Multicast service delivery over high throughput satellite in a Ka spot-beam network

1. A satellite communication system comprising:

one or more satellite gateway earth stations; and

a satellite configured to communicate with a plurality of terminals via a plurality of spot beams formed by the satellite, each of the plurality of terminals being arranged to receive communications via the satellite and a respective spot beam of the plurality of spot beams, wherein:

the one or more satellite gateway earth stations is arranged to receive one or more multicast streams from an external network, and

when a satellite gateway earth station of the one or more satellite gateway earth stations is configured to be in a static forwarding mode, the satellite gateway earth station is statically configured to replicate and forward each of the one or more multicast streams over one or more first respective outroute carriers of at least one first respective spot beam of the plurality of spot beams regardless of whether any terminals are arranged to actively receive any of the one or more multicast streams, and

when the satellite gateway earth station is configured to be in a dynamic forwarding mode, the satellite gateway earth station is dynamically configured to replicate and forward ones of the one or more multicast streams over one or more second respective outroute carriers of at least one second respective spot beam of the plurality of spot beams only when at least one respective terminal is arranged to actively receive each of the ones of the one or more multicast streams over the one or more second respective outroute carriers of the at least one second respective spot beam of the plurality of spot beams.

2. The satellite communication system of claim 1 , wherein the plurality of spot beams are Ka-band spot beams.

3. The satellite communication system of claim 1 , further comprising:

the plurality of terminals, wherein

each of the plurality of terminals that are in an active mode include a proxy agent, such that the proxy agent in each respective terminal of the plurality of terminals that are in the active mode makes a determination whether to forward a received multicast stream on a local area network only when at least one respective active receiver is downstream of the respective terminal of the plurality of terminals that are in the active mode.

4. The satellite communication system of claim 1 , further comprising:

the plurality of terminals, wherein

each terminal of the plurality of terminals belonging to any multicast group advertises a respective current eligible outroute modulation coding and multicast membership information based on an individual link condition of the each terminal to the satellite gateway earth station, and

responsive to receiving the advertised respective current eligible outroute modulation coding and multicast membership information from each of the plurality of terminals belonging to the any multicast group, the satellite gateway earth station sends the multicast stream for a multicast group on a lowest or most robust advertised outroute modulation coding advertised by each terminal of the plurality of terminals receiving the multicast stream on the multicast group.

5. The satellite communication system of claim 3 , wherein

when the satellite gateway earth station is configured to be in the dynamic forwarding mode, the respective proxy agent in each of the plurality of terminals, that are arranged to actively receive at least one respective multicast stream of the ones of the one or more multicast streams, forwards information to the satellite gateway earth station informing the satellite gateway earth station to forward the at least one respective multicast stream of the ones of the one or more received multicast streams over the one or more second respective outroute carrier of the at least one second respective spot beam associated with each of the plurality of terminals that are arranged to actively receive the at least one respective multicast stream of the ones of the one or more multicast streams.

6. The satellite communication system of claim 5 , further comprising:

a peering router arranged to communicate with the external network and the satellite gateway earth station, wherein the satellite gateway earth station sends a join signal to the peering router for each multicast address associated with a multicast stream that the satellite gateway earth station is configured to forward.

7. The satellite communication system of claim 1 , wherein

the satellite gateway earth station is configured to map one or more multicast IP addresses to a single layer 2 spacelink MAC address, such that the satellite gateway earth station sends a packet associated with one of the one or more multicast IP addresses to a plurality of destination terminals using the single layer 2 spacelink MAC address over one or more outroute carriers of one or more spot beams associated with any of the plurality of destination terminals.

8. The satellite communication system of claim 7 , wherein packets having a respective multicast IP address that matches any one of the one or more mapped multicast IP addresses are encrypted based on a single multicast key before the packets are sent, using the single layer 2 spacelink MAC address, to respective terminals.

9. The satellite communication system of claim 7 , wherein

the layer 2 spacelink MAC address includes a virtual network operator identifier to ensure that the layer 2 spacelink address is unique across layer 2 spacelink addresses for a plurality of virtual network operators.

10. The satellite communication system of claim 7 , wherein:

the satellite gateway earth station comprises a key dispatcher for distributing a multicast session key to ones of the plurality of terminals belonging to a multicast session and for handling requests for the multicast session key from at least one of the ones of the plurality of terminals belonging to the multicast session; and

the satellite gateway earth station encrypts, using the multicast session key, traffic to be sent to the at least one of the ones of the plurality of terminals belonging to a multicast group.

11. The satellite communication system of claim 10 , wherein the multicast session supports a hitless key update mechanism.

12. The satellite communication system of claim 1 , wherein a priority of multicast traffic is configurable either statically or through differentiated services code point marking.

13. The satellite communication system of claim 12 , wherein a virtual network operator is permitted to specify policies that drive which multicast sessions are dropped during oversubscription or congestion.

14. A method for providing support for multicast sessions in a satellite communication system, the method comprising:

receiving, by a satellite gateway earth station, a multicast stream from an external network;

replicating and forwarding, by the satellite gateway earth station, the multicast stream over at least one respective outroute carrier of at least one respective spot beam of a plurality of spot beams of a satellite regardless of whether one or more terminals are arranged to actively receive the multicast stream over the at least one respective outroute carrier, when the satellite gateway earth station is configured to be in a static forwarding mode; and

replicating and forwarding, by the satellite gateway earth station, the multicast stream over at least one respective outroute carrier of at least one respective spot beam of a plurality of spot beams of a satellite only when a respective terminal is arranged to actively receive the multicast stream over each of the at least one respective outroute carrier of each of the at least one respective spot beam, when the satellite gateway earth station is configured to be in a dynamic forwarding mode.

15. The method of claim 14 , further comprising:

receiving information, by the satellite gateway earth station from a terminal via a satellite, the information informing the satellite gateway earth station to forward received traffic from the multicast stream to the terminal via an outroute of a spot beam of the satellite that communicates with the terminal, when the satellite gateway earth station is configured to be in the dynamic forwarding mode.

16. The method of claim 14 , further comprising:

mapping, by the satellite gateway earth station, one or more multicast IP addresses to a single layer 2 spacelink MAC address, such that the satellite gateway earth station sends a packet associated with any of the one or more multicast IP addresses to a plurality of destination terminals using the single layer 2 spacelink MAC address over one or more outroute carriers of one or more spot beams associated with any of the plurality of destination terminals.

17. The method of claim 16 , wherein the layer 2 spacelink MAC address includes a virtual network operator identifier.

18. The method of claim 14 , further comprising:

distributing a multicast session key, by a key dispatcher included in the satellite gateway earth station, to ones of a plurality of terminals associated with a multicast session of the multicast stream; and

encrypting, using the multicast session key, multicast traffic of the multicast stream before sending the multicast traffic to the ones of the plurality of terminals associated with the multicast session.

19. The method of claim 18 , further comprising:

storing, by a key management system, effective master keys in a database, each of the effective master keys being based on a respective master key associated with a respective terminal, each of the respective master keys being unique among the master keys associated with the respective terminals;

generating, by the key management system, a root session key;

generating, by the key management system, a multicast session key based on the root session key;

encrypting, by the satellite gateway earth station, the multicast session key by a respective effective session master key for each respective terminal of the multicast session to produce a respective encrypted multicast session key for each of the respective terminals of the multicast session; and

providing, by the satellite gateway earth station, each respective encrypted multicast session key to a corresponding respective terminal of the multicast session.

20. The method of claim 14 , further comprising:

either statically configuring a priority of a multicast session including the multicast stream, or configuring the priority of the multicast session through differentiated services code point marking.

21. The method of claim 20 , further comprising:

providing a facility for a virtual network operator to specify policies that drive which multicast sessions are dropped during oversubscription or congestion.