KR20050024327A - Applying session services based on packet flows - Google Patents

Abstract

In a networked computer environment, session services are used to apply specific processing to data exchange between processes. In a wireless communication network, a single wireless link is typically shared among multiple users over a wireless channel, which is allocated on demand and switched between users. In order to initiate and employ a session service for the target packet containing the flow, the packet sent over the radio link is properly signaled and tagged. A method of identifying and applying a session service to a wireless link includes employing a flow identifier and a filter to identify a packet flow corresponding to a message received over the wireless link. The packet flow corresponds to a session and is mapped to at least one session service. The mapped session service is then applied to the received message. The session service can thus be applied transparently to the packet flow over the wireless link independently of other packet flows that may be transmitted over the wireless link.

Description

System and method to apply session service according to packet flow {APPLYING SESSION SERVICES BASED ON PACKET FLOWS}

In networked computer environments, session services are often used to apply certain processing to data exchange between processes. Such exchanges, or sessions, comprise a series of packets called packet flows, which packets can usually benefit collectively by sharing a common context and applying one or more session services. Packet flows are typically employed between processes that communicate over a network, often in a client / server configuration. Session services include protocol optimizations such as proxy services and header compression, or conversion of different protocol types, which can be transparent to end users.

Often, a single physical connection, such as a dialup modem line, carries multiple packets corresponding to multiple packet flows. However, session services typically apply to physical connections as a whole. As such, the particular session service applies to all packets sent over the physical connection. Application of session services does not distinguish between different packet flows delivered over a connection. Individual flows, and thus the associated processing, may incur processing overhead associated with a particular session service regardless of whether the session processing is required or desired for the corresponding packet flow.

In a wireless communication network, a wireless link is typically shared among multiple users over a wireless channel, which is allocated by the scheduler on demand and switched between users. In order to initiate and employ a session service for the target packet containing the packet flow, the packet sent over the radio link is properly signaled and tagged. Accordingly, it is desirable to provide a mechanism for signaling the initiation of a particular session service by a sender and a receiver over a wireless link to tag the affected packet to indicate the session service applied to each packet.

The above and other objects, features, and advantages of the present invention will become apparent from the more detailed description of the preferred embodiments of the present invention, which is illustrated in the accompanying drawings in which like reference numerals represent the same parts in different drawings.

1 is a diagram of a wireless communication system using a wireless communication link suitable for use with the present invention.

2 is a diagram illustrating wireless packet flow over a wireless link between a subscriber access unit and a base station processor.

3 is a diagram illustrating a mapping of a packet flow and a session service in a flow mapper.

4 is a flowchart for mapping a packet flow to a session service.

5A and 5B show an example of a process of instantiating a new packet flow.

6 is a diagram illustrating the downloading of a session service identifier from a common global repository.

In a wireless communication system, a method of identifying and applying a session service to a wireless link includes establishing a connection that includes a wireless link and receiving a transmission message over the connection. Packet flows are identified or established over the wireless link corresponding to the received messages using flow identifiers and transmission profile filters. The packet flow corresponds to a session and is mapped to at least one session service. The mapped session service is applied to the received message. In this way, the session service can be transparently applied to packet flows over the wireless link, independent of other packet flows that may be transmitted over the same wireless link.

A particular packet flow (flow) is associated with one or more session services that apply to packets (messages) sent through that flow. The flow is identified by the flow ID in the message itself, or by matching the message to a transmission profile that characterizes the flow. A characteristic of a flow establishes a packet stream context or common denominator of the packet that contains the flow. For example, a packet containing streaming audio information is typically large, while an http packet containing an acknowledgment (ACK) is relatively small. By identifying packet flows, complementary session services can be applied to each endpoint of the radio link, i.e., the header compression applied upon delivery over the radio link must be decompressed upon reception.

The traffic flow mapping message is used to initiate a flow and associate a session service with that flow. As such, both endpoints of the wireless link, typically the base station processor (base station) and the subscriber access unit (subscriber), can identify the flow and associated session service.

Session services may be identified with reference to tables of applicable session services. Once established, the session service applies to all packets of the flow. In another embodiment, the table may be stored in a common repository and thus downloaded in a standardized format from a remote source. By standardizing the session service table, the session service identifier can be widely spread and recognized.

EMBODIMENT OF THE INVENTION Hereinafter, the preferable Example of this invention is described.

In a wireless communication network, a wireless link provides a connection between a transmitting process and a receiving process. The wireless link is usually part of the overall connection between the transmitting process and the receiving process, which also includes the wired link at each side of the wireless link. The connection between the transmitting and receiving process includes a packet flow. Each packet flow represents a specific packet flow context that indicates the type of data passed between processes, such as an internet web page or streaming audio. As such, there may be multiple connections, ie multiple packet flows, between the transmitting process and the receiving process. In addition, each flow may include packets of different sessions between multiple peer processes. Since each flow has a specific packet flow context that represents a substantial characteristic of the type of data being delivered, it is desirable to apply a particular session service to each flow.

Session services are dual ended or peer-to-peer mechanisms that add functionality to existing user data sessions or provide new application capabilities. As such, the session service is an additional processing step applied to or performed on the packet. The session service may provide a separate application for protocol optimization such as header compression, protocol conversion such as TCP proxy service, or additional processing such as QOS (quality of service) processing and verification or encryption. Other session services may be applied in accordance with the present invention. In a particular embodiment, the TCP proxy service is currently pending US patent application Ser. No. 09 / 850,531, filed May 7, 2001, entitled "Daul Split Proxy Gateway for Improving Throughput Performance Over a Wireless Interface." Office document number 2479.2079-001), which is hereby incorporated by reference herein. In a wireless communication network, session services can be applied only to flows over the wireless link or to the entire connection, and can be passed (continuously) from the wired link over the wireless link.

1 illustrates a wireless communication system 10 employing a wireless communication link suitable for use with the present invention. Referring to FIG. 1, a plurality of subscriber access units 14a-14c are in wireless communication with a base station processor 16 (base station) via a radio link 22. Base station 16 also communicates with a data network, such as the Internet 18, via a wired link 20. Subscriber 14, via wired link 24, typically has customer premises equipment (CPE) 32, such as desktop PCs 32a, 32c, personal digital assistant (PDA) 36b, and cordless phone 32d. Provides wireless Internet access against. Note that the wireless functionality provided by subscriber access unit 14 may be in a standalone device or may be embedded in CPE 32 invoked by user 32 '. In other cases, the CPE 32 functions to communicate with the Internet 18 and operates to communicate with the remote node 26 via the base station 16 using the wired links 20, 24 and the wireless link 22. It is possible.

2 illustrates a wireless packet flow over a communication link between subscriber 14 and base station 16. Referring again to FIG. 1 in conjunction with FIG. 2, the radio link 22 between the subscriber 14 and the base station 16 also includes a packet flow 28. Packet flow 28 corresponds to one or more sessions over wireless link 22 and is part of an inter-process connection (session) that includes wired links 20, 24. Each session of the packet flow 28 corresponds to a process P1, P2, P3 at the subscriber 14. Complementary processes P1 ′, P 2 ′, P 3 ′ that are the sender or receiver reside at the remote end of the connection to one of the remote nodes 26. The flow mapper 30 for allocating and determining the packet flow corresponding to each message packet and for applying the respective session service resides at each endpoint of the radio link 22, at the subscriber 14 and at the base station 16. The function of the flow mapper will be described later.

It should be noted that the packet flow includes packets that are related by sharing a common denominator, such as the type of specific content. As noted above, the packet flow may thus include packets corresponding to one or more sessions between peer processes. The term "session" refers to a connection between two application processes, in which packets are related because of a common source and destination. The correspondence between sessions and packet flows typically depends on the protocols and processes that communicate so and includes parameters such as, for example, source addresses (sometimes called sets of five), destination addresses, source ports, destination ports, TCP connection protocols. Other packet flow / session mappings are known to those skilled in the art. As such, the packets delivered with the session will likely be one or more packet flows, as described below for applying the session service to the flow.

Therefore, a connection is established between the process and its complementary counterparts P1-P1 ', P2-P2', and P3-P3 ', respectively, to employ the wired 20, 24 and wireless 22 links. Message packets sent over the radio link 22 from one process to another process are assigned to the flow 28 by the flow mapper 30 on the sending side of the radio link 22 to flow mapper 30 on the receiving side. ') Is identified as belonging to the flow 28. The flow mapper 30 on the transmitting side applies the session service associated with the assigned (determined) flow, and the flow mapper 30 'on the receiving side also applies the session service associated with the determined flow.

As described above, the flow mapper 30, 30 'resides at both endpoints of the wireless link at subscriber 14 and base station 16, and is received from the wired link 20, 24 or from the wireless link 22. Identifies a packet that has been dropped. When a packet is received from the radio link 22, the packet already has a flow ID attached by the sender, ie by the subscriber 14 or the base station 16. The received flow ID is mapped to a list of known flow IDs to determine the flow to determine the session service associated with that flow.

If the packet is to be received from the wireline side, the corresponding flow must be determined. The flow profile table, described in more detail below, is used to match the characteristics of the message to a profile of a known packet flow using a filter. Elements such as sender IP address, destination IP address, TCP / IP port number, proxy ID, etc. may be used to match the packet to the flow through the filter. Once the flow is determined, in addition to applying the session service associated with the flow, a corresponding flow ID is attached to the packet.

Flows requiring specific processing provided by the session service are listed in the flow table accordingly. Packets that do not match a particular flow will not require specific processing and will not trigger the application of the session service. However, such a packet will nevertheless be delivered to the appropriate destination via packet routing independent of the application of the session service defined herein. Alternatively, a wildcard, or "catch all" entry (filter) may be added to the transmission profile table to include packets that do not trigger other entries.

The new flow can be instantiated in various ways. Certain applications may have a need for certain types of processing. The transport profile table entry corresponding to the session service table may be downloaded from an external source described below. Alternatively, if no match is found in the transmission profile table, creation of a new transmission profile entry is started. When a new flow is instantiated, the flow ID is determined from the new flow, and a traffic flow signaling message is employed to transmit new flow information to the receiving side flow mapper 30 'via the radio link 22.

3 is a diagram illustrating mapping of packet flows and session services in the flow mapper 30. Referring to FIG. 3, a table included in the flow mapper is shown. The flow mapper 30 includes a flow table 200, a transmission profile table 202, and a session service table 204. Flow table 200 identifies the packet flow by flow ID 206. Process field 208 may be employed to identify the local process (es) to which the field corresponds, but packet routing information, such as port number, is actually used for delivery. Also shown is a filter 210 that describes a packet flow. The transmission profile table 204 has transmission parameters 212 that describe each packet flow. The transmission parameter 212 describes a profile of each packet flow so that packets of the flow can be identified by the content, and includes a profile entry 216 for each packet flow. Exemplary transmission parameters include filter ID (FID) 214a, type 214b, source IP address 214c, destination IP address 214d, port ID 214e, TCP / TP transmission flag 214f, and flow. Direction 214g. The transmission parameters shown are exemplary and other embodiments may employ filters with other fields and / or information. Each element of the list 218 includes a session service index 220 in the session service table 204, which represents the applicable session service 222. The session service table 204 includes a session service entry 224 referenced by the session service index 220 described below. It should be noted that the session service index 220 of the session service list 218 is merely illustrative. Depending on the particular implementation, there are other mechanisms for associating the session service 222 with the profile service 216, such as direct inclusion of the session service 222, alternate pointers, or array references in the transport profile table 202. It may be implemented, and it will be apparent to those skilled in the art.

Therefore, the applicable session service 222, which is applied to a particular message packet, identifies the flow in flow mapper 30 via flow ID 206 or profile entry 216 and from that profile entry 216 applies. Can be determined by mapping to the corresponding session service entry 224 representing the session service 222 being established. As described above, the message packet mapped by the flow mapper 30 includes input and output message packets. Since the message packet received from the remote flow mapper 30 via the wireless link 22 (FIG. 2) has the flow ID 306 identified and attached to the message packet, lookup is possible in the flow table 200. Sending over the radio link 22 Message packets received over the crisis wired links 20, 24 are identified by matching with the profile entry 216 in the transmission profile table 202. The illustrated flow mapper 30 is shown from the perspective of the subscriber 14 for illustration, but may equally apply to any endpoint of the wireless link 22.

4 is a flowchart for mapping a packet flow to a session service. 4 and 2, as shown in step 100, an input packet is detected by the flow mapper 30. And as in step 102, a check is made to determine whether an input packet has been received from the wireless link 22 or from the wired links 20, 24. As mentioned above, the flow mapper 30 resides at both endpoints of the radio link 22. If a packet was received from the radio link 22, the flow ID was attached to the message before transmission. As shown in step 104, a lookup is performed in the flow table to match the packet to the packet flow. The flow ID is indexed in the session service table, as shown in step 120. The corresponding session service is determined as shown in step 122 and added to the message packet as shown in step 124. As shown in step 126, the packet is then sent over the wired link 24 to the corresponding process P1-P3.

If a packet was received over the wired links 20, 24, as will be described later, as shown in step 106, a comparison with the message packet characteristics in the transmission profile table is performed. As shown in step 108, a check is made to determine whether a match was in the transmission profile table. If there is no match, no session service is required for this packet, or a new flow entry is created via the exchange of traffic flow signaling messages as described above with respect to FIG. 3 and as shown in step 110. If there was a match, as shown in step 111, the flow ID is read from the transmission profile table. In either case, the newly created or found flow ID is appended to the message as indicated in step 112. The corresponding session service is indexed in the session service table, as shown in step 114, and applied to the message packet as shown in step 116. The message is then sent over the radio link 22 as a packet of the determined flow, as indicated in step 118 for the remote flow mapper 30 to receive.

Note that the flow ID determined before sending the radio transmission is determined as described above and appended to the message before the transmission. The flow ID may be attached in various ways known in the art. In a particular embodiment, the flow ID is encapsulated into an additional packet header that includes the flow ID. Other implementation protocols may be employed. Upon receipt of a radio transmission, the flow ID is stripped off to extract a packet in its format before radio transmission. In this way, the flow ID can be attached and removed from the message packet without interfering with other transmissions and other data in the packet.

5A and 5B show an example of a process of instantiating a new flow. Referring to Figures 5A and 5B and again to Figure 2, process P1 attempts to initiate a streaming video request. Process P1 creates a message packet 300 indicating the request and sends it to subscriber 14 via wired link 24. The flow mapper 30 receives the message packet 300 and attempts to find the corresponding profile entry 216 in the transmission profile table 202. Since there is no match, the flow mapper 30 determines whether to instantiate a new packet flow in the flow mapper 30. A new flow profile entry 226 is created for the streaming video request that indicates the remote destination of field 214d 'and assigned to filter FID 206. Because these requirements are relatively small, the header compression system is chosen. As indicated by system service index 218a, system service index 218 (SS3), system service 222 for header compression is initiated.

New flow profile entry 228 is also created for the received return streaming video message packet with filter FID 107 and has a source ID field 214c 'of its streaming video source matching 214d'. The system service for RT QOS (Quality of Service) processing is selected. Since there is not yet a system service 222 entry for RT QOS, a new entry 224 is created for the system service index 218b of SS4 and associated with the flow profile entry 228. The RT QOS system service is illustrative and may likewise employ other system services for applying flow specific processing or operations.

The flow mapper 30 creates a traffic flow signaling message 302 and sends it to the base station 16 representing the new flows F4 and F5. Following a traffic flow signaling message that establishes complementary system service processing in the remote flow mapper 30 ', the streaming video request message 300 is framed for transmission 304 over the wireless link. After processing via the remote destination 214d ', the streaming video packet 306 is received by the base station 16. The base station with consistent traffic flow signaling matches the message source to flow profile entry 228. The flow mapper 30 'attaches the flow ID F5 to the message 308 and sends it to the subscriber 14 via the wireless link 22. The flow mapper 30 at the subscriber 14 reads the flow ID F5, finds the corresponding flow ID 206 in the flow table 200, and maps it to the system service index SS5 for RT QOS processing. do.

Another streaming video request 310 is sent from process P1 and a corresponding match is found for FID 106 in the transmission profile table. As such, system service index 218a is found to indicate header compression and added to the request, and sent as message packet 312 via flow F4. System service flow mapping continued in this way until the flow was no longer needed, and the corresponding entry was updated with another sequence of traffic flow signaling messages.

In another embodiment shown in FIG. 6, the system service index 220 is standardized in the system service table 204 stored in the common repository 230. This common repository is accessed via the Internet 18 and is employed to periodically download the current version of the system service table 204 and the version of the system service itself. The common repository may be a Wireless Internet Facility (WIF), an LDAP directory, or other web service accessible by the subscriber 14 and the base station 16. The plurality of base stations 16a-16n can access and download the system service table 204 from the common repository 230. Each of the base stations 16a-16n sends the downloaded system service table 204 and associated files to each of the subscribers 14a-14n with which the base station is communicating. In this way, a standardized index for each applicable system service is maintained through the wireless communication system 100.

System services can vary in complexity and depth of implementation. As such, details of executable files and other implementations may be subject to revisions and changes for the same session service. Periodic downloads from the common repository may be done to upgrade and / or add system services. In addition, additional flow profile entries (filters) may be added to correspond to or identify new session services or new needs for session services. In this case too, the profile table can be downloaded from the common repository. For large service providers, multiple flow mappers 30, 30 'can be implemented at multiple sites. As such, periodic downloading of the current state of the system service provides timely consistency between the multiple flow mappers 30, 30 'employing the system service.

A method of applying the system services described herein is to associate input packets with packet flows. Matching a message packet to a flow profile does not require exactly matching every packet in the flow to avoid flow interruption. Other mechanisms also ensure delivery of message packets to the target recipient. The application of the session service is to improve the throughput by applying an operation that reduces the overhead and increases the routing speed of the packet. If, for example, a packet between two processes that must trigger a profile for header compression does not conform to the profile, the message packet is still delivered, although there will be no benefit of header compression. However, if the session service is applied to the transmitting side of the radio link, a flow ID is appended and a complementary session service such as header decompression is applied. As such, all packets between the two processes need not necessarily match a particular flow profile transmitting over the wireless link, but packets that are matched and thus processed according to system services at the transmitting side of the wireless link are complementary at the receiving side of the wireless link. Received Therefore, the session service described herein applies consistently at both endpoints of the radio link. In addition, such services can be performed on one side and performed at one endpoint along the radio link, or on both sides, complementarily applied at both endpoints of the radio link.

Those skilled in the art will appreciate that systems and methods of applying the system services described herein include a) permanently stored information on non-recordable storage media, such as ROM devices, b) floppy disks, magnetic tapes, CDs, RAM devices, and other magnetic and optical devices. Information variably stored on a recordable storage medium, such as a medium, or c) via a communication medium to a computer via a communication medium using baseband signaling or broadband signaling technology in an electronic network such as the Internet or a telephone modem line. The information may be delivered to the wireless device in a number of formats, including but not limited to the information conveyed. The operation and method may be implemented in software executable by a processor or as an instruction set loaded on a carrier. Alternatively, the operation and method may be implemented in whole or in part using a hardware component such as an application specific integrated circuit (ASIC), a state machine, a controller, or other hardware component or device, or a combination of hardware, software, and firmware components. Can be.

Although the present invention has been specifically disclosed and described with reference to the preferred embodiments, those skilled in the art will understand that various changes may be made in form and detail without departing from the scope of the invention as defined by the appended claims. .

Claims (16)

A method of identifying and applying a session service to a wireless link, Establishing a connection that includes the wireless link; Receiving a transmission message via the connection; Identifying a packet flow corresponding to a message received over the wireless link; Mapping the identified packet flows to at least one session service; Applying a mapped session service to the received message. The method of claim 1, wherein the wireless link further comprises a plurality of packet flows, each of which corresponds solely to at least one session service. The method of claim 1, wherein identifying the packet flow further comprises comparing the message with a transmission profile. The method of claim 1, Establishing a flow ID representing the packet flow; Attaching the flow ID to a message. 5. The method of claim 4, wherein establishing the flow ID further comprises a traffic flow mapping message suitable for providing traffic flow mapping signaling over a wireless link. The method of claim 1, wherein identifying the packet flow further comprises examining a flow ID representing the packet flow. 2. The method of claim 1 wherein each of the packet flows corresponds to a message stream between a transmitting process and a receiving process. 8. The method of claim 7, wherein the message stream corresponds to a common context. 2. The method of claim 1, further comprising generating a new packet flow if an existing packet flow corresponding to the received message is not identified. 2. The method of claim 1, further comprising sending a traffic flow mapping message indicating a flow ID. 11. The method of claim 10, further comprising sending a traffic flow mapping message between an access terminal and a base station over the wireless link. 2. The method of claim 1, wherein mapping the packet flow further comprises referring to a session service index that indicates a particular session service.  The method of claim 1, Referencing a list of session services from a common repository, Mapping the packet further comprises indexing a list from the common repository. The method of claim 1, wherein identifying the packet flow comprises: Checking a transmission parameter of the message; Comparing the transmission parameter with a transmission profile of a known packet flow; Based on the transmission parameter, further comprising a din system for matching one of the transmission profiles. 2. The method of claim 1, further comprising generating a new packet flow in response to a traffic flow mapping message. A system for identifying a session service and applying it to a wireless link, A connection comprising a wireless link having at least one packet flow corresponding to a flow context; A flow mapper operable to receive a message over the connection and identify a packet flow corresponding to the received message; A flow table embedded in the flow mapper operable to map the identified packet flows to at least one session service; A system service manager operable to apply the at least one session service to the received message.