IN TODAY'S RIGOROUS business environment, conducting trade is more and more a global endeavor, and workers are on the go more often than not. Jobs frequently require -- or allow, depending on your point of view -- employees to work remotely from home, on the road, and almost everywhere in between. Workers must be able to log in to their companies' networks at any moment during the day, regardless of where they happen to be working.
This Internet protocol will let users access their companies' network from any location and remain connected -- and productive -- regardless of the systems they're using.
TECHNOLOGY CASE
With Mobile IP, a node will be able to change its link without changing its IP address, maintaining communications. Users will be able to switch from a wired connection to a wireless one without encountering service interruptions.
PROS
CONS
IN TODAY'S RIGOROUS business environment, conducting trade is more and more a global endeavor, and workers are on the go more often than not. Jobs frequently require -- or allow, depending on your point of view -- employees to work remotely from home, on the road, and almost everywhere in between. Workers must be able to log in to their companies' networks at any moment during the day, regardless of where they happen to be working.
So mobile computing continues to flourish, fueled in part by vendors' tremendous advances in mobile devices, including notebooks, palmtop computers, electronic organizers, and smart phones. At the same time, organizations have become more dependent on network computing, building sophisticated networks that link mobile employees to their desktop PCs.
These factors -- a growing mobile workforce, a greater reliance on network computing, and advances in portable computing technology -- make necessary a new wireless IP standard that will allow mobile computers to communicate with other computers, fixed or mobile.
An Internet Engineering Task Force (IETF) Working Group is developing that standard, called Mobile IP.
Based on the TCP/IP suite of protocols, Mobile IP is a new Internet standard for the Web and private networks. Hardware and software vendors will be able to standardize on Mobile IP and build products, including portable computers and the infrastructure over which they will communicate, that will interoperate.
Most importantly, Mobile IP will give users a great degree of mobility across private and public networks. Mobility is a node's capability of changing its network link while preserving existing communications; it allows a node to change its point of attachment from one link to another while using the same IP address. For instance, an employee using a laptop plugged into the company's network will be able to disconnect from the wire connection, take the laptop to a new location, and maintain a wireless connection to the network and applications.
The new standard will offer a huge advantage over current mobile network protocols, and businesses will reap the benefits from Mobile IP quickly. Users will be able to remain plugged in and productive, capable of working from any location in the world. With the new protocol in place, for example, users will be able to carry laptops anywhere in a company's buildings, use whatever media -- network jack or wireless antenna -- are available, and access corporate data as if they are sitting at their usual desks.
Present protocol problems
Currently, a mobile computer can transfer data to and from a company's network only by being jacked in to a phone line and making a connection. IP is associated with a fixed network, so Internet routing cannot deliver IP packets to computers that change their locations. But Mobile IP will allow mobile computers to log in to a network wirelessly, regardless of location and without requiring that connection.
Unlike other technologies, Mobile IP is independent of the physical medium over which a mobile computer communicates, such as radio channels or fiber-optic cables. Also, it will allow mobile computers to change location without forcing users to restart their applications or disturb ongoing communications.
Computers communicate by transmitting and receiving data over a network, and a protocol is a set of rules and procedures that govern how two or more computers cooperate to accomplish a specific set of functions over that network. IP provides routing capabilities in the Internet by assigning IP addresses to every node, including hosts and routers. Each node has one IP address assigned to it though which it connects to a link.
One of the problems that Mobile IP should solve is associated with IP routing. When a node moves from one link to another via TCP/IP, it cannot communicate at the new location unless it changes its IP address to reflect the network prefix assigned to the new link.
IP routing is based on the network-prefix portion of the destination's IP address, thus allowing routers to maintain a single network-prefix route instead of as many individual routes as there are hosts. This is the key component to scalability on the Internet, but it limits a user's mobility.
Because of network-prefix routing, a node that moves from one link to another and does not change its IP address will not be able to receive packets at the new link. Host-specific routing can resolve this problem, but it suffers from scalability and security problems. It allows users to change the node's IP address as they move from one location to another, but does not solve the problem entirely.
This is where Mobile IP comes in to facilitate mobile computing.Unlike other protocols and host-specific routing, Mobile IP is robust, scalable, and secure, and it is not media-dependent. It is designed to allow nodes to move from one link to another without changing their IP addresses and without interrupting current network communications.
Mobile IP is unique in that it supports heterogeneous and homogenous mobility; it isn't dependent on any specific hardware or type of network. Other remote computing standards, such as CDPD (cellular digital packet data) and IEEE 802.11 (Wireless LANs), provide mobility only within their respective networks and do not support networks of different media.
Three new entities
This Internet protocol is being built around three new functional entities: a mobile node, a home agent, and a foreign agent. The mobile node can change its point of attachment from one network to another while maintaining all existing communications. The home agent resides on a router or a workstation on the mobile node's home subnet. The foreign agent resides on a router or workstation on the foreign network that the mobile node is visiting.
When the mobile node is on its home subnet, it informs the home agent of its presence and then will work as though it were connected to the network via a traditional link.
But the way packets are delivered to the mobile node change when that node connects to a foreign network. Next, the mobile node gets its care-of address, which is the foreign agent's IP address. The mobile node then registers with its home agent and gives the home agent its new care-of address.
At this point, the mobile node has registered with its home agent. Also, IP traffic addressed to the mobile node is being received by the home agent, encapsulated in another IP packet, and then tunneled to the foreign agent. In the final step of the process, the foreign agent forwards the packet to the mobile node.
These three new entities will change the way mobile users work. Mobile IP will let users seamlessly roam all networks, access applications from anywhere, and maintain ongoing connections. It will let users disconnect and switch from a wire connection to a wireless LAN interface without enduring network service interruptions. In addition, Mobile IP will allow users to move from one network link to another without having to restart their applications, which they must now do with IP.
Deploying Mobile IP
But before Mobile IP can be adopted widely, the IETF Working Group has a few obstacles to overcome, most importantly network security.
Firewalls are a significant stumbling block for Mobile IP because they obstruct all classes of incoming packets that do not meet specific criteria, such as having an unknown IP address; Mobile IP uses temporary, and thus unknown, IP addresses to let nodes change links. To resolve this problem, the IETF must work with firewall vendors to allow privileged users access through their company's firewall when using a Mobile IP temporary IP address.
In addition, vendors have to begin producing hardware and software that support Mobile IP. Although vendors haven't specified a deadline for building these products, chances are they will support the new protocol as soon as the security issues are ironed out.
When Mobile IP becomes more widely supported, deploying it will be fairly straightforward. To make it available to your mobile workforce, you will have to upgrade your routers (host home agents and foreign agents) and install mobile node software on all portable computers. No substantial security threats will be introduced by applying Mobile IP to your enterprise.
Also, network administrators will be able to configure agents remotely, monitor their performance, and manage registration with foreign agents using Version 2 of the Simple Network Management Protocol (SNMPv2).
Eventually, hardware and software will be released with Mobile IP support built in. This protocol most likely will be integrated into notebooks first. It will also affect handheld computers and other mobile devices; in the future, vendors should be able to support business-critical applications using Mobile IP, thereby letting users access specific application suites via their smart phones.
When Mobile IP is adopted readily, it will provide a huge improvement over the way users now communicate with their organizations. It will offer mobility on the Internet that is scalable, robust, and secure, and it will allow nodes to maintain all current communication while changing locations. But until all routers can support home agents and foreign agents and all new notebooks, handheld computers, and PDAs (personal digital assistants) that come loaded with mobile node software, users will continue to be restricted in their mobility.
In the long term, Mobile IP will change the way we all work. Anyone with access to the Internet will be able to build a computing environment wherever he or she goes. Having this kind of ubiquitous access to the Internet will free users from the ties that have traditionally bound them to their desktops. In addition, seamless roaming and access to applications will make users more productive, and they will be able to access applications on the fly, perhaps giving them an edge on the competition.
All of this will mean a boom in mobile computing. The computing industry has already seen the eager, widespread adoption of palm-sized devices, pocket organizers, and notebooks with wireless capabilities. The mobile workforce will only continue embracing such devices as they make users jobs -- and lives -- easier.
Senior analyst Ana Orubeondo (ana_orubeondo@infoworld.com) covers wireless networking, telephony, and remote access.