IE20010343A1 - Communications Network - Google Patents

Abstract

A communications network having a loop backbone passing around Ireland and a plurality of spurs running inland, the loop backbone being formed by a plurality of switching stations connected by fibre optic cables which run undersea for at least part of their length, the spurs being connected to the loop backbone by the switching stations, being formed by fibre optic cables and running inland along waterways.

Description

Hates to a communications network structure and particularly to mmunications network to provide an Internet infrastructure for Ireland.

Recently, there has been very rapid growth in Internet usage worldwide and in particular in the United Kingdom. This growth has taken place both in the number of users and in the amount of usage. It is generally predicted that high rates of growth of Internet usage both in numbers and amount of usage in the United Kingdom and worldwide will continue for the foreseeable future. However, the growth predicted and expected on social and economic grounds will be unsustainable in the United Kingdom because growth will expand the amount of Internet usage beyond the capacity of the existing communications infrastructure.

At present the majority of United Kingdom and Irish Internet traffic is routed through the North American Internet infrastructure because there is no United Kingdom or European communications network to carry the Internet traffic.

Although new technical methods of providing Internet access and new contractual arrangements for providing and funding such access are currently being developed by many Internet service providers, communications companies and electronic equipment manufacturers these new technical and commercial services do not increase the ability of existing communications networks to carry the resulting additional traffic.

Currently, Internet and other digital communications traffic in the United Kingdom and Ireland passes through the existing telephone network for at least a part of its connection path and ultimately relies on traffic through the Internet infrastructure nainly based in North America.

The telephone network was never designed for high speed digital data transfer and the existing North American Internet infrastructure is being used to its capacity by traffic originating in North America and cannot be expected to continue to expand rapidly enough to provide sufficient excess capacity to deal with Internet traffic originating in the United Kingdom and Ireland.

Internet users are already experiencing difficulties due to lack of capacity ofthe existing Internet access infrastructure. These difficulties include variable speed of user connections to Internet service providers, lack of reliability of connection to the Internet ΙΕ Ο 1 fl Η ϊ and a variable speed of delivery of information through the Internet, and it is easily noticeable by Internet users in the United Kingdom that the severity of these problems currently fluctuates during the day based on demand in North America because of the dependence of UK and Irish Internet traffic on the North American Internet infrastructure. All of these problems will continue to get worse for the foreseeable future.

Clearly the best solution to these problems is to construct a dedicated high capacity data communications network for the United Kingdom and for Ireland in order to provide UK and Irish Internet infrastructures. All of the necessary technology to construct such infrastructures having a high enough capacity to deal with current Internet and other digital data traffic and to allow for predicted increases, at least for a sufficient time for a rolling upgrade program to keep pace with growth, already exists, but there are two major problems in constructing such a network.

The first problem is the cost of setting up such a network and the second problem is the difficulty of obtaining the necessary rights to physically install the physical network of cables required to provide the network.

It should be understood that a physical cable network will be essential because there is no possibility of transmitting the required amounts of data using wireless systems.

The first problem of cost can be overcome because of the obvious potential profits to be made from the network. However, the second problem is harder to resolve.

The difficulty of obtaining the necessary permission to lay or place the physical cable network will directly increase costs because of the necessity to pay for the right to put the physical cable network in place and also in the resulting delays due to*the requirement to negotiate with many thousands of land owners and utilities organisations. These delays in time translate into additional cost and make it harder to obtain the necessary commercial funding to begin installing the network because of the delay and uncertainty as to how long it will be before the network is able to begin generating revenue.

This invention provides a communications network structure overcoming these difficulties, at least in part.

This invention provides a communications network having a loop backbone passing around Ireland and a plurality of spurs running inland, the loop backbone being formed by a plurality of switching stations connected by fibre optic cables which run undersea for at least part of their length, the spurs being connected to the loop backbone by the switching stations, being formed by fibreoptic cables and running inland along waterways.

Embodiments of the invention will now be described by way of example only with reference to the accompanying diagrammatic figures, in which; Figure 1 shows the physical structure of a network according to the invention serving the UK mainland; Figure 2 shows the logical structure of the network of Figure 1; Figure 3 shows the logical structure of a network serving the whole of the UK and Ireland; Figure 4 shows the logical structure of an alternative network serving the whole of the UK and Ireland; and Figure 5 shows a physical layout of the network of Figure 4.

It will be understood that a similar network to that illustrated in Figures 1 and 2 may be adapted to serve Ireland alone, by employing the principles discussed herein. Specifically the loop backbone may pass around Ireland with a plurality of spurs running inland, independently of any requirement for a loop passing around the UK mainland. The term Ireland includes both Northern Ireland and the Irish Republic.

A first embodiment of a communications network structure according to the invention is shown in Figures 1 and 2.

As shown in Figure 2, the Internet structure is a logical loop 1 forming a digital communication backbone for the network and extending around the UK mainland and connected to population centres by a plurality of spurs 2 running inland.

As shown in Figure 1, physically, the network is provided by a plurality of routing and switching stations 3 spaced apart around the coastline of the UK mainland and situated at or close to the coast. The routing and switching stations 3 are interconnected by high capacity fibreoptic cable links 4 which run underwater off the coast between the switching and routing stations 3.

In order to allow users to be connected to the communication systems backbone loop 1, spurs run inland from the routing and switching stations 3 along watercourses into urban areas. For clarity, the spurs and lower level details of the system are not shown in Figure 1.

Further branches or connections to other digital communications networks can then be made from the spurs 2 as required.

The physical location of the ring backbone loop cables 4 undersea will help to protect the system from physical harm to the cables 4 themselves. Further, the difficulties of obtaining permission to lay the backbone loop cables 4 will be greatly reduced because the great majority of the cables can be laid below the high tide mark so that no specific permission to lay the cables needs to be obtained.

It will of course be necessary to obtain suitable permission from land owners and other interested parties to place and construct the routing and switching stations 3 and the lengths of the backbone cables 4 passing between each routing and switching station 3 and the sea. However, it will be understood that such negotiation with a relatively small number of parties for the placing of the individual routing and switching stations 3 and the short lengths of cable to and from the sea will be far simpler and cheaper than similar negotiations to allow the backbone cables 4 to be laid on land. This is particularly the case because there will normally be sufficient geographical leeway in the location of each switching and routing station 3 that any unusually difficult or greedy authorities or land owners can simply be avoided by placing the routing and switching stations 3 elsewhere.

Similar advantages are obtained by running the spurs 2 from the routing and switching stations 3 inland to urban and other inland areas along watercourses. Again, running the cables along watercourses underwater will provide physical protection for the spur cables and the difficulty of negotiating necessary rights to physically put the network in place will again be greatly reduced.

It will be necessary to obtain permission from relevant authorities to lay the cables along watercourses but the number of relevant authorities or landowners from whom permission must be sought will be greatly reduced compared to running the spur cables overland.

Running the spur cables along watercourses is regarded as particularly advantageous because for historical reasons all significant urban areas in the UK and Ireland are built around and along watercourses.

Forming the backbone as a loop instead of a trunk and branch type network will provide a redundancy advantage because there will always be two routes by which any connection can be made around the backbone loop 1. This will provide a system with redundancy which will allow it to continue operating in the event of damage or failure of one or more routing and switching stations 3 or links 4. This will also simplify maintenance and upgrading of the system because it will allow elements in the system to be taken out of service temporarily in the course of upgrading or maintenance without any deterioration in service provided to users. Another advantage of the loop structure is that the availability of alternate connection paths in opposite directions around the loop can be used to provide the ability to cope with sudden surges in demand.

As noted above, the network backbone loop and spurs will be formed by fibreoptic cables and it is expected that lower level parts of the network would also be fonned by fibreoptic cables, although connection to other data carrying networks using alternative technology is possible at any point in the network.

It is preferred that the capacity of data transmission between two adjacent routing and switching stations 3 along the backbone cables 4 should be at least 1 Terabit per second and preferably at least 10 Terabits per second. The actual fibres of the fibreoptic cable will be enclosed and protected in a semi-rigid cable structure as is commonly used for underwater cable links and it is preferred to place the cable in a trench, possibly within a further rigid or semi-rigid pipe surrounding the cable, in order to provide maximum physical protection for the cable against accidental damage.

In order to allow easy access for maintenance or upgrading it is preferred to have the routing and switching stations 3 on land but they could be placed underwater if desired. This might be convenient in some circumstances, for example to allow islands to be served. However, it is preferred to keep all of the backbone loop routing and switching stations 3 on land and to have spurs running under the sea to serve islands with underwater routing and switching stations on the spurs to serve individual islands if required.

It is preferred not to use underwater repeaters in order to avoid access problems for maintenance or upgrading and it is preferred instead to have sufficient routing and switching stations 3 that underwater repeaters will not be required. However, underwater repeaters could be employed if necessary.

It is expected that all of the routing and switching stations 3 will support a spur 2 to serve at least local requirements. However, in practice it may be found that in sparsely populated areas such as the North Scottish coast local demand is insufficient to justify IE Ο 1 0 3 4 3 such a spur, in which case the routing and switching station 3 would simply act as a repeater.

The part of the backbone loop cables 4 most exposed to accidental damage are sections running on land and in shallow water, particularly above the high tide mark. Accordingly, it may be preferred in some cases to install junction stations in each of the backbone loop links 4 below the high tide mark in order to simplify replacement of damaged parts of the cable in this most exposed section without disturbing the section of the cable 4 running in deeper water. These junction stations could incorporate repeaters to compensate for junction signal losses if required.

The spurs 2 would preferably have a minimum capacity of 2.5 Gigabits per second with a maximum capacity equal to that of the backbone loop. There is no reason why the spur should not have greater capacity than the backbone loop, and this could occur during upgrading of the system, but the capacity of the spur above the capacity of the backbone loop could not be used.

Where the spurs run along natural watercourses such as rivers the spur cables should be buried in a trench beneath the river bed when possible and may be further encased in a rigid or semi-rigid pipe for further protection. Although running spur cables below river beds is preferred, it may be necessary to run the spur cables beneath the river banks in order to avoid weirs, locks or other obstructions in the river bed or where geological conditions make a trench beneath the river bed unusable.

Where convenient, the spur cables may also be run along artificial watercourses. Where the spur cables are run along canals it may be convenient to run the cable in a trench beneath the canal towpath rather than along the canal bed in order to avoid damage to the canal structure. The cable could be further encased in a pipe for protection as required. Similar considerations may apply in urban areas where rivers have been enclosed within artificial banks and effectively canalised.

Using currently available fibreoptic technology a maximum spacing between the routing and switching stations 3 or intermediate repeaters can be as much as 600 to 1000 kilometres. Accordingly, since the total length of the UK coastline is around 2,500 kilometres there will be no technical difficulty in arranging for the routing and switching stations 3 to be placed sufficiently close together for the system to operate without intermediate repeaters.

In Figure I a system with 22 routing and switching stations 3 is shown. The precise number of routing and switching stations 3 used can be varied as required by the expected traffic levels, but is preferred that at least 12 routing and switching stations 3 be provided. If upgrading of the system requires the addition of more spurs, this can be carried out either by providing additional spurs from the existing routing and switching stations 3 or by providing additional routing and switching stations 3 to support the additional spurs. Such additional routing and switching stations 3 can be provided by replacing a single section of the backbone loop cable 4 with two sections connecting the new routing and switching station 3 to the adjacent routing and switching stations 3 or new cables could be provided in parallel with the existing cable 4 to increase the redundancy and capacity of the system.

In order to maximise redundancy it is preferred that the capacity of the backbone loop 1 be constant around the whole loop. However, where very large amounts of traffic occur on particular sections of the loop it may be desirable to increase the capacity of these sections above the capacity of the rest of the loop. For example, it may be necessary to increase the capacity of the loop sections in the South East of England near London to cope with higher traffic volumes than the sections of the backbone loop passing around the North of Scotland. However, this will reduce the level of redundancy provided by the system.

There are a number of options for the arrangement of the spurs and lower level connections linked to the spurs. The spurs could be arranged as simple point-to-point trunk and branch type systems where end routers or switches connected to users are linked linearly through a local backbone router to a spur and on to the backbone loop. Alternatively, multiple spurs from each backbone routing and switching station 3 may be arranged in a logical ring with either a single or dual loop structure. As a further alternative, spurs from different ones of the routing and switching stations 3 could be interconnected to form a mesh network.

Any of these arrangements, or other known network architectures, could be used and in practice it is likely that different arrangements will be used in different parts of the network.

It is preferred that each routing and switching station 3 connects multiple spurs to the loop backbone 1 and that these multiple spurs are themselves arranged in a logical ring structure. For example, a ring of spurs running at 10 Gigabits per second and connected to a routing and switching station 3 would itself be connected to one or more further rings with an equal or lower capacity.

Spurs from the routing and switching stations 3 may run undersea to connect to islands such as the Channel, Hebrides, Orkney or Shetland Islands as well as running inland.

The backbone loop itself may be connected at some or all of the routing and switching stations 3 to other communications networks.

As explained above, the basis of the invention is the provision of a communications system backbone loop around the coast of Ireland with routing and switching stations supporting spurs of this loop. The spurs run inland along watercourses and multiple spurs may be supported by each routing and switching station. It should be understood that this does not imply that the multiple spurs supported by each routing and switching station must run along the same water course, although this is possible. Where multiple spurs are connected to a single routing and switching station the spurs can be run up different watercourses in the same area by running the spurs undersea along the coast and then into the watercourses at river mouths. Because of the ability of fibreoptic cables to support links between stations hundreds of kilometres long, the additional cable length required to run the spurs out to sea and along the coast should not have any impact on performance.

Though it is preferred to run the spurs and subsidiary branches of the spurs along watercourses where possible in order to simplify setting up the network, it is not essential that all spurs run along watercourses and it will of course be essential in order to connect to users that at some point the spurs or branches from the spurs are taken out of watercourses to physically connect to users on land or to other communications networks.

In Figures 1 and 2 the physical and logical arrangement of a first embodiment of a communications network according to the invention for the UK mainland is shown.

In order to extend this to cover the whole of the United Kingdom or the whole of the British Isles, that is the United Kingdom and the Republic of Ireland, spurs could be run across the Irish sea from the loop backbone and up suitable water courses in Northern Ireland and the Irish Republic. ΙΕΟ 1 0345 However, in order to extend the system to cover the whole of the United Kingdom and Ireland it is preferred to extend the loop backbone around the whole of the British Isles.

Referring to Figure 3 a first logical illustration of a second embodiment of the invention in which the loop backbone 5 extends around the whole of the British Isles is shown.

An alternative structure according to a third embodiment of the invention is shown logically in Figure 4 and physically in Figure 5 where the system has been extended to comprise two loops 1 and 6, the first loop 1 extending around the UK mainland similarly to the first embodiment and the second loop 6 extending around Northern Ireland and the Irish Republic. The two loops 1 and 6 are connected in a logical figure of eight double ring.

As can be seen in Figure 5, a convenient location to link the first and second rings 1 and 6 is the Isle of Man 7. However, additional connections between the two loops 1 and 6, such as link 8 could be provided to increase redundancy.

It will be realised that the specific geographical locations of system components, system capacity and numbers of routing and switching stations and spurs described above and shown in the figures are intended purely as illustrative examples and do not limit the scope of protection provided, which is defined by the appended claims.

In the specification the terms “comprise, comprises, comprised and comprising” or any variation thereof and the terms “include, includes, included and including” or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa.

The invention is not limited to the embodiment hereinbefore described, but may be varied in both construction and detail within the scope of the claims.

Claims (7)

Claims:

1. A communications network having a loop backbone passing around Ireland and a plurality of spurs running inland, the loop backbone being formed by a plurality of switching stations connected by fibre optic cables which run undersea for at least part of their length, the spurs being connected to the loop backbone by the switching stations, being formed by fibreoptic cables and running inland along waterways.

2. A network according to claim 1, in which the switching stations are on land.

3. A network according to claim 1 or claim 2, in which at least some of the switching stations connect multiple spurs to the loop backbone.

4. A network according to claim 3, in which the multiple spurs form a loop structure.

5. A network according to any preceding claim, in which spurs running along rivers run below the river bed for a substantial part of their length.

6. A communications network according to any preceding claim, in which the network is able to support Internet compliant traffic.

7. A communications network substantially as shown in or as described with reference to any one of the accompanying drawings.