CN101095331A

CN101095331A - A system and method for selecting a multicast ip address

Info

Publication number: CN101095331A
Application number: CN 200580045840
Authority: CN
Inventors: 加里·罗伯特·古特克内希特; 马克·A·麦克利里
Original assignee: Thomson Licensing SAS
Current assignee: Thomson Licensing SAS
Priority date: 2005-10-26
Filing date: 2005-10-26
Publication date: 2007-12-26

Abstract

The disclosed embodiment relates to a system and method used for selecting constitution and broadcast IP address, in particular to a method which includes the steps of selecting a first IP address from a plurality of IP addresses, executing hash calculation of the first IP address to establish a first hashed value corresponding to the first IP address, determining whether the first hashed value corresponds to a second IP address that is being used, and allocating the first IP address if the first hashed value does not correspond to the second IP address that is being used.

Description

Be used to select the system and method for multicast ip address

Technical field

The present invention relates generally to and send video or other numerical data on network.More specifically, the present invention relates to the system that a kind of selection is used for the multicast group (multicast group) of group broadcasting video frequency, audio frequency or other data on Internet protocol (" IP ") network.

Background technology

These chapters and sections are intended to introduce and describe below and/or the claimed relevant various prior aries of many aspects of the present invention to the reader.Believe that this discussion helps to provide background technology so that understand many aspects of the present invention better to the reader.Therefore, should be understood that, read these statements from this angle, and should be with its statement as prior art.

In the past few years, most of people recognize, and are more and more general such as the satellite TV system of DirecTV.In fact, because the introducing of DirecTV in 1994, more than 1,200 ten thousand American families begin to become satellite TV subscribers.Live in the place of relatively easy installation and clutch disk formula satellite tv antenna most houses not sharing an entrance with others among these subscribers.For example, satellite dish can be installed on the roof.

Yet, a lot of potential subscribers live or tent in multitenant unit (" MDU "), for example hotel or the high-rise block of flats.Unfortunately, provide satellite TV can relate to extra challenge for each flat in the MDU.It is unpractical providing and connect a satellite dish for each resident family, and/or extremely expensive.For example, in the high-rise block of flats that has 1,000 apartments, it is unpractical at the building roof 1,000 satellite dish being installed.Some traditional systems have avoided these problems by being the analog signal that can be sent to a plurality of resident families by single coaxial cable with the digital satellite television conversion of signals.Yet these systems provide limited channel, compare with all-digital signal, and quality descends, and the satellite television that the user was accustomed to that can't provide house not sharing an entrance with others to live is experienced.

Need a kind of improved system and/or method, be used for providing satellite television to multitenant unit.

Summary of the invention

Aspect some that proposes below on scope to be consistent with at first claimed the present invention.Should be appreciated that these aspects only propose to be used for to provide the brief description of some form that perhaps the present invention present to the reader, and these aspects and be not intended to limit the scope of the invention.In fact, the many aspects that do not provide below the present invention can comprise.

The disclosed embodiments relate to the system and method that is used to select multicast ip address.More specifically, provide a kind of method, having comprised: from a plurality of IP address, selected an IP address; Hash (hash) is carried out in the one IP address to be calculated to create and corresponding first hashed value in an IP address; Determine whether first hashed value is corresponding with the 2nd IP address of using; And if first hashed value is corresponding with the 2nd IP address of using, and then distributes an IP address.

Description of drawings

During detailed explanation, advantage of the present invention will become apparent below reading in conjunction with the accompanying drawings, in the accompanying drawing:

Fig. 1 is the block diagram of exemplary according to an embodiment of the invention satellite Internet Protocol Television system;

Fig. 2 is another embodiment of exemplary satellite Internet Protocol Television system shown in Figure 1 of the present invention;

Fig. 3 is the block diagram of exemplary satellite gateway of the present invention; And

Fig. 4 shows the flow chart of exemplary technique scheme that is used to select multicast ip address according to the embodiment of the invention.

Embodiment

The one or more specific embodiments of various details.For the concise and to the point description of these embodiment is provided, all features of actual execution mode are not described in specification.Should be realized that, as in any engineering or the design object, in the exploitation of any actual execution mode, must make the specific decision-making of a plurality of execution modes, to realize developer's specific purpose, the compatibility of for example relevant and commercial relative restrictions with system, and this is different for different execution modes.In addition, should be realized that perhaps this exploitation is complicated and consuming time, but for benefiting from those of ordinary skill of the present disclosure, be the regular works of design, making and manufacturing.

Turn to Fig. 1, Reference numeral 10 is represented substantially and is shown block diagram according to the exemplary satellite Internet Protocol Television system of an embodiment.As shown in the figure, in one embodiment, system 10 can comprise head end (head-end) unit, IP distributing network (IP distribution network) 20 and one or more set-top box (" STB ") 22a to 22n of one or more satellite dish 12a to 12m, for example satellite gateway 14.Yet those of ordinary skill in the art can recognize that the embodiment of system 10 shown in Figure 1 only is that of system 10 may embodiment.Similarly, in optional embodiment, assembly shown in the reconfigurable or omission system 10 perhaps can add add-on assemble to system 10.For example, under the situation of small modification, system 10 can be configured to distributed non-satellite video and audio service.

Satellite dish 12a-12m can be configured to receiver, video, audio frequency or from other categorical data earth-circling satellite transmission and TV-related.To describe below, in one embodiment, satellite dish 12a-12m configuration is used to be received in the DirecTV that the KU wave band of from 10.7 to 12.75 Gigahertzs (" GHz ") is worked out.Yet, in optional embodiment, configurable direct broadcasting satellite (" DBS ") or TVRO television receive-only (" TVRO ") signal, for example Dish network signal, ExpressVu signal, the StarChoice signal etc. that are used to receive other type of satellite dish 12a-12m.In other not satellite-based system, can omit satellite dish 12a-12m in the system 10.

In one embodiment, the low noise block among the satellite dish 12a-12m (" LNB ") is from around ground satellite receiving inputted signal, and these input signals is converted to the frequency of the L-band of 950 and 2150 megahertzes (" MHz ").To describe in further detail below in conjunction with Fig. 2, the configurable one or more input satellite TV signals that are used to be received on the characteristic frequency and have particular polarization of among the satellite 12a-12m each (being called transponder (transponder)), and be used for these satellite-signals are converted to the L-band signal, each L-band signal can comprise a plurality of videos or audio signal.

As shown in Figure 1, satellite dish 12a-12m configurable being used for sends to head-end unit or gateway server with the L-band signal, and for example satellite gateway 14.In optional non-satellite embodiment, head-end unit can be wired television receiver, high definition television receiver or other video distribution system.

Satellite gateway 14 comprises that satellite is tuning, demodulation Multiplexing module 16 and IP wrapper (wrapper) module 18.Module 16 can comprise a plurality of tuners, demodulator and demodulation multiplexer, with will from satellite 12a-12m send through the modulation and multiplexing L-band conversion of signals be a plurality of single programs transport stream (" SPTS "), each SPTS all is loaded with service (for example audio frequency of the video of television channel, television channel, program guide etc.).In one embodiment, module 16 configuration is used for all services of being received at satellite dish 12a-12m, produces the single programs transport stream.Yet in optional embodiment, the subclass of the service that module 16 can be only received at satellite dish 12a-12m produces transport stream.

Satellite is tuning, demodulation Multiplexing module 16 can send to SPTS IP wrapper module 18.In one embodiment, IP wrapper module 18 is grouped into the data among the SPTS a plurality of Internet protocols (" the IP ") grouping that is adapted at transmission on the IP distributing network 20 again.For example, IP wrapper module 18 can be converted to the DirectTV protocol packet among the SPTS IP grouping.In addition, 18 configurable being used for of IP wrapper from the request of STB 22a-22n reception server, and with IP SPTS multicast (that is, broadcasting to one or more STB 22a-22n by the IP address) these STB 22a-22n to the request special services.

In optional embodiment, the also configurable not IP agreement SPTS of requested service of one of multicast STB22a-22n that is used for of IP wrapper module 18.Should be noted that

module

16 and 18 only is an one exemplary embodiment of satellite gateway 14.In optional embodiment, for example below in conjunction with Fig. 2 and 3 described embodiment,

module

16 and 18 function can be redistributed or make up in multiple suitable assembly or module.

IP distributing network 20 can comprise one or more routers, switch, modulator-demodulator, splitter or bridge.For example, in one embodiment, satellite gateway 14 can with main-frame (distribution frame, " MDF ") link to each other, MDF links to each other with intermediate distrubuting frame (" IDF "), IDF links to each other with the coaxial cable of Ethernet bridge, and Ethernet bridge links to each other with router, one or more the linking to each other among router and the STB 22a-22n.In another embodiment, IP distributing network 20 can be the MDF that links to each other with Digital Subscriber Line Access Multiplexer (" DSLAM "), and DSLAM links to each other with the DSL modulator-demodulator, and the DSL modulator-demodulator links to each other with router.In another embodiment, the IP distributing network can comprise wireless network, for example 802.11 or the WiMax network.In such an embodiment, STB 2a-22n can comprise that configuration is used for the wireless receiver of receiving group IP address.Those of ordinary skill in the art will appreciate that the foregoing description only is exemplary.Equally, in optional embodiment, can in system 10, adopt the IP distributing network of a large amount of appropriate formats.

IP distributing network 20 can link to each other with one or more STB 22a-22n.STB 22a-22n can be video, audio frequency or other data receiver that can receive for example IP grouping of IP SPTS on IP distributing network 20 of arbitrarily suitable type.Can recognize that term set-top box used herein (" STB ") not only can comprise the equipment that is positioned on the television set.But STB22a-22n can be at television set, display or computer-internal or outside any apparatus or device, is described as can be configured to video recorder including, but not limited to video component, computer, radio telephone or other form at this.In one embodiment, STB 22a-22n can be that configuration is used for receiving for example DirectTV receiver of the service of video and/or audio by (other input) ethernet port.In optional embodiment, STB 22a-22n can design and/or dispose the multicast transmission that is used to receive on coaxial cable, twisted-pair feeder, the copper cash, perhaps via for example wireless transmission of the wireless standard of IEEE 802.11 standards.

As mentioned above, system 10 can receive video, audio frequency and/or other data that satellite sends in the space, and these data of processing/conversion are so that distribution on IP distributing network 20.Therefore, Fig. 2 is another embodiment according to the exemplary satellite Internet Protocol Television system 10 of an embodiment.Fig. 2 shows three exemplary satellite dish 12a-12c.Each satellite dish 12a-12c is configurable to be used to receive from one or more signals around the ground satellite.Those of ordinary skill in the art can recognize, mentions satellite and the signal that comes from satellite transmission with the rail groove (orbital slot) at satellite place usually.For example, satellite dish 12a configuration is used to receive the signal from the DirecTV satellite of the rail groove that is positioned at 101 degree.Similarly, satellite dish 12b receives the signal from the satellite that is positioned at 119 degree, and satellite dish 12c receives the signal from the satellite of the rail groove that is positioned at 110 degree.Can recognize that in optional embodiment, satellite dish 12a-12c can receive from being positioned at for example signal of a plurality of other satellites of a plurality of rail grooves of 95 degree rail grooves.In addition, satellite dish 12a-12c can also dispose the satellite-signal that is used to receive polarization.For example, in Fig. 2, satellite dish 12a configuration is used to receive the signal of left side polarization (being " 101L " shown in the figure) and right polarization (being depicted as " 101R ").

As above in conjunction with Figure 1, satellite dish 12a-12c can receive the satellite-signal of KU wave band, and these conversion of signals are the L-band signal that will send to satellite gateway 14.Yet, in certain embodiments, can before arrive satellite gateway 14, the L-band signal that satellite dish 12a-12c is produced be merged into signal still less or be split into more signal.For example, as shown in Figure 2, can will merge into single L-band signal from the L-band signal of disc type

satellite tv antenna

12b and 12c by switch 24, this single L-band signal comprises the L-band signal from the satellite of the satellite of 110 degree and 119 degree.

As shown in the figure, system 10 also can comprise a plurality of 1: 2

splitter

26a, 26b, 26c and 26d, be used for being divided into two L-band signals from the L-band signal that satellite dish 12a-12c sends, each L-band signal comprises half of service of the L-band signal before the division.In optional embodiment, splitter 26a-26b can omit or be integrated among satellite gateway 14a and the 14b in 1: 2.

The L-band signal that newly divides can be sent to

satellite gateway

14a and 14b from 1: 2 splitter 26a-26d.The embodiment of system 10 shown in Figure 2 comprises two satellite gateway 14a and 14b.Yet in optional embodiment, system 10 can comprise the satellite gateway 14 of any proper number.For example, in one embodiment, system can comprise three satellite gateways 14.

Satellite gateway

14a and 14b also can further segment the L-band signal, then be tuned to one or more services on the L-band signal, can be grouped into the IP grouping again and one or more SPTS of multicast on IP distributing network 20 to produce.In addition, one or

more satellite gateway

14a, 14b also can link to each other with PSTN (" PSTN ") 28.Because satellite gateway 14a, b link to each other with PSTN 28, so STB 22a-22n can pass through IP distributing network 20 and satellite gateway 14a, b, provider communicates with satellite service.This function has advantageously been eliminated the needs that directly link to each other with PSTN 28 for each independent STB22a-22n.

IP distributing network 20 also can link to each other with ISP (" ISP ") 30.In one embodiment, other suitable equipment (not shown) that IP distributing network 20 can be used for linking to each other to STB 22a-22n and/or with IP distributing network 20 provides Internet service, and for example high-speed data inserts.

As mentioned above, satellite gateway 14a, b can dispose and be used to receive a plurality of L-band signals, producing a plurality of SPTS, and the SPTS that multicast is asked on IP distributing network 20.Referring now to Fig. 3, Fig. 3 shows the block diagram of exemplary satellite gateway 14.As shown in the figure, satellite gateway 14a, b comprise power supply 40, two front end 41a and 41b and rear ends 52.Power supply 40 can be any one in a plurality of industrial standard AC or the DC power supply, configurablely is used to make front end 41a, b and rear end 52 can carry out following described function.

Satellite gateway 14a, b also can comprise two front end 41a, b.In one embodiment, each front end 41a, b are all configurable is used for receiving from two L-band signals inputs with reference to figure 2 described 1: 2 splitter 26a-26d.For example, front end 41a can receive two L-band signals from 1: 2 splitter 26a, and front end 41b can receive two L-band signals from 1: 2 splitter 26b.In one embodiment, each L-band of input front end 41a, b includes eight or service still less.

Front end 41a, b can use 1: 4 L-

band splitter

42a, 42b, 42c and 42d further to segment the L-band input then.In case segmented, then the L-band signal can be by entering four groups (bank) 44a, 44b, 44c and the 44d of dual tuner links.Among the group 44a-44d each dual tuner links all configurable be used for be tuned to two services in the L-band signal that receives by independent dual tuner links, to produce SPTS.Each dual tuner links can send to SPTS one of Low Voltage Differential Signal (" LVDS ")

driver

48a, 48b, 48c and 48d then.Lvds driver 48a-48d is configurable to be used to amplify the L-band transmission signals to send to rear end 52.In optional embodiment, replace lvds driver 48a-48d, can adopt multi-form differential driver and/or amplifier.Other embodiment can adopt all transmission signals serializations, to be routed to rear end 52 in the lump.

As shown in the figure, front end 41a, b also can comprise microprocessor 46a and 46b.In one embodiment, microprocessor 46a, 46b may command and/or relay commands are to the group 44a-44d and 1 of dual tuner links: 4L wave band splitter 42a-42d.Microprocessor 46a, b can comprise the ST10 microprocessor that adopts ST microelectric technique to produce.Microprocessor 46a, b can link to each other with 50b with sender module 50a with the LVDS receiver.LVDS receiver/sender module 50a, b can make things convenient for the communication between components on microprocessor 46a, b and the rear end 52, and be as described below.

Next turn to rear end 52, rear end 52 comprises LVDS

receiver

54a, 54b, 54c and 54d, and LVDS

receiver

54a, 54b, 54c and 54d configuration are used to receive the transmission stream signal that lvds driver 48a-48d is sent.Rear end 52 also comprises LVDS receiver/sender module 56a and 56b, and LVDS receiver/sender module 56a and 56b configuration are used for communicating with LVDS receiver/sender module 50a, b.

As shown in the figure, LVDS receiver 54a-54d and LVDS receiver/transmitter 56a, b configuration is used for communicating with transmission processor 58a and 58b.In one embodiment, transmission processor 58a, b configuration is used for being received in front end 41a, b by SPTS that dual tuner links produced.For example, in one embodiment,

transmission processor

58a, 58b be configurable to be used to produce 16 SPTS.Transmission processor 58a, b be configurable be used for SPTS be grouped into again can be on IP distributing network 20 the IP grouping of multicast.For example, transmission processor 58a, b can be grouped into the IP protocol packet again with the DirecTV protocol packet, these IP are multicast to one or more STB 22a-22n then on the IP address.

Transmission processor 58a, b can also link to each other with for example 32, the bus 62 of 66Mz peripheral component interconnect (" PCI ") bus.By bus 62, transmission processor 58a, b can communicate with network processing unit 70, Ethernet interface 84 and/or expansion slot 66.The configurable requests that are used to receive from STB 22a-22n of network processes 70, and command transfer processor 58a, b multicast institute requested service at service.In one embodiment, network processing unit is the IXP425 network processing unit that intel produces.Although not shown, network processing unit 70 can also dispose the panel (front panel) that is used for status data is sent to satellite gateway 14a, b, or supports debugging or supervision to satellite gateway 14a, b by debug port.

As shown in the figure, transmission processor 58a, b also can link to each other with Ethernet interface 68 via bus 62.In one embodiment, Ethernet interface 68 provides towards the copper cash of IP distributing network 20 or the gigabit ethernet interface of optical fiber interface.In addition, bus 62 also can link to each other with the expansion slot of for example pci expansion slot, so that can upgrade or expand satellite gateway 14a, b.

Transmission processor 58a, b also can link to each other with contour (host bus) 64.In one embodiment, contour 64 is 16 bit data bus that transmission processor 58a, b are connected to modulator-demodulator 72, and wherein 72 configurable being used for of modulator-demodulator communicate by aforesaid PSTN 28.In optional embodiment, modulator-demodulator 72 also can link to each other with bus 62.

As mentioned above, satellite gateway 14 is configurable to be used to receive for example service of television video, audio frequency or other data, and by IP distributing network 20 with these service multicast to STB 22a-22n.In one embodiment, STB 22a-22n adopts Ethernet integrated circuit (" IC "), at every specific interested multicast among the STB22a-22n, and monitoring IP distributing network 20.In other words, the Ethernet IC in each of STB 22a-22n can be at for sending the transmission on the IP address that each those service of just using is being used among the STB 22a-22n, monitoring IP distributing network 20.For example, satellite gateway 14 can be with first group of STB on service multicast to the IP address, and with second group of STB on second service multicast to the, the two IP addresses.In this example, first group of interior Ethernet IC of STB can monitor IP distributing network 20 at the activity on the IP address, and second group of interior Ethernet IC of STB can monitor at the activity on the 2nd IP address.Ethernet IC can compare with just monitored IP address by the IP address that will import grouping, monitors at the activity on the particular ip address.

Yet, typically,, hash is carried out in the IP address calculate in order to reduce the computation complexity of Ethernet IC, be reduced to simpler number, to simplify this comparison.For example, the value that is reduced to 6 bits can be calculated through hash in the IP address of 32 bits.Yet those of ordinary skill in the art will recognize that the IP address of 32 bits provides up to a million unduplicated ident values, and the value of 6 bits only provides 64 unique values, and these unique values can be described as hash table bucket (hashbucket).Therefore, calculate the complexity that has reduced Ethernet IC, can in system 10, introduce additional challenge although hash is carried out in the IP address.For example, calculate the IP address that becomes 6 identical bit values if two incoherent multicast group adopt through hash, then the STB that monitors at one of these IP addresses will interrupt for two addresses.Discontinuous or the distortion of playback that these unwanted interruptions can cause the video and/or audio on the STB 22a-22n.Thus, hope reduces the hash collision in the multicast group.

Therefore, Fig. 4 shows the flow chart that is used to select the exemplary technique scheme 80 of multicast ip address according to an embodiment.Technical scheme 80 can be carried out by satellite gateway 14.As following further as described in, the multicast ip address that technical scheme 80 can make things convenient for 14 pairs of satellite gateways to be evenly distributed in available a plurality of hash table buckets is selected.For example, technical scheme 80 can be selected a multicast ip address in each hash table bucket, till each hash table bucket all has an IP address, in each hash table bucket, select no more than two IP addresses then, up to existing and corresponding two the IP addresses of each hash table bucket, and so on.

As shown in the figure, technical scheme 80 starts from being provided with and equals 1 counter variable MaxBucketCount, with array HashBuchetCount zero clearing, and will remain the multicast address pool and reset.MaxBucketCount can indicate the hash that is allowed by satellite gateway 14 to calculate the maximum number of the IP address of same Hash list cell.The HashBuchetCount array can comprise position at each HashCount (for example for the hashed value of 6 bits, 64 spaces).The HashBuchetCount array can be stored current distribution and the number corresponding multicast ip address of each hash table bucket.For example, if satellite gateway 14 has distributed and hash table bucket 1 and 6 corresponding IP addresses, then array position 1 and 6 each will comprise several 1.Residue multicast address pool can be an IP address list, and is wherein as described below, and described IP address is (1) the current IP address of multicast satellite services and IP address that does not temporarily remove from the multicast ip address pond (2) of not being used for.

Next, shown in piece 84, satellite gateway 14 can be waited for the service request from one of STB 22a-22n.In case receive service request, then shown in piece 86, satellite gateway 14 can determine whether remained multicast address in the multicast address pond.If residue has multicast ip address in the multicast address pond, then shown in piece 88, satellite gateway 14 can be selected one of remaining ip address, and shown in piece 90, and the variable n that equals selected hash table bucket number is set.Shown in piece 92, satellite gateway 14 can be checked the HashBuchetCount array then, whether surpasses MaxBucketCount with the value among the position n that determines to be stored in the HashBuchetCount array.For example, if MaxBucketCount is 1, then satellite gateway 14 determine with corresponding HashBuchetCount array position, selected IP address whether less than 1 (promptly equaling 0).

If be not less than MaxBucketCount with the position in the corresponding HashBuchetCount array of hash table bucket that is associated of residue multicast address, then shown in piece 94, satellite gateway 14 can be removed selected multicast address from residue multicast address pool.After from residue multicast address pool, removing selected multicast ip address, as shown in Figure 4, technical scheme 80 pieces 86 of getting back to capable of circulation.By this way, satellite gateway 14 can continue to check the multicast ip address in the residue multicast address pool, up to find with HashBuchetCount array intermediate value less than the corresponding multicast ip address in the position of MaxBucketCount till, perhaps till from the multicast address pond, removing all residue multicast ip address.

Get back to piece 92, if with the value of the corresponding HashBuchetCount array of hashed value of selected IP address less than MaxBucketCount, then shown in piece 96, satellite gateway 14 can distribute selected multicast address, and with the corresponding position of the HashBucket of selected multicast address the HashBuchetCount array is increased progressively.Make after the HashBuchetCount array increases progressively, technical scheme 80 pieces 84 of getting back to capable of circulation, and wait for another service request from one of STB 22a-22n.

As mentioned above, satellite gateway 14 pieces 86 of getting back to capable of circulation are till it has distributed a multicast ip address, perhaps up to removed all IP addresses from residue multicast address pool till.In case from the multicast address pond, removed all multicast address, then technical scheme 80 can make MaxBucketCount variable increment (this makes and gives each hash table bucket with an IP address assignment again), and the residue of resetting multicast address pool is to comprise current all multicast address that do not used by satellite gateway 14.After the residue multicast address pool of resetting, as mentioned above, technical scheme 80 can turn back to piece 86.By this way, technical scheme 80 is distributed an IP address by each list cell, has an IP address up to all hash table buckets, and perhaps remaining does not have in the multicast address pool to have made things convenient for mean allocation IP address in hash table bucket till the IP available address.

Can be easily carry out multiple modification and adopt the plurality of optional form the present invention, the accompanying drawing example of passing the imperial examinations at the provincial level shows specific embodiment simultaneously, and is described in detail at this.Yet, should be appreciated that the present invention also is not intended to be subject to particular forms disclosed.But the present invention covers all modifications, equivalent and the optional thing that falls in the spirit and scope of the invention that is defined by the following claims.

Claims

1. method comprises:

From a plurality of IP address, select an IP address;

Hash is carried out in the one IP address to be calculated to create and corresponding first hashed value in an IP address;

Determine whether first hashed value is corresponding with the 2nd IP address of using; And

If first hashed value is not corresponding with the 2nd IP address of using, then distribute an IP address.

2. method according to claim 1 wherein, is carried out hash to an IP address and is calculated and to comprise an IP address is calculated as 6 bit values from 32 bit value hash.

3. method according to claim 1 comprises: if first hashed value is not corresponding with the 2nd IP address of using, then use an IP address that satellite service is multicast to set-top box (22).

4. method according to claim 3 wherein, determines whether to use the 2nd IP address to comprise: to determine whether to use the 2nd IP address multicast satellite services.

5. method according to claim 3 comprises: receive the request at satellite service from set-top box (22).

6. method according to claim 3, wherein, multicast satellite services comprises: multicast DirecTV service.

7. method according to claim 1 comprises:

If first hashed value is corresponding with the 2nd IP address of using, then select the 3rd IP address; And

Hash is carried out in the 3rd IP address to be calculated to create second hashed value.

8. a head-end unit (14), configuration is used for:

From a plurality of IP address, select an IP address;

9. head-end unit according to claim 8 (14), wherein, satellite gateway (14) configuration is used for an IP address is calculated as 6 bit values from 32 bit value hash.

10. head-end unit according to claim 8 (14), wherein, satellite gateway (14) configuration is used for: if first hashed value is not corresponding with the 2nd IP address of using, then use an IP address that satellite service is multicast to set-top box (22).

11. head-end unit according to claim 10 (14), wherein, satellite gateway (14) configuration is used to determine whether using the 2nd IP address multicast satellite services.

12. head-end unit according to claim 10 (14), wherein, satellite gateway (14) configuration is used for receiving the request at satellite service from set-top box (22).

13. head-end unit according to claim 10 (14), wherein, satellite gateway (14) configuration is used for multicast DirecTV service.

14. head-end unit according to claim 8 (14), wherein, satellite gateway (14) configuration is used for:

15. a head-end unit (14) comprising:

Be used for selecting the device of an IP address from a plurality of IP address;

Being used for that hash is carried out in an IP address calculates with the device of establishment with corresponding first hashed value in an IP address;

Be used for determining first hashed value whether with the corresponding device in the 2nd IP address that is using; And

Be used for when first hashed value is not corresponding with the 2nd IP address of using, distributing the device of an IP address.

16. head-end unit according to claim 15 (14) wherein, is carried out hash to an IP address and is calculated and to comprise an IP address is calculated as 6 bit values from 32 bit value hash.

17. head-end unit according to claim 15 (14) comprising: be used for when first hashed value is not corresponding with the 2nd IP address of using, using an IP address satellite service to be multicast to the device of set-top box (22).

18. head-end unit according to claim 17 (14) wherein, is used to determine whether to use the device of the 2nd IP address to comprise: the device that is used to determine whether to use the 2nd IP address multicast satellite services.

19. head-end unit according to claim 17 (14) comprising: be used for receiving device at the request of satellite service from set-top box (22).

20. head-end unit according to claim 17 (14) comprising:

Be used for when first hashed value is corresponding with the 2nd IP address of using, selecting the device of the 3rd IP address; And

Being used for that hash is carried out in the 3rd IP address calculates to create the device of second hashed value.