1. A method comprising:
provisioning a first virtual connection between a first device and a second device;
provisioning a second virtual connection between the first device and the second device;
receiving a data flow at the first device;
duplicating the data flow to generated duplicated data flows;
transmitting the duplicated data flows to the second device via the first virtual connection and the second virtual connection;
receiving the duplicated data flows at the second device via the first virtual connection and the second virtual connection;
determining a performance characteristic of the data flow received via the first virtual connection;
determining the performance characteristic of the data flow received via the second virtual connection;
selecting, for forwarding, the data flow received via the first virtual connection or the data flow received via the second virtual connection based on the performance characteristics of the data flow received via the first virtual connection and the performance characteristic of the data flow received via the second virtual connection; and
forwarding the selected data flow.
2. The method of claim 1, wherein the first virtual connection and the second virtual connection comprise Ethernet virtual connections (EVCs).
3. The method of claim 2, wherein the first virtual connection comprises an active EVC and the second virtual connection comprises a backup EVC configured to provide automated backup protection for the active EVC.
4. The method of claim 1, further comprising:
compensating for differential delay associated with data received via the first virtual connection and the second virtual connection.
5. The method of claim 1, wherein the data flow comprises a packet flow having a plurality of packets therein.
6. The method of claim 5, wherein the performance characteristic comprises a packet loss characteristic or a packet error characteristic.
7. The method of claim 5, wherein selecting the data flow received via the first virtual connection or the data flow received via the second virtual connection based on the performance characteristics of the data flow received via the first virtual connection and the performance characteristic of the data flow received via the second virtual connection, further comprises comparing the plurality of packets received via the first virtual connection with the plurality of packets received via the second virtual connection.
8. The method of claim 7, further comprising:
inserting a sequence number into each packet in the packet flow, wherein the sequence numbers comprise incremented numbers representative of an order of packets within the packet flow,
wherein comparing the plurality of packets received via the first virtual connection with the plurality of packets received via the second virtual connection is performed based on their respective sequence numbers.
9. The method of claim 8, further comprising:
identifying packets in the non-selected packet flow that correspond to identified missing or damaged packets in the selected packet flow; and
inserting the identified packets into the selected packet flow prior to forwarding the selected packet flow.
10. A system, comprising:
a first network device;
a second network device coupled to the first network device via a first virtual connection and a second virtual connection,
wherein the first network device comprises:
a first switching device configured to output a first data flow for transmission via the first virtual connection and a second data flow for transmission via the second virtual connection, wherein the first data flow is substantially identical to the second data flow,
wherein the first switching device is configured to transmit the first data flow and the second data flow to the second device via the first and second virtual connections, respectively;
wherein the second network device comprises:
a second switching device configured to receive the first data flow and the second data flow via the first virtual connection and the second virtual connection, respectively,
wherein the second switching device is configured to determine a performance characteristic of the first data flow and a performance characteristic of the second data flow,
wherein the second switching device is configured to select, for forwarding, the first data flow or the second data flow based on a comparison of the performance characteristics of the first data flow and the second data flow, and
wherein the second switching device is configured to forward the selected data flow.
11. The system of claim 10, wherein the first virtual connection and the second virtual connection comprise Ethernet virtual connections (EVCs).
12. The system of claim 10, wherein the second switching device is further configured to compensate for differential delay associated with data received via the first virtual connection and the second virtual connection.
13. The system of claim 10, wherein the first data flow and the second data flow comprise first and second packet flows having a plurality of packets.
14. The system of claim 13, wherein the performance characteristic comprises at least one of a packet loss characteristic or a packet error characteristic, and
wherein the second switching device is configured to select, the first packet flow or the second packet flow based on the at least one of the packet loss characteristic or the packet error characteristic of the first packet flow and the second packet flow.
15. The system of claim 13, wherein the second switching device is further configured to compare the plurality of packets received via the first virtual connection with the plurality of packets received via the second virtual connection on a packet-by-packet basis.
16. The system of claim 15, wherein the first switching device is further configured to insert a sequence number into packets in the first and second packet flows, wherein the sequence numbers comprise incremented numbers representative of an order of packets within the first and second packet flows, respectively, and
wherein the second switching device is further configured to compare the plurality of packets received via the first virtual connection with the plurality of packets received via the second virtual connection based on their respective sequence numbers.
17. The system of claim 16, wherein the first switching device is further configured to insert the sequence numbers into respective headers of each packet in the first and second packet flows.
18. A method, comprising:
provisioning a first virtual connection between a first network device and a second network device;
provisioning a second virtual connection between the first network device and the second network device,
wherein the first virtual connection and the second virtual connection comprise different physical paths;
duplicating a received packet flow to generate a first packet flow and a second packet flow;
transmitting the first packet flow to the second network device via the first virtual connection;
transmitting the second packet flow to the second network device via the second virtual connection;
comparing, at the second network device, packets received via the first virtual connection with packets received via the second virtual connection;
selecting the first packet flow or the second packet flow based on the comparing; and
forwarding the selected packet flow.
19. The method of claim 18, further comprising:
identifying a failure of the first virtual connection or the second virtual connection;
selecting, for forwarding, the packet flow transmitted via the other of the first virtual connection or the second virtual connection; and
forwarding the selected packet flow.
20. The method of claim 19, wherein the selecting and forwarding of the selected packet flow is performed in less than 50 milliseconds.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A soft handoff system comprising a correspondent host, a first base station, a second base station, and a mobile terminal, wherein the correspondent host transmits messages to said first base station where said first base station retransmits said messages to said second base station using IP-in-IP encapsulation between said base stations, wherein said base stations encapsulate and de-encapsulate packets, wherein said mobile terminal is in an area serviceable by and receives said messages from both said first base station and said second base station, and wherein at least one of said first and second base stations is configured to determine when to initiate a soft handoff.
2. A mobile terminal configured to receive a first message from a first base station and a second message from a second base station, wherein the mobile terminal experiences soft handoff between said first and second base stations, said soft handoff using IP-in-IP encapsulation in which said first base station transmits said first message to both said mobile terminal and said second base station, and wherein said IP-in-IP encapsulation is applied to said first message toward said second base station, and wherein said second base station transmits a content included in the first message with said IP-in-IP encapsulation received from said first base station to said mobile terminal as said second message, and wherein said base stations encapsulate and de-encapsulate packets, and wherein at least one of said first and second base stations is configured to determine when to initiate said soft handoff.
3. A soft handoff system comprising:
a correspondent host;
a first base station that transmits packets to a mobile station;
a second base station; and,
said mobile station,
wherein packets from said correspondent host are transmitted to said first base station, wherein said packets are encapsulated with a header, and sent to said second base station, and wherein said header is removed from said packet and the content of said packet is transmitted to said mobile station, said packets being transmitted from both said first base station and said second base station to said mobile terminal while experiencing soft handoff, and wherein at least one of said first and second base stations is configured to determine when to initiate said soft handoff.
4. The system according to claim 3, wherein said packets are exchanged in an IP network.
5. The system according to claim 4, wherein said IP network is part of a CDMA network.
6. The system according to claim 3, wherein a second packet from said correspondent host is transmitted to said second base station, wherein said second packet is encapsulated with a second header and sent to said first base station, and wherein said second header is removed from said second packet and the content of said second packet is transmitted to said mobile station.
7. The system according to claim 3, wherein said mobile station transmits a first data unit to said first base station and said mobile station transmits a second data unit to said second base station.
8. The system according to claim 7, wherein said second base station transmits a second packet containing content received from said mobile station to said correspondent host or to said first base station.
9. A method for performing soft handoff using IP-in-IP encapsulation between base stations, said method comprising:
transmitting messages from a first base station to both a mobile terminal and a second base station;
applying said IP-in-IP encapsulation to messages toward said second base station; and
transmitting from said second base station a content of messages with IP-in-IP encapsulation received from said first base station to said mobile terminal,
wherein said base stations are configured to encapsulate and de-encapsulate IP packets, and
wherein at least one of said first and second base stations is configured to determine when to initiate said soft handoff.
10. A method for performing soft handoff using IP-in-IP encapsulation between base stations, comprising:
receiving at a mobile terminal a first message transmitted by a first base station; and
receiving at said mobile terminal a second message transmitted by a second base station,
wherein said second base station generates said second message based on said first message that said second base station receives from said first base station,
wherein said first and second base stations perform encapsulation and de-encapsulation of IP packets for transferring said messages from said first base station to said second base station, and
wherein at least one of said first and second base stations is configured to determine when to initiate said soft handoff.
11. A method for performing soft handoff, in which a set of packets are transmitted to a mobile terminal from both a first base station and a second base station while said mobile terminal is experiencing soft handoff comprising the steps of:
transmitting a packet from a correspondent host to said first base station;
encapsulating said packet with a new header;
transmitting said packet with said new header to said second base station;
removing said new header at said second base station;
transmitting content in said packet to said mobile station, and
wherein at least one of said first and second base stations is configured to determine when to initiate said soft handoff.
12. The method according to claim 11, wherein said packet is routed in an IP network.
13. The method according to claim 12, wherein said IP network is a part of a CDMA network.
14. The method according to claim 11, further comprising the steps of:
transmitting a second packet from said correspondent host to said second base station;
adding a second header to said second packet;
transmitting said second packet and said second header to said first base station;
removing said second header; and
transmitting the content contained within said second packet to said mobile station.
15. The method according to claim 11, further comprising the steps of:
receiving a first data unit transmitted from said mobile station at said first base station; and
receiving a second data unit from said mobile station at said second base station.
16. The method according to claim 15, further comprising the steps of:
receiving a second packet containing content received from said mobile station at said correspondent host or to said first base station.
17. A method for a mobile station to experience soft handoff between base stations using IP-in-IP encapsulation, comprising:
transmitting from a first base station a packet to said mobile station;
encapsulating a content included in said packet at said first base station;
transmitting said encapsulated content from said first base station to a second base station,
wherein said second base station is configured to transmit said content included in said encapsulated content to said mobile station during soft hand off, and
wherein at least one of said first and second base stations is configured to determine when to initiate said soft handoff.
18. A method for performing soft handoff for a mobile station in which packets are transferred with both a first base station and a second base station when a mobile terminal is in an area serviceable by both said first base station and said second base station, said method comprising:
transmitting a packet from a correspondent host to said first base station,
encapsulating at said first base station content in said packet with a new header,
transmitting said content with said new header from said first base station to said second base station,
removing said new header at said second base station,
transmitting said content from said first base station to said mobile station, and
transmitting said content from said second base station to said mobile station,
wherein at least one of said first and second base stations is configured to determine when to initiate said soft handoff.
19. The method according to claim 18, wherein said packet is routed in an IP network.
20. The method according to claim 19, wherein said IP network is a part of a CDMA network.
21. The method according to claim 18, further comprising the steps of:
transmitting a first data unit from said mobile station to said first base station; and
transmitting a second data unit from said mobile station to said second base station.
22. The method according to claim 18, further comprising the steps of:
transmitting a second packet containing content received from said mobile station to said correspondent host or to said first base station.
23. The system according to claim 3, said first base station further comprising:
an output through which said packets received from said correspondent host are transmitted to said mobile station, such that said mobile station receives packets from said first base station and said second base station,
wherein said first base station and said second base station both transmitting said packets from said correspondent host results in soft-handoff between said first base station and said second base station.
24. The method according to claim 11, further comprising the step of:
transmitting from said first base station to said mobile terminal said packet from said correspondent host,
wherein said first base station and said second base station both transmitting said packets from said correspondent host results in soft-handoff between said first base station and said second base station.
25. The method according to claim 18, further comprising the step of:
receiving a third packet at said mobile station, said third packet having been transmitted from said first base station, said first base station having received said third packet encapsulated by a third header, said third header having been added by said second base station.
26. The soft handoff system according to claim 3, wherein a network management system monitors a delay between said messages.
27. The mobile terminal according to claim 2, wherein the transmission from said first base station to said mobile terminal and the transmission from said second base station to said mobile terminal occur simultaneously.
28. The soft handoff system according to claim 3, wherein said encapsulation header includes an option field that specifies a time for said second base station to transmit said packets to said mobile terminal.
29. The method according to claim 9, said mobile terminal monitoring a delay between reception of messages originating from said first base station and said second base station and reporting said delay to at least one of said base stations.
30. The method according to claim 9, wherein said base stations transmit said messages to said mobile terminal simultaneously.
31. The method according to claim 11, wherein said new header includes a field specifying a time for said second base station to transmit said packet.
32. The method according to claim 9, wherein the encapsulation includes a field specifying a time for the second base station to transmit packets to the mobile terminal.
33. The method according to claim 18, wherein said receiving step receives said content from both said first base station and said second base station simultaneously.