DMVPN vs Mobile IP

DMVPN vs Mobile IPNowadays, there are more and more applications running on a mobile environment such as, M2M, services for passengers, telemetering, etc… These applications often rely on several wireless access technologies (LTE, 3G, Wi-Fi, Satellite…) to implement the connectivity to the on-board network.

In these kind of scenarios, very often the WAN IP changes have an impact on the continuity of applications running at the central office or on the internet. Therefore, there have been several initiatives to provide continuous connectivity in scenarios where the WAN IP is dynamic. The most common ones use Mobile IP or a combination of standard protocols, which mix DMVPNs with dynamic routing.

Mobile IP

Mobile IP is an open standard that allows users to keep the same IP address, stay connected and maintain ongoing applications, while roaming between different IP networks. Hence ensuring that a roaming device could continue communication without sessions or connections being dropped.
mobile IP FDM

This standard is based on identifying each roaming device, (mobile node, MN) by its home address disregarding its current location in the Internet.  Away from its Home Network, a mobile node is associated with a care-of-address (CoA), which identifies its current location in the Foreign Network, and its home address is associated with the local endpoint of a tunnel to its Home Agent.

Mobile IP specifies how a mobile node registers with its home agent and how the home agent routes datagrams to the mobile node through the tunnel.

Due to this standard’s design, telecom carriers need to implement Mobile IP infrastructure inside their core network. Access network equipment (Foreign Agent, FA in the diagram) also need to implement the same standard and have the ability of build up the GRE tunnels. In scenarios where we use two different telecom carriers, the Home Agent should be implemented by a transversal service that is able to build the tunnels through both carriers’ networks.

For the above-mentioned reasons, deploying Mobile IP is complex.

DMVPN an alternative to Mobile IP

There are other safer tunnel-based technologies which allow changes on the WAN IP address. Using a VPN allows to configure connectivity between two LAN networks independently of the routing changes inside the network the tunnel is going through.

DMVPNs are the typical approach used to build a VPN between two devices with dynamic WAN IP and it is a much more mature technology and spread out than Mobile IP. Building a DMVPN requires a public fixed IP at the central side (HUB). While spokes could have dynamic or fixed public IPs.

mobile IP FDM2

Using a protocol named NHRP (Next Hop Resolution Protocol) the different Spokes can be registered into the HUB allowing to set up a VPN between two Spokes without going through the HUB.  Also, if a Spoke changes its WAN IP, it will send an update to the hub updating its new address.

As well as in Mobile IP, the convergence of the technology requires some time. In addition, the change of two cellular networks from different carriers (LTE module needs to reboot and re-register in the new network) also requires some time. However, in real mobile environments (such as in-vehicle connectivity) the change between carriers is not instantaneous (the coverage from one carrier gradually lowers while the coverage of the other cellular network is improving gradually).

The combination of a device with two cellular modules allow having two simultaneous cellular networks available to provide the service. In this case, each module will connect to each cellular network and build up two tunnels (one through each telecom carrier) which will coexist until the coverage of one of the carriers is much stronger than the other. Adding an appropriate dynamic routing protocol configured at both extremes of the tunnel with fast update features and different priorities in the exported routes, allow application continuity whenever any WAN link is down or quality is not sufficient.

mobile IP FDM3

DMVPN , an efficient solution that minimizes costs

Mobile IP requires additional infrastructure and a very complex deployment on the Telecom Carriers’ side. The solution based on DMVPNs is completely independent from the Telecom Carriers and does not require additional costs, as well as allowing to configure simultaneous connections through different Carriers without any difficulty. This is why Teldat deploys DMVPN technology for its mobile scenarios, whether on trains, buses or any other type of vehicles, via our routers H1-Rail, H2-Automotive or similar.

Can 4G/LTE become a main line connection?

4g networksPerhaps this question  has to be clarified somewhat.

Indeed, slower and more mature cellular lines 2G and 3G lines are already main line connections in certain scenarios, especially in those segments which are not so dependent on large bandwidth, but at the same time are extremely dependent on mobility. A typical example is that of remote cash point machines deployed across the world in all sorts locations (shopping malls, airports, sports centers, etc.). Many banks came to conclusion some time ago that the difficulty of connecting these machines to a wired connection, made cellular connectivity much more viable.

In which cases can 4g and LTE be a good alternative to fixed line connection?

However, the real question that needs an answering today is; can 4G/LTE become an alternative to WAN (Wide Area Network) fixed line connection? Starting from the bottom upwards, we could say, yes it can be that alternative, because there are many vertical markets that require broadband on the one hand and cellular connectivity on the other.

Retail is a market which is definitely changing and could benefit from 4G/LTE. Haven’t we walked into department stores which frequently seem to be changing their sales items’ layout on the shop floor? Such mobility makes the use of wired connection difficult and if they use applications such as digital signage among others, which are becoming increasing popular, a large wireless broadband is necessary for correct functionality.

Also within the retail sector, pop up shops and kiosk are prime candidates to have 4G/LTE as their main line connectivity. They always need fast and temporary deployment accompanied with the increasing requirement to connect to the central sites for reasonably large amount of data flows.

Public transport can hugely benefit from 4G/LTE main line connection. Many cities are installing security cameras onboard buses, trains and similar forms of transport. These images cannot only be stored on the vehicles, but with 4G/LTE live connections can be established with the city control rooms, increasing employee and traveller security. Moreover, once 4G/LTE is installed on public transport, many authorities use the opportunity of having cellular broadband onboard to offers its clients Internet connection and hence increase customer satisfaction and loyalty to public transport. Hence, staying away from private transport which most cities want to reduce.

Healthcare is another important cliente of 4G/LTE main line connectivity for its emergency vehicles (ambulances, etc.). Not only to track the vehicles, as in the transport sector, but also to have its medical equipment onboard connected to the Hospital with the specialists. So in extreme cases lives can even be saved, when critical patients haven’t the time to arrive at the Hospitals. On a more routine scenario, rural areas can clearly have their doctors’ consultancies or even individual patients, connected to their specialists who are located in the more urban parts of their country.

Although these vertical markets are of interest, and very much so, there is a common business set up, across most of the world today that can use 4G/LTE as main line connectivity. That is, the branch office scenario in its different shapes, types and sizes.

The role of 4G/LTE on a global scenario

It is true that in highly wired cities there would be a good debate as to whether 4G/LTE would be a better option for branches located in these areas. However, as soon as we move away to smaller towns and especially the more rural areas, then the 4G/LTE alternative would be quite convincing, basically because if available, the bandwidth would be wider on 4G/LTE in these areas, than what a wired connection can probably offer.

Moreover, we must bear in mind that what can be classified today as a “branch office” spread across a nation’s geographical terrain, may be many more establishments than the traditional local bank branch or post office. Companies are developing mini-branch sales offices with perhaps only one or two employees, but they need them to be connected and able to work on all the type company applications. These applications require a broadband with significant width. For this scenario, 4G/LTE would fit perfectly.

From a different perspective, there are many traditional establishments which before would not be classified within the branch office / head office connected scenario, but now do fall into this category. For example, many public sector establishments, such as schools, doctors’ consultancies, etc. are now becoming more and more connected to their “head office”. All of these “new branch office scenarios” need to be connected to their central site or simply to the cloud, from where they require to establish data flows in both directions.

Routers, VPN and Security

However, independently of fixed line or 4G/LTE connection, we do have to remain cautious in all scenarios as always, else the standards that we are accustomed to will not be maintained. Hence, whether the connection is being made from a larger city branch office on wired connection or from a much smaller rural office on 4G/LTE, we need the VPN to be as secure as always. The same router types and operating systems should be used for fixed line or 4G/LTE connections, else the economies of scale achieved within the ICT department will be lost and the data being routed around the countries and the world would viable to hackers, etc..

Teldat not only has years of experience in manufacturing cellular routers from the beginning of 2G technology through the entire 3G development, but already has excellent devices with proved and successful deployments of cellular 4G/LTE scenarios in different parts of the world. Do not hesitate to contact us and we will help you solving all your doubts!