| 摘要 |
<p>Seamless communication handoff is achieved by establishing a protocol tunnel to route leftover packets between network access nodes during the handoff. For example, in a mobile IP-based system, a mobile node may perform a handoff from a first access node that is associated with a first routing node to a second access node that is associated with a second routing node. To prevent the loss of any packets that may be in route for delivery to or from the first routing node during the handoff, the mobile node establishes a protocol tunnel with the first access node via the second access node. On the forward-link, packets being delivered from the first routing node are routed over the protocol tunnel to the second access node and then to the mobile node. On the reverse-link, packets being sent to the first routing node are routed over the protocol tunnel from the mobile node to the second access node and then to the first routing node. In conjunction with these operations, the mobile node concurrently maintains separate IP interfaces for the routing nodes. In addition, steps are taken to ensure that packets are routed to the appropriate IP interface during the handoff.</p> |
