1. A system comprising: a terminal; a first core network node; a second core network node; a device for managing subscriber information; and a gateway; wherein a connection between the terminal and the first core network node has been established, the terminal is configured to: send an Attach Request to the second core network node after the first core network node restarts, the second core network node is configured to: receive the Attach Request from the terminal, then send an Update Location Request to the device, the device is configured to: receive the Update Location Request from the second core network node, then send a Cancel Location Request to the first core network node, and the first core network node is configured to: send a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to the gateway based on having received the Cancel Location Request from the device.

2. A terminal, wherein a connection between the terminal and a first core network node has been established, configured to: send an Attach Request to a second core network node after the first core network node restarts, so that the second core network node sends an Update Location Request to a device for managing subscriber information, and then the device sends a Cancel Location Request to the first core network node, and the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device.

3. A first core network node, wherein a connection between a terminal and the first core network node has been established, configured to: send a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received a Cancel Location Request from a device for managing subscriber information, wherein the terminal is configured to: send an Attach Request to a second core network node after the first core network node restarts, the second core network node is configured to: receive the Attach Request from the terminal, then send an Update Location Request to the device, and the device is configured to: receive the Update Location Request from the second core network node, then send the Cancel Location Request to the first core network node.

4. A second core network node, wherein a connection between a terminal and a first core network node has been established, configured to: receive an Attach Request from the terminal, then send an Update Location Request to a device for managing subscriber information, so that the device sends a Cancel Location Request to the first core network node, and the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device, wherein the terminal is configured to: send the Attach Request to the second core network node after the first core network node restarts.

5. A device for managing subscriber information, wherein a connection between a terminal and a first core network node has been established, configured to: receive an Update Location Request from a second core network node, then send a Cancel Location Request to the first core network node, so that the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device, wherein the terminal is configured to: send an Attach Request to the second core network node after the first core network node restarts, the second core network node is configured to: receive the Attach Request from the terminal, then send the Update Location Request to the device.

6. A gateway, wherein a connection between a terminal and a first core network node has been established, configured to: receive a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure from the first core network node, wherein the terminal is configured to: send an Attach Request to a second core network node after the first core network node restarts, the second core network node is configured to: receive the Attach Request from the terminal, then send an Update Location Request to a device for managing subscriber information, the device is configured to: receive the Update Location Request from the second core network node, then send a Cancel Location Request to the first core network node, and the first core network node is configured to: send the Downlink Data Notification Acknowledge or the Downlink Data Notification Failure to the gateway based on having received the Cancel Location Request from the device.

7. A method, wherein a connection between a terminal and a first core network node has been established, comprising: sending an Attach Request to a second core network node after the first core network node restarts, so that the second core network node sends an Update Location Request to a device for managing subscriber information, and then the device sends a Cancel Location Request to the first core network node, and the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device. 8. A method, wherein a connection between a terminal and a first core network node has been established, comprising: sending a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received a Cancel Location Request from a device for managing subscriber information, wherein the terminal is configured to: send an Attach Request to a second core network node after the first core network node restarts, the second core network node is configured to: receive the Attach Request from the terminal, then send an Update Location Request to the device, and the device is configured to: receive the Update Location Request from the second core network node, then send the Cancel Location Request to the first core network node.

9. A method, wherein a connection between a terminal and a first core network node has been established, comprising: receiving an Attach Request from the terminal; then sending an Update Location Request to a device for managing subscriber information, so that the device sends a Cancel Location Request to the first core network node, and the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device, wherein the terminal is configured to: send the Attach Request to a second core network node after the first core network node restarts.

10. A method, wherein a connection between a terminal and a first core network node has been established, comprising: receiving an Update Location Request from a second core network node; then sending a Cancel Location Request to the first core network node, so that the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from a device for managing subscriber information, wherein the terminal is configured to: send an Attach Request to the second core network node after the first core network node restarts, the second core network node is configured to: receive the Attach Request from the terminal, then send the Update Location Request to the device.

11. A method, wherein a connection between a terminal and a first core network node has been established, comprising: receiving a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure from the first core network node, wherein the terminal is configured to: send an Attach Request to a second core network node after the first core network node restarts, the second core network node is configured to: receive the Attach Request from the terminal, then send an Update Location Request to a device for managing subscriber information, the device is configured to: receive the Update Location Request from the second core network node, then send a Cancel Location Request to the first core network node, and the first core network node is configured to: send the Downlink Data Notification Acknowledge or the Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device.

We Claim:
1. A system comprising:
a terminal;
a first core network node;
a second core network node;
a device for managing subscriber information; and
a gateway; wherein
a connection between the terminal and the first core network node has been established,
the terminal is configured to:
send an Attach Request to the second core network node after the first core network node restarts,
the second core network node is configured to:
receive the Attach Request from the terminal, then
send an Update Location Request to the device,
the device is configured to:
receive the Update Location Request from the second core network node, then
send a Cancel Location Request to the first core network node, and the first core network node is configured to:
send a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to the gateway based on having received the Cancel Location Request from the device.
2. A terminal, wherein a connection between the terminal and a
first core network node has been established, configured to:
send an Attach Request to a second core network node after the first core network node restarts, so that

the second core network node sends an Update Location Request to a device for managing subscriber information, and then
the device sends a Cancel Location Request to the first core network node, and
the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device.
3. A first core network node, wherein a connection between a terminal and the first core network node has been established, configured to:
send a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received a Cancel Location Request from a device for managing subscriber information, wherein
the terminal is configured to:
send an Attach Request to a second core network node after the first core network node restarts,
the second core network node is configured to:
receive the Attach Request from the terminal, then
send an Update Location Request to the device, and
the device is configured to:
receive the Update Location Request from the second core network node, then
send the Cancel Location Request to the first core network node.

4. A second core network node, wherein a connection between a
terminal and a first core network node has been established, configured
to:
receive an Attach Request from the terminal, then send an Update Location Request to a device for managing subscriber information, so that
the device sends a Cancel Location Request to the first core network node, and
the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device, wherein
the terminal is configured to:
send the Attach Request to the second core network node after the first core network node restarts.
5. A device for managing subscriber information, wherein a
connection between a terminal and a first core network node has been
established, configured to:
receive an Update Location Request from a second core network node, then send a Cancel Location Request to the first core network node, so that
the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device, wherein
the terminal is configured to:
send an Attach Request to the second core network node after the first core network node restarts,
the second core network node is configured to:

receive the Attach Request from the terminal, then send the Update Location Request to the device.
6. A gateway, wherein a connection between a terminal and a first
core network node has been established, configured to:
receive a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure from the first core network node, wherein
the terminal is configured to:
send an Attach Request to a second core network node after the first core network node restarts,
the second core network node is configured to:
receive the Attach Request from the terminal, then
send an Update Location Request to a device for managing subscriber information,
the device is configured to:
receive the Update Location Request from the second core network node, then
send a Cancel Location Request to the first core network node, and
the first core network node is configured to:
send the Downlink Data Notification Acknowledge or the Downlink Data Notification Failure to the gateway based on having received the Cancel Location Request from the device.
7. A method, wherein a connection between a terminal and a first
core network node has been established, comprising:

sending an Attach Request to a second core network node after the first core network node restarts, so that
the second core network node sends an Update Location Request to a device for managing subscriber information, and then
the device sends a Cancel Location Request to the first core network node, and
the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device. 8. A method, wherein a connection between a terminal and a first core network node has been established, comprising:
sending a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received a Cancel Location Request from a device for managing subscriber information, wherein
the terminal is configured to:
send an Attach Request to a second core network node after the first core network node restarts,
the second core network node is configured to:
receive the Attach Request from the terminal, then
send an Update Location Request to the device, and
the device is configured to:
receive the Update Location Request from the second core network node, then
send the Cancel Location Request to the first core network node.
9. A method, wherein a connection between a terminal and a first core network node has been established, comprising:

receiving an Attach Request from the terminal; then
sending an Update Location Request to a device for managing subscriber information, so that
the device sends a Cancel Location Request to the first core network node, and
the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device, wherein
the terminal is configured to:
send the Attach Request to a second core network node after the first core network node restarts.
10. A method, wherein a connection between a terminal and a first core network node has been established, comprising:
receiving an Update Location Request from a second core network node; then
sending a Cancel Location Request to the first core network node, so that
the first core network node sends a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from a device for managing subscriber information, wherein
the terminal is configured to:
send an Attach Request to the second core network node after the first core network node restarts,
the second core network node is configured to:
receive the Attach Request from the terminal, then
send the Update Location Request to the device.

11. A method, wherein a connection between a terminal and a first core network node has been established, comprising:
receiving a Downlink Data Notification Acknowledge or a Downlink Data Notification Failure from the first core network node, wherein
the terminal is configured to:
send an Attach Request to a second core network node after the first core network node restarts,
the second core network node is configured to:
receive the Attach Request from the terminal, then
send an Update Location Request to a device for managing subscriber information,
the device is configured to:
receive the Update Location Request from the second core network node, then
send a Cancel Location Request to the first core network node, and
the first core network node is configured to:
send the Downlink Data Notification Acknowledge or the Downlink Data Notification Failure to a gateway based on having received the Cancel Location Request from the device.