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     1.4 +\chapter{The future of communication}
     1.5 +As globalization proceeds, long distance communication becomes more and more important. This chapter tries to locate trends in communication methods and their impact on the future for communication. The insights gathered from the analysis will be applied to \masqmail, afterwards.
     1.6 +
     1.7 +
     1.8 +\section{Communication methods}
     1.9 +Today's long distance communication methods are either written or spoken information. And on the other side, they can be classified by the time between responses.
    1.10 +
    1.11 +A classification of long distance communication methods is shown in figure %\ref{fig:}.
    1.12 +% slow     |              |             |
    1.13 +%          |              | letter      | days
    1.14 +%          |              |             |
    1.15 +%          |              |             |
    1.16 +%          | answering    | email       |
    1.17 +%          |   machine    | telefax     | few seconds
    1.18 +%          |              | SMS         |
    1.19 +% fast     |              |             |
    1.20 +%          | telephone    | IM          | real time
    1.21 +% -----------------------------------------------------
    1.22 +% response | spoken       | written     | delivery time
    1.23 +
    1.24 +% TODO: find reference literature
    1.25 +
    1.26 +\subsection{Speed}
    1.27 +Communication gets faster in general. Slow mediums as letters get substituted by electronic mail, which is delivered within seconds. Also communication becomes more transmitted through digital channels. This can be seen at the telephone which's information is now more and more transported in bits over the internet link. Also telefaxes are succeeded by email or are transported within email. Instant messaging can be seen as the written couterpart to the telephone; not to substitute it completely, but to be used if it is more useful for the information to transmit.
    1.28 +
    1.29 +Many of the digital communication methods gained success by beeing cheaper than their counterparts. One example here is instant messaging in contrast to the telephone. As phoning costs fell, it became more popular again. The last years showed, that communication cost degreased dropped generally, caused by the transport through digital channels. And nothing to see, that would make them rise again.
    1.30 +
    1.31 +It seems as if in future will be low-cost communication methods available, which will be digitally transmitted.
    1.32 +
    1.33 +
    1.34 +\subsection{Variety}
    1.35 +Regarding the variety of communication methods shows a change, too. Communication systems are more easy to establish today, so more get established. This leads to more methods a person uses. But not only in the amount, also in parallel. For example when two people talk to each other on the phone, one might send a URI\footnote{Uniform Resource Identifier} by email meanwhile, because oral communication is not well suited to exchange such data. Another example for in parallel used communication channels is video chatting. Ony typically sees the other person, talks to it, and additionally has a instant messaging facility for exchanging written information.
    1.36 +
    1.37 +Parallel usage of different kinds of communication channels will be important in future. The most common combinations are one for spoken and one for written information. But one for dialogs and one for sending documents will be important too.
    1.38 +
    1.39 +
    1.40 +\subsection{Hardware}
    1.41 +Next about the hardware needed for communicating. On the one side stands the telephone, now available as the mobile phone. It provides spoken dialog by calling, spoken messages with the included answering machine and written messages in form of short message service. On the other side stands the letter and its relatives. They need pen and paper, a telefax machine or in most today's cases a computer. They typically send documents, only instant messaging is focused on dialog.
    1.42 +
    1.43 +The last years finally brought the two groups together, with \name{smart phones} being the merging element. Smart phones are computers in the size of mobile phones. They provide both functions, using it as telephones and as computers.
    1.44 +
    1.45 +It matches well the requirements of telephoning and short message service, for which it was designed of course. Also providing being suitable for instant messaging in what is needed additionally to the telephone and short message service. The only problem is the minimal keyboard available to insert text. This also affects writing documents in case of email. It can be done but not very comfortably. Further communication methods include voice and video messages.
    1.46 +
    1.47 +This leaves us with the need for ordinary computers for the field of exchanging documents, and as better input hardware for all written input.
    1.48 +
    1.49 +
    1.50 +
    1.51 +\section{Trends for electronic mail}
    1.52 +The previous section stated that electronic mail will still be important in future to complete the communication methods provided by phone and instant messaging.
    1.53 +
    1.54 +But will emailing in future not be the same as emailing now. This will mainly affect how email is transfered.
    1.55 +
    1.56 +\subsection{Provider oriented emailing}
    1.57 +Today's email structure is heavily dependent on email providers. This means, most people have email addresses from some provider. These can be the provider of their online connection (e.g.\ \NAME{AOL}, \name{T\~Online}), freemail provider (e.g.\ \NAME{GMX}, \name{Yahoo}, \name{Hotmail}) or provider that offer enhanced mail services that one needs to pay for. Outgoing mail is send either with the webmail client of the provider or using \name{mail user agent}s sending it to the provider for relay. Incoming mail is read with the webmail client or retrieved from the provider via \NAME{POP3} or \NAME{IMAP} to the local computer to be read in the \name{mail user agent}. This means all mail sending and receiving work is done by the provider.
    1.58 +
    1.59 +The reason therefor is originated in the time when people used dial-up connections to the internet. A mail server needs to be online to receive email. Sending mail is no problem, but receiving it is hardly possible with an \MTA\ being few time online. Internet service providers had servers running all day long connected to the internet. So they offered email service.
    1.60 +
    1.61 +\subsection{Provider independence}
    1.62 +Nowadays, dial-up internet access is rare; the majority has broadband internet access paying a flat rate for it. So being online or not does not affect costs anymore, even traffic is unlimited. Today it is possible to have an own mail server running at home. The last technical problem remaining are the changing \NAME{IP} addresses one gets assigned every 24 hours. But this is easily solvable with one of the dynamic \NAME{DNS} services around; they provide the mapping of a fixed domain name to the changing \NAME{IP} addresses.
    1.63 +
    1.64 +Home servers become popular in these days, for central data storage and multi media services. Being assembled of energy efficient elements, power consumption is no big problem anymore. These home servers will replace video recorders and music collections in the near future. It is also realistic that they will manage heating systems and intercoms too. Given the future leads to this direction, it is a logical step to have email and other communication will be provided by the (or one of) the own server aswell.
    1.65 +
    1.66 +After \mta{}s have not been popular for users in the last time, the next years might bring them back to them. Maybe in a few years nearly everyone will have one running at home \dots\ possibly without knowing about it.
    1.67 +
    1.68 +
    1.69 +\subsection{Is email future-safe?}
    1.70 +It seems as if electronic mail or a similar technology has good chances to survive the next decades. This bases on the assumption that it always will be important to send information messages. These can be notes from other people, or notifications from systems (like a broken or full hard drive in the home server, or the coffee machine ran out of coffee beans). Other communication technologies are not as suitable for this kind of messages, as email, short message service, voice mail, and the like. Telephone talks are more focused on dialog and normally interrupt people. These kind of messages should not interrupt people, unless urgent, and they do not need two-way information exchange. The second argument appies to instant messaging too. If only one message is to be send, one does not need instant messaging. Thus, one type of one-way message sending technology will survive.
    1.71 +
    1.72 +Whether email will be the one surviving, or short message service, or another one, does not matter. Probably it will be \name{unified messaging}, which includes all of the other ones in it, anyway. \MTA{}s are a kind of software needed for all of these messaging methods---programs that transfer and receive messages.
    1.73 +
    1.74 +
    1.75 +\subsection{Pushing versus polling}
    1.76 +The retrieval of email is a field that is about to change now. The old way is to fetch email by polling the server that holds the personal mail box. This polling is done in regular intervals, often once every five to thirty minutes. The mail transfer from the mail box to the \name{mail user agent} is initiated from the mail client side. The disadvantage herewith is the delay between mail actually arriving on the server and the user finally having the message on his screen.
    1.77 +
    1.78 +To remove this disadvantage, \name{push email} was invented. Here the server is not polled every few minutes about new mail, but the server pushes new mail directly to the client on arrival. The transfer is initiated by the server. This concept became popular with the smart phones; they were able to do emailing, but the traffic caused by polling the server often was expensive. The concept workes well with mobile phones where the provider knows about the client, but it seems not to be a choice for computers since the provider needs to have some kind of login to push data to the computer.
    1.79 +
    1.80 +The push concept, however could swap over to computers when using a home server and no external provider. A possible scenario is a home server receiving mail from the internet and pushing it to computers and smart phones. The configuration could be done by the user through some simple interface, like one configures his telephone system to have different telephone numbers ring on specified phones.
    1.81 +%FIXME: add reference to push email
    1.82 +
    1.83 +
    1.84 +\subsection{Internet Mail 2000}
    1.85 +Another concept to redesign the electronic mail system, but this time focused on mail transfer is named ``Internet Mail 2000''. It was proposed by Daniel J.\ Bernstein, the creater of \name{qmail}. Similar approaches were independently introduced by others too.
    1.86 +
    1.87 +As main change it makes the sender have the responsibility of mail storage; only a notification about a mail message gets send to the receiver, who can fetch the message then from the sender's server. This is in contrast to the \NAME{SMTP} mail architecture, where mail and the responsibility for it is transfered from the sender to the receiver.
    1.88 +
    1.89 +\name{Mail transfer agent}s are still important in this mail architecture, but in a slightly different way. Their job is not transfering mail anymore---this makes the name missleading---they are used to transport the notifications about new mail to the destinations. This is a quite similar job as they do in the \NAME{SMTP} model. The real transfer of the mail can be done in any way, for example via \NAME{FTP} or \NAME{SCP}.
    1.90 +
    1.91 +
    1.92 +
    1.93 +
    1.94 +\section{What will be important}
    1.95 +%which MTA has a good position
    1.96 +
    1.97 +
    1.98 +\section{\masqmail\ in five years}
    1.99 +%requirements
   1.100 +%which parts to do
   1.101 +%how to make masqmail future-safe
   1.102 +
   1.103 +
   1.104 +\section{How would \masqmail\ be designed now}
   1.105 +%what would be needed
   1.106 +%would one create it at all?