Patent Application
20140036807
The present application relates generally to WLAN access to a cellular network, more specifically, to providing multiple virtual services over a WLAN interface.
A need exists to provide multiple concurrent services over WLAN (Wireless Local Area Network). For example when WLAN is used to provide access to cellular data networks, it is desirable to provide access to multiple PDNs (Packet Data Networks). This capability is currently done on 3G/4G networks where, e.g., IMS (IP Multimedia Subsystem) and Internet access can be simultaneously provided. Each of these services is identified via their APNs (Access Point Name). It is the name of a network, where a network in 3GPP terminology is called Packet Data Network (PDN). In the 3GPP core network, there is a gateway called PGW (Packet Data Network Gateway). This is a PDN GW; i.e. a gateway towards one or more PDNs. Between the UE (User Equipment; e.g., Wi-Fi client) and PGW(s) one or more “PDN connections” are setup. Each PDN connection is a virtual point-to-point link from a UE to a PDN. A UE initiates the setup of a PDN connection. When it does that, it may include an APN. Each PDN connection has one IP address. As each PDN may have its own IP address range, it can occur that two PDN connections to different PDNs get the same IP address. Herein, the term “PDN” may be used for a “PDN connection.” Thus, the IP address spaces for each of the different services may overlap, making IP address resolution of the services impossible. What is needed is a means to provide multiple virtual point-to-point links between the device and one or more PDNs.
Other approaches have been proposed to solve this problem, including running VLANs (Virtual Local Area Networks, e.g., IEEE 802.1Q) over WLAN, and performing tunneling over WLAN (using e.g. GRE—Generic Routing Encapsulation). The approach described below is potentially simpler to implement than the alternatives, reducing device cost and power consumption and the basic frame structure is already implemented in some existing devices.
The present invention is directed to alleviating the problems of the prior art. In particular, the present invention proposes to use the IEEE 802.11 WDS (Wireless Distribution System) four-address frame format to segregate multiple virtual services over a single WLAN interface.
According to one aspect of the present invention, a method provides to a client access to multiple packet data network (PDN) connections—preferably over WLAN, each PDN providing a dedicated PDN connection (e.g., Skype, Netflix, etc.), a single PDN capable of providing multiple services. The client (e.g., User Equipment (UE) such as a cell phone) is provided with a number of virtual MAC (Media Access Control) addresses. Each of the virtual MAC addresses is assigned to a dedicated PDN connection and each dedicated PDN connection is associated with one of the PDNs. One of the virtual MAC addresses is then provided via a 4 address MAC frame for the client to communicate with the associated data service. When communicating with a data service via a PDN connection, the virtual MAC address associated with the PDN connection is then included in a 4 address MAC frame.
In a preferred embodiment, the client is a Wi-Fi client, and the Wi-Fi client is communicating with the associated data service over a cellular data network.
According to another aspect of the present invention, apparatus providing to a client, access to a plurality of PDNs, each PDN providing a dedicated PDN connection, includes an Access Point (AP) configured to communicate with (i) the client and (ii) the plurality of PDNs. The AP may be configured to provide the client a plurality of virtual MAC addresses, and to assign each of the virtual MAC addresses to a dedicated PDN connection, where each dedicated PDN connection is associated with one of the PDNs. The AP is further configured to provide one of the virtual MAC addresses via a 4 address MAC frame for the client to communicate with the associated data service. In alternative embodiments, the virtual MAC addresses may be (i) pre-loaded onto the UE (User Equipment, e.g., a cell phone) as pre-configured global MACs (e.g., for each data service), (ii) administered by the network (fixed or 3GPP (3rd Generation Partnership Project) AAA (Authentication, Authorization and Accounting protocol)) and sent to UE at authentication, and/or (iii) negotiated dynamically when the UE needs it (e.g. based on ARP (Address Resolution Protocol)). In alternatives (ii) and (iii), the virtual MAC addresses may be supplied to the UE through the AP.
According to a further aspect of the present invention, at least one computer-readable, non-transitory medium is provided, which contains program code which, when loaded into one or more processors of an AP, causes the one or more processors to provide to a client access to a plurality of PDNs, where each PDN provides a dedicated PDN connection. The program code causes the one or more processors to provide the client a plurality of virtual Media Access Control (MAC) addresses; where each of the virtual MAC addresses corresponds to a dedicated PDN connection, each dedicated PDN connection being associated with one of the PDNs; and deliver one of the virtual MAC addresses via a 4 address MAC frame for the client to use when the client is communicating with the associated data service.
Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
a is a diagram illustrating the general 802.11 frame format;
b is a diagram illustrating the 802.11 frame format in accordance with the preferred embodiments;
In order to lighten the following description, the following acronyms will be used herein:
In overview, the present invention proposes a solution for SaMOG (S2a-based Mobility over GTP) phase 2. For the first PDN connection, additional information elements are proposed to be added to EAP-AKA (Extendible Authentication Protocol-Authentication and Key Agreement). These information elements may carry e.g. handover indicator or APN. For additional PDN connections, traffic may be separated on a per-PDN connection basis using four MAC addresses in the 802.11 frame. A control protocol may be used to setup and teardown additional PDN connections.
Typically, the first PDN/NSWO (Non Seamless WLAN Offload) connection over WLAN uses the per-UE point-to-point link as defined in TS 23.402 clause 16. Standard IEEE 802.11 messaging is used over the Wi-Fi air link. As defined in IEEE 802.11-2007 section 7.2.2, a normal data frame uses three address fields. E.g. for an uplink frame (To DS=1 and From DS=0 in table 7-7 of IEEE 802.11-2007):
To achieve a per-UE-and-PDN point-to-point link for additional PDN/NSWO connections, all four address fields in the MAC data frame header are used in accordance with the present invention. Frames are sent/received with header fields To DS=1 and From DS=1 as defined in table 7-7 of IEEE 802.11-2007. E.g. for an uplink frame:
In the present invention, for each additional PDN connection, there is a virtual MAC address on the UE. This address is preferably unique within the scope of the UE. A virtual MAC address combined with the physical MAC address of the UE provides a globally unique identification for a PDN/NSWO connection. The TWAG and the UE can use this identification to correlate a packet to the correct PDN/NSWO connection.
Preferably, the 4-address MAC frame is used only over the Wi-Fi air link. Between the access point and TWAG, standard (wired) Ethernet frames are used. For an additional PDN connection, the UE virtual MAC address may be used between the access point and TWAG. The solution may be: (1) In the downlink, the AP preferably is able to know which physical MAC belongs to a virtual MAC. This may be a new AP requirement. It may learn this from uplink packets, though. (2) If we the physical MAC is not used between AP and TWAG, but only use the virtual MAC, then the virtual MAC should be unique within the scope of a TWAG. So, some kind of MAC negotiation mechanism can be used. This could be done with the control protocol in the next section. Alternatively, some other mechanism e.g. VLANs between AP and TWAG may be used.
WLCP (WLAN Control Protocol) is a new protocol (related to SaMOG). The details are to be defined in Wi-Fi Alliance or 3GPP. WLCP could use the 4-address field as well; e.g. a dedicated virtual MAC is used to denote WLCP packets. The WLCP packets may be defined by Wi-Fi Alliance or stage 3 in 3GPP. A WLCP packet may e.g. indicate “attach” including APN and handover indicator.
a, is a diagram which illustrates the general format of the 802.11 MAC frame format. The MAC frame format comprises a set of fields that occur in a fixed order in all frames. There are three address fields in the MAC frame format, four when the ad hoc or the Wireless Distribution System (WDS) mode is being used. These fields are used to indicate the basic service set identifier (BSSID), source address, destination address, transmitting station address, and receiving station address. The usage of the four address fields in each frame type is indicated by the abbreviations BSSID, Destination Address (DA), Source Address (SA), Receiver Address (RA), and Transmitter Address (TA).
b, is a diagram which illustrates the format of the 802.11 4-address MAC frame format according to the preferred embodiments. It is similar to
In
In
In the prior art, the UE typically can have only a single connection over the WLAN. The UE will not be able to concurrently access more than one PDN connection. As indicated earlier, when the WLAN is used to provide access to cellular data networks, it is desirable to provide access to multiple PDNs (packet data networks). As will be described further below, in the preferred embodiments, the IEEE 802.11 WDS (Wireless Distribution System) four-address frame format (280) is used to segregate multiple virtual services over a single WLAN interface. A four-address format currently may be used to create wireless repeater products, where one pair of addresses defines the ultimate source and destination address, and the other pair defines the next hop address. In the preferred embodiments on the other hand, the format is modified to enable multiple virtual services to be associated with multiple virtual addresses.
The Wi-Fi client (302) is provided access to multiple packet data networks (PDNs) via a cellular data network (304), where each PDN provides a dedicated PDN connection. More specifically, the Wi-Fi client (302) is provided with a number of virtual MAC addresses (312) and (314). Each virtual MAC address (312) and (314) is assigned to a dedicated PDN connection and each dedicated PDN connection is associated with one of the packet data networks. The Wi-Fi client's virtual MAC address for the requested data service is then delivered via a 4 address MAC frame (inner address) when the Wi-Fi client (302) is communicating with the associated data service over the cellular data network (304).
For an upstream frame (device to network), the receiver address is the wireless access point (310) address MAC BSSAD1 (307; outer address), and the destination address is the wireless access gateway address, while the transmitter address is the device (302) physical address (316) and the source address is the device (302) virtual address (312; inner address) and/or (314; inner address). For a downstream frame (network to device), the transmitter address is the access point (310) address and the source address is the wireless access gateway, while the receiver address is the device (302) physical address (316) and the destination address is the device (302) virtual address (312) and/or (314).
For single APN connections, only the transmitter address and the receiver address will be used on the upstream and downstream respectively. The need to use multiple PDN connections is indicated when the device initially connects to the network, or when an additional APN is needed, by using, e.g. extensions to EAP (Extensible Authentication Protocol) or DHCP (Dynamic Host Control Protocol). In this case the source and destination address fields will be used instead of transmitter and receiver.
For a first PDN connection, the normal Wi-Fi MAC address format is used. No change is necessary compared to unmodified UE. The 4-MAC address MAC format is then used between UE and AP for additional PDN connections. The 4-MAC frame in the upstream, i.e. between UE and AP will comprise:
On the downstream side, that is between the AP and UE, the 4-MAC frame format will comprise:
Now, between the AP and the TWAG, normal addressing is used; e.g. using UE MAC@2 for the 2nd PDN connection. The virtual MAC addresses may assigned to the UE by:
For authentication (EAP and 802.1X) and for the first PDN connection, the UE uses its first MAC address and normal Wi-Fi MAC frame for addressing. This way, an easier UE implementation can be achieved when only a single PDN connection is used.
For an additional PDN connection, the UE uses another virtual MAC address. All signaling over Wi-Fi is done using the 4-address MAC frame. For PDN connections, DHCP extensions may be used (when DCHP is the control plane protocol) to indicate handover and a non-default APN. Downlink frames are always sent L2 (Layer 2) unicast (including e.g. RA and IP multicast). The 4-address MAC frames use the same encryption over Wi-Fi as the normal MAC frames.
This procedure is related to the case when the UE has an established a PDN/NSWO connection over WLAN and wishes to establish one or more additional PDN/NSWO connections over such access. This procedure is also used to request for connectivity to an additional PDN/NSWO connection over WLAN when the UE is simultaneously connected to such access and a 3GPP access, and the UE already has active PDN/NSWO connections over both the accesses. The UE establishes a separate point-to-point link to the TWAG for each additional PDN/NSWO connection.
There can be more than one PDN connection per APN when GTP is used between the TWAN and the PDN GW. During the establishment of a new PDN connection, the TWAN allocates and sends a default S2a bearer ID to the PDN GW. The default S2a bearer ID is unique in the scope of the UE within a TWAG, i.e. the IMSI (International Mobile Subscriber Identity) and the default S2a bearer ID together identify a PDN connection within a TWAG. In order to be able to identify a specific established PDN connection, both the TWAG and the PDN GW preferably store the default S2a bearer ID. The establishment of an additional PDN/NSWO connection should not impact the first PDN/NSWO connection. As a separate point-to-point link is used for each additional PDN/NSWO connection, traffic separation can be achieved between all PDN/NSWO connections including the first.
For connectivity to multiple PDNs the following preferably applies:
The steps in
The procedure outlined in
If dynamic policy provisioning is not deployed, the optional steps of interaction between the PDN GW and PCRF preferably do not occur. Instead, the PDN GW may employ static configured policies.
The present invention can be realized in hardware, or a combination of hardware and software. Any kind of computing system, or other apparatus adapted for carrying out the methods described herein, is suited to perform the functions described herein. A typical combination of hardware and software could be a specialized computer system, e.g., a router, having one or more processing elements and a computer program stored on a storage medium that, when loaded and executed, controls the computer system such that it carries out the methods described herein. The present invention can also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which, when loaded in a computing system is able to carry out these methods. Storage medium refers to any volatile or non-volatile storage device.
Computer program or application in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following a) conversion to another language, code or notation; b) reproduction in a different material form. Computer readable medium means any non-transitory medium capable of storing program code which, when loaded into one or more processors, causes functions to be performed as described herein.
Thus, one embodiment is a computer readable medium containing computer readable instruction that, when executed by a processor, cause the processor to perform functions for maintaining clock synchronization between a first and a second radio.
All documents, specifications, clauses, etc. discussed herein are hereby incorporated into this disclosure by reference.
In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. A variety of modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the invention, which is limited only by the following claims.
This application claims priority to U.S. Provisional Patent Appln. No. 61/677,079, filed Jul. 30, 2012, the contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61677079 | Jul 2012 | US |
