Tracent Technologies - Office Connectivity White Paper

Small Office Connectivity White Paper
by Stuart W. Stevenson, CPA, MCP
Tracent Technologies, Inc.

Overview

This document outlines several general approaches to implementation of Internet connectivity for an office LAN (Local Area Network) environment.

The objectives are as follows:

Provide inbound and outbound Internet e-mail capability for all office personnel to facilitate communications with customers, vendors, prospects, etc.

Optionally, to provide office personnel the ability to access World Wide Web sites (WWW) from their desktop without the need for individual modems and phone connections.

The options presented are as follows:

Option 1: Modem Based E-Mail Only Solution

Option 2: Modem Based Proxy Solution

Option 3: ISDN Dial-Up Solution

Option 4: Dedicated ISDN 128k Solution

If you have any questions or comments regarding this information, or if you would like to discuss specific options for your location, please contact the author at stuart@tracent.net.

Option 1: Modem Based E-Mail Only Solution

This approach will utilize a dial-up Internet connection and a local e-mail server to periodically connect to the internet via modem and collect all incoming mail, and forward all outgoing mail.

Users on the Internet would send messages to anyone@yourcompany.com, which would be routed to a "store and forward" e-mail server on the Internet. According to a pre-determined schedule, a local e-mail server at your office would dial into the Internet via standard phone line and modem. During these connections, all inbound mail waiting on the Store and Forward server will be downloaded to your local mail server. Likewise, any outbound mail will be uploaded from your local server to the Store and Forward server for delivery on the Internet.

Once inbound messages are downloaded to the local server, they will be "parsed" to determine local addressees, and then placed in the appropriate local mailbox.

This solution has the following advantages and disadvantages:

Advantages	Disadvantages

Low cost An existing modem or fax phone line can be used No firewall needed for internal security Standard single-user "dial-up" internet account can be used	Inbound and outbound mail can be delayed due to polling schedule No ability to access WWW from the local desktop Local administration required for local mail server Consumes local resources on a Windows95/98 or Windows NT computer to act as the mail server

Approximate Cost of this solution:*
Description	Typical Setup/Acquisition Cost	Typical Ongoing Monthly Cost

Local Email Server Software	$300.00	N/A
Dial-up Internet Access Account	35.00	25.00
56kb Modem	125.00	N/A
Analog phone line**	75.00	55.00
Local Computer to act as a Mail Server	(use existing computer)	N/A
Store & Forward mail service	25.00	25.00

Total	$560.00	$105.00
* Prices shown are typical estimates. Your prices may vary depending on local market conditions and specific requirements of your environment.
** Assumes a new phone line is required. An existing modem or fax line could be used. Phone rates are approximate. Check with your local carrier for specific pricing.

Option 2: Modem Based Proxy Solution

This option is similar to Option 1, with the addition of a Proxy Server to the local network. A proxy server accepts packets of information from local workstations and determines if the message is bound for the Internet or a local address. If addressed to the Internet, the proxy server will connect to the Internet via modem, then forward the packet of information to the appropriate Internet server. A proxy server also provides firewall capability by hiding all internal addresses from the Internet producing essentially a one-way type of connection.

This option places the responsibility to initiate a connection to the Internet with the proxy server rather than the mail server (it too would use the proxy server). The proxy server will automatically connect to the Internet when it detects an outbound network message packet, and automatically disconnect after a pre-set idle period.

It is possible to place both the mail server and proxy server software on the same physical computer. However, performance of that computer would suffer. The mail server software and the proxy software are individually small workloads, suitable to operate in the background on a workstation. If combined on a single workstation, the multi-purpose server should have a dedicated computer.

The local mail server is optional in this configuration. However, without a local mail server, the proxy will attempt an Internet connection every time a user checks for new mail. This could cause the Internet connection to become "nailed" and thus subject to dedicated connection rates, which are significantly higher than dial-up rates.

Advantages	Disadvantages

All local users can access WWW, FTP, Chat, etc. from the Internet via the local network Moderate cost Current "modem" phone line can be used Firewall provides internal security Standard single-user "dial-up" internet account can be used	Inbound and outbound mail can be delayed due to polling schedule Capacity of an analog phone line is practically limited to 1 or 2 simultaneous local users Local administration required for local mail server Consumes local resources on two Windows95/98/NT computers to act as the mail and proxy servers, or a single dedicated Windows95/98/NT computer

Approximate Cost of this solution:*
Description	Typical Setup/Acquisition Cost	Typical Ongoing Monthly Cost

Local Email Server Software	$300.00	N/A
Proxy Server Software	200.00	N/A
Dial-up Internet Access Account	35.00	25.00
56kb Modem	125.00	N/A
Analog phone line**	75.00	55.00
Local Computer to act as a Proxy Server	(use existing computer)	N/A
Local Computer to act as a Mail Server	(use existing computer)	N/A
Store & Forward mail service	25.00	25.00

Total	$685.00	$105.00
* Prices shown are typical estimates. Your prices may vary depending on local market conditions and specific requirements of your environment.
** Assumes a new phone line is required. An existing modem or fax line could be used. Phone rates are approximate. Check with your local carrier for specific pricing.

Option 3: ISDN Dial-Up Solution

This solution differs in that it utilizes an ISDN phone line to connect to the Internet. An ISDN line is a digital phone line available from your local phone company. It carries three signals across the line simultaneously: a 16k "D" channel which is used for telephone system switching, caller ID information, etc.; and two 64k "B" channels, each of which can be used independently for voice/modem/fax or digital data signals. Each B channel has its own phone number and can be used as a normal analog line if the "terminal adapter" includes "pots" (Plain Old Telephone Service) connections. Additionally, both B channels can be "Bonded" together to produce a single 128k connection. This will require a special Internet account and is not available in all areas.

The ISDN line is connected to a "Router." The router attaches directly to your network and routes information packets bound for the Internet to the ISDN line, while leaving local traffic strictly internal. The router we recommend includes an integrated terminal adapter and two POTS ports, so that either B channel can be used as a standard phone line if desired. It also provides an internal proxy/firewall service like that described in Option 2, such that separate proxy server software and computer is not required.

ISDN connections typically require less than two seconds to dial, connect and authenticate with an Internet server. Typical analog modems often require 45 to 120 seconds to accomplish the same tasks. This means that users on a dial-up ISDN connection do not normally realize that the Internet connection is not a permanent connection.

With Option 3 a local mail server is not required. The fast connection times combined with the high speed data transfer rates (2 to 4 times faster than analog modems) make it feasible to have all mail services hosted externally on the Internet. However, you may still want to consider a local mail server so that internal e-mail messages are not sent out to the Internet, only to be retrieved from the Internet by another local user. There is a remote possibility that such messages could be intercepted while they are exposed to the Internet. Also, depending on how frequently users check for new mail, your Internet connection could be kept active for long periods of time, possibly forcing higher dedicated connection rates to be imposed.

Advantages	Disadvantages

All local users can access WWW, FTP, Chat, etc. from the Internet via the local network Moderate cost Fast 64k or 128k connection Connections are initiated almost instantaneously Firewall provides internal security Standard single-user "dial-up" internet account can be used Initial 64k connection can later be upgraded to 128 with no additional hardware or software costs Unused B channel can be used as an additional analog phone line	A new ISDN phone line must be installed If a local mail server is used local administration will be required If no local mail server is used, internal mail traffic will be exposed to the Internet until retrieved by the recipient Some local telephone companies charge for use of ISDN B channels on a per-minute basis.

Approximate Cost of this solution:*
Description	Typical Setup/Acquisition Cost	Typical Ongoing Monthly Cost

ISDN Router/Terminal Adapter	400.00	N/A
Dial-up 64k Internet Access Account	35.00	25.00
ISDN phone line**	75.00	70.00

Sub Total	$510.00	$95.00

Local Mail Server Option
Local Email Server Software	$300.00	N/A
Store & Forward mail service	25.00	25.00

Local Mail Server Total	$835.00	$120.00
- Or -
Remote Mail Hosting Option
Remote Mail Hosting service	25.00	25.00

Remote Mail Host Total	$535.00	$120.00
* Prices shown are typical estimates. Your prices may vary depending on local market conditions and specific requirements of your environment.
** Assumes a new ISDN phone line is required. An existing unused ISDN line could be used. Phone rates are approximate for the Dallas/Fort Worth area and assume a non-metered tariff. Check with your local carrier for specific pricing.

Option 4: Dedicated ISDN 128k Solution

This option is identical to Option 3 with the exception that the connection will be "nailed" and available 24 hours a day, 7 days a week. This option includes static IP addresses for your network, which means that you can host your own Internet Servers if desired. Typically, the only server you would want to consider hosting would be your e-mail.

If you have an internal e-mail server, you would not need an external mail host or store and forward service. Your mail server would be available to send or receive mail at all times, and it would have a permanent Internet address so that inbound messages can find their way directly to your server instantly.

Advantages	Disadvantages

All local users can access WWW, FTP, Chat, etc. from the Internet via the local network Fast 128k connection (twice the speed of option 3, five times the effective speed of option 2) Connection is available continuously Not subject to busy signals when trying to connect during peak periods Firewall provides internal security No external mail services required if local Mail server utilized	A new ISDN phone line must be installed If a local mail server is used local administration will be required If no local mail server is used, internal mail traffic will be exposed to the Internet until retrieved by the recipient Higher ongoing costs

Approximate Cost of this solution:*
Description	Typical Setup/Acquisition Cost	Typical Ongoing Monthly Cost

ISDN Router/Terminal Adapter	400.00	N/A
Dedicated 128k Internet Access Account	595.00	325.00
ISDN phone line**	75.00	70.00

Sub Total	$1,070.00	$395.00

Local Mail Server Option
Local Email Server Software	$300.00	N/A

Local Mail Server Total	$1,370.00	$395.00
- Or -
Remote Mail Hosting Option
Remote Mail Hosting service	25.00	25.00

Remote Mail Host Total	$1,095.00	$420.00
* Prices shown are typical estimates. Your prices may vary depending on local market conditions and specific requirements of your environment.
** Assumes a new ISDN phone line is required. An existing unused ISDN line could be used. Phone rates are approximate for the Dallas/Fort Worth area and assume a non-metered tariff. Check with your local carrier for specific pricing.

If you have any questions or comments regarding this information, or if you would like to discuss specific options for your location, please contact the author at stuart@tracent.net.