Patent Application
20060149858
The following presents a simplified summary of the subject invention in order to provide a basic understanding of some aspects of the subject invention. This summary is not an extensive overview of the subject invention. It is not intended to identify key/critical elements of the subject invention or to delineate the scope of the subject invention. Its sole purpose is to present some concepts of the subject invention in a simplified form as a prelude to the more detailed description that is presented later.
An extensible architecture for untrusted medium (e.g., wireless) device configuration via trusted medium is described below. The architecture can be employed to associate a device that utilizes an untrusted medium (e.g., wireless connection). Association is effected using a trusted medium, for example, a wired connection.
The architecture includes systems and methods for establishing a wireless universal serial bus (WUSB) connection between a connecting device and a host device using a trusted medium, such as a wired connection. In one implementation, the connecting device sends an association request through the trusted medium to the host device. The association request includes device attributes associated with the WUSM component of the connecting device. In response, the host device parses and validates the association request and determines connection attributes for connecting using WUSB. The host device sends a response with the connection attributes through the trusted medium to the connecting device. Using the connection attributes, the connecting device configures the WUSB component and establishes a WUSB connection with the host device.
The subject invention is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the subject invention. It may be evident, however, that the subject invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the subject invention.
As used in this application, the terms “component,” “handler,” “model,” “system,” and the like are intended to refer to a computer-related entity, either hardware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a server and the server can be a component. One or more components may reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. Also, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate via local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems via the signal). Computer components can be stored, for example, on computer readable media including, but not limited to, an ASIC (application specific integrated circuit), CD (compact disc), DVD (digital video disk), ROM (read only memory), floppy disk, hard disk, EEPROM (electrically erasable programmable read only memory) and memory stick in accordance with the subject invention.
Further, “trusted medium” refers to a trusted connection over which association information can be transferred in order to associate an untrusted medium. Examples of trusted media include, but are not limited to, a serial connection, a parallel connection and/or a universal serial bus (USB) connection “Untrusted medium” refers to a medium which is being associated in order to establish trust. Wireless connection(s) such as Bluetooth and/or IEEE 802.11 are examples of untrusted media.
Referring to
An “association request” refers to a block of data sent from the device 110 to a driver 120 in order to initiate association. The association request can then be forwarded to an association manager 130 which forward to the association request to an appropriate handler 140. An “association response” refers to a block of data sent from the driver 120 to the device 110 in order to complete association (e.g., successful and/or unsuccessful).
The architecture 100 can facilitate configuration of the device 110 to communicate (e.g., securely) via an untrusted medium (e.g., wireless connection). Configuration of the device 110 can be based, at least in part, upon information exchanged via a trusted medium (e.g., wired connection). In one example, the device 110 sends an association request to the driver 120 and receives an association response from the driver 120. If the association is successful, the association response can include, for example, configuration information (e.g., encryption key) to enable the device 110 to communicate (e.g., securely) via the untrusted medium. If the association is unsuccessful, the association response can include, for example, error information.
In one example, the device 110 is a wireless-enabled digital camera that also includes a USB connection. The USB connection (trusted medium) can be employed to configure the wireless connection (untrusted medium) of the digital camera. For example, a “found new hardware” wizard can be employed to choose and/create a wireless profile to transfer to the digital camera via the architecture 100. Once the profile information has been transferred to the digital camera via the USB connection, the USB connection can be disconnected and the digital camera can communicate via the wireless connection.
For example, the driver 120 can channel an association request received via a trusted medium from a device 110 to the association manager 130. The driver 120 further can provide an association response received from the association manager 130 to the device 110 via the trusted medium. In another example, the driver 120 generates and provides an association request to the association manager 130. Optionally, the driver 120 can further determine an appropriate time for issuance of an association request.
In yet another example, a particular driver 120 can be employed to configure a plurality of untrusted media. For example, a driver 120 can be employed to communicate via a USB connection to a plurality of devices 110 that communicate via a plurality of untrusted media.
The association manager 130 provides association data to the appropriate components. The association manager 130 can receive an association request from a driver 120. Based, at least in part, upon routing information in the association request, the association manager 130 can provide information associated with the association request to a particular handler 140 for processing. Once the particular handler 140 has completed processing of the association request, the handler 140 can provide an association response to the association manager 130. Based, at least in part, upon routing information in the association response, the association manager 130 can provide the association response to the requesting driver 120.
The handler 140 interfaces with a service (not shown) that implements device installation. In one example, the handler 140 is the only component of the architecture 100 that has explicit knowledge of the association request. The handler 140 take action based, at least in part, upon contents of the association request, as described in greater detail below. For example, the action(s) can be dependent upon the connection type sought to be established by the association request. Once the particular handler 140 has completed processing of the association request, the handler 140 can provide an association response to the association manager 130.
The architecture 100 can include a handler registry 150 which stores identification information associated with one or more handlers 140. The association manager 130 can employ the identification information stored in the handler registry 150 to determine to which of a plurality of handlers 140 to provide a particular association request.
Further, the architecture 100 can, optionally, include a driver registry 160 that stores identification information associated with one or more drivers 120. The association manager 130 can employ the identification information stored in the driver registry 160 to determine which of one or more drivers 120 to instantiate, for example, during initialization (as discussed below).
While depicted as a single entity, those skilled in the art will recognize that the device 110 can include an object that sends and/or receives association requests and an object (e.g., target device) that ultimately is associated with a host.
In one example, the architecture 100 supports only one association request and associated association response. In this example, the information needed from the device 110 to facilitate association is embedded in the association request. Similarly, the information needed for the device 110 to facilitate association is embedded in the association response.
Referring to
In one example, association request(s) and/or association response(s) are organized in a parse-able stream. The stream comprises a series of attribute(s) with each attribute having a defined type and associated data. This facilitates flexibility and extensibility of the architecture. An exemplary attribute structure is set forth in Table 1:
This exemplary attribute structure can be defined, for example, as:
In one example, there are several pre-defined attribute types that are intended to be used by the system itself (e.g., common to many association types), and are not specific to any particular association type.
Association Request
In this example, an association request is a series of attributes. The first attribute is the AssociationType. This is used to identify which handler to which the request should be directed. In this example, this value is a GUID that is defined by the handler (or some specification associated with the handler). For example, in order to associate a Bluetooth device, there can be a Bluetooth specific GUID, and a handler that has specified that it handles that particular GUID.
The second attribute in the association request is the length. This is the total length of all of the attributes in this request including the AssociationType and Length field itself. This is used to aide in parsing, so that if a component is not interested in a specific AssociationType, it can skip over the whole request as opposed to having to parse each attribute within it.
In this example, the attribute(s) that immediately follow the length are defined carefully in order to facilitate simple devices to be able to implement basic association with minimal processing (e.g., device(s) having silicon-only solutions with no firmware). In order to achieve this, being able to simply jump to a pre-defined offset in a structure in order to extract desired data can be helpful. Thus, in this example, the attributes immediately following the length contain the minimal amount of data needed to carry out basic association. Further, the attributes can be laid out in a pre-defined order and always be present. In one example, substantially all of this required data is contained within a single attribute. In this example, any variable length fields are located at the end of these basic attributes so as to not affect the offset in the association request.
In another example, several attributes are employed, each containing a small amount of data. Thus, it is to be appreciated that any number of attribute(s), if any, can follow, for example, in order to provide extended functionality.
Association Response
Turning to
An association response attribute 320 is a piece of data comprising an attribute type, length, and data. Similar to the association request discussed above, in one example, the association response is a series of attributes. In this example, the first attribute is the AssociationType. This is used to echo the AssociationType of the association request that resulted in this response.
The second attribute in the association response is the length. This is the total length of all of the attributes in this request including the AssociationType and length field itself. This is used to aide in parsing, so that if a component is not interested in a specific AssociationType, it can skip over the response as opposed to having to parse each attribute within it.
The third attribute of the association response is the AssociationStatus. This is to notify the device as to the result of the association request. In this example, if the association process was successful, then this value will be 0x0000, meaning that the device can continue to read the attributes in the association response. If the value is 0xc0001, then the host could not find a handler that can handle the specified AssociationType. In this case, the device should not make any assumptions about further attributes in the association response.
The attribute(s) immediately following the AssociationStatus can be defined carefully as discussed above to allow simple devices to be able to implement basic association with minimal processing. In this example, in order to achieve this, being able to simply jump to a pre-defined offset in a structure in order to extract desired data is necessary. So these attributes contain the minimal amount of data needed to carry out basic association. They are also laid out in a pre-defined order and always be present in this example. Any variable length fields are located at the end of these basic attributes so as to not affect the offset in the association request. Any number of attributes, if any, can follow in order to provide extended functionality.
Referring to
The association manager 410 is responsible for providing association data (e.g., association request(s) and/or association response(s)) to the appropriate components (e.g., handler and/or driver). The manager communication component 420 can receive association request(s) from driver(s) (not shown). The manager communication component 420 can provide at least part of the association request (e.g., association request header) to the handler identification component 430.
Based on the information provided by the manager communication component 420 and identification information stored in the handler registry 150, the handler identification component 430 identifies the particular handler (not shown) to which the association request is to be provided. In one example, the association manger 410 loads the handler identified by the handler identification component 430. In another example, handler(s) are loaded at initialization (as discussed in greater detail below). Thereafter, the manager communication component 420 provides information associated with the association request to the handler identified by the handler identification component 430.
Once the handler has processed the association request, the handler provides an association response to the manager communication component 420. The manager communication component 420 then provides the association response to the requesting driver.
In one example, the association manager 410 validates the association request. For example, the association manager 410 can determine whether is well-formed. If the request is not well-formed, then the association manager 410 can generate an association response indicating the association request was malformed (e.g., status attribute set to ERROR_MALFORMED_ASSOCIATION_REQUEST) and provide the association response to the requesting driver. In this example, the association manager 410 utilizes the following criteria to determine whether an association request is well-formed:
Next, the association manager 410 determines if there is a handler that has registered for the specified association type included in the association request (e.g., GUID stored in the handler registry 150). If a handler is not found, then the association manager 410 can generate an association response indicating that the association type requested is not supported and provide the association response to the requesting driver.
If a handler is found, in this example, the association manager 410 can parse the association request and extract a list of attribute(s). The association manager 410 can then provide the list of extracted attribute(s) to the particular handler.
If the association manager 410 is unsuccessful in providing the list of extracted attribute(s) to the particular handler, the association manager 410 can generate an association response indicating that the particular handler was not responsive and provide the association response to the requesting driver.
If the association manager 410 is successful in providing the list of extracted attribute(s) the particular handler, upon completion of processing by the handler, in this example, the association manager 410 receives an association response attribute list from the handler. The association manager 410 can determine whether the association response attribute list is well-formed. For example:
If the response is well-formed, then the association manager 410 generates an association response (e.g., byte array) based, at least in part, upon the association response attribute list. For example, the association manager 410 can:
The association manager 410 can then provide the association response to the requesting driver.
In one example, the association manager implements the following interface:
SendAssociationRequest( ) is called by driver(s) in order to begin the association process. The association response is returned as a byte array which can easily be sent back to the device. In one example, it is the responsibility of the driver to free the AssociationResponse.
Turning to
The association manager 510 is responsible for providing association data (e.g., association request(s) and/or association response(s)) to the appropriate components (e.g., handler and/or driver), as discussed previously. However, in this example, the initialization component 520 employs information stored in the driver registry 160 to determine which of one or more drivers (not shown) to instantiate, for example, during initialization of the system 500. For example, driver(s) can be registered during configuration of a computer system (not shown) (e.g., manually and/or automatically).
In one example, upon system initialization, the initialization component 520 identifies driver(s) and handler(s) based, at least in part, upon information stored in the driver registry 160 and handler registry 150, respectively. Thereafter, the initialization component 520 creates instances of the identified handler(s) and the identified driver(s).
In this example, for each of the handlers, the association manager 510 can retrieve an association type count and allocate an associated storage buffer (e.g., association type count * sizeof (GUID)). This buffer can be used to retrieve the association types from the handler. In another example, the handler allocates the storage space and provides it to the association manager.
The association types can be an array of GUIDs that represent the specific association types that the handler supports. For each of the GUIDs retrieved, an entry can be added to a list of GUID to Handler mappings stored in the handler registry. For example:
This list of mappings can then be employed by the association manager 510 to determine routing of association requests to the appropriate handler.
In this example, once the handlers have been created and their association types discovered, the initialization component 520 activates the drivers. Activation occurs after the handlers have been loaded and initialized to ensure that association request(s) are not received until the handlers have been discovered and loaded. For example, to activate a driver, a “Start( )” method can be invoked.
Next, referring to
The handler 610 (along with possibly other component(s) (not shown)) consumes the association request and generates information associated with an association response.
For example, the request component 620 can receive information associated with an association request (e.g., the association request and/or a parsed list of attributes) from an association manager (not shown). The request component 620 can parse the contents of the information associated with the association request to determine what action(s) are to be taken. The association processor 640 facilitates action(s) via the service 650. Action(s) of can be dependent upon, for example, the connection type sought to be established. Once the action(s) have been completed, the association processor 640 can provide information regarding the association to the response component 630. The response component 630 can then generate information associated with an association response (e.g., an association response and/or list of attributes) which can be provided to the association manager.
In one example, a plurality of handlers 610 implement the following COM interface:
In this example, “manager” is an interface pointer to the association manager. Further, “AssociationTypes” returns an array of AssociationType GUIDs that the PONG Handler can handle. Similarly, “AssociationTypeCount” is the number of AssociationTypes that the PONG Handler can handle. “HandleAssociationRequest( )” is called by the association manager when it receives an association request that the handler 610 reported it supported. “RequestAttributes” is a list of attribute structures. The handler 610 is expected to allocate the memory necessary to return the ResponseAttributes which is a list of attribute structures which are the attributes that will be returned to the device (not shown).
In another example, the handler 610 stores information about the device, for example, in a database for future installation once the device is discovered on the target medium. For example, a particular handler 610 can be related to a Wi-Fi target medium. In this example, device(s) desiring to employ the Wi-Fi target medium send association request(s) and receive association response(s) in the form of attribute lists. The attribute lists can be provided by the handler 610 to an association manager which can then form an association response.
With respect to Tables 9, 10 and 11 below, “attribute” refers to a friendly name associated with an attribute element. “Attribute ID” is an identifier (e.g., number) used to identify the attribute element in the attribute list. “Length” refers to the length of the data in an attribute element. Attribute lengths can be varied and/or fixed and, in this example, are expressed in bytes. A length value can also specify a maximum length. In the association response, in one example, fixed lengths can be used so that the offset to the value is deterministic; aiding the ability of a device to parse the response. The actual value of the attribute may not use up the entire length allocated for the data. In these cases, an additional field can specify the actual length of the attributes data. “Allowed Values” refers to the allowed values field describes the values to be supported by the device. If an allowed value is required, it means the device must support that value if it contained in the attribute list. Unless otherwise stated in Tables 9, 10 and/or 11, values should be assumed to be required. If an allowed value is optional, the device need not support the value, but should be prepared for it to be contained in the attribute list. Optional values may become required in future versions of this specification.
Wireless Protocols
The IEEE 802.11 set of standards defines two network types: encrypted networks (e.g., WEP networks) and unencrypted networks. Owing to the well-known weaknesses of the WEP protocol, the wireless industry implemented support for the IEEE 802.1x standard as a mechanism for addressing the key deficiencies in the WEP protocol, those being user authentication, encryption key management and encryption key distribution. For WEP-encrypted networks, the user needs to provide an encryption key and for 802.1× enabled networks the key is provided automatically if the user has a valid credential (e.g., such as a digital certificate or username and password). For 802.11 networks which are encrypted, this presents a usability problem as it is currently not possible to determine a priori whether the user needs to enter the WEP key or whether the network supports 802.1×, in which case they do not have to enter it.
To address the underlying weaknesses of the WEP algorithm, which has been shown to be cryptographically weak, a security enhancement to the 802.11 set of standards was introduced, called Wi-Fi Protected Access (WPA). WPA also addresses some of the usability issues of the original 802.11 standard by specifying an information element which WPA-capable access points include in their beacon frame. This information element describes inter alia whether the network requires the user to enter the encryption key called WPA pre-shared key mode (WPA-PSK) or whether the key is provided automatically by virtue of the user's credential, referred to as “WPA mode”.
Wired Equivalent Privacy
WEP is defined by the IEEE 802.11 standard and is intended to provide a level of data confidentiality that is equivalent to a wired network. Due to the nature of wireless LAN networks, implementing a security infrastructure that monitors physical access to the network can be difficult. Unlike a wired network where a physical connection is required, anyone within range of a wireless access point (AP) can conceivably send and receive frames as well as listen for other frames being sent. This makes eavesdropping and remote sniffing of wireless LAN frames very easy.
WEP provides data confidentiality services by encrypting the data sent between wireless nodes. WEP encryption for an 802.11 frame is indicated by setting a WEP flag in the MAC header of the 802.11 frame. WEP provides data integrity for random errors by including an integrity check value (ICV) in the encrypted portion of the wireless frame.
The following tables illustrates the two shared keys that WEP defines:
WEP encryption employs the RC4 symmetric stream cipher with 40-bit and 104-bit encryption keys.
Wi-Fi Protected Access
WPA is a Wi-Fi standard designed to improved upon the security features of WEP. Unlike WEP, 802.1x authentication is required in WPA. With WPA, rekeying of both unicast and global encryption keys is required. For the unicast encryption key, the Temporal Key Integrity Protocol (TKIP) changes the key for every frame, and the change is synchronized between the wireless client and the wireless access point (AP). For the global encryption key, WPA includes a facility for the wireless AP to advertise the changed key to the connected wireless clients.
TKIP replaces WEP with an encryption algorithm that is stronger than the WEP algorithm. TKIP also provides for verification of the security configuration after the encryption keys are determined; synchronized changing of the unicast encryption key for each frame; and, determination of a unique starting unicast encryption key for each pre-shared key authentication.
WPA further employs a method know as “Michael” that specifies an algorithm that calculates an 8-byte message integrity code (MIC). The MIC is placed between the data portion of the IEEE 802.11 frame and the 4-byte integrity check value (ICV). The MIC field is encrypted together with the frame data and the ICV.
WPA is an interim standard that will be replaced with the IEEE's 802.11i standard upon its completion.
Wi-Fi Handler
The association type is an attribute contained in the header section of the association request and association response, and is separate from data attributes. This attribute is used by the association manager to forward the association request(s) to the correct handler. In this example, a Wi-Fi handler 410 has the following required association type:
The data section of the association request includes attributes that are specific to the attribute type. The following table identifies exemplary attributes that an association manager can forward to a Wi-Fi handler 610:
MAC Address
The MAC Address is 6 byte value that contains the 48 bit value of the MAC Address. For example: 0x00 0x07 0xE9 0x4C 0xA8 0x1C.\
Network Authentication Type Flags
This set of flags allows a device to signal which “Network Authentication type” types are supported. This information can be used for diagnostic purposes. If a device fails to support the required attributes, then the user can be notified of this and given actionable instructs to correct the problem. In this example, the value of this field is a bitwise OR of one or more of the following values:
In this example, other values are reserved and set to 0.
Data Encryption Type Flags
This set of flags allows a device to signal which “Data Encryption type” types are supported. This information can be used for diagnostic purposes. If a device fails to support the required attributes, then the user can be notified of this and given actionable instructs to correct the problem. In this example, the value of this field is a bitwise OR of one or more of the following values:
Again, in this example, other values are reserved and set to 0.
Connection Type Flags
This set of flags allows a device to signal which “Connection type” types are supported. This information is used for diagnostic purposes. If a device fails to support the required attributes, then the user can be notified of this and given actionable instructs to correct the problem. The value of this field is a bitwise OR of one or more of the following values:
In this example, other values are reserved and are set to 0.
Based, at least in part, upon the handler 610's interaction with the service 650, the response component 630 generates information associated with an association response. Continuing with the Wi-Fi handler example, Table 11 identifies exemplary association response attributes. The lengths of the attributes in the attribute list in this example are fixed. Thus, device manufactures can easily jump to the appropriate offset to read the value of any given attribute in the response. Offsets refer to the start of the attribute.
SSID
The SSID is a string used in broadcasting wireless networks, as discussed previously.
Network Key
The network key is a string used to secure the network. In this example, the following attributes are placed as constraints on the allowed values of the Network key. The Device will have to be prepared to accept or reject the following configurations:
WEP Key
When the data auth type is WEP, the Network key is either an ASCII or HEX representation of a 40-bit or 104-bit WEP key. The type can be determined by the length of the string.
WPAPSK Pass Phrase
If the network key attribute is a 0-63 char ASCII string and the “network authentication type” attribute is WPA, the network key attribute is used as a pass phrase to derive the WPA binary key.
Key Provided Automatically (802.1x)
The “Key Provided Automatically (802.1x)” attribute dictates whether or not the Network Key is provided via 801.x This is typically set to 0 in cases where WPA-PSK, or WEP are used to secure the wireless network.
Network Authentication Type
The network authentication type indicates what type of security mechanism is required to join a particular network. The flag set specifies which of the following mechanisms is used:
In this example, other values are reserved and are set to 0. Significantly, unlike the association request, these flags are mutually exclusive—only one flag can be set at a given time.
Data Encryption Type
This value specifies the encryption mechanism deployed by the wireless network. The flag set specifies which of the following mechanisms is used:
All other values are reserved and are set to 0. Significantly, unlike the association request, these flags are mutually exclusive—only one flag can be set at a given time.
Connection Type
Connection type defines the type of wireless network. The flag set specifies which of the following mechanisms is used:
All other values are reserved and are set to 0. These flags are mutually exclusive.
Turning next to
The trusted medium communication component 720 interfaces with a device 740 via a trusted medium (e.g., USB connection). In one example, the trusted medium communication component 720 receives an association request from the device 740 (e.g., association request initiated time independent of device enumeration). In another example, the trusted medium communication component 720 receives notification of a request to issue an association request. Thereafter, the driver 710 generates an association request which is sent to an association manager (not shown) via the driver communication component 730.
In one example, driver(s) 710 implement the following interface:
“Manager” is an interface pointer to the association manager so that the driver can call SendAssociationRequest. Start( ) is called by the association manager when it wishes for the driver to begin detecting and issuing new association requests. Stop( ) is called by the association manager when it whishes for the driver to stop issuing new association requests (e.g., when a user desires to disable association over a particular trusted medium).
In one example, a particular driver 710 can be related to a USB trusted medium. In this example, device(s) desiring to employ an untrusted medium send association request(s) and receive association response(s) securely through the driver 710.
For device(s) that implement dynamic association functionality, where association requests can be generated independent of device enumeration, in one example, there is an optional Interrupt IN endpoint. This endpoint facilitates notifications of new association requests. The standard endpoint descriptor for this optional endpoint can be found in Table 14:
If a device's interface does not contain the optional endpoint, then association will only occur at enumeration time. If such a device wishes to initiate the association process, it will have to do a device initiated USB reset. This will cause the device to be re-enumerated by the host, at which point the host will retrieve the association request(s) from the device. In another example, a device can also implement HUB functionality to cause the association function to come and go as the device wishes.
Since the control endpoint is the only mandatory endpoint for a device that supports an association interface, the necessary data transfers happen over that endpoint. In this example, these transfers are in the form of association class requests.
Table 15 depicts a list of association class requests that must be supported by a device in one example.
GET_ASSOCIATION_INFORMATION
This request retrieves an association information structure from the device. The association information includes a list of REQUEST_INFO blocks. Each REQUEST_INFO block pertains to a single association request that the device wishes to issue:
Table 17 illustrates an exemplary ASSOCIATION_INFORMATION structure:
Table 18 provides exemplary Association Information Flag information:
Table 19 illustrates an exemplary REQUEST_INFO structure:
GET_ASSOCIATION_REQUEST
This request retrieves a particular association request from the device. The request is identified by the RequestID value in the wValue field:
In this example, a request block is a 4 KB block of data. The maximum transfer size of a control transfer is 64 KB, so 16 request blocks can be theoretically transferred in each GET_ASSOCIATION_REQUEST. The actual amount of data to be transferred is specified by the wLength field. The BlockNumber specified in the wValue field identifies the starting block number for this control transfer. So, in this example, the device 540 should return association request data for the request specified by RequestID starting at offset BlockNumber * 4 KB, and transferring wLength bytes.
SET_ASSOCIATION_RESPONSE
This request sends a response to a specific association request identified by the RequestID value in the wValue field:
In this example, the TrasferFlags value is the bitwise OR of zero or more of the values found in Table 22:
Association Interrupt-In Message(s)
NewAssociationRequest
This interrupt IN message indicates to the host that the device has new or modified association request(s) that need to be processed. Upon receiving this message, the host can issue a GET_ASSOCIATION_INFORMATION request, and process the requests accordingly.
It is to be appreciated that the system 100, device 110, association manager 120, handler 130, driver 140, handler registry 150, driver registry 160, system 400, association manager 410, manager communication component 420, handler identification component 430, association manager 510, initialization component 520, system 600, handler 610, request component 620, response component 630, association processor 640, service 650, system 700, driver 710, trusted medium communication component 720, driver communication component 730 and/or the device 740 can be computer components as that term is defined herein.
Turning briefly to
The subject invention may be described in the general context of computer-executable instructions, such as program modules, executed by one or more components. Generally, program modules include routines, programs, objects, data structures, etc. that perform particular tasks or implement particular abstract data types. Typically the functionality of the program modules may be combined or distributed as desired in various embodiments.
Referring to
At 840, a determination is made as to whether the association was successful. If the determination at 840 is NO, no further processing occurs. If the determination at 840 is YES, at 850, information associated with the association response is employed to connect (e.g., the device) via an untrusted medium (e.g., wireless connection).
Turning next to
At 950, an association response is received, for example, from the association manager. At 960, information associated with the association response is provided to the requesting device. For example, the information can include the entire association response and/or a portion of the association response. Thereafter, no further processing occurs.
Next, referring to
At 1016, a determination is made as to whether substantially all of the association information has been received, for example, by the driver. If the determination at 1016 is NO, processing continues at 1008. If the determination at 1016 is YES, at 1020, a determination is made as to whether PendingRequestCount is greater than zero. If the determination at 1020 is NO, no further processing occurs.
If the determination at 1020 is YES, at 1024, a request is identified to handle (e.g., by the driver). At 1028, the size of the transfer (e.g., association request) is determined. At 1032, a GET_ASSOCIATION_REQUEST is sent. At 1036, a determination is made as to whether there is more request data. If the determination at 1036 is YES, process continues at 1028. If the determination at 1036 is NO, at 1040, the association requested is handled and an association response is generated (e.g., by an association manager and/or handler).
At 1040, the size of the association response transfer is determined. At 1048, a SET_ASSOCIATION_RESPONSE is sent. At 1052, a determination is made as to whether there is more response data. If the determination at 1052 is YES, processing continues at 1044. If the determination at 1052 is NO, at 1056, a determination is made as to whether there are more requests.
If the determination at 1056 is YES, processing continues at 1024. If the determination at 1056 is NO, at 1060 a determination is made as to whether an additional requests flag has been sent in the association information. If the determination at 1060 is YES, processing continues at 1008. If the determination at 1060 is NO, no further processing occurs.
Referring next to
If the determination at 1340 is YES, at 1370, information associated with the association request is sent to the handler. For example, the information can comprise the association request and/or a portion of the association request (e.g., attribute list(s)).
At 1380, information associated with an association response is received from the handler. At 1360, an association response is provided to the requesting driver.
Turning to
If the determination at 1412 is YES, at 1424, a handler for the association request is located. At 1428, a determination is made as to whether a handler has been found. If the determination at 1428 is NO, at 1432, an association response indicating association type not supported is generated, and, processing continues at 1420.
If the determination at 1428 is YES, at 1436, the association request is parsed and a list of attribute(s) is built. At 1440, the attribute list is sent to the identified handler. At 1444, response information is received from the handler. At 1448, a determination is made as to whether the association was successful. If the determination at 1448 is NO, at 1452, an association response is generated indicating an appropriate error status, and, processing continues at 1420.
If the determination at 1448 is YES, at 1456, the response format is validated. At 1460, a determination is made as to whether the response is well-formed. If the determination at 1460 is NO, at 1464, an association response indicating an appropriate error status is generated, and, processing continues at 1420.
If the determination at 1460 is YES, at 1468, an association response is generated based on the response from the handler. At 1420, the association response is provided to the requesting driver, and, no further processing occurs.
Referring to
In order to provide additional context for various aspects of the subject invention,
With reference to
The system bus 1818 can be any of several types of bus structure(s) including the memory bus or memory controller, a peripheral bus or external bus, and/or a local bus using any variety of available bus architectures including, but not limited to, an 8-bit bus, Industrial Standard Architecture (ISA), Micro-Channel Architecture (MSA), Extended ISA (EISA), Intelligent Drive Electronics (IDE), VESA Local Bus (VLB), Peripheral Component Interconnect (PCI), Universal Serial Bus (USB), Advanced Graphics Port (AGP), Personal Computer Memory Card International Association bus (PCMCIA), and Small Computer Systems Interface (SCSI).
The system memory 1816 includes volatile memory 1820 and nonvolatile memory 1822. The basic input/output system (BIOS), containing the basic routines to transfer information between elements within the computer 1812, such as during start-up, is stored in nonvolatile memory 1822. By way of illustration, and not limitation, nonvolatile memory 1822 can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable ROM (EEPROM), or flash memory. Volatile memory 1820 includes random access memory (RAM), which acts as external cache memory. By way of illustration and not limitation, RAM is available in many forms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM).
Computer 1812 also includes removable/nonremovable, volatile/nonvolatile computer storage media.
It is to be appreciated that
A user enters commands or information into the computer 1812 through input device(s) 1836. Input devices 1836 include, but are not limited to, a pointing device such as a mouse, trackball, stylus, touch pad, keyboard, microphone, joystick, game pad, satellite dish, scanner, TV tuner card, digital camera, digital video camera, web camera, and the like. These and other input devices connect to the processing unit 1814 through the system bus 1818 via interface port(s) 1838. Interface port(s) 1838 include, for example, a serial port, a parallel port, a game port, and a universal serial bus (USB). Output device(s) 1840 use some of the same type of ports as input device(s) 1836. Thus, for example, a USB port may be used to provide input to computer 1812, and to output information from computer 1812 to an output device 1840. Output adapter 1842 is provided to illustrate that there are some output devices 1840 like monitors, speakers, and printers among other output devices 1840 that require special adapters. The output adapters 1842 include, by way of illustration and not limitation, video and sound cards that provide a means of connection between the output device 1840 and the system bus 1818. It should be noted that other devices and/or systems of devices provide both input and output capabilities such as remote computer(s) 1844.
Computer 1812 can operate in a networked environment using logical connections to one or more remote computers, such as remote computer(s) 1844. The remote computer(s) 1844 can be a personal computer, a server, a router, a network PC, a workstation, a microprocessor based appliance, a peer device or other common network node and the like, and typically includes many or all of the elements described relative to computer 1812. For purposes of brevity, only a memory storage device 1846 is illustrated with remote computer(s) 1844. Remote computer(s) 1844 is logically connected to computer 1812 through a network interface 1848 and then physically connected via communication connection 1850. Network interface 1848 encompasses communication networks such as local-area networks (LAN) and wide-area networks (WAN). LAN technologies include Fiber Distributed Data Interface (FDDI), Copper Distributed Data Interface (CDDI), Ethernet/IEEE 802.3, Token Ring/IEEE 802.5 and the like. WAN technologies include, but are not limited to, point-to-point links, circuit switching networks like Integrated Services Digital Networks (ISDN) and variations thereon, packet switching networks, and Digital Subscriber Lines (DSL).
Communication connection(s) 1850 refers to the hardware/software employed to connect the network interface 1848 to the bus 1818. While communication connection 1850 is shown for illustrative clarity inside computer 1812, it can also be external to computer 1812. The hardware/software necessary for connection to the network interface 1848 includes, for exemplary purposes only, internal and external technologies such as, modems including regular telephone grade modems, cable modems and DSL modems, ISDN adapters, and Ethernet cards.
In an example embodiment, the extensible architecture may be implemented as a Plug and Go (PONG) architecture that includes wireless universal serial bus (WUSB) support.
Drivers 1920-1922 are responsible for interfacing with either some form of hardware, or another software component. Drivers 1920-1922 are responsible for channeling requests from manager 1905 to devices over the trusted medium.
Each of the drivers 1920-1922 may detect when a new request should be issued, and it either retrieves or generates the request. This request is passed to manager 1905, who will later return a response to the driver.
Multiple handlers can use the same driver (i.e. multiple target medium can use the same trusted medium). Drivers 1920-1922 may not require any knowledge of the details of the request block or the response block.
Handlers 1910-1912 are responsible for interfacing with the service that implements device installation/association. Handlers 1910-1912 may be directly related to the target medium and may be the only component that needs to have explicit knowledge of the attributes in the request block for that specific target medium. There are global attributes that can be used by other components also.
Handlers 1910-1912 may be configured to handle any type of target medium, such as a wireless medium. As shown in
The PONG system 1900 enables devices to send requests and responses that include attributes associated with WUSB. For a request passed from the device to the handler, an attribute list may include association type, connection device ID, connection key, device setup class GUID, supported band groups, integrator site URL, or the like. The association type is an attribute contained in the header section of the request and response, and is separate from data attributes. The association type attribute is used by a manager to forward requests to the correct handler. Table 24 shows an example specification of an association type attribute.
The terms in Table 24 and the tables below are defined as:
Attribute name: The friendly name associated with an attribute element.
Attribute ID: This number is used to identify the attribute element in the attribute list.
Length: The length of the data in an attribute element. Attribute lengths can be varied or fixed and are expressed in bytes. A length value may also specify a maximum length. In the response, fixed lengths are used so that the offset to the value is deterministic, aiding the ability of a device to parse the response. The actual value of the attribute may not use up the entire length allocated for the data. In these cases, an additional field specifies the actual length of the attributes data.
M/O: This field conveys whether a variable is mandatory or optional. Mandatory attribute elements will always be contained in a list of attributes. Optional value will not necessarily be present. “Mandatory” and “Optional” are expressed with an M or 0.
Allowed Values: The allowed values field describes the values to be supported by the device. If an allowed value is required, it means the device supports that value if it is contained in the attribute list. Unless otherwise stated in the table, values should be assumed to be required. If an allowed value is optional, the device need not support the value, but should be prepared for it to be contained in the attribute list. Optional values may become required in future versions of this specification
The data section of a request may contain attributes that are specific to the attribute type. Table 25 shows example request attributes that may be forwarded to a WUSB handler:
Connection Device ID (CDID) is the device ID of the wireless USB device. If the device had previously been assigned a device ID (whether from the factory, a previous association attempt, user input, etc), it may wish to utilize the same ID. By reusing an existing ID, then a host may behave differently knowing that it has seen the device before. It may also make it easier for devices which can be associated with multiple hosts simultaneously. For example, CDID can be sent by the device if the device wishes to preserve the same CDID across multiple hosts, or to indicate that it has already been associated with this host. The host can either overwrite this value, or it can reuse this value.
If this attribute is missing, or the value is all zeros, then the host will assume that the device requires a new device ID. The host will generate this unique ID and return it to the device in the association response.
Connection Key (CK) is the key which will be used to facilitate mutual authentication and to generate session encryption keys as described in the WUSB specification. CK can be sent by the device if the device needed to have a hard-coded connection key. A device may wish to include this attribute in the request if it has the inability to store a generated key (no NVRAM). It is not recommended, however, for devices to hardcode these keys, but rather they should allow the host to dynamically generate them for better security.
If this attribute is missing, or the value is all zeros, then the host will assume that the device requires a CK to be generated and will return the CK in the association response.
Device Setup Class GUID is one of the supported setup class GUIDs. Providing this value in the association request allows the display of appropriate icons for the device, or to implement some system or user defined policy. This value may be used to determine what type of device is being associated. GUID can be used to match against an installed device setup class on the host to determine things such as icons, descriptions, etc. This will also help display appropriate information in any UI to help the user identify the particular device.
Supported Band Groups may be used to determine which channels the host radio should choose from when picking a channel. For example, supported Band Groups can be used by the host to determine what PHY channels it can use. Without this information from the device, the host would be required to change to a channel in band group 1 since that is the only band group that is required to be supported by all devices. This would lead to all hosts and devices choosing to use band group 1, thus crowding the channels, and diminishing the value of the other band groups. If this information is communicated to the host at association time, the host will know the supported channels for all devices which may possibly connect to the host, thus allowing the host to possibly choose channels in other band groups.
A 1 in a bit position indicates all of the bands and channels in the associated PHY bandgroup are supported. A 1 in bit position 0 indicates that all bands in band group one are supported.
Integrator Site URL can be used in UI to provide information to the user about the device by providing the link to the device's details on the USB-IF website.
Table 26 shows example response attributes that may be forwarded to a WUSB device. The example offsets are shown in the table. Also, the header attributes may be accounted for the first 19 bytes of the attribute list.
For responses pass from the handler to the device, an attribute list may include connection host ID, connection device ID, connection key, preferred channels, host region, or the like. Connection Host ID (CHID) is the unique host ID. The device can use this ID to locate the host's beacon, thereby locating the host. Connection Device ID (CDID) is the unique device ID. This ID uniquely identifies the device to the host specified by CHID. It is not guaranteed to be unique across multiple hosts. Connection Key (CK) is for establishing reconnections using this context. The CK may be a 128-bit CCM key.
Preferred Channels can be specified in the host response in order to inform the device of the preferred channel order that the host is using. This can optimize the process of searching for the host by giving the device hints about the relative likelihood that the host would be on any given channel. The device can search for the host in the order that the host specified, thus making it more likely that the device would find the host on one of the first few channels scanned, rather than scanning in a linear order.
Host Region can be specified in the host response in order to notify the device about what region it is operating in. The device can use this information to change its radio operational properties to region specific values.
In one embodiment, the lengths of the attributes in the attribute list may be fixed. Thus, device manufactures can easily jump to the appropriate offset to read the value of any given attribute in the response. Offsets refer to the start of the attribute.
Other attributes may be used for requests and responses between devices and handlers. These other attributes may include hardware and compatible ID, channel ID, band group, device manufacturer string, device description string, host string, class of device GUID, manufacturer URL, device Icon, association secret key, or the like. Association secret key is a PONG specific key written to a device. The device typically would not reveal the association secret key, except through PONG. The next time that the device attaches, the association secret key is retrieved and is used to authenticate the device. The use of association secret key may enable performing tasks, such as silently updating the association information without asking the user, allowing the device to retain its CDID, or the like. Without using the association key, it may be possible for two devices with the same CDID (e.g. obtained from another host, stolen from another device, or the like) to affect the ability for the devices to connect to the PC.
Following are two example scenarios that can be achieved using the architecture and WUSB connection mechanisms described above:
Scenario 1-WUSB Portable Player with PC:
Todd gets a new wired+wireless USB portable player that worked with Windows Media Player to synchronize. On opening the box, he removes the player and adds the included recharable batteries to the player. He then follows the instructions to install 3rd party software and then attach the player to the PC using the wired USB cable to charge the batteries. While charging the batteries, the player is also bonded to the PC for Wireless USB connectivity and even initiates device synchronization over wired USB.
Once the cable is unplugged and the device is within range, the user should not see any new dialogs for wireless USB device detection and the device should just start working.
Scenario 2-Cell Phone and Storage with PC:
Jack has a PC and a WUSB storage device that are preassociated. When Jack associates his WUSB cell phone with the PC, he gets the option to also associate the other WUSB devices (that may have 1 free connection slot) with the cell phone. This increases the value of the PC and simplifies the end users connection experience.
4 example association models for associating a WUSB device are included below for illustration:
UI Approach—Use a connect button (once devices are in proximity) on both systems and identify the device from a UI list of pairable devices within proximity.
Serial # Approach—This is very similar to the UI approach but once the user has identified the device from the UI, the user has to type in a serial number from the device on to the host, to enable security.
USB Cable Approach—Use a generic USB cable to plug in the wireless USB device into the host that you want to associate with. The wire can be used for regular operation or charging along with association.
USB Flash Key—Use a generic USB Mass Storage device (e.g. a USB Flash Device) to store and exchange identification and security information between the device and host.
PONG system 1900 shown in
To connect to host device 2100, connecting WUSB device sends a request to driver 1921 through wired component 2105. For example, connecting WUSB device 2112 may be connected to wired component 2105 through a wire USB cable. The request includes information for associating WUSB device 2112 with host device 2100, such as the attributes discussed above.
Driver 1921 sends the request to manager 1905, which parses and validates the information in the request. In particular, manager 1905 may determine the type of connection in the request and whether the information in the request is valid for the standard related to the connection. In this example, manager 1905 determines that the request is associated with a WUSB connection. Manager 1905 validates the device attributes in the request. If the request is valid, manager 1905 provides the WUSB connection information, such as device attributes, to WUSB handler 1912.
WUSB handler 1912 processes the connection information and provides host connection information to manager 1905 in response to the request. The host connection information includes connection attributes that are used to connect using WUSB. Manager 1905 provides the host connection information with the connection attributes to driver 1921, which sends the connection information to connecting WUSB device 2112 through wired component 2105. Connecting WUSB device 2112 then uses the connection information for self-configuring and connecting to host device 2100. For example, connecting WUSB device 2112 may adjust the WUSB component to the configuration required by host device 2100, such as channel, region, or the like. Connecting WUSB device 2112 may also send information to host device 2100 with a key, a host ID and a device ID identified in the received connection information.
At block 2206, the WUSB device attributes are sent to a WUSB handler. At bock 2208, connection attributes are received from the WUSB handler. The connection attributes enable the WUSB device to connect to the host device. At block 2210, the connection attributes are sent to the WUSB device through the trusted medium.
The following sections A-C are specific to the protocol used by a PONG system over the USB trusted medium and illustrates the layout of various interface and endpoint descriptors needed to implement PONG over USB on the PONG Target Device.
A. Pong Device Interface
Table 27 is a representation of the interface descriptor and provides details on the values to be filled in for a PONG device over USB. For most rows, a particular value or set of values is provided. Vendors may choose from the specified range and all other values may be RESERVED for future use.
A string may be used to identify the device that is being associated. The string may be localized in the USB string descriptors. An example of a good string would be “PONG—Wireless USB Mouse”. In one example embodiment, the PONG interfaces are not grouped with Interface Association Descriptor. A USB device may not be configured to have more than 1 PONG interface per configuration.
B. Pong Device Endpoints
To allow for really cheap devices, a control endpoint may be used and an interrupt endpoint is optional (for advanced features). Using the control endpoint also allows for Low Speed USB devices. The control endpoint (endpoint 0x00) does NOT need to be described under the interface descriptor and must be present on all USB devices.
Smart devices can choose to implement association functionality after device enumeration is completed. To achieve this, the device may implement the optional Interrupt IN endpoint. This endpoint will facilitate notifications of new association requests. An example of standard endpoint descriptor for this optional endpoint is shown in Table 28 as Interrupt-IN Endpoint Descriptor.
If a device's PONG interface does not contain the optional endpoint, association may occur at enumeration time. If such a device wishes to initiate the association process, it may perform a device initiated USB reset. This may cause the device to be re-enumerated by the host, at which point the host may retrieve the association requests from the device. A device could also implement HUB functionality to cause the device to come as go.
C. Pong Class Specific Requests
All PONG data transfers occur over the control endpoint. These transfers may be in the form of PONG class requests. Table 29 shows the list of PONG class requests that are supported by a PONG device. Calid values of bRequest are shown.
C.1. Get Association Information
This request retrieves an association_information structure from the device. The association_information contains a list of REQUEST_INFO blocks. Each REQUEST_INFO block pertains to a single association request that the device wishes to issue. Table 30 shows an example GET_ASSOCIATION_INFORMATION request.
Table 31 shows an example association_information data structure. The first few bytes (e.g. 3 bytes) of the data structure may be a header section.
Table 32 shows example association_information flags.
Table 33 shows a request_info structure.
C.2. GET_ASSOCIATION_REQUEST
This request retrieves a particular association request from the device. The request is identified by the RequestID value in the wValue field. Table 34 shows an example GET_ASSOCIATION_REQUEST request.
A request block may be a 4 KB block of data. The maximum transfer size of a control transfer may be set at 64 KB. Accordingly, 16 request blocks can be theoretically transferred in each GET_ASSOCIATION_REQUEST. The actual amount of data to be transferred is specified by the wLength field. The BlockNumber specified in the wValue field identifies the starting block number for this control transfer. The device may return association request data for the request specified by RequestID starting at offset BlockNumber * 4 KB, and transferring wLength bytes.
C.3. SET_ASSOCIATION_RESPONSE
This request sends a response to a specific association request identified by the RequestID value in the wValue field. Table 35 shows an example SET_ASSOCIATION_RESPONSE.
The TrasferFlags value is the bitwise or of zero or more of the values. An example TrasferFlags value is shown in TABLE 36.
The PONG system may implement interrupt IN messages. For example, a NewAssociationRequest is an interrupt IN message that may be used to indicate to the host that the device has new or modified association requests that need to be processed. Upon receiving this message, the host will issue a GET_ASSOCIATION_INFORMATION request, and process the requests accordingly. Table 37 shows an example NewAssociationRequest.
At block 2304, GET_ASSOCIATION_INFORMATION is sent. In one implementation, the request includes at least 3 bytes of data. At block 2306, the size of the total association information is determined. The size may be determined by
Size=3+sizeof(REQUEST—INFO)* PendingRequestCount
At decision block 2308, a determination is made whether all association information have been received. If not, process 2300 returns to block 2304. If all association request have been received, process 2300 moves to decision block 2310 where a determination is made whether there is any pending request. For example, the determination may be made by determining whether the PendingRequestCount data structure is greater than 0. If there is no pending request (e.g. PendingRequestCount=0), process 2300 ends. If there are pending requests, process 2300 goes to block 2312 where the process chooses a request to handle.
At block 2314, the size of the transfer is determined. This size may be determined by
Size=max(bytes left, N*4 KB (where 0<N<=16))
At block 2316, GET_ASSOCIATION_REQUEST is sent for the appropriate amount of data. RequestID should match that in the association information. BlockNumber should be the starting block number to be returned. At decision block 2318, a determination is made whether there is more request data. If so, process 2300 returns to block 2314, If not, the process goes to block 2320 where the association request is handled and a response is generated.
At block 2322, the size of the response transfer is determined. At block 2324, GET_ASSOCIATION_RESPONSE is sent for the appropriate amount of data. RequestID should match that of the request. If this transfer contains the last byte of the response, then LastBlock should be set. At decision block 2326, a determination is made whether there is more data. If so, process 2300 goes back to block 2322. If there is no more data, the process continues at decision block 2328 where a determination is made whether there are more requests. If so, process 2300 goes back to block 2312. If there are no more requests, the process moves to decision block 2330 where a determination is made whether the AdditionalRequests flag was set in the association information. If so, process 2300 goes back to block 2304. If the flag is not set, the process ends.
It may be possible that a device that supports a PONG interface is not actually ready to send a PONG Association Request at the time of device enumeration. For example, maybe the device is actually some type of cradle for other devices that support PONG over some proprietary interface. The USB PONG device was already enumerated long before the target device is inserted into the cradle. The above described systems and techniques provide a mechanism to notify the PONG driver that it needs to retrieve new association information.
There may also be a need for certain devices to support multiple association requests (e.g. device with multiple target media). These individual association requests could either be dependant on one another or totally independent. Independent association is where a device wishes to associate multiple target media at once, without caring about the order of associating the target media. The above described systems and techniques support a scenario where after receiving an association response from the host, the device decides to issue a new association request as a result of that response.
What has been described above includes examples of the described subject invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the subject invention, but one of ordinary skill in the art may recognize that many further combinations and permutations of the subject invention are possible. Accordingly, the subject invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.
This application claims the benefits of an earlier filed provisional application, Application No. 60/689,610, filed Jun. 10, 2005. This application is a continuation-in-part of and claims the benefits of an earlier filed non-provisional application titled “EXTENSIBLE ARCHITECTURE FOR UNTRUSTED MEDIUM DEVICE CONFIGURATION VIA TRUSTED MEDIUM”, application Ser. No. 11/026,193, filed Dec. 30, 2004.
| Number | Date | Country | |
|---|---|---|---|
| 60689610 | Jun 2005 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11026193 | Dec 2004 | US |
| Child | 11246510 | Oct 2005 | US |
