Patent application title: METHODS AND APPARATUS FOR TRANSMITTING DATA STREAMS VIA A HETEROGENEOUS NETWORK
Matthew Xavier Mora (Fremont, CA, US)
Ashley Ian Butterworth (Normanhurst, AU)
Andrew Yanowitz (Ben Lomond, CA, US)
Andrew Yanowitz (Ben Lomond, CA, US)
Niel David Warren (Soquel, CA, US)
IPC8 Class: AH04L2908FI
Class name: Electrical computers and digital processing systems: multicomputer data transferring computer-to-computer session/connection establishing
Publication date: 2015-02-19
Patent application number: 20150052257
Methods and apparatus that enable a community of devices having differing
underlying protocols to stream media data such as video or audio data. In
one exemplary embodiment, this invention enables IEEE 1394-compliant
("FireWire" enabled) devices to communicate across an Ethernet
infrastructure, such as one enabled by the Ethernet AVB Standard(s). This
enhances connectivity, and also supports obviating one or more physical
ports within the device(s). In another embodiment, or more wireless
transports are utilized.
3. An apparatus configured to interoperate with a heterogeneous fabric, comprising: an interface to the heterogeneous fabric, the heterogeneous fabric configured to support multiple different device protocols; a user interface; a processor; and a non-transitory computer readable apparatus having a storage medium with at least one computer program stored thereon, the at least one computer program configured to, when executed on the processor, cause the apparatus to: responsive to a connection to the heterogeneous fabric, register the apparatus with a network daemon; identify one or more other devices connected to the heterogeneous fabric via the network daemon; and responsive to a user request via the user interface, initiate a data connection to at least a target device of the one or more other devices within a user session.
4. The apparatus of claim 3, wherein the user session is initiated and terminated based at least in part on user input received by the user interface.
5. The apparatus of claim 3, wherein the interface to the heterogeneous fabric is configured to format packets of a first protocol into packets of a second protocol, the second protocol being native to the heterogeneous fabric.
6. The apparatus of claim 3, wherein the first protocol is native to the target device.
 This application is a divisional of and claims priority to co-owned and co-pending U.S. patent application Ser. No. 13/784,689 of the same title filed Mar. 4, 2013, issuing as U.S. Pat. No. 8,843,670 on Sep. 23, 2014, which is a divisional of U.S. patent application Ser. No. 12/572,995 of the same title filed Oct. 2, 2009, now U.S. Pat. No. 8,392,631, which claims priority to U.S. Provisional Patent Application Ser. No. 61/195,141 filed Oct. 2, 2008 of the same title, each of which are incorporated by reference herein in their entirety.
 A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.
BACKGROUND OF THE INVENTION
 1. Field of Invention
 The present invention relates generally to the field of data networks and device data sharing. More particularly, in one exemplary aspect, the present invention is directed to methods and apparatus enabling a heterogeneous community of devices (e.g., those which operate according to a FireWire or Ethernet AVB protocol) to interoperate seamlessly and transfer data and media (e.g., audio and video) there between.
 2. Description of Related Technology
 Modern electronic equipment has greatly enhanced the quality of life for many. However, as the use of such equipment has increased, so has the need to connect equipment of differing types purchased from different manufacturers. For example, while a computer and a digital camera may each be useful when used alone, the ability to connect the digital camera to the computer and exchange information (e.g., photos, video) between the two makes the combination even more useful. Therefore, a need was apparent for a serial bus standard that would allow for the connection and communication between such devices.
 The IEEE 13944995 standard (and its associated trade names "FireWire®" (Apple Inc.), "i.LINK" (Sony), and "Lynx" (Texas Instruments), etc.) was developed to satisfy this need. This standard revolutionized the consumer electronics industry by providing a serial bus management system that featured high speeds and the ability to "hot" connect equipment to the bus; that is, the ability to connect equipment without first turning off the existing connected equipment. Since its adoption, the IEEE 1394-1995 standard has seen acceptance in the marketplace with many major electronics and computer manufacturers providing IEEE 1394-1995 connections on equipment that they sell. Several variants of IEEE 1394 have also been developed and widely deployed which improve and enhance various system characteristics (including e.g., higher speeds and longer connection paths).
 In addition to IEEE 1394 based standards, a new standard being proposed at the time of the filing of the present application is herein referred to as the "Ethernet AVB standard". Ethernet AVB is a new standard being developed for transmitting audio and video data across an 802.1 Ethernet link. Existing Ethernet standards guarantee packet delivery; Ethernet AVB is expected to provide additional capabilities enabling isochronous data transfer. Specifically, Ethernet AVB provides guarantees on maximum latency and minimum bandwidth that enable "streaming" applications, which were previously limited due to requirements for low latency isochronous transfer of audio and video.
Unsatisfied Need for Interoperability
 Due to the widespread existing deployments of existing IEEE 1394 devices, and the virtually universal Ethernet infrastructure, a solution for providing interoperability for the two standards seamlessly (with respect to various types of media) would greatly enhance the overall utility of both. Such a solution does not currently exist.
 Another issue relates to the increasing "disappearance" of physical ports on hardware devices such as computers, video cameras, etc. over time. These physical ports (including FireWire ports) are becoming less prolific on new generation devices because, inter alia, aggressive form factor reductions no longer allow distinct connectors for all supported I/O technologies. Thus, physical space for the port and the extra cost of the port make it a strong candidate for removal. For example, in the MacBook Air product manufactured by the Assignee hereof, connectors include only a USB port, power port and a video port. Neither a physical FireWire port nor Ethernet port are present on the device. As the number of (FireWire and other) ports disappear, so do the connectivity opportunities for devices using that port specification. Hence, in order to maintain FireWire support and distribution over such devices, other "ways off of" and "ways onto" the device are needed.
 Accordingly, improved methods and apparatus are needed for providing data stream delivery between two differing protocols, such as for example Ethernet AVB, and IEEE 1394. Such an improved solution should operate seamlessly and without adversely impacting user experience on existing apparatus. Moreover, such "multi-lingual" data stream delivery would be operable without requiring undue hardware or other modification to implementations already deployed. To these ends, such data delivery schemes should minimally support "master-slave" operation, where a dynamically bridging multi-lingual device performs all translation for its localized network, without requiring its non-enabled slave devices to do so.
 Multiple clients would also advantageously work cooperatively to simultaneously source and sink isochronous datastreams, each independently capable of additionally splitting or merging multiple isochronous data streams.
 Lastly, such improved apparatus and methods would enable the use of IEEE 1394-compliant devices across any geography or topology, such as by piggybacking on existing Ethernet infrastructure.
SUMMARY OF THE INVENTION
 The present invention satisfies the foregoing needs by providing, inter alia, improved apparatus and methods for bridging data (including audio and video or other multimedia data) across networks or devices using different protocols.
 In one aspect of the invention, a method for sending a message from a source device to a target device is disclosed. In one embodiment, the message is sent via a fabric or other intermediary architecture, and said source device operates with a first protocol, and said fabric operates with a second protocol, said first and second protocols being different. The method comprises: associating said source device with a software entity; associating said target device with said software entity; responsive to said associations of said source device and said target device, negotiating one or more parameters related to data stream requirements; receiving at least one message compliant with said first protocol from said source device; formatting said at least one messages to be compliant with said second protocol, and said negotiated one or more parameters; and transmitting said formatted at least one messages via said fabric.
 In one variant, said source device and fabric are characterized by isochronous transfer parameters.
 In another variant, the first protocol comprises a 1394-compliant protocol, and the second comprises an Ethernet AVB compliant protocol.
 In a second aspect of the invention, a source device adapted for isochronous data transfer is disclosed.
 In a third aspect of the invention, a transfer medium adapted to facilitate media/data transfer between different protocol environments is disclosed. In one embodiment, the medium comprises a fabric capable of connecting 1394.1 bridge portals and that is capable of transferring any serial bus subaction from one portal to its co-portal, and that supports bidirectional, non-blocking transfer of asynchronous request subactions, asynchronous response subactions, and isochronous subactions.
 In a fourth aspect, a computer readable medium comprising at least one computer program adapted transfer media/data between different protocol environments is disclosed.
 In a fifth aspect of the invention, a client device adapted to run the aforementioned program is disclosed. In one variant, the client device comprises a desktop or portable computer. In another variant, the client device comprises a personal media device or PDA. In yet another embodiment, the device comprises a network router, such as a home LAN or switch or router.
 In a sixth aspect of the invention, a portal architecture is disclosed. In one embodiment, the portals comprise 1394.1-compliant portals disposed on each side of an Ethernet AVB network, and which employ AVC command interpreters. This approach allows existing FireWire software to "see" FireWire devices that are not physically connected to the local FireWire bus (or if there is no local FireWire bus at all).
 In a seventh aspect of the invention, one or more wireless protocols are utilized as the bearer(s) for the transported media content.
 In an eighth aspect of the invention, business models and associated methods of doing business are disclosed.
 In a ninth aspect, a method of managing connectivity over a heterogeneous fabric is disclosed. In one exemplary embodiment, the method includes: receiving an indication of one or more capabilities associated with a first device, the first device having a first protocol associated therewith and the first device being coupled to the heterogeneous fabric, responsive to the indication, storing at least one device capability associated with the first device, and responsive to a received request for a connection to a target device, providing the at least one stored device capability to the target device.
 In a variant, the target device has a second protocol associated therewith.
 In a tenth aspect, an apparatus configured to manage connectivity of a heterogeneous fabric is disclosed. In one embodiment, the apparatus includes an interface, a processor, and a computer readable storage medium.
 In a variant, the computer storage medium includes instructions configured to, when executed by the processor: responsive to a device having a first protocol associated therewith being coupled to the heterogeneous fabric, the fabric having a second protocol different from the first protocol, identify one or more device capabilities, store the one or more device capabilities, and responsive to the device requesting connection to a target device, provide the stored one or more device capabilities to the target device. The device and the target device in one implementation initiate a data connection via the heterogeneous fabric without further intervention by the apparatus.
 In an eleventh aspect, an apparatus for interoperation with a heterogeneous fabric is disclosed. In an exemplary embodiment, the apparatus includes: an interface to the heterogeneous fabric, the heterogeneous fabric comprising multiple different device protocols, a user interface, a processor, and a computer readable apparatus having a storage medium.
 In a variant, the storage medium includes a computer program configured to, when executed by the processor, cause the apparatus to: responsive to a connection to the heterogeneous fabric, register with a network daemon, identify one or more other devices connected to the heterogeneous fabric via the network daemon, and responsive to a user request via the user interface, initiate a data connection to at least a target device of the one or more other devices within a user session.
 Other features and advantages of the present invention will immediately be recognized by persons of ordinary skill in the art with reference to the attached drawings and detailed description of exemplary embodiments as given below.
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1 is a logical flow diagram illustrating one embodiment of the generalized method of transferring data across a heterogeneous protocol environment according to the invention.
 FIG. 2 is block diagram illustrating one embodiment of an apparatus adapted to transfer data across a heterogeneous protocol environment.
 FIG. 3 is a graphical illustration of protocol stack interactions between two exemplary devices as part of the data transfer of FIG. 1.
 FIG. 3A is a graphical illustration of one embodiment of a data packet structure according to the invention.
 FIG. 3B is a high layer representation of one exemplary embodiment of a software system comprising a user and kernel space, according to the present invention.
 FIG. 3C is a graphical representation of one embodiment of kernel space additions useful for implementing the heterogeneous protocol data transfer functionality of the present invention.
 FIG. 3D is another graphical representation of various components of the protocol stack of FIG. 3C, and their interrelationships.
 FIG. 3E is a graphical representation of one embodiment of user space additions useful for implementing the heterogeneous protocol data transfer functionality of the present invention.
 FIG. 3F is a block diagram of one exemplary embodiment of a software architecture employing a proxy for interfacing between a first device and various software processes on the same or different device, using the kernel space and user space components of FIGS. 3C and 3E, respectively.
 FIG. 4 is a block diagram illustrating one exemplary heterogeneous community of devices according to the invention.
 FIGS. 5A-5D are block diagrams illustrating various different user scenarios consistent with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
 Reference is now made to the drawings, wherein like numerals refer to like parts throughout.
 As used herein, the terms "client device", "end user device" and "user equipment" or "UE" include, but are not limited to cellular telephones, smartphones (such as for example an iPhone®), personal computers (PCs), such as for example an iMac®, Mac Pro®, Mac Mini® or MacBook®, and minicomputers, whether desktop, laptop, or otherwise, as well as mobile devices such as handheld computers, PDAs, video cameras, set-top boxes, personal media devices (PMDs), such as for example an iPod®, or any combinations of the foregoing.
 As used herein, the term "computer program" or "software" is meant to include any sequence or human or machine cognizable steps which perform a function. Such program may be rendered in virtually any programming language or environment including, for example, C/C++, Fortran, COBOL, PASCAL, assembly language, markup languages (e.g., HTML, SGML, XML, VoXML), and the like, as well as object-oriented environments such as the Common Object Request Broker Architecture (CORBA), Java® (including J2ME, Java Beans, etc.), Binary Runtime Environment (BREW), and the like.
 As used herein, the terms "Ethernet AVB" and "Ethernet AVB Standards" refer, without limitation, to any one or more of the following as applicable: (i) IEEE Std. P1722; (ii) IEEE Std. P802.1AS; (iii) IEEE Std. P802.1Qat; (iv) IEEE Std. P802.1Qav; (v) IEEE Std. P802.1AB; (vi) IEEE Std P802.1BA; (vii) IEEE Std. P1722; and (viii) IEEE Std. 1394TA 2006021, each of the foregoing being incorporated herein by reference in its entirety.
 As used herein, the terms "IEEE 1394" and FireWire" refer without limitation to any one or more of the following as applicable: (i) IEEE Std. 1394-1995; (ii) IEEE Std. 1394a-2000 amendment; (iii) IEEE Std. 1394b-2002 amendment; and (iv) IEEE Std. 1394c-2006 amendment, each of the foregoing being incorporated herein by reference in its entirety.
 As used herein, the term "integrated circuit (IC)" refers to any type of device having any level of integration (including without limitation ULSI, VLSI, and LSI) and irrespective of process or base materials (including, without limitation Si, SiGe, CMOS and GaAs). ICs may include, for example, memory devices (e.g., DRAM, SRAM, DDRAM, EEPROM/Flash, and ROM), digital processors, SoC devices, FPGAs, ASICs, ADCs, DACs, transceivers, memory controllers, and other devices, as well as any combinations thereof.
 As used herein, the term "memory" includes any type of integrated circuit or other storage device adapted for storing digital data including, without limitation, ROM. PROM, EEPROM, DRAM, SDRAM, DDR/2 SDRAM, EDO/FPMS, RLDRAM, SRAM, "flash" memory (e.g., NAND/NOR), and PSRAM.
 As used herein, the terms "microprocessor" and "digital processor" are meant generally to include all types of digital processing devices including, without limitation, digital signal processors (DSPs), reduced instruction set computers (RISC), general-purpose (CISC) processors, microprocessors, gate arrays (e.g., FPGAs), PLDs, reconfigurable compute fabrics (RCFs), array processors, secure microprocessors, and application-specific integrated circuits (ASICs). Such digital processors may be contained on a single unitary IC die, or distributed across multiple components.
 As used herein, the terms "network" and "bearer network" refer generally to any type of data, telecommunications or other network including, without limitation, data networks (including MANs, PANs, WANs, LANs, WLANs, micronets, piconets, internets, and intranets), hybrid fiber coax (HFC) networks, satellite networks, cellular networks, and telco networks. Such networks or portions thereof may utilize any one or more different topologies (e.g., ring, bus, star, loop, etc.), transmission media (e.g., wired/RF cable, RF wireless, millimeter wave, optical, etc.) and/or communications or networking protocols (e.g., SONET, DOCSIS, IEEE Std. 802.3, 802.11, ATM, X.25, Frame Relay, 3GPP, 3GPP2, WiMAX, WAP, SIP, UDP, FTP, RTP/RTCP, H.323, etc.).
 As used herein, the terms "network interface" or "interface" typically refer to any signal, data, or software interface with a component, network or process including, without limitation, those of the FireWire (e.g., FW400, FW800, etc.), USB (e.g., USB2), Ethernet (e.g., 10/100, 10/100/1000 (Gigabit Ethernet), 10-Gig-E, etc.), MoCA, Serial ATA (e.g., SATA, e-SATA, SATAII), Ultra-ATA/DMA, Coaxsys (e.g., TVnet®), radio frequency tuner (e.g., in-band or OOB, cable modem, etc.), Wi-Fi (802.11a,b,g,n), WiMAX (802.16), PAN (802.15), IrDA or other wireless families.
 As used herein, the term "wireless" means any wireless signal, data, communication, or other interface including without limitation Wi-Fi (IEEE Std. 802.11), Bluetooth, 3G (3GPP, 3GPP2, UMTS), HSDPAIHSUPA, TDMA, CDMA (e.g., IS-95A, WCDMA, etc.), FHSS, DSSS, GSM, PAN (IEEE Std. 802.15), WiMAX (IEEE Std. 802.16), MWBA (IEEE Std. 802.20), narrowband/FDMA, OFDM, LTE, PCS/DCS, analog cellular, CDPD, satellite systems, millimeter wave or microwave systems, acoustic, and infrared (i.e., IrDA).
 As used herein, the terms "WLAN" and "wireless LAN" refer generally to any system wherein a wireless or air interface is employed between two devices, and which provides at least local area networking capability. Wi-Fi systems are one exemplary instance of WLANs.
 In one aspect, the present invention discloses, inter alia, methods and apparatus that enable a community of heterogeneous isochronous devices having differing underlying protocols to stream data such as video or audio data. In one exemplary embodiment, this invention enables IEEE 1394-compliant ("FireWire" enabled) devices to communicate across an Ethernet infrastructure, such as one enabled by the recent Ethernet AVB Standard(s).
 In one variant, the invention enables an IEEE 1394 device to stream data to an Ethernet AVB-compliant device (or vice versa).
 In another variant, an IEEE 1394 device may stream data to another IEEE 1394 device via an Ethernet AVB-compliant fabric.
 In a second alternate embodiment, this invention enables IEEE 1394-compliant ("FireWire" enabled) devices to communicate across a wireless network infrastructure, such as one enabled by IEEE 802.11 (Wireless Local Area Networks).
 In another aspect, methods and apparatus are disclosed which enable flexible connection management for an isochronous system having multiple sources and targets (e.g. an audio network). In one embodiment, such flexible connection management is provided for without regard to the direction or distribution of datastreams.
 In yet another aspect of the invention, an implementation-dependent data "fabric" is disclosed. In one embodiment, the fabric is adapted for compliance with IEEE 1394.1 bridging requirements, and comprises apparatus adapted to interconnect the 1394.1 bridge portals that is capable of transferring any serial bus subaction from one portal to its co-portal, and that supports bidirectional, non-blocking transfer of asynchronous request subactions, asynchronous response subactions, and isochronous subactions.
 In one variant, the fabric is limited in geographical extent (e.g., the bridge portals and fabric are each located within a common device enclosure or even on a common substrate or module within the device).
 In another variant, the fabric is physically extensive (e.g., the bridge's portals are located in more disparate locations, such as in separate rooms of a house, or even in separate buildings).
 In a second alternate embodiment, the fabric is adapted for wireless operation. In one such embodiment, the fabric is adapted for compliance with IEEE 802.11 (Wireless Local Area Networks).
 Advantageously, the methods and apparatus of the exemplary embodiment of the present invention are agnostic (work with) any of the variants of the FireWire 1394 standard.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
 Exemplary embodiments of the present invention are now described in detail. While these embodiments are primarily discussed in the context of an isochronous network of devices having differing protocols, and more specifically to a heterogeneous network of IEEE 1394-compliant and Ethernet AVB devices, it will be recognized by those of ordinary skill that the present invention is not so limited, and in fact may be used in other types of applications, and with different protocols.
 The following brief discussion of standards and their associated descendents is useful for understanding one or more aspects of the present invention.
 So-called "Ethernet AVB Standards" include: (i) IEEE Std. P1722--Streaming Transport; (ii) IEEE Std. P802.1AS; (iii) IEEE Std. P802.1Qat; (iv) IEEE Std. P802.1Qav; (v) IEEE Std. P802.1AB; (vi) IEEE Std P802.1BA; (vii) IEEE Std P802.1BA; and (viii) IEEE Std. 1394TA 2006021, each of the foregoing which are incorporated herein by reference in their entirety.
 As of 2007, IEEE 1394 was a composite of four documents: the original IEEE Std. 1394-1995, the IEEE Std. 1394a-2000 amendment, the IEEE Std. 1394b-2002 amendment, and the IEEE Std. 1394c-2006 amendment. On Jun. 12, 2008, all these amendments as well as errata and some technical updates were incorporated into a superseding standard IEEE Std. 1394-2008.
IEEE 1394-1995 ("FireWire 400")
 FireWire 400 can transfer data between various interconnected devices at data rates of 100, 200, or 400 Mbps half-duplex data rates (the actual transfer rates are 98.304, 196.608, and 393.216 Mbps. These different transfer modes are commonly referred to as S100, S200, and S400. Under this standard, cable length is also limited, although several cables can be daisy-chained using repeaters, hubs, etc. often present in FireWire equipment (although there is a maximum "total" chained length limitation also).
 An amendment to the original standard (IEEE 1394a) was released in 2000 which both clarified and enhanced the original specification. Support for asynchronous streaming was added, as was faster bus reconfiguration, packet concatenation, and a power-conserving "suspend" mode of operation. 1394a also standardized use of the 4-pin (non-power) connector.
IEEE 1394b-2002 ("FireWire 800")
 FireWire 800 or S800 was introduced commercially by Apple Inc. in 2003. This newer (1394b) specification allows a transfer rate of 786.432 Mbps full-duplex via a new encoding scheme often referred to as "beta" mode. It is backwards compatible to the slower rates of FW400 described above. However, while the IEEE 1394a and IEEE 1394b standards are compatible, FireWire 800's connector is different from FireWire 400's connector, making the cables incompatible. A "bilingual" cable is available which allows the connection of legacy devices to the new port.
 The 1394b specification supports data rates up to 3200 Mbit/s (S1600 and 53200) over beta-mode or optical connections up to 100 meters in length. Standard CAT-5e unshielded twisted pair supports 100 meters at S100. The original 1394/1394a standards used data/strobe (D/S) encoding (called legacy mode) on the signal wires, while 1394b added a new data encoding scheme called 8B10B.
IEEE 1394c-2006 ("FireWire S800T")
 IEEE 1394c-2006 was published on Jun. 8, 2007, and provides several changes including: (i) a new port specification which provides 800 Mbit/s over the same RJ45 connectors with CAT-5e cable which is specified in IEEE 802.3 clause 40 (gigabit Ethernet over copper twisted pair); (ii) automatic negotiation that allows the same port to connect to either IEEE Std 1394 (FireWire) or IEEE 802.3 (Ethernet) devices.
IEEE Std. 1394.1
 FireWire bridging (IEEE 1394.1) was designed to support longer distances and more devices on a network. Currently, 63 devices is the maximum number of devices allowed on a single FireWire bus. The 1394.1 bridging allows the connection of multiple busses for expanding the number of devices. Also, by expanding the number of busses, the maximum distance between devices can be expanded as well. IEEE 1394.1 defines a "bridge" as consisting " . . . of two bridge portals (each with its associated PHY and link), queues (FIFOs) for asynchronous and isochronous subactions (which collectively form an implementation-dependent fabric between the two portals), cycle timers, route maps, and configuration ROM." However, it is appreciated that the foregoing definition is implementation specific, and the present invention is in no way so limited. More broadly, as used throughout, the term "bridging", "bridge", etc. refers to the physical and logical apparatus necessary to connect a first network technology to a second network technology. Such methods and apparatus may be physical (e.g., hardware/firmware implementations), logical (e.g., software implementations), or any combination thereof.
 In addition to the foregoing standards and protocols, others have been adopted (or are under development) which relate to A/V transmission:
IEEE Std. 802.1Qat
 IEEE Std. 802.1Qat ("Standard for Local and Metropolitan Area Networks--Virtual Bridged Local Area Networks--Amendment: 9: Stream Reservation Protocol (SRP)"), which is incorporated herein by reference in its entirety, provides for reservation of bandwidth on the network (including between end stations through a number of bridges). A "listener" requests bandwidth to a "talker" and bridges ask each other along the chain if there is sufficient bandwidth to support adding the stream.
IEEE Std. 802.1Qav
 IEEE P802.1 Qav ("IEEE Standard for Local and Metropolitan Area Networks--Virtual Bridged Local Area Networks--Amendment: Forwarding and Queuing Enhancements for Time-Sensitive Streams"), which is incorporated herein by reference in its entirety, specifies how to queue packets to not burst traffic across the network. Bridges are used to automatically shape traffic.
IEEE Std. 802.1AB
 IEEE Std. 802.1AB ("Station and Media Access Control Connectivity Discovery--Apr. 5, 2005"), which is incorporated herein by reference in its entirety, discloses Link Layer capability discovery; i.e., discovery of what capabilities the ends of the link have. This protocol may be used to tell end stations what priority to send class-A and class-B traffic, and may be used by some bridges to enable AVB functionality.
IEEE Std P802.1BA
 IEEE Std P802.1BA ("Audio Video Bridging (AVB) Systems--Draft PAR--Feb. 1, 2008), which is incorporated herein by reference in its entirety, discloses profiles that select features, options, configurations, defaults, protocols and procedures of bridges, stations and LANs that are necessary to build networks that are capable of transporting time sensitive audio and/or video data streams.
IEEE Std. 1394TA 2006021
 IEEE Std. 1394TA 2006021 ("Networking IEEE 1394 Clusters via UWB over Coaxial Cable--Part 3: FCP and CMP over IPv4"), which is incorporated herein by reference in its entirety, describes discovering and controlling device configurations, and connection management. It is based on the 1394 TA Specifications, and uses (i) UDP/IP for communications, and (ii) Bonjour® protocol for discovery and removal notifications.
IEEE Std. 802.1AS and "AppleAS"
 IEEE Standard 802.1AS ("IEEE Standard for Local and Metropolitan Area Networks--Timing and Synchronization for Time-Sensitive Applications in Bridged Local Area Networks"), which is incorporated herein by reference in its entirety, provides mechanisms for synchronizing frequency of clocks, and for measuring the propagation delay across a link. It also provides a NIC-to-bridge interface in bridged network, and NIC-to-NIC in a two-machine network. It is based on IEEE 1588, and requires ingress/egress time stamping in the MAC (i.e., Sync, PDelay_Request, and PDelay_Response frames time-stamped on egress and ingress).
 The AppleAS protocol is an implementation of the IEEE 802.1AS protocol developed in interest of the Assignee. The functionality of AppleAS is described in greater detail herein. Briefly, AppleAS comprises an abstraction layer that isolates the vendor code from differences in Ethernet AVB hardware, and can still function without dedicated hardware (though at a reduced precision of time synchronization). It resolves or reconciles the IEEE 801.1 AS clock with the resident system's CPU clock, such that the software can relate system time to network time, and vice versa. In one implementation, the protocol is implemented in NIC hardware, and is IEEE 802.1AS-compliant. In another implementation, only the hardware time stamping is applied in the hardware, and IEEE-802.1 AS protocol is implemented in software.
Extension of FireWire "Bridging"--
 The FireWire® protocol allows for high-speed data transfer between two or more devices. The protocol can maximally support sixty-three (63) devices on a single FireWire bus. FireWire bridging according to IEEE 1394.1 allows the connection of multiple busses for expanding the number of devices. The bridging component is described within the IEEE 1394.1 specification as being comprised of: (i) a serial bus bridge; (ii) two bridge portals (each with its associated PHY and link), (iii) queues (FIFOs) for asynchronous and isochronous subactions (which collectively form an implementation-dependent fabric between the two portals), (iv) cycle timers, (v) route maps, and (vi) configuration ROM.
 In one embodiment, the present invention provides such an "implementation-dependent fabric" using an Ethernet AVB cloud. As used herein, an AVB "cloud" refers to a collection of AVB devices that support all the AVB protocols. Any legacy Ethernet device added to an AVB switch would terminate the cloud at that port. Accordingly, AVB devices may exist which are not a part of the "cloud" structure (e.g. legacy AVB devices, etc.).
 The exemplary fabric is adapted for compliance with IEEE 1394.1 bridging requirements, and comprises apparatus adapted to interconnect the 1394.1 bridge portals that is capable of transferring any serial bus subaction from one portal to its co-portal. The fabric also supports bidirectional, non-blocking transfer of asynchronous request subactions, asynchronous response subactions, and isochronous subactions.
 Previous software implementations of FireWire-based audio have typically had similar topologies to Universal Serial Bus (USB) "Host-to-device" models, due to the relatively inconvenient nature of physically wiring complex networks, despite FireWire device capabilities. By augmenting the FireWire capabilities with Ethernet AVB, and the corresponding ubiquitous Ethernet infrastructure, such limitations are advantageously removed. Thus, while prior art implementations may implement a single centralized supervisory computer; the peer-to-peer nature of the FireWire/Ethernet AVB bus is not so limited. Hence, in another aspect of the present invention, the functionality between connection management and datastream management is logically separated.
 Such additional flexibility enables multiple additional use case scenarios. In one embodiment, a FireWire network with multiple connection managers (e.g., computers) and one or more devices (e.g., speakers, microphones, iPods, etc.) may have any number of conveniently selectable interconnections and topologies.
 In another embodiment, a connection manager (e.g. computer) may be separate from a data source/sink (e.g., Home Theater Receiver, etc.).
 In yet another embodiment, the merging and splitting of data sources can be separated from connection management. Similarly, the connection management can be performed in isolation from the data being routed between the devices (e.g., data is not routed within the connection manager).
 Referring now to FIG. 1, a first embodiment of the generalized process 100 for integrating an isochronous network of devices having differing networking protocols according to the present invention is described.
 At step 102, a first isochronous network having at least one first device capable of operating with at least a first and a second protocol interfaces is initialized, and connects to an interconnection fabric which utilizes its second protocol interface. The initialization procedures may comprise for example registration with a local or remote software entity, such as a network daemon described hereinafter.
 In one embodiment, the first protocol interface is an IEEE 1394.1-compliant interface, and the second protocol interface is an Ethernet AVB interface. The interconnection fabric comprises an Ethernet AVB-compliant network cloud.
 At step 104, an external device operating with at least a second protocol interface is initialized, and connects to the interconnection fabric utilizing its second protocol interface. In one embodiment, the external or second device additionally comprises a first protocol interface (not physically connected to the first device); the second device is physically connected to a target isochronous device via its first protocol interface (wherein the term "target" is applied for clarity rather than to indicate direction of data transfer). The target device can also be part of the second device.
 At step 106, the first device determines the existence of the second device. In one embodiment, such identification is accomplished via a software entity, such as a software daemon. The identification is performed local to either the first and or the second device. In an alternate embodiment, such identification is performed at a third party connection management entity.
 At step 108, the first device negotiates one or more isochronous parameters to connect with the second device. In one embodiment, such isochronous parameters may comprise for example: (i) audio sample formats, (ii) sample rates, and (iii) channel numbers, etc.
 A source isochronous device in logical connection with the first device via the first device's first protocol interface receives (or transmits) an isochronous data stream to the target isochronous device (wherein the term "source" is applied for clarity rather than as an indication of data transfer).
 At step 110, the first and second devices provide a logical bridge between the first and second differing isochronous protocols. In one embodiment, the management of the first and second devices and corresponding source and target nodes is performed within a graphical user interface (GUI) or other such mechanism well known to those of ordinary skill in the computer arts.
 At step 112, isochronous data is transferred via the logical bridge. In one variant, the isochronous data stream transferred comprises at least one stream of audio and/or video. Multiple source and target devices may exist, each receiving and or transmitting at least one stream of audio, and or video.
 Referring now to FIG. 2, an exemplary apparatus 200 useful in implementing the methods of the present invention is illustrated. While a specific device configuration and layout is shown and discussed, it is recognized that other implementations can be readily implemented by one of ordinary skill given the present disclosure. For example, various components may be divided and/or placed within other devices, integrated into one physical form factor, etc.
 The illustrated embodiment of the apparatus 200 comprises a device such as a portable (laptop or handheld) computer, or audio/video capture, or synthesis system capable of receiving or transmitting an isochronous datastream across two or more differing protocols. In one exemplary implementation, the multi-lingual functionality is performed within a dedicated processing device coupled to physical connectors for each protocol (e.g., a IEEE 1394 connector and an 802.3 Ethernet connector accessible on the back of the device), distributed throughout the equipment enclosure, as described in greater detail subsequently herein.
 As shown in FIG. 2, the apparatus 200 comprises a processing subsystem 202, operational memories 204, a first physical connector 206 corresponding to a first protocol, and a second physical connector 208 corresponding to a second protocol, and a power subsystem 210. In one exemplary embodiment, the first physical connection corresponds to a FireWire (IEEE 1394) multi-pin interface (whether 4-pin, 6-pin, or otherwise), and the second physical connection corresponds to an Ethernet AVB interface (e.g., RJ-45 connector). It will be appreciated that any number of different or similar physical connections (for example, multiple homogeneous and heterogeneous ports) may be used consistent with the invention as well.
 The processing subsystem 202 comprises a central processing unit (CPU) or digital processor, such as a microprocessor, digital signal processor, field-programmable gate array, or plurality of processing components mounted on one or more substrates. The processing subsystem is tightly coupled to operational memory 204 which may include for example SRAM, FLASH and SDRAM components. The processing subsystem may also comprise additional co-processors, such as a dedicated graphics accelerator, network processor (NP), or audio processor. A direct memory access (DMA) subsystem (not shown) of the type well known in the art may also be utilized with the processor and memory in order to facilitate memory accesses. In one embodiment, a time scheduled Ethernet DMA hardware is used for scheduling Ethernet packets at the proper rate (e.g. 8000 packets per second). Normally, Ethernet DMA hardware is used when streaming data or a group of descriptors. Ethernet DMA transmits as soon as the data arrives in the hardware queues. For Ethernet AVB, Ethernet data is queued in a priority queue with "time to send" values, such that the Ethernet DMA hardware is able to schedule packets out at the proper rate and proper time.
 The illustrated power management subsystem (PMS) 210 comprises a controller for power delivery and battery management (if so equipped), and/or a plurality of discrete electrical components (not shown). Additionally, a chemical battery cell such as a Lithium Ion (Li-ion), or Nickel Cadmium (Ni--Cd) battery provides power to the device apparatus when disconnected from a parent power source such as a 115 VAC wall outlet/transformer.
 The illustrated mass storage subsystem 212 comprises an integrated circuit memory for storing a computer readable program, and/or a plurality of discrete electrical components (e.g. motor, controller, and hard disks, etc.). Typical embodiments of such storage subsystems are hard disk drives common to the art. Other alternate embodiments may use non-volatile solid-state memory, such as NAND/NOR FLASH, ROM, etc.
 In certain embodiments, the device may further comprise one or more of target or source components. Such components consume or produce isochronous data streams. Typical embodiments may include: speakers 252, microphones 254, cameras 256, DVD and CD disk players 258, or monitors 260. Such target/source components may be integrated within the device 200, or stand-alone in nature (e.g., connected to the apparatus 200 via interposed cabling, wireless links, etc.).
 In another embodiment of the invention, the apparatus comprises a network switch or router adapted to perform data transport between two devices (e.g., one operating according to a FireWire protocol, and one operating according to an Ethernet protocol). For example, in one variant, the apparatus comprises a "super hub" that includes both FireWire and Ethernet AVB ports on the hub, and which performs the translation to and from each protocol.
 In still another embodiment, the apparatus comprises a removable/portable "dongle" (e.g., adapter or converter). In one variant, the dongle has a FireWire port on one end, and an Ethernet AVB port on the other. The dongle is plugged into the FireWire port or Ethernet port on one device (or is otherwise connected to the port indirectly, such as via a male/female, male/male, or female/female interconnection cable), and similarly connected at its other end to the other device. The dongle contains sufficient processing capability and software to perform the protocol "translation" described elsewhere herein. It will also be appreciated that the dangle may be configured for "one-to-many" operation (e.g., one port of a first protocol, and multiple ports for the other protocol).
 The following software descriptions further illustrate one exemplary embodiment useful in implementing a heterogeneous network of audio devices for providing audio and/or video stream transfers, according to the present invention. While this specific embodiment has functionality divided into kernel and user space operations, these distinctions should not be construed as limiting as these components may be implemented both in kernel space, and/or in user space.
 Moreover, while the following description relates primarily focused on audio data transfer, the invention is in no way limited to audio data, and in fact may support video and other multimedia data types. Video formats supported may include for example (and without limitation) IEC 61883-x based protocols such as IEC 61883-1, 61883-3, 61883-4, 61883-6, and 61883-7). See Appendix I hereto for a listing of some relevant "video" standards that may be utilized in conjunction with the methods and apparatus of the present invention to facilitate, format and control video delivery over different bearer protocols.
 Various components are used in the illustrated embodiment to provide the required functionality. Aspects of the functionality of these components are described below. The aforementioned components are also provided via a computer program listing appendix entitled "AppleAS SOURCE CODE" disclosed in Appendix II, herein incorporated in its entirety.
Ethernet 802.1 AS Driver
 AppleAS kext (Kernel Extension) is one embodiment of the 802.1 AS Ethernet driver. It implements the IEEE 802.1 AS protocol and provides an API for mapping 802.1 AS grandmaster time to Host CPU time in nanoseconds.
 Referring now to FIG. 3, a software system 300 is shown, useful in describing one exemplary software or protocol stack resident within a plurality of exemplary devices. As shown, each entity of the software stack 302 within each device communicates with the corresponding entities of other devices. A connection manager 304 (AppleAudioNetworkingDaemon) is also shown. The entities comprise: AppleAudioNetworking 310, ApplelsochChannelMapper Kext (Kernel Extension) 320, and AppleFireWireAVBBridge Kext 330. Two supplemental software components are also utilized: AVCDescriptors Framework (not shown), IOFireWireMultiIsoehListener 340.
 The daemon (AppleAudioNetworkingDaemon) 304 is responsible for performing device capability discovery, connection management and handling device communications. The daemon sits above the various kernel extensions needed for performing channel mapping, bridging and audio streaming, and the frameworks which provide device discovery, connection management calls and descriptor parsing.
 The AppleAudioNetworking entity 310 provides application-level management via a graphical user interface for configuring devices and the network of devices. The application entity receives connection management information from the daemon 304. The application entity 310 is responsible for configuring kernel extensions, talking with devices and performing local device discovery. AppleAudioNetworking handles discovery and configuration aspects of the AppleFWAudio 312 driver within user space, rather than within the kernel. Drivers may be stored in operating system (OS) kernels to offload device management from higher-level software. AppleAudioNetworking handles audio device management functionality explicitly, as audio devices may not necessarily be local to the AppleAudioNetworking software.
 AppleAudioNetworking further provides, in the illustrated embodiment, support for AVB (Audio Video Bridging) devices using AVC (Advanced Video Coding)-over-IP (Internet Protocol), as previously referenced herein.
 AppleAudioNetworking is supplemented with three (3) components: (i) AppleFWAudio kext 312, (ii) FWAUserLib framework 314, and (iii) AVCVideoServices library 316. AppleFWAudio kext enables audio streaming. Devices are created and configured through the FWAUserLib framework with the connection management being handled with the daemon (described hereinafter). The AVCVideoServices library performs discovery of FireWire and AVC-over-IP devices, reading of device configurations, performing device communication and connection management of AVC-over-IP devices.
 The IOFireWireMultilsochListener 340 is a software function which allows multiple clients on one node to "listen in" to the same isochronous channel. The IOFireWireMultilsochListener does not restrict the number of input isochronous contexts available. While the IOFireWireMultilsochListener may perform basic formatting operations (e.g., modifying headers, address translation, etc.) to service various clients, it does not alter the datastream itself. The IOFireWireMultilsochListener splits each isochronous channel to the AppleFWAudio, AppleFireWireAVBBridge (AFAB) Kext. AppleFWAudio, and AFAB are critical to connection management.
 The AppleFireWireAVBBridge (AFAB) 330 kext performs the bridging of the local FireWire bus to an AVB network/cloud. The AFAB uses the IEC 61883/IIDC packet format of the AVBTP draft specification previously referenced herein to encapsulate the FireWire isochronous packet. The AFAB is a two-way bridge, capable of both transmitting and receiving AVB packets. The AFAB may support any number of input and output streams, each of which may have differing channel counts. A user client enables local and or remote configuration of the AFAR.
 The AVCDescriptors framework (not shown) is a Foundation-based Objective-C framework that performs parsing of AVC device descriptors into an object-based hierarchy that can be easily used for getting and setting properties of the descriptors. AVCDescriptors will accept either the binary descriptor from the device or the appropriate dictionary from AVCVideoServices. The AVCDescriptors may produce a binary or dictionary version of the descriptors suitable for AVCVideoServices or programming into a device. The AVCDescriptors presents information necessary for management within a localized database, such that each FireWire node can track other FireWire, and Ethernet AVB members. In one embodiment, the AVCDescriptors is a software program for translating IEEE 1394 based AVC device descriptors into the industry standard XML format for storage or modification. AVCDescriptors additionally supports conversion from the XML format to IEEE 1394 binary descriptor format. The XML outputs of the AVCDescriptors are used by the controller to discover the capabilities and parameters of the device, including such qualities as device name, names of plugs/streams, internal routing, etc. The binary outputs of AVCDescriptors are used natively within connected IEEE 1394 compliant busses.
 FIG. 3A illustrates one exemplary packet structure useful with the present invention. The illustrated packet structure comprises three components: a first header 352, a second header comprising one or more isochronous parameters 354, and a payload 356. The packet, when being bridged from one protocol to another, utilizes the first header 352 so as to comply with the "bridged to" protocol. Information is parsed from the parameters field 354, to determine any differences (e.g. sample rates) and or requirements to modify the payload. The payload 356 is packaged for use at the destination.
 While the packets share the same structure regardless of the source or destination of the packet, it is appreciated that in certain embodiments one or more elements of the packet structure may require modification to accommodate differing endpoints. For example, packets from a first IEEE 1394 compliant bus transmitted into an AVB cloud will have large portions of the payload 356 filled with data when connecting to a second IEEE 1394 compliant bus via the AVB cloud. Alternately, the same payload may be considerably smaller, when being transmitted to an AVB device within the AVB cloud. Furthermore, packets from an AVB device in an AVB cloud to an IEEE 1394 compliant may have smaller payloads, and may require padding with null data by an intelligent component, such as the AVB/FireWire bridge component.
 In the illustrated embodiment, the first header 352 comprises an Ethernet (IEEE Std. 802) header of the type well known in the art, while the second header comprises an IEEE P1722 header. The payload illustrated is a FireWire packet payload of the type well known in the art. It will be appreciated, however, that other packet headers and structures (as well as different protocols) may be used consistent with the invention.
 FIG. 3B is a high layer representation 360 of the software system components; as shown, the system is separated between user-land (applications and APIs) 362 and the kernel (drivers) 364. AppleFireWireAVB Proxy 366 is the controlling software component that sets up the Ethernet to FireWire mapping and instantiates the components needed for the bridging of protocols.
 FIG. 3C is a graphical representation of one embodiment of an exemplary protocol stack (kernel space) 370 implementing the heterogeneous protocol data transfer functionality of the present invention. The exemplary protocol stack includes the additional components: AppleAS 371, AppleMAAP 372, Apple1722Ethernet 373, Apple 1722Dispatcher 374 and AppleFireWireAVBBridge. IONetworkFamily 375 and Ethernet Drivers 376 are pre-existing Ethernet protocol stack components; similarly the FireWire Stack 374 uses existing FireWire stack in the current system.
 In the exemplary embodiment, the current FireWire stack, Ethernet stack, user-land API and associated software components are combined in accordance with one or more aspects of the present invention. Specifically, the present invention enables user-land software operation, regardless of physical link characteristics. The isochronous stream data may be received from either the Ethernet or IEEE 1394 link. Moreover, the existing applications and APIs running on the system cannot directly access the physical links; thus higher level software remains unaware of link specific operation. The separation of user space from kernel space seamlessly provides isochronous data to the upper layer software without requiring configuration for either Ethernet AVB of FireWire protocols. Consequently, existing FireWire applications, like "iMovie", can run without requiring modification.
 FIG. 3D is another graphical representation 380 of various components of the example protocol stack of FIG. 3C, and their interrelationships. As shown in FIG. 3D, components added in the kernel space include: (i) AppleAVBInterface; (ii) AppleAS (802.1AS time synchronization) 371; (iii) AppleVirtualAS (802.1AS time synchronization for unsupported hardware) 381; (iv) AppleMAAP (dynamic allocation of multicast MAC addresses) 372; (v) Apple1722Dispatcher (routes AVB frames between multiple clients) 374; (vi) Apple1722Client (abstract client class) 382; (vii) Apple1722Ethernet (client subclass for Ethernet interface); and (viii) AppleFireWireAVBBridge.
 FIG. 3E is a graphical representation 390 of one embodiment of an exemplary protocol stack (user space) implementing the heterogeneous protocol data transfer functionality of the present invention. The exemplary user space additions are two (2) peer entities: AppleAudioNetworking 391 and AppleAVBFireWireProxy 392. The AppleAudioNetworking software module is resident to the Ethernet AVB device, whereas the AppleAVBFireWireProxy software module communicates with the Firewire device. It should be noted that both modules may or may not be co-located within the same device, depending on implementation, etc.
 FIG. 3F is a block diagram of one embodiment of a software architecture 395 employing a proxy for interfacing between a first device and various software processes on the same or different device. As shown in FIG. 3F, the kernel space and user space components of FIGS. 3C and 3E, respectively are used to bridge between a FireWire network, and an Ethernet AVB network, via the proxy software entity.
 Referring now to FIG. 4, one exemplary heterogeneous community 400 of the aforementioned devices useful in illustrating the methods and apparatus of the invention is described. As shown in FIG. 4, device 200A is physically interconnected to another device 200B via a common bus 406 (e.g. IEEE 1394), and logically interconnected via the aforementioned software functions. Each group of devices negotiates their internal addressing within a localized network. Bridging portals are devices which "bridge" from the localized network to an external device 200C (e.g., another device of similar or differing nature). Bridging portals provide connection 404 to a fabric 402, wherein the fabric must be capable of transferring any serial bus subaction from the bridging portal to its destination device (e.g. co-bridging portal, external device, etc.). The localized network may utilize a protocol (e.g., IEEE 1394.1), which is different than the interconnecting fabric (e.g. Ethernet AVB).
 As previously described herein, the "fabric" of the present embodiment may be conceptualized as a set of FIFOs that support bidirectional, non-blocking transfer of asynchronous request subactions, asynchronous response subactions, and isochronous subactions. The fabric could be modest in geographical extent, as when the bridge portal and external device are located within a single enclosure. Conversely, the fabric could be physically extensive, as could be the case if a bridge's portal was located in separate room from the external device.
 In one exemplary embodiment, the devices 200 are FireWire devices compliant with IEEE 1394, and the fabric 402 is an Ethernet AVB-compliant "cloud". As shown, an IEEE 1394.1 compatible portal 200A is on at least one side of the Ethernet AVB network, and employs AVC command interpreters in the portals to allow existing FireWire software to "see". FireWire and Ethernet AVB devices (i.e. 200C, 200D) that are not physically connected to the local FireWire bus via the Ethernet AVB connection 404.
 In yet another exemplary embodiment, a pair of bridging portals (200A and 200C) may bridge two separate busses (406) having a first protocol, via a fabric (402) having a second different protocol with suitable isochronous properties. Such bridging portals are responsible for converting the information on one bus for transfer to the co-bridging portal on the other bus. The connection fabric between portals could be an internal bus, system bus, or any other interconnection readily understood by those skilled in the electronic arts. If the connection fabric between portals is private, the portals may send packets via the connection fabric without any additional processing (e.g. encryption). Certain interconnection fabrics are desirable for varying purposes; for instance, an Ethernet AVB network between bridging portals can enable significant geographic distance between a first and second network. If the fabric is an Ethernet AVB network, then the portals could be put anywhere on the Ethernet AVB cloud and still function correctly.
Example Use Scenarios
 In a first example, the Assignee manufactures and releases a new computer that has no FireWire ports but does include the new Ethernet AVB hardware. With a small dongle that implements the FireWire to AVB protocol conversion described in this patent, the user can connect the FireWire audio device to the dongle and then connect the dongle to the new computer via the Ethernet jack. The FireWireAVB proxy software on the computer will then connect to the FireWire audio device as if it is now an AVB audio device. The AppleEthernetAudio driver will enumerate and discover the device, presenting it to the Audio sub-system. Audio applications adapted to operate with FireWire type devices will operate seamlessly with the new computer. The bridging "dongle" will transparently enable the software to see the FireWire Audio device as if it was directly connected to a FireWire port.
 In another aspect of this invention, a first computer can physically incorporate the "dongle" that is mentioned above to enable play through operation by a second computer on a computer network. The first computer with both FireWire and AVB compliant Ethernet hardware can act as a bridge between FireWire and Ethernet AVB. The software on the first computer would provide an "AVC FireWire device sharing mode" to the system software so that any computer (e.g. second computer) on the network could see the FireWire device attached to the first computer. A second computer on the network may then connect to the first computer over the Ethernet AVB network and use the services provided by the FireWire device. In this mode, an unmodified AVC FireWire application like iMovie running on the second computer, could operatively utilize the FireWire device resident to the first computer; iMovie could operate as if it was directly connected to the FireWire device.
 The following example user scenarios (FIG. 5A-D) illustrate some possible application environments enabled by the methods and apparatus of the present invention. These scenarios are only exemplary, and the invention is in no way limited thereto.
 With respect to FIG. 5A, a regular user (Jack) is a Macintosh® ("Mac") computer user and has been for many years. He owns a FireWire audio device (FAD) 502. He has been using the Mac OS X Leopard® operating system for a long time, and has just upgraded to the latest Mac OS X, FatCat®. Jack plugs in his FAD, starts Logic Pro, which is his digital audio workstation software (DAW) and sets it to use his FAD. He then proceeds to do what he has previously done with his DAW.
 Mac OS X FatCat includes a new FireWire audio architecture supporting networking, and has added support for the new AVB specification; however Jack is not interested in any of these features and has never launched the AppleAudioNetworking application. None-the-less, he expects his FAD to behave exactly the same as it always has in previous versions of Mac OS X.
 Referring now to FIG. 5B, a studio user (Bob) is a sound engineer at a recording studio. He uses Mac OS X as his platform of choice, and has many FADs around his studio. Bob has recently switched to the new Mac OS X FatCat because he has heard about the new FireWire audio networking feature.
 Bob launches the AppleAudioNetworking application, and connects his all his FADs (which comprise two 2-channel FADs and 3 18-channel FADs) to his MacPro. He also connects several other Macintoshes to the FireWire bus to act as channel mappers. He configures his local Macintosh to have a 30 channel input, and output CoreAudio device consisting of three 10-channel input streams and one 42-channel output stream. He connects the 3 input streams to 3 of his 18 channel FADs. He creates a channel mapper on one of the remote machines that takes a 42-channel input stream, and outputs three 10-channel streams. He connects the input stream of the mapper to the output stream of his MacPro, and the 3 output streams to his 18-channel FADs. Bob also creates a channel mapper on another of his remote machines that takes a 42-channel input stream and outputs 6 2-channel streams. He connects the input stream of the mapper to the output stream of his MacPro, and the output streams to each of the 2-channel FADs. He adjusts the mapping so that the 2-channel FADs streams are connected to the last 12 channels rather than the first 12 channels. Bob then saves the configuration so that he can use it again.
 Bob opens up the Logic (DAW) and configures it to use his new 30-channel input and 42-channel output device. He sets up appropriate mixes on the last 12 channels for the 2-channel FADs to be used as stage monitors, and sets up appropriate mixes on the first 30 channels. Bob then starts his recording session. When Bob has finished his recording session, and copied his audio, he turns off all of his equipment.
 The next day Bob comes back to continue recording with the same setup. He turns on all of his equipment, starts his DAW and commences the day's activities.
 Referring to FIG. 5C, a live performance user (John) works at a concert hall. They have recently upgraded their system to use new high-speed Ethernet-based AVB and FireWire devices and Mac OS X FatCat as the control and configuration platform. The control room is equipped with several MacPro devices running various software applications needed to control their concert hall, and to run the AppleAudioNetworking software to configure their sound system.
 The concert hall is fitted with AVB-equipped speakers rigs all being wired back to a central AVB cloud synchronized to a class-A specification. The MacPro devices in the control room, as well as several under the stage, are also connected to the live sound AVB cloud as well as a secondary communications cloud. A central AVB based mixing board 510 is provided in the control room, which can have configurations saved and loaded by a computer over the AVB cloud.
 A new concert is being planned and setup in the hall. John's task is to set up the sound system. He sits down at the main configuration computer, opens AppleAudioNetworking, and loads a copy of the clean default sound network configuration. He adjusts the configuration for the particulars of the concert. One of the special features of this concert is a FireWire-based sound effects box which is triggered by the audio. This box is connected to one of the MacPro devices under the stage. The technicians on stage have already set this up, and so a new display icon has appeared in AppleAudioNetworking to represent this device. John needs to connect this to the mixing board.
 While John was configuring the sound system routing, someone else was setting the mixing board configuration to add an extra stream for the sound effects box. They pass this file to John, who uploads it to the mixing board via a vendor plug-in in AppleAudioNetworking. John now has an extra output stream on the mixing board to connect to the special effects box. John connects the new output on the mixing board to the input of the special effects box, and AppleAudioNetworking establishes a connection between the two via a bridge on the MacPro to which the special effects box is connected. John then saves this configuration for the concert.
 On the day of the concert, John loads up the saved configuration and then runs through the usual pre-concert checks.
 Referring to FIG. 5D, an experimenter (Eve) is an experienced Mac OS X user. She has just upgraded to Mac OS X FatCat. She has noticed a new feature of the operating system (audio networking). She has been exploring her system, and has discovered the AppleAudioNetworking application. She launches the application and is presented with the current configuration of her system. She has no FireWire or AVB devices, so all she sees is an icon for her local Mac. She opens the README link to find out more information about what she can do with the system/software.
 She reads that she can set up multiple Macs on the same network to talk to each other, and send audio directly between the machines. Since she has two Macs running Mac OS X FatCat, she decides to set up an audio network to play with. She enables multi-Mac support on each of her machines, since it is a private network which nobody else can connect to, she decides to not enable password authentication.
 On both Macs she creates a 2-channel AVB device. On one of her machines she connects the input of each machine to the output of the other machine. On one machine she opens up "System Preferences" and sets the AVB device as the output device. She then opens iTunes® and starts playing her music. On the other machine, she enables pass-through from the AVB device to the built-in speakers, and her music begins playing from her speakers.
 In another aspect of the invention, the aforementioned protocols used on the various communicating devices may comprise wireless protocols such as for example WLAN, PAN, or WAN/MAN protocols.
 Wired operation may statically reserve resources to enable operation. For instance, Ethernet AVB requires each node between the source and targets to reserve resources for datastream transmission, thus providing a bandwidth, and latency guarantee. Transmission and reception of data is relatively reliable for wired devices; however, wireless devices may fade in and out of service, causing considerable complication. A wireless linkage in combination with a wired link may fade out unexpectedly, leaving unused reserved resources on the wired network. Methods and apparatus for bridging wireless/wired devices must also provide for "clean up" operations.
 Under one embodiment, wireless operation of one or more components of the aforementioned heterogeneous networks is envisaged. In addition to providing a bridging access from a first wired protocol to a second wireless protocol, concurrent monitoring, diagnosis and re-routing of wireless/wired links are desired to minimize unnecessary resource utilization during a "fade out". In one variant, each of the bridging devices, the target or the source may transmit a link condition signal relating current status of the isochronous stream. A bridging element within a heterogeneous network may monitor the reliability of one or more wireless links, and transmit feedback to the source device, thus enabling the source device (and any associated wire line "hops") to throttle their reserved resources accordingly.
 In another embodiment of the wireless/wired invention, a bridging element within a heterogeneous network may register a relative estimation of wireless robustness for use with the connection management software. In one variant, the connection management software may maintain an entry for each wireless device, related to relative wireless data rate. Such an entry may be e.g., a relative measurement of bit error rate (BER), signal to noise (SNR), or any of the other plethora of useful link-related measurements commonly known to those skilled in the telecommunications arts. In another variant, such an entry may additionally include a total number of subscribers actively connected to a datastream, to accommodate the requirements of broadcast and or multicast operation. For example, one or more subscribers may drop off without adversely affecting the experience of other broadcast subscribers.
 In yet another embodiment of the wireless/partially wireless invention, a bridging element within a heterogeneous network having a wireless source and destination may continuously poll each wireless link for to modify its operation. In one variant, the bridging element may regularly insert, re-process or sniff packets being received and transmitted to dynamically size the reserved resources to only what the weakest link may serve. Alternatively, the bridging element may perform such monitoring to dynamically size the reserved resources to only what the strongest receiving link may serve (as applicable within a broadcast or multicast situation).
 In yet another embodiment of the wireless/partially wireless invention, a bridging element within a heterogeneous network may receive link updates from one or more target device attached to a bus on the second protocol. For example, a bridging element connecting two differing wire line protocols may receive notification from one such protocol that a wireless linkage downstream has failed (e.g., a device on a wireless hub, which is connected to the bridging portal via wire line). Alternatively, a bridging element connecting a wireless protocol to a wired protocol may receive notification that a wireless link downstream of the wired protocol has failed (e.g. an Ethernet AVB cloud connecting a wireless device on a bridging node to a wireless LAN, etc.
 A channel mapping element may also be utilized consistent with the invention. Under one embodiment, the mapping element adaptively resizes channels based at least in part on the wireless channel reception. For example, one or more channels of channel mapping functionality may be preprocessed based at least in part on the expected wireless link quality.
 Other implementations and variations of the foregoing features will be appreciated by those of ordinary skill given the present disclosure.
Business Methods and Models
 In another aspect of the invention, various business models and methods of doing business relating the aforementioned heterogeneous networks are envisaged.
 In one aspect, the ability to obviate one or more ports on a device is inherently less expensive. For example, a device manufacturer or service provider can support similar features to their preexisting products or services with a smaller bill of materials (BOM) for the correspondingly reduction in components (e.g. port connections, driver hardware, etc.). Furthermore, replacement of high cost port solutions (e.g. FireWire) with lower cost port solutions (e.g. Ethernet AVB) would also advantageously work to reduce manufacturing cost.
 In another aspect, an adapter device capable of bridging between a first network, to a pre-existing device having a second network connection type could be manufactured and sold, so as to maintain backward compatibility. Consistent support of backward compatibility is generally considered in customer's determination of price; and customers will ostensibly be willing to pay more for consumer electronics devices which are supported through time, rather than made obsolete. Furthermore, the manufacture and sale of adapter devices (commonly referred to in the arts as a "dongle") is also profitable, in some cases providing opportunities for third party licensing fees.
 In one embodiment, a device capable of both connection operation and streaming operation may require a software patch sold after purchase, to enable one, or both features. In a related embodiment, connection management is a relatively sporadic software function, whereas streaming data has specific requirements on the data path. These differences may be leveraged in manufacturing such specialized devices.
 It will also be appreciated that the methods and apparatus described herein, by allowing for isochronous data networking spanning varying protocols and networks, and limited software modifications to extant infrastructure and devices, also provide an intrinsic cost benefit over prior art isochronous data networking technologies. Specifically, by obviating the expense of infrastructure through reuse of existing networking technology, some of the cost and complexity associated with such isochronous networking can be avoided, and customer systems made simpler and "thinner" in terms of capability.
 Moreover, greater levels of connectivity between devices can be achieved, even when the pervasiveness of certain types of physical ports (e.g., 1394) has decreased with time.
 It will be recognized that while certain aspects of the invention are described in terms of a specific sequence of steps of a method, these descriptions are only illustrative of the broader methods of the invention, and may be modified as required by the particular application. Certain steps may be rendered unnecessary or optional under certain circumstances. Additionally, certain steps or functionality may be added to the disclosed embodiments, or the order of performance of two or more steps permuted. All such variations are considered to be encompassed within the invention disclosed and claimed herein.
 While the above detailed description has shown, described, and pointed out novel features of the invention as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made by those skilled in the art without departing from the invention. The foregoing description is of the best mode presently contemplated of carrying out the invention. This description is in no way meant to be limiting, but rather should be taken as illustrative of the general principles of the invention. The scope of the invention should be determined with reference to the claims.
Other Standards and Technologies
 IEC 61883-1 ("Consumer audio/video equipment--Digital interface--Part 1: General"--February 1998), incorporated by reference herein in its entirety, is a standard that describes, inter alia: (i) isochronous Plug Control Registers; (ii) Connection Management Protocol (CMP); (iii) Function Control Protocol (FCP); and (iv) Common Isochronous Packet (CIP) headers. It is useful for the transport of isochronous data when using AV/C, DVC, MPEG, or AMP.
AV/C General Specification
 AV/C General Specification (Accepted by 1394 TA (version 4.2), and including 1998010--"Enhancements to the AV/C General Specification 3.0", 1998001--"AV/C Digital Interface Command Set General Specification", and 1996002--"AV/C Digital Interface Command Set") each incorporated by reference herein in its entirety, defines inter alia general commands used to control consumer audio/video electronics. It utilizes 1394 Unit architectures, and is useful for implementation of audio/video devices, and for software driver development.
MPEG4 Over 1394
 MPEG4 over 1394 is not yet standardized; a study group is investigating the need/demand for a specification to transport MPEG4 (including H.264) over 1394, and identifying which parts of MPEG4 are applicable. The group is also discussing strategies for a specification (i.e., encapsulating in MPEG2-TS over 61883-4, or transport MPEG-4 in `native` form over 1394). This standard (when finalized) would be applicable for all devices sending MPEG4 streams over 1394.
 IEC 61883-6 ("Consumer audio/video equipment--Digital interface--Part 6: Audio and music data transmission protocol"--February 1998), incorporated by reference herein in its entirety, is a standard that describes Audio/Music Transport Protocol across 1394. It is useful for devices transporting formatted Audio or Music streams over 1394.
 IEC 61833-2 ("Consumer audio/video equipment--Digital interface--Part 2: SD-DVCR data transmission"--February 1998), incorporated by reference herein in its entirety, is a standard that describes SD-DVCR Transport Protocol across 1394. It is useful for devices transporting SD-DVCR over 1394.
 IEC 61883-3 ("Consumer audio/video equipment--Digital interface--Part 3: HD-DVCR data transmission"--February 1998), incorporated by reference herein in its entirety, is a standard that describes an HD-DVCR Transport Protocol across 1394.
 IEC 61883-5 ("Consumer audio/video equipment--Digital interface--Part 5: SDL-DVCR data transmission (TA4)"--February 1998), incorporated by reference herein in its entirety, is a standard that describes SDL-DVCR Transport Protocol across 1394.
 IEC 61883-4 ("Consumer audio/video equipment--Digital interface--Part 4: MPEG2-TS data transmission"--February 1998), incorporated by reference herein in its entirety, is a standard that describes MPEG Transport Streams (TS) (including DVB TS) across 1394.
 IEC 61883-7 ("Consumer audio/video equipment--Digital interface--Part 7: Transmission of ITU-R BO.1294 System B"--February 1998), incorporated by reference herein in its entirety, is a standard that describes MPEG Transport Streams (TS) for DSS (not quite the same as standard MPEG-2) across 1394.
 TA 1998005 ("AV/C Tuner Broadcast System Specification--Digital Video Broadcast (DVB)--1998), incorporated by reference herein in its entirety, is a standard that describes AV/C control enhancements for Digital Video Broadcast (DVB) video tuners. It is useful for devices doing DVB video tuning controlled across 1394.
Patent applications by Andrew Yanowitz, Ben Lomond, CA US
Patent applications by Ashley Ian Butterworth, Normanhurst AU
Patent applications by Matthew Xavier Mora, Fremont, CA US
Patent applications by Niel David Warren, Soquel, CA US
Patent applications in class COMPUTER-TO-COMPUTER SESSION/CONNECTION ESTABLISHING
Patent applications in all subclasses COMPUTER-TO-COMPUTER SESSION/CONNECTION ESTABLISHING