only one crew member using such services can easily congest the entire network. Firewall and virus detection The IP traffic filter also acts as a firewall. Viruses, Trojans, spyware and other kinds of malware are automatically stopped before the satellite link to avoid inefficient bandwidth usage. The anti-virus and threats filters are updated regularly. Monitoring Monitoring reports can be generated on a weekly or monthly basis, listing most used services, applications and bandwidth MCP bandwidth boosters benefits: Satellite link tuning: Data compression, adaptive FEC, POC and TCP tuning boosts bandwidth for the aggregated data traffic over satellite link. The combination mitigates the negative bandwidth effects characterizing VSAT data links. Multiple data links benefits: Added availability, uptime and increased bandwidth in coastal areas as well as near the oil rigs or in satellite- shadow. The function makes the data network on board more stable and efficient. IP traffic filters benefits: Controlling what services that are run on top of IP network. Helps to avoid unintentional bandwidth outage, and reserve required resources to corporate network as well as provide suitable service level of the welfare network. References: [1] Bandwidth tradeoff between TCP and link-level FEC, Chadi Barakat *, Eitan Altman channels in addition to the on board data networks (Ethernet and WiFi). Figure 6: MCP bandwidth boosters and multiple data link bundling Facebook s wall and chat features could be allowed, while more bandwidth intensive Facebook-applications, like games, are restricted. All video streaming could be restricted, as well as content categories like adult or gambling. Automatic SW updates can be restricted, or limited to certain times of day. consumers. It is possible to report usage for each device or user, and even identify which devices are virus infected. MCP updates the Traffic Filter configuration based on customer request. Conclusions The innovative MCP technology empowers your crew with a vast set of mobile communication The system does not conflict with any corporate PBX and DECT telephony systems, but optimises data going over the satellite link, as well as offloading the satellite link by optionally providing other data carriers. The system increases availability, uptime and performance of the total network. The result is higher quality services for crew, operators and other guests on board - any time and at any location.