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Mobile Router

Category: Basics | Comments (2)

The mobile router is a type of router which doesn't need any wireless links. One of its biggest advantages is that it can work with virtually any type of interface. This means that it can be used with Fast Ethernet and Ethernet connections, and the mobile router will be jacked in for a set period of time with multiple locations.

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It is an excellent router to use in situations where DHCP won't function properly since you're re-addressing consistently. If your routers don't currently move around, but you would like them to, mobile routers can allow you to achieve this. For example, a vehicle could have a routed network inside it, and you could move inside the range of numerous wireless hubs as you move about.

Even vehicles such as airplanes could make use of mobile routers. If an aircraft has a router inside it, it can establish contact with satellites and ground stations. To understand the power of mobile routers, it is first important to understand Mobile IP. With Mobile IP, the goal is to operate with an IP address which is fixed as you move around.

To the Home Agent router, the address will be showcased for the purpose of routing it, and it will appear local. As the node for the Mobile IP is transported, there won't be any changes for routes inside the corporate routing tables. It is also possible for the Mobile IP to function with the routing tables for the Internet. To achieve this, you need the proper support for protocols, as well as Foreign Agents and the Home Agent Router.

Mobile Router Features

The Foreign Agent routers will function with the host for Mobile IP in order to register the fresh roaming locations via the Home Agent router. Advertisements which come through the Foreign Agent will alert the Mobile Router of its presence, and this will be done while the Mobile node is roaming.

The Mobile Node will transmit the registration method for the Home Agent, and this will be accomplished through the fresh Foreign Agent, and the Home Agent will be notified that the message must be sent through the tunnel into the "Care Of" address. Packets which are sent out from the Correspondent node" to the mobile node will get routed inside the Home Agent router.

How Mobile Router Operates

The Home Agent router will tunnel the packets into the Foreign Agent router, which should be close to the mobile node. The Foreign Agent router will also be responsible for de-encapsulating packets via the tunnel, and must transmit them for the mobile node which is connected (which will be the visitor).

The return packets will be transferred from the Mobile node to the Foreign agent, and then into the Correspondent node. The only exception to this is when reverse tunneling as been enabled. For this to work in the proper manner, the mobile node will need to make use of a distinct Mobile IP stack which knows how to operate with the Foreign Agent router. It will also need to know hot to transmit the Register messages for the Home Agent.

There is some "cheating" which will occur on the MAC layer for the subnet among the Mobile Node, and the Foreign Agent. When it comes to outbound traffic, the Mobile Node will set the Foreign Agent as the default gateway, and this will be done in a dynamic manner.

It will then forward traffic into it, regardless of whether or not they are on top of the identical subnet. For traffic which is going near the Mobile Node, the Foreign Agent must make use of the host route, as well as the regional ARP entry to obtain traffic for the Mobile Node, even when the address may not be the actual local subnet.

If you find that you're roaming inside fresh subnets every half hour or so, it can become quite tiresome, and the Mobile Router may not be useful.

One thing that I should also note is that the readdressing for DHCP every half hour will make it difficult to download large documents from the web, and it will also be difficult to obtain IOS images. If you find that you need an IP address which is fixed, then the Mobile IP is a solution which is highly scalable.

You can have an "always on" instant messaging, which means that you won't have to log in with every fresh address. You can also work with VOIP, and you can process FTP transfers or additional applications that normally wouldn't be very mobile. 

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With Mobile IP, you can begin an application, and it can operate while you are roaming. The fixed IP address is what allows for this continuing connectivity.

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Very nice tutorial on Mobile routers.. thanks for the information
Comment posted by: vamseedhar r sane on 2008-07-12T19:43:28
Does a mobile router exits that allows a VPN connection to a corporate network using an EV-DO Sprint broadband card? Does it actually work?
Comment posted by: Bill on 2009-08-21T23:01:27

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