Mobile IP address no longer silence Wireless LAN Access Service (1)

The "Wireless LAN Access Service" suddenly went viral overnight. This kind of service, also known as "Hot Spot", uses wireless LAN technologies such as IEEE802.11b and IEEE802.11a, which can be up to 11 Mbit/s (or up to 36 Mbit/s) at a low cost when going out) high-speed Internet access.

At present, Japanese NTT communication and other companies are providing related services in terms of mobile Internet Service (MIS. NTT East Japan started testing services in June 6, and NTT West Japan will also start providing such services in July 1. Carriers such as NTT DoCoMo and Japan Telecom are also conducting empirical tests.

The wireless LAN Access Service is used in restaurants, hotel halls, stations, and other places, just like the term "Spot" in its alias "Hot Spot. When drinking coffee in a restaurant, waiting for a car at a station, or having a moderate person in the hotel lobby, you can access the Internet and use your personal computer or PDA (portable information terminal) to send and receive emails, or perform Web access.

Currently, this service covers a limited number of regions, and its convenience is not too high. However, if the available areas continue to grow, it will certainly become a very attractive service. Although there are still a lot of disturbing aspects in terms of security, this is also caused by the use of methods.

If the service area is further expanded, the regions are connected to each other to meet the access requirements in the mobile status. In this way, a key technology is required when the service area that can access the wireless LAN changes from "point" to "area. This technology is "Mobile IP ".

Mobile IP technology began to appear

Generally, in an IP network, when a PC connected to a certain subnet moves to an area covered by another subnet, if it is not converted to an IP address that contains a new website in time, the IP data packets cannot be sent to the PC. A subnet usually refers to an IP network area divided by routers. If you use the wireless LAN Access Service while moving the access location, once the access location is beyond the subnet coverage, the communication will not continue.

In this case, the Mobile IP technology is used. The so-called mobile IP address refers to the technology where the same IP address can be used in multiple regions on the IP network. This technology is achieved by using a special router called Home Agent and Foreign Agent to manage the network where the network terminal is located.

In fact, compared with other communication operators, MIS operators initially imagined to provide wireless LAN access services with "surface" features, and ensured the continuity of IP communication by using mobile IP addresses. In addition, three companies, such as KDDI, KDDI Research Institute, and Cisco system, developed a data communication system that can automatically switch between the third-generation mobile phone (3G) and wireless LAN access, and from ~ A simple demonstration was conducted at the Business SHOW 2002 TOKYO on the 24 th. The system uses the Mobile IP technology.

After reading this, the reader may ask, "isn't the Mobile IP used for the mobile phone that can send and receive emails in the mobile status ?". The answer to this question is: Half "YES" and half "NO ".

Only the "EZweb" provided by KDDI is applicable to online mobile phone services that can be accessed via mobile phones. In the backbone IP network of the Data Service field, KDDI has already imported the Mobile IP technology. Not only does Ezweb service use the mobile IP technology, but the group communication service PacketOne also uses this technology. However, the Mobile IP technology is only applicable to KDDI users. The reason is that the user's mobile terminal must support mobile IP addresses.

In NTT DoCoMo's "I mode" and J-Phone's "J-SKY", Mobile IP technology is not used. Further, it means that no IP address is allocated in the mobile terminal. These two services do not use the IP technology inside the network, but use their own developed protocols to use the gateway server configured with the Internet for IP conversion.