|
Using Netvoyager Thin Clients & ADSL for remote sites,
an implementation reality?
Overview
With the availability of business grade ADSL with low contention ratios from
many national carriers, it makes good business sense to consider broadband internet
(ADSL) as a means for remote branch connectivity using thin clients and server-based
computing. This is a more cost effective method of connectivity than the alternatives
such as ISDN, KiloStream or MegaStream services.
The Objective
In this document we will explore the feasibility of using ADSL to connect thin
clients at remote sites to HQ application servers. Thin clients in any environment
require very small amounts of bandwidth to operate, in fact 96kbp is sufficient.
The performance issue is more related to the latency of the packs travelling
between two points than the actual bandwidth. Using ADSL makes this method of
connectivity a practical solution, if implemented effectively.
The Landscape
Many companies already expose their internal networks to the internet to provide
its users with access to remote services, such as web sites and online information
services. This is done securely through properly configured routers and firewalls.
Therefore the concept of connecting the internal secure network to the outside
world is nothing new.
The Method
Connecting branch offices to the head office over the internet as a transport
mechanism is not a major leap in strategy.
As businesses expand, branch offices demand that their connections to central
sites are reliable, secure and provide multiple services. Virtual Private Networks
(VPNs) protect information between remote offices and central sites as it travels
across the Internet. IP Security (IPSec) can be used to guarantee that the data
passing across these VPNs is encrypted, providing another layer of network security.
Further security can be achieved by strict TCP port and site-to-site controls.
Nowadays, most mid-range xDSL routers (sub £500) can be used in branch
offices and provide all the necessary features such as, DHCP, firewalls, IPSec,
VPN and access lists. This reduces the need for expensive routers and servers
in the branch offices. The figure below shows a typical IPSec VPN. Any number
of remote access and site-to-site connections can be involved between branch
offices and central sites.
Adding Netvoyager thin clients to the mix
As the above describes and illustrates how to connect sites with ADSL, now
it is the opportunity to discuss how to add Netvoyager thin clients. With this
design, Citrix MetaFrame and Microsoft Terminal Servers can reside at HQ whilst
providing all the necessary application hosting and serving. The remote site
would only have thin clients and printers, without the need to have any servers
or local administration at the remote site. Therefore, the thin clients connect
to the HQ servers over the ADSL network. This configuration reduces the cost
of computing considerably at the remote site when compared to the traditional
remote server/PC models.
Dual Links
The diagram shows two ADSL links per site. This is an ideal set-up, providing
link resilience and traffic load balancing. In addition to these two beneficial
features, two links are also ideal to drive thin client traffic on one link
and printing traffic on another. This configuration removes the exposure of
non-thin client traffic affecting thin client screen response. It is not essential
to provide two ADSL links per site if the only traffic transversing these links
are ICA and RDP protocols between thin clients and Citrix and Terminal Services.
Relevant links on this topic:
http://support.microsoft.com/default.aspx?scid=kb;en-us;299801
http://www.cisco.com/warp/public/794/dsl_ipsec.html
Disclaimer
This document is for illustration purposes only and subject to change at anytime
without notice.
|
