THE BASICS OF REMOTE
VIDEO ACCESS
English Version1.0
ww.lorexcctv.com
Copyright © 2006 Lorex Technology Inc.
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Background to the Technology
Types of Surveillance Systems
In discussing video surveillance systems there are three types to consider;
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Direct Surveillance
Local Network Surveillance
Remote Network Surveillance
Direct Surveillance Systems display the video images on a monitor or PC-system screen without using a data
network, as shown in the following figure. Only the cameras connected to the monitor or the PC-system can be
viewed on their respective systems;
PC Video System
Monitor
Figure 1: Direct Surveillance Systems
Network Surveillance systems use a data network to connect to the video devices, so that the video signals can
be accessed using a digital data protocol across the network. To do this the devices need to be designed for
Internet Protocol (IP) networking.
What is the difference between Local and Remote Network Surveillance?
If you wish to view the video images from any of the network-enabled video devices using a viewer application or
web browser that is connected to the Local Area Network(LAN), such as the PC(a) in the figure below, then this
is considered local network surveillance. In this case the video signals never reach the Internet and there is no
special setup required. If you wish to view the video from a network location not directly connected to the LAN
you must go through the Internet. This is considered remote network surveillance and remote access
configuration is required. The two figures below illustrate the differences between these.
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PC Video
Network Switch
Network Camera
PC (a)
Figure 2: Local Network Surveillance
In the figure 2 above, the video is displayed on a computer, PC(a), that is connected to the Local Area Network.
In the following figure 3, the video is being monitored by a computer PC(b) that is attached to the Internet at
some remote location. Hence all connections from the remote computer needs to traverse the Internet Gateway
between the Internet, or Wide Area Network (WAN) and the Local Area Network (LAN) to reach the Video
device. The video signal need to traverse the gateway in the reverse direction.
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PC Video System
Monitor
Video Server
Gateway/Switch
Network Camera
PC (b)
Figure 3: Remote Network Surveillance
When you are viewing the video signals across the Internet, you need to consider;
How do I configure my gateway/router?
This question depends on the particular model of router you have. Nearly all models support some form of
inbound TCP/IP routing, or port forwarding, and there are many resources to help you to forward an incoming
connection to your video device, including online guides and technical support from Lorex Technology Inc.
(http://lorexstore.strategcvista.com/article.aspx?aid=3). You can also refer to www.portforward.com for
details on a large variety of routers.
How to I locate the video devices?
The second question depends on the nature of your Internet connection. If you are fortunate to have a static IP
Address, then this is all you will need. Static IP Addresses are typically available to corporations and
organizations that run servers. Service providers charge substantially more for static IP addresses and will often
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rent them in blocks. If, like most broadband Internet users, you have a service provider who assigns you a
temporary IP Address and changes it from time to time, then you will need to sign up for a Dynamic DNS service.
What is the difference between a Static and Dynamic IP Addresses?
IP Addresses are the numbers used by the Internet Protocol(IP) to identify your computer or device. Every
computer or device that wants to communicate over the Internet must have an address, unique to that computer
or device. Internet Service Providers can issue IP Addresses in two ways;
Static assignment: This is simply determining the address to be used and (usually manually) entering it into the
computer or device. The number will not change, and may not be used by any other device.
Dynamic assignment: This utilizes a protocol calls Dynamic Host Configuration Protocol (DHCP) that generates
an IP Address and leases(i.e. provides) it to your computer or device for a predetermined length of time. After
that time expires, your computer or device must request a new IP Address. There is usually no guarantee that
the new IP Address will be the same as the old one, and in many practical instances it isn't.
What is the difference between an internal and an external IP Addresses?
Every device that communicates over the Internet must have a unique IP Address. These are all external, or
public, IP Addresses. However, there are ranges of IP Addresses that are excluded from this address space, so
that they can be used internally by devices connected via Local Area Networks. These are internal, or private, IP
Addresses. If devices that are using internal addresses wish to communicate with devices on the Internet, they
must pass their messages through a network gateway, which will map the internal IP Addresses into a valid
external IP Address. This is called Network Address Translation (NAT), as shown in the following figure.
Internet
LAN
IP Address in msg
on the Internet
from: 216.176.57.75
to: 216.099.34.23
IP Address in msg
on the LAN
from: 192.168.1.55
Device
Gateway/Router
to: 216.099.34.23
Figure 4: Example of Network Address Translation
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What is port forwarding?
Internet Protocols use IP Addresses to identify devices on the Internet, and ports to identify specific services
within the devices. When a network gateway maps the messages coming from the Internet to individual internal
IP Addresses(i.e. devices) on the LAN it does so on a per port basis. This is known as port forwarding.
Internet
LAN
Device A
Device B
msg to
216.176.57.75
port 8000
Gateway/Router
msg to
216.176.57.75
port 8001
Figure 4: Example of Port Forwarding
What is Domain Name Service (DNS)?
As most Internet users are aware, servers on the Internet are usually identified by their Universal Resource
Locators, or URLs. These are protocol identifiers and domains and subdomains arranged in an hierarchy
separated by periods ('.'), for example; http://www.strategcvista.com However, the real network addresses that
are commonly used to communicate over the Internet are called IP Addresses. The device that converts a URL
into the associated IP Address is called a name server. When your computer wants to access an Internet site, it
first makes a call to the name server to resolve the URL into an IP Address. Then it will access the named site.
Name servers do more than just translate URLs. They also share their information with other name servers to
form an hierarchical, distributed database, collectively called a Domain Name System (DNS).
What does a Dynamic DNS service do?
The DDNS service has 2 components to it. When you register your device, you are assigned a unique identifier
that you program into your video device. You are also assigned a fixed URL that corresponds to your video
device. Then from time to time or when the IP Address of your device changes, this device sends a message to
the DDNS server on the Internet which instructs the server to capture and record your real network IP address
and propagate it into the DNS.
When you want to locate your video device, you will enter the fixed URL into the web browser or video application
address field. No matter what your real IP Address is at the time, the DNS system will be able to translate the
URL into the current IP Address and enable the browser or application to communicate with the video server, via
the network router. There are free and commercial DDNS services available. Both of these work the same way,
but the commercial (paid) services guarantee a higher level of service. lorexcctv.net is a DDNS service that
is bundled with Lorex Technology Inc. Remote Access products and provides a reliable and easy way to connect to
these devices. There are no recurring payments for this service.
Implementing Remove Access
Where is the best place to start?
The first step in implementing remote access is to get Local network access working properly, using the same
client computer application or browser as you intend to use for remote access later on. Use the instructions
provided with the product, as setup methods will vary from product to product. There may well be a utility PC-
application to help you do this.
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Once this is up and working you should then configure the gateway/router for remote network access and finally
sign up for DDNS service and then set up the video device to work with the service.
What does setting up a gateway/router involve?
Since there is a wide variety of gateway/routers available, you may have one that is not explicitly described in the
video device setup documentation. In this case use the video device setup information and the gateway/router
manual information to translate the port forwarding instructions to match the gateway/router being used. If this is
not successful, use the Internet to find the setup information, for example by visiting
If this is still not sufficient, make use of the available e-mail or phone dial-in technical support.
You can test that the external Internet data path is correct by entering the external IP Address into the client
video application or browser. If the port forwarding has been done correctly, this should result in the same video
picture as the local network access. There are a number of ways to find the external IP Address, including
entering the following address in a browser;
Is Dynamic DNS really necessary?
DDNS is necessary if you have an external IP Address that is subject to change from time to time. This will
generally apply to all broadband residential Internet services, including DSL, Cable TV and Wireless Internet. In
addition, the ability to use a familiar URL to access the video, rather than a numeric IP Address, is a good reason
to sign up for the DDNS service.
Note that whenever the IP Address is changed it takes a short while, typically a few minutes, for the DDNS
service to be notified and propagate the change through the network.
What do I need on the client side to display video?
There are a few choices you will have;
1. PC-based client application.
Lorex Technology Inc. provides a Windows-PC software application for each Lorex Technology Inc.
video product that supports remote access. The applications must be installed on the remote
PC and configured with the address of each video device to be accessed.
2. Web-browser access.
Standalone remote access video servers can be viewed using a web browser. All the servers will work with
Microsoft Internet Explorer. Other browsers may also be used if they support Java applets.
Glossary
DDNS
Dynamic Domain Name Service(DDNS) is the service used by a host system (device on a LAN) to register its
current external IP address (as provided by the ISP) with the external DDNS system. This is associated with a
Universal Resource Locator (URL) to make looking up the IP Address possible.
Since many ISP providers change the IP address of the connected computer every several minutes, to connect a
remote system to a host system for remote video surveillance requires that
DHCP
Dynamic Host Configuration Protocol (DHCP), is a protocol used for automating the assignment of Dynamic IP
addresses for computers.
Dynamic IP Address
A Dynamic IP address is an IP address that is leased (i.e. provided) to you automatically by your ISP while you
are on the Internet. Once the lease expires it needs to be renewed and the new IP Address may be different
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from the previous one.
Gateway
A gateway is a device that connects 2 different networks together. The gateway will perform any address and
protocol translations required so that messages can flow between the networks.
IP Address
Computing devices connected to the Internet, are identified by a unique network number. This number is called
an IP Address (IP = Internet Protocol). Each IP Address consists of 4 numbers in the range 0-255, and is written
as; aaa.bbb.ccc.ddd, e.g. 216.176.57.75
MAC Address
The Media Access Control(MAC) Address is your device’s 12-digit network hardware address that identifies the
device on a LAN. The MAC hardware address is unique to each network product.
MAC Addresses follow a specific format mm-mm-mm-ss-ss-ss. The mm’s are the manufacturer’s ID number and
the ss’s identify the product’s ID number.
Network Address Translation (NAT)
NAT is the process by which a device on a LAN, using a private/internal IP Address can communicate with a
device on the Internet via a network gateway. The internal IP Address is translated to the public/external of the
network gateway.
Static (Fixed) IP Address
A Static IP address is an IP address, which never changes, that is provided to you by your Internet Service
Provider (ISP).
URL
The Universal Resource Locator (URL) is a user-friendly name, comprising a protocol, an hierarchy of domain
names and port number(optional), that is entered into an application or web browser address field to access
Conclusion
The information provided here will enable the reader to have a basic understanding of the Remote Network
Access technology and to relate this to the specific remote access setup procedures of the various video device
products.
To find out more about our available products and detail setup instructions, please visit our website at:
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