need LAN vs WAN design advice for VFP 8.0 5

[jrumbaug]

I have a VFP 8.0 project that will link 4 doctor offices. 6 computers at the main location and 2 at each of the other 3 for a total of 12 computers. There will be about 20 tables holding about 100 megs of data. They will be entering services and info for about 60 patients a day. At an estimated total of 20 differnet entries per patient, I expect the number of read/writes to be about 1,200 per 8 hours or 2 a minute.

For a network of this size I ask:

QUESTION 1: Since Foxpro does the processing at the client, not the server, will it work the same on a WAN as it would an a LAN?
QUESTION 2: What would be a typical hardware recomendation for the link between the Satilite offices and the main office where the data is stored?
QUESTION 3: Any program changes I should consider since this is a WAN rather than LAN

 

[Mike Gagnon]

jrumbaug

If budget is not an issue, I would recommend a powerful enough server centralizing one single application, using Citrix Metaframe with Windows 2000 server. But this isn't really a VFP issue, since this suggestion would apply to any application.

QUESTION 1: Since Foxpro does the processing at the client, not the server, will it work the same on a WAN as it would an a LAN?

If you put data and application on the server, the processing would be done at the server side (hence the suggestion of a powerfull enough server, perhaps dual processors and lots of RAM and SCSI drives.)


Mike Gagnon

If you want to get the best response to a question, please check out FAQ184-2483 first.

 

[wgcs]

There are really several questions here:

1) How to connect the satellite offices with the data store.
1.a) Direct-Dialup
1.a.1) Regular Telephone (Slow)
1.a.2) ISDN/other 'leased line' (fast)
1.b) Internet
1.b.1) Regular Telephone Dial-up ISP (slow)
1.b.2) ISDN/Cable/ASDL (fast)
1.b.3) Other Leased Line (fast, $$$ expensive)
1.c) How to locate the data store if using the internet
1.c.1) Dedicated server (expensive)
1.c.2) Leased Server (cheaper)
1.c.3) Dynamic Dns (cheap, not 24/7) DynDns.org, selfhost.com

2) How to implement the multi-user VFP program?
2.a) Terminal Services / File Access Multi-user: Program always runs on server
2.a.1) Only screen images are transferred on network. Acceptable on a fast connection.
2.b) Client-located EXE / File Access Multi-user:
2.b.1) Lots of data transfers across the network
2.b.2) File locking presents index corruption problems
2.c) Client-located EXE / SQL Server (or MSDE, or MySql)
2.c.1) Little data transfers across network
2.c.2) Fast client program
2.c.3) Requires setup of the DB server, and possible licensing if MSDE or MySql is deemed insufficient. (However, for the scope mentioned, it's well-within MSDE's defined limits).

Personnally, I'd choose:

1.b.2, 1.c.3 and 2.c:

Internet communication
Server Runs MySql or MSDE
Server has DSL or Cable connection
Server uses a Dynamic DNS service
Clients run VFP, access the MySql/MSDE server across the internet. MySql/MSDE security & access rights MUST be setup properly... no bad passwords!
Clients can use DSL/Cable or Dial-up internet access.

 

[Steve Bowman]

This is a real out there plan! But if you have not started to build yet it would be worth the looking into working with newer methods of application building. I will explain a bit. I have some of the same issues needing to give access for updating records searching records etc... for our entire client base and for those who choose to I supply a "fat client" internet connected. I have built several neutral WebServices (Soap) some VFP and some .NET for the updating, searching and so on. This architecture as I work with it is quickly becoming my method of choice. Most of the Client Applications are pure VFP and MS Soap Client. For years I chugged along with Network (LAN) programming in an increasingly WAN world, and at the end of the day it just doesn't make sense to build new (WAN) applications in a (LAN) architecture.

Steve Bowman
steve.bowman@ultraex.com

 

[EzLogic]

Keep in mind, that: What happens when the DSL/ISDN goes down at the doctors office. Does that mean he cannot access teh server?

A Slow dialup must be in place.


Ali Koumaiha
TeknoSoft Inc
Farmington Hills, Michigan

 

[ramani]

Hi Mike Gagnon

If you put data and application on the server, the processing would be done at the server side (hence the suggestion of a powerfull enough server, perhaps dual processors and lots of RAM and SCSI drives.)

I disagree with you on this. The processing will not be done at the server side on LAN unless VFP is only a front-end and a data server is used. OR am I reading something wrong ?

That is the reason for distributing the applications in a LAN environment while the shared data is on the server side. This FAQ could be helpful on this..
An Application starter (with auto copy from server into local station).
faq184-4492


____________________________________________
ramani - (Subramanian.G)

http://winnersoft.coolfreepages.com/

When you ask VFP questions, please add VFP version.
Merry Christmas & Happy New Year

 

[Mike Gagnon]

Ramani

I disagree with you on this. The processing will not be done at the server side on LAN unless VFP is only a front-end and a data server is used. OR am I reading something wrong ?

I believe the poater is asking about a WAN not a LAN. will it work the same on a WAN

Citrix Metaframe is a WAN and not a LAN. Citrix metaframe is like a super PCAnywhere, where you log in from outside the LAN environment and access the server directly and use the application that sits on the server (including application and data). Thus the processing is done at the server side.



Mike Gagnon

If you want to get the best response to a question, please check out FAQ184-2483 first.

 

[jrumbaug]

I want to thank everyone for the information. I have learned soooo much these last few days. I think I have made a decision.
1) Citrix Metaframe sounds good, but I'm concerned about the cost. I believe it is currently about $1,000 per client. I am also worried about the hardware requirements.
2) I had considered replicating the database localy at all 4 locations, but I have been given another consult that this is a dificult to maintain.
3) I have considered just mapping a drive via a dsl or t1 connection. But again, I'm concerend about monthly costs and stability.
4) It looks like I'm going with VFP front end and SQL on the server. In a few days I'll probably be posting questions about cursoradapters with SQL.

Jim Rumbaugh

 

[badukist]

I currently work on a project with VFP frontend and Firebird as server. The app must work well over an existing DSL connection and in our LAN. I used the same design for remote offices clients as for local LAN users.
Some details:
-all data for lookup, static or not frequently modified tables are downloaded locally and used for lookups and what is needed to set up transactions details.
-at server, all changes are logged using triggers, so is easy for clients to check if those tables are changed. In this case, download only changes from log tables and apply them to local tables.
-we use a compressed tunnel utility , ZeBeDee, that can compress traffic between clients and server.

Works so well, that is hard to notice that app works over a slow connection.

 

[jimoo]

So many options, and I'll throw in one more solution. You can look at Rick Strah's Web-Connect product at

http://www.west-wind.com

You can write a fat web-app that access the data over the net. You can even create an work-offline module in case the connection is down or if you needed to take the app with you and there is no connection available.

I have a sample app, on mysite, but it does not contain the source code. Unfortunately, we have too much invested in the source code at this time and have not recovered our development costs so we can't post it free.

However, the code was developed by looking at Rick's samples and posting questions to his message board.

If you're interested in seeing how it works you can download and install the sample from my site. They are under "samples"

The sample that fits this need the most is called, "Two-Way Desktop Application (Web-Service)"



Jim Osieczonek
Delta Business Group, LLC

http://www.deltabg.com

 

[tekytippy]

We actually link several sites just using Terminal Server. Its a lot cheaper than Citrix and works great.

All out data is stored at the head office on a data server and the remote sites dial in over broadband to a terminal server also situated at head office. As screen session information and printed details are the only data sent to the remote sites this works well.

Have more than one terminal server at head office as a backup!

 

[LSV]

I have virtually the same project you do.
Since I had FoxPro as client and data server on a LAN, (I actually tried mapping from remote office - EXTREMELY slow) the natural step, for remote office was:

VFP 8 as front end, SQL Server 2000 as back end. Project is near completion. Feel free to ask me any specific questions, as I can see you will encounter the same experiences.

Cheers