Abstract: A method of managing a network for delivering content to a client device, where content segments are delivered over multicast to a proxy. The received segments are stored at the proxy, before delivery of those segments is made from the proxy to the client device over unicast. Whilst the proxy receives further segments over multicast, it probes the network by making unicast requests for data (dummy data or additional content segments), and receiving those segments over unicast from the content server. The multicast rate reception rate and the unicast (probe) rate are measured and a maximum network throughput is calculated as the sum of these two rates. Subsequent segments are then delivered from the proxy to the client device at the calculated maximum network throughput rate, or at some rate dependent thereon.

Abstract: Described is a method of delivering content over a network using an approach referred to as “Multicast Assisted Unicast Delivery” (MAUD), as a multicast network is used to assist, rather than substituting for, an otherwise unicast path. Content is requested by client devices from a content server over unicast. The responses containing the requested content are separated into two components: a first component containing elements that are specific to individual client devices (for example session specific data), and a second component that is common to all client devices (typically this is the video content being requested). The first component can be delivered over unicast and the second component over multicast. Identifiers are introduced into each of the first and second components to aid recombination of the components to form the original responses. The separation and recombination are handled by suitably configured proxy servers.

Abstract: Examples of the present invention provide a method of reducing the latency in streaming live media by a client from a server. The client uses manifest information to determine the “live edge” of the live media stream, where the live edge is represented by the segment from the media stream corresponding to the current time. The client then uses this to identify the next segment, which is the segment in time that will next become available. The client then starts making repeated polling requests for that next segment until the segment becomes available. As a result, the newest possible segment is obtained by the client as soon as it becomes available, and latency is reduced. Further, when adopted by all clients, the latency variation between clients is also reduced.

Abstract: Described is a method of delivery of content to a client device. In particular, the method can be applied to hybrid unicast/multicast delivery networks, where content is provided by a content server to a root proxy, and that root proxy delivers the content to edge proxies over multicast. However, requests for that content in the form of HTTP GET requests from a client device are received by an edge proxy, which subsequently sends an HTTP HEAD request for header information associated with that content directly to the content server. The content server responds over unicast with a suitable response to the HTTP HEAD request, which is received by the edge proxy. The edge proxy takes the response together with the payload from the content segment received over multicast, to generate a client specific content segment for delivery to the client device over unicast.

Abstract: A method of managing a network for delivering content to a client device, where content segments are delivered to a proxy in a multicast group, before delivery from the proxy to the client device over unicast. The proxy intermittently leaves the multicast group to probe the network by making unicast request for content segments, receiving those segments over unicast from the content server and forwarding those segments onto the client device. This allows the client device to determine the maximum throughput between the content server and the client device via the proxy, and thus the client device can use its adaptive bit rate algorithms to determine if the network can support a switch to a higher bit rate stream, and request a higher bit rate stream accordingly. The higher bit rate stream can be serviced by the proxy joining or establishing a suitable multicast group.

Abstract: Described is a method of delivery of content to a client device. In particular, the method can be applied to hybrid unicast/multicast delivery networks, where content is provided by a content server to a root proxy, and that root proxy delivers the content to edge proxies over multicast. However, requests for that content in the form of HTTP GET requests from a client device are received by an edge proxy, which subsequently sends an HTTP HEAD request for header information associated with that content directly to the content server. The content server responds over unicast with a suitable response to the HTTP HEAD request, which is received by the edge proxy. The edge proxy takes the response together with the payload from the content segment received over multicast, to generate a client specific content segment for delivery to the client device over unicast.

Abstract: Described is a method of managing a network for delivering content in a hybrid unicast/multicast network, where content is requested by clients over unicast, but all or some of the content is delivered in part over multicast. A client requests content (in the form of segments) and receive the responses (segments) over unicast via a first proxy. The first proxy measures the time between requests and associated requested segment sizes. These measurements are used to effectively determine a unicast request rate given by the segment size divided by the time between requests. Subsequent requested segments can then be delivered over multicast over a portion of the route to the client using a multicast rate that is set as a function of (for example, 110% of) the unicast request rate. In general, the multicast path will be from a second proxy to the first proxy.

Abstract: Described is a method of managing a network for delivering content in a hybrid unicast/multicast network, where content is requested by clients over unicast, but all or some of the content is delivered in part over multicast. Typically, a client requests content (in the form of segments) via a first proxy. The segments are delivered to the first proxy over multicast from a second proxy, before onward transmission to the requesting client over unicast. The segments are also cached at the first proxy, and can be transmitted over unicast to other clients requesting those segments. However, problems can arise if cached segments are transmitted to clients too quickly. In one solution, the first proxy measures the multicast rate of delivery of segments from the second proxy over multicast, and limits the transmission rate of those segments over unicast to requesting clients to no greater than the measured multicast delivery rate.

Abstract: Described is a method of managing a network for delivering content in a hybrid unicast/multicast network, where content is requested by clients over unicast, but all or some of the content is delivered in part over multicast. A client requests content (in the form of segments) and receive the responses (segments) over unicast via a first proxy. The first proxy measures the time between requests and associated requested segment sizes. These measurements are used to effectively determine a unicast request rate given by the segment size divided by the time between requests. Subsequent requested segments can then be delivered over multicast over a portion of the route to the client using a multicast rate that is set as a function of (for example, 110% of) the unicast request rate. In general, the multicast path will be from a second proxy to the first proxy.

Abstract: Presented are methods for converting a multicast media stream to unicast segments, for delivery over generic IP networks such the Internet. The unicast segments can be converted back again to a multicast stream that is identical to the original multicast stream closer to the consuming client device. Information required to regenerate a multicast stream from the generated unicast segments that is identical to the original multicast stream is also encoded into the file name of the generated unicast segments. Additionally, RTP header information from the multicast stream that is not required when the unicast segments are generated are stored in files linked to the generated unicast segments, enabling the multicast stream that is regenerated to be identical to the original multicast stream even at the RTP level.

Abstract: Described is a method of delivering content over network using an approach referred to here as “Multicast Assisted Unicast Delivery” (MAUD), as a multicast network is used to assist, rather than substituting for, an otherwise unicast path. Content is requested by client devices from a content server over unicast. These unicast requests are sent via a first and a second proxy, before being sent by the second proxy to the content server, all over unicast. The responses containing the requested content is sent back to the second proxy over unicast from the content server. The second proxy processes the received unicast responses and sends the responses over a multicast stream to the first proxy. The first proxy processes the received responses and sends them onto the requesting client devices over unicast.

Abstract: Described is a method of delivering content over a network using an approach referred to as “Multicast Assisted Unicast Delivery” (MAUD), as a multicast network is used to assist, rather than substituting for, an otherwise unicast path. Content is requested by client devices from a content server over unicast. The responses containing the requested content are separated into two components: a first component containing elements that are specific to individual client devices (for example session specific data), and a second component that is common to all client devices (typically this is the video content being requested). The first component can be delivered over unicast and the second component over multicast. Identifiers are introduced into each of the first and second components to aid recombination of the components to form the original responses. The separation and recombination are handled by suitably configured proxy servers.

Abstract: Presented are methods for converting a multicast media stream to unicast segments, for delivery over generic IP networks such the Internet. The unicast segments can be converted back again to a multicast stream that is identical to the original multicast stream closer to the consuming client device. Information required to regenerate a multicast stream from the generated unicast segments that is identical to the original multicast stream is also encoded into the file name of the generated unicast segments. Additionally, RTP header information from the multicast stream that is not required when the unicast segments are generated are stored in files linked to the generated unicast segments, enabling the multicast stream that is regenerated to be identical to the original multicast stream even at the RTP level.

Abstract: Presented are methods for converting a multicast media stream to unicast segments, for delivery over generic IP networks such the Internet. The unicast segments can be converted back again to a multicast stream that is identical to the original multicast stream closer to the consuming client device. Information required to regenerate a multicast stream from the generated unicast segments that is identical to the original multicast stream is also encoded into the file name of the generated unicast segments. Additionally, RTP header information from the multicast stream that is not required when the unicast segments are generated are stored in files linked to the generated unicast segments, enabling the multicast stream that is regenerated to be identical to the original multicast stream even at the RTP level.

Abstract: Examples of the present invention provide a method of converting a multicast stream into unicast segments. In particular, sequence identifiers are generated based on a clock reference field in the transport stream packets that make up the multicast stream. Every time a new sequence identifier is calculated, a new unicast segment is generated and assigned with the new sequence identifier. Transport stream packets are placed into the new segment until a packet is processed that causes a new sequence identifier to be generated, at which point another new segment is generated and packets placed into that segment. In an improved method, random access indicators in the transports stream packets are used to further constrain when a new segment is generated, to ensure that new segments are coincident with a packet having a random access indicator. This improvement makes random access easier back and forth between and within a stream.

Abstract: The invention presents a method of providing feedback for receipt of a multicast video stream. The feedback mechanism allows the number of clients receiving over multicast to be determined, which can then be used to manage multicast delivery, including switching decisions between multicast and unicast. Video content is delivered over a multicast stream from a content server to a plurality of client devices. The client devices are each configured to respond at regular intervals whilst receiving the multicast video stream by transmitting an HTTP HEAD request message to the content server. The HTTP HEAD request refers to metadata relating to a manifest file associated with the video stream. The number of client devices receiving the multicast video stream is determined based on the number of HEAD requests received at the content server.

Abstract: Examples of the present invention provide a method of reducing the latency in streaming live media by a client from a server. The client uses manifest information to determine the “live edge” of the live media stream, where the live edge is represented by the segment from the media stream corresponding to the current time. The client then uses this to identify the next segment, which is the segment in time that will next become available. The client then starts making repeated polling requests for that next segment until the segment becomes available. As a result, the newest possible segment is obtained by the client as soon as it becomes available, and latency is reduced. Further, when adopted by all clients, the latency variation between clients is also reduced.

Abstract: Examples of the present invention provide a method of converting a multicast stream into unicast segments. In particular, sequence identifiers are generated based on a clock reference field in the transport stream packets that make up the multicast stream. Every time a new sequence identifier is calculated, a new unicast segment is generated and assigned with the new sequence identifier. Transport stream packets are placed into the new segment until a packet is processed that causes a new sequence identifier to be generated, at which point another new segment is generated and packets placed into that segment. In an improved method, random access indicators in the transports stream packets are used to further constrain when a new segment is generated, to ensure that new segments are coincident with a packet having a random access indicator. This improvement makes random access easier back and forth between and within a stream.

Abstract: The invention presents a method of generating a multicast stream for transporting video content such as live TV. First, the video content is encoded, and segmented into temporal chunks. Each chunk is then encapsulated in one or more RTP pacets, depending on the size of the chunk, and each RTP packet is marked with a chunk marker to indicate which of the packets the boundaries between chunks lie. The multicast stream is then generated by encapsulating the RTP packets, preferably using UDP in IP packets. The chunk marker is provided for by a special field in the RTP payload header. The chunk marker can be a chunk index or a chunk offset. Both, individually and in combination, can be used to determine the boundary between chunks.

Abstract: The invention presents a method of providing feedback for receipt of a multicast video stream. The feedback mechanism allows the number of clients receiving over multicast to be determined, which can then be used to manage multicast delivery, including switching decisions between multicast and unicast. Video content is delivered over a multicast stream from a content server to a plurality of client devices. The client devices are each configured to respond at regular intervals whilst receiving the multicast video stream by transmitting an HTTP HEAD request message to the content server. The HTTP HEAD request refers to metadata relating to a manifest file associated with the video stream. The number of client devices receiving the multicast video stream is determined based on the number of HEAD requests received at the content server.