The White Paper issued by WoMaster explains the redundant gateway mechanism for industrial Ethernet ring network. The White Paper explains the difference between Gateway and Default Gateway and introduces WoMaster's redundant gateway solution.

1. 1
Redundant Gateway Mechanism
for
Industrial Ethernet Ring network
White Paper
Ada Su / FAE Engineer

2. Table of Contents
1. Background ........................................................................... 1
2. Gateway vs. Default Gateway............................................... 1
2.1 What is Gateway .....................................................................................1
2.2 What is Default Gateway .......................................................................2
2.3 How Traffic Moves Through a Default Gateway.................................3
2.4 How to Find Your Default Gateway IP Address..................................3
3. WoMaster Redundant Gateway Solution............................. 4
3.1 Current Situation......................................................................................4
3.2 WoMaster Redundant Gateway Technology ......................................6
4. Effects and Advantages........................................................ 8
5. Conclusion ............................................................................ 9

3. 1
1. Background
When we are going to take a plane and travel abroad, we must know where
the boarding gate is, so that we can fly to the sky and reach the destination.
In the world of Internet, a device needs to have a gateway to connect to the
network. Just this way, the packet can pass through network to the correct
destination.
However, if the Gateway is failed, all devices that under the gateway will not
possible to transmit data, even get on internet.
2. Gateway vs. Default Gateway
2.1 What is Gateway
In terms of a communications network, gateway it is defined as a
network node that allows a network communication to interact with
another network with different protocols. In laymen terms, gateway
allows two different networks to communicate with each other. It
contains devices such as impedance matching devices, protocol
translators, fault isolators, rate converters, or signal translators in order
to allow system interoperability.
A protocol translation/mapping gateway interconnects networks that
have different network protocol technologies. Gateways acts as a
network point that acts as an entrance to another network. The
gateway can also serves as the network to connect the computer to
the internet. Many routers are available with the gateway technology,
which knows where to direct the packet of data when it arrives at the
gateway. Gateways are often associated with both routers and
switches.

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2.2 What is Default Gateway
Default gateway is a computer or a computer program that configured
to perform the tasks of a traditional gateway. These are often used by
ISP or computer servers that act as gateway between different
systems. Wikipedia describes „default gateway‟ as “the node on the
computer network that the network software uses when an IP address
does not match any other routes in the routing table.”
When getting an internet connection, an ISP usually provides a device
that allows the user to connect to the internet; these devices are
known as modems. In organizational systems a computer is used as a
node to connect the internal networks to the external networks, such
as the Internet.
A default gateway is used to allow devices in one network to
communicate with devices in another network. For example, If your
computer, is requesting an internet webpage, the request first runs
through your default gateway before exiting the local network to reach
the internet.
An easier way to understand a default gateway might be to think of it
as an intermediate device between the local network and the internet.
It's necessary for transferring internal data out to the internet, and then
back again. So, the default gateway device passes traffic from the
local subnet to devices on other subnets.
The default gateway often connects the local network to the internet,
although internal gateways for communication within a local network
also exist.
Note: The word default in this term just means that it's the default
device that's looked for when information needs to be sent through the
network.

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2.3 How Traffic Moves Through a Default Gateway
All the clients on a network point to a default gateway that should be
used to route their traffic. The default gateway on your home network,
for example, understands certain routes that must be taken in order to
move your internet requests from your computer out of your network
and onto the next piece of equipment that can understand what needs
to be done.
From there, the same process happens until your data eventually
reaches its intended destination. With each network that the traffic hits,
that network's default gateway serves its own purpose in order to relay
the information back out to the internet and ultimately back to your
device that originally requested it. If traffic is bound for other internal
devices and not a device external to the local network, the default
gateway is still used to understand the request, but instead of sending
the data out of the network, it points it to the correct local device. This
is all understood based on the IP address that the originating device is
requesting.
2.4 How to Find Your Default Gateway IP Address
You might need to know the IP address of the default gateway if
there's a network problem or if you need to make changes to your
router. In WoMaster products, IP address of the default gateway can
be accessed through WebGUI with the IP address 192.168.10.1 as
default settings.

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Or through Command Prompt with show ip bridge commands for
finding the default gateway address.
3. WoMaster Redundant Gateway Solution
3.1 Current Situation
In general, the industrial network architecture will set redundant
network like Ring topology to ensure the reliability of the network.

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When a node in the ring network fails, the data packet will be
transmitted through the redundant path according to the redundant
network mechanism such as ERPS, to keep the data transmission of
the network.
However, when there are multiple nodes in the ring network fail at the
same time, the Ring redundant network will be cut in pieces, and
cause some devices will not be able to transmit information and get on
the network properly.

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3.2 WoMaster Redundant Gateway Technology
WoMaster proposes a redundant gateway technology based on the
ERPS mechanism. It will check the gateway status during the switches
monitor the ERPS Ring network connection status. When the main
gateway is not available, the redundant gateway will change its IP
address to the main gateway's one, and replace the main gateway. So
the devices in the network can normally transmit information and
connect to the network.
WoMaster Redundant Gateway feature can be applied to its wired and
wireless products. If we enable the redundant gateway function in a
wireless product such as WR322G, when the main gateway is
unreachable, the WR322G which is the redundant gateway will cover
the main gateway as master and transmit the data via LTE or Wi-Fi
network, until the connection is stable and the main gateway is
reachable.

9. 7
• Normal Status – In Backup state
• Backup Status – in Master state

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WoMaster also provides multiple redundant gateway settings, on the
other words, there can be more than one redundant gateway in a
network. So that you no longer have to worry about the multiple nodes
fail in a network.
4. Effects and Advantages
Compared with 3rd
party's redundant gateway mechanisms, WoMaster's
Redundant Gateway Solution provides the following advantages:
 Easy to set up:
Normally, the redundant gateway mechanism relied on the transmission
of BPDUs between the primary and secondary gateway to confirm the
status of each other. WoMaster Redundant Gateway solution can be
achieved without changing the settings of the primary gateway.
 Support L2 devices:
WoMaster Redundant Gateway mechanism supports L2 devices,
provides users with the most economical solution.

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 Operate with existing redundant network
It can be used with existing redundant network protocols to speed up
the detection of failure and backup.
 High Compatibility
Highly compatible with wireless gateway devices.
5. Conclusion
WoMaster Redundant Gateway Solution fixes the failure of multiple nodes
issue in the Ring redundant network. It is very easy to setup and can be
operated with existing redundant network. It can be applied in a L2 device,
provide most economical solution.
If you still want to know more, please contact us at help@womaster.eu.
About WoMaster
WoMaster Group is an international group based in Europe, with over 20
years of industrial market experience. We provide rugged products with
customer oriented support for critical applications such as railway, power and
utility, waste water, intelligent transportation and IP surveillance.
The WoMaster brand‟s name distinguishes our target markets as well as
symbolizes the nature sources which enforced us to become Master brand for
Industrial Data Communication Market.