Why should we not be afraid of broadband and IP communications? asks WebWayOne.
The development of the Internet and the World Wide Web over the past 20 years has been staggering. They have become part of our everyday life and the lifeblood of business. Many confuse them as one and the same, but they are not.
The Internet is a series of computers or servers all linked together across the globe via the Telecommunications Network by powerful Network Routers. These routers have the ability to re-route data traffic to many destinations so that any break in the network can be bypassed to ensure the data traffic is delivered. The Internet is an incredibly resilient data network that relies on the Backbone Telecommunications network to function, and this infrastructure is exactly that which is used by the PSTN.
The World Wide Web (www) is a series of websites stored on computers (servers) around the globe containing information in the form of web pages, or specific data that can be downloaded to a local PC or server. The location of the servers at Telecommunications locations across the globe is called a Point of Presence (POP). Websites are used for news & entertainment (BBC, SKY), information (Wikipedia, AskJeeves), Communications via e-mail (Hotmail, Googlemail), downloads (I-tunes, BBC i-player) and private banking.
Web browsing and downloading from the www is the most popular use of the Internet by consumers; however data transactions or โMachine to Machineโ applications are the most common in business. An Alarm Transmission System (such as WebWay IP/GPRS) is also a Machine to Machine application, and does not use the World Wide Web at all.
Broadband is the Internet service delivery that co-exists with PSTN/voice over the copper last mile (that is, itโs on the same circuit into your home or business as your telephone). At the Local Exchange, the last mile is terminated within a piece of equipment called a DSLAM (Digital Subscriber Line Access Multiplexor). The DSLAM is connected to the backbone. The bandwidth available at the end of the last mile is dictated by the distance your equipment is from the DSLAM, the further away you are, the lower the bandwidth available. As we demand more and more from our service providers, the copper loop becomes the choke point and hence the drive to provide fibre communications direct to the door although improvements in DSLAM technology and the condition of individual circuits have led to increases in performance. Fibre to the door will not only provide high speed access for those who already have broadband, but to those who live outside the range of the Local Exchange/DSLAM.
The capability of the DSLAM to deliver bandwidth is determined by the number of people who have access to it, and how many are accessing the service at the same time. Bandwidth availability is shared amongst its concurrent users and this is known as contention.
Browsing websites and downloading data via the Internet requires varying degrees of bandwidth requirements. Inefficient websites will increase demand on bandwidth, as will downloading large files, such as music, film or images. The larger the file, the longer it will take to download successfully to your computer. If there are a lot of users contending for the bandwidth from the DSLAM, the download time will be affected and this is the most common perception that the โInternet is slowโ.
In addition, contention can be a problem at the POP. Popular websites will generate interest and there may be many people trying to access the site at the same time. The ability for the website to handle multiple concurrent connections depends on the processing power of the servers that host the site and the efficiency of the communications feeding into the POP. If a website attracts huge demands from users the delivery will become slower and slower until the site cannot function any longer, commonly referred to as a โcrashโ.
Therefore the Internet itself is not slow or unreliable, it is use of the World Wide Web, inefficiencies of the website (or service delivery to it) and contention either locally or at the POP that combines to create this perception to the end user.
Businesses and ATS providers utilise โMachine to machineโ applications for data communications. They use the Internet to allow one device to communicate directly with another. Therefore machine to machine communication is very similar to making a direct telephone call in the PSTN world. The transmitting device will have an individual number (this is an IP address rather than a telephone number) as will the equipment that is receiving the โcallโ.
Both ends of the systems will be located behind a firewall. In basic terms the firewall is used to protect the device (or Local Area Network, LAN) from unsolicited access or attack. Therefore the firewall will only accept communication access inbound from trusted sources. DOS attacks will be identified as unsolicited inbound access which firewalls will recognise and simply ignore as they are not from trusted sources.
Bandwidth requirement is dictated by the application and the efficiency of the communications delivery at the POP. In an ATS, the POP is the Monitoring Centre Transceiver (MCT) at the ARC itself (or the host within the hosted system). The communications delivery is diverse and scalable to allow for concurrent connections from many SPTs that are deployed in the field. Bandwidth requirements for polling messages and alarm messages are very small. For example a WebWayOne SPT uses a very efficient delivery mechanism. IP/GPRS or GPRS/PSTN SPTs will require a maximum of 160bytes of data for each message which is encrypted (so that the message cannot be read) and sequenced (so that it cannot be replayed). This means that contention has no effect upon the ability for a broadband based SPT to communicate unlike browsing the www.
Corporate businesses utilise the public Internet but have an obvious desire to protect any confidential information or data as it is communicated across the network. In these instances the business will purchase a โManagedโ or โPrivateโ Network from a provider. This simply means that the network provider deploys equipment (routers and switches) which run software that connects all of its remote locations or branches together. The branches then operate as if they were communicating on a LAN. For example, a chain of stores are all connected to the public network via a broadband circuit, however the routers installed in each branch will only communicate with other routers belonging to the business. Unless permission is granted by the head office there is no access to the public Internet or the www. The Managed Network is there to provide secure and private communications for the business.
Unless the corporate is willing to invest in diverse network cabling into the building or to request dedicated bandwidth allocation from the service provider, each branch will be subject to network contention in the same way as any other user of the public Internet.
The telecommunications network is designed to be efficient and provide a general availability of greater than 99.8% for all forms of communication.
Managed networks do not increase the reliability of the network. They provide added data communications security to larger businesses through software deployment.
IP based Alarm Transmission Systems do not utilise the World Wide Web for transmission purposes.
IP based Alarm Transmission Systems have very low bandwidth requirements and are therefore not susceptible to network contention.
Alarm data signalled across the Internet should be encrypted and sequenced so that the messages cannot be read or replayed (WebWayOne SPTs use 128AES encryption, sequencing and substitution protection on both IP/GPRS & GPRS/PSTN solutions).
Denial of service (DOS) attacks to PSTN, ISDN and broadband are a threat and it is the responsibility of the signalling provider and the ARC to protect against and identify these through deployment of well proven industry standard security techniques and communications resilience.
In conclusion
An ATS can utilise any form of communication and all have their own benefits. However the arguments against the use of IP based communications for ATS are based on a lack of understanding or misinterpretation of basic communication techniques. On the other hand, those arguments as to why PSTN is allegedly more reliable are flawed in much the same way and we must remember that PSTN, ISDN, Broadband and GSM services all utilise the public and common telecommunications network.
