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TCP/IP Tutorial and Technical Overview - IBM Redbooks

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At any traveling location, there are always multiple service providers for<br />

competition in the wireless market, <strong>and</strong> multiple network prefixes are available.<br />

Mobile <strong>IP</strong>v6 provides binding support for the address to an attached visiting<br />

network. The native <strong>IP</strong>v6 routing header also supports route selection for a<br />

packet to go through desired networks. The capability allows network service<br />

provider selection. And as a result, it enforces a security <strong>and</strong> service policy by<br />

going through only authorized gateway service nodes.<br />

There are certain enhancements in <strong>IP</strong>v6 that are particularly well suited to the<br />

mobile environment, including:<br />

► A mobile node uses a temporary address while away from home location. It<br />

can use the <strong>IP</strong>v6 Destination Optional header to store its home address. An<br />

intended destination can access the field to get the mobile node’s home<br />

address for substitution when processing the packet.<br />

► A mobile station can list the all routing header for the packets to follow a<br />

particular paths in order to connect to a selective service provider network.<br />

► Also, most packets sent to a mobile node while it is away from its home<br />

location can be tunneled by using <strong>IP</strong>v6 routing (extension) headers, rather<br />

than a complete encapsulation, as used in Mobile <strong>IP</strong>v4, which reduces the<br />

processing cost of delivering packets to mobile nodes.<br />

► Unlike Mobile <strong>IP</strong>v4, there is no requirement for routers to act as “foreign<br />

agents” on behalf of the mobile node, because neighbor discovery <strong>and</strong><br />

address autoconfiguration allow the node to operate away from home without<br />

any special support from a local router.<br />

► The dynamic home agent address discovery mechanism in Mobile <strong>IP</strong>v6<br />

returns a single reply to the mobile node. The directed broadcast approach<br />

used in <strong>IP</strong>v4 returns separate replies from each home agent.<br />

To better use the native <strong>IP</strong>v6 capabilities in next generation (3G) wireless<br />

network <strong>and</strong> service, the <strong>IP</strong>v6 working group <strong>and</strong> 3rd Generation Partnership<br />

Project (or 3GPP) working group has conducted joint discussions. As a result of<br />

adopting native <strong>IP</strong>v6 features (for example, <strong>IP</strong>v6 address prefix allocation <strong>and</strong> so<br />

on), they ensure that h<strong>and</strong>sets are compatible with mobile computers in sharing<br />

drivers <strong>and</strong> related software.<br />

Chapter 9. <strong>IP</strong> version 6 373

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