United States Patent (19)
`Tam et al.
`
`USOO6115751A
`Patent Number:
`11
`(45) Date of Patent:
`
`6,115,751
`*Sep. 5, 2000
`
`54) TECHNIQUE FOR CAPTURING
`INFORMATION NEEDED TO IMPLEMENT
`TRANSMISSION PRIORITY ROUTING
`ASSETEREOUS NODES OFA
`75 Inventors: Ulrica Tam, Belmont; Steven H. Berl,
`Piedmont, both of Calif.
`
`73 Assignee: Cisco Technology, Inc., San Jose, Calif.
`*
`Notice:
`This patent issued on a continued pros-
`ecution application filed under 37 CFR
`1.53(d), and is subject to the twenty year
`tent t
`isions of 35 U.S.C.
`f Ry) rm proVISIons o
`
`21 Appl. No.: 08/833,837
`22 Filed:
`Apr. 10, 1997
`7
`51) Int. Cl.' ................................................... G06F 15/173
`52 U.S. Cl. ........................... 709/240; 709/239; 709/224
`58 Field of Search ............................ 395/2007, 200.54,
`395/200.62, 200.55, 200.56; 709/240, 224,
`232, 225, 226, 239
`
`56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,484.326 11/1984 Turner ..................................... 370/253
`4,775,973 10/1988 Tomberliln et al. ..
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`4,922,486
`5/1990 Lidinsky et al. .......................... 370/60
`5,210,750 5/1993 Nassehi et al. ...
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`5,218,676 6/1993 Ben-Ayed et al.
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`5,251,209 10/1993 Jurkevich et al.
`... 370/468
`5,261,060 11/1993 Free ..............
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`5,274,631 12/1993 Bhardwaj .................................. 370/60
`5,416,769 5/1995 Karol ........................................ 370/60
`5,440,744 8/1995 Jacobson et al
`... 395/650
`5,446,888 8/1995 Pyne ..................
`... 395/600
`5,473,608 12/1995 Gagne et al. .....
`... 370/85.13
`5,517,620 5/1996 Hashimoto et al.
`... 395/200.72
`5,546,549 8/1996 Barrett et al. ........................... 395/309
`5,561,669 10/1996 Lenney et al. ......................... 370/60.1
`
`5,634,006 5/1997 Baugher et al. ................... 395/200.06
`5,664,105 9/1997 Keisling et al.
`... 395/200.54
`5,719,942 2/1998 Aldred et al. ............................. 380/49
`5,737,526 4/1998 Periasamy et al. ................ 395/200.71
`5,748.925
`5/1998 Waclawsky et al. ................... 710/131
`5,787,237 7/1998 Reilly ...................................... 395/112
`5,848,233 12/1998 Radia et al. ....................... 395/187.01
`OTHER PUBLICATIONS
`Designing APPN Internetworks, http://www.cisco.com/
`univerca/cc/td/doc/cisintwk/idg4/nd2006.htm,
`Copyright
`9.
`s
`pyrig
`1989 to 1998, pp. 1 to 39.
`, pp
`Formats
`Architecture
`IBM Systems
`Network
`s
`GA27–3136-16, Copyright IBM Corp. 1977, 1996, pp. 1-1
`to B24.
`Systems Network Architecture IBM APPN Architecture
`Reference, SC30-3422-04, Copyright International Busi
`ness Machines Corporation, 1986-1996, pp. 1-1 to X43.
`Network Working Group Request for Comments: 1795;
`Internetwork Technology Institute; A. Bartky, Editor; Sync
`Research, Inc.; Apr., 1995; pp. 1-91.
`Nilausen, Jesper-APPN Networks; John Wiley & Sons,
`Ltd. 1994; APPN Basics, 2:11-83.
`Primary Examiner Zarni Maun
`y
`g
`Attorney, Agent, or Firm-Cesari & McKenna
`57
`ABSTRACT
`A technique efficiently captures information required to
`create a filter used by Switching nodes of a heterogeneous
`network to implement transmission priority routing of data
`traffic over a connection network between end nodes of the
`network. A bounded time interval, i.e., a time window, is
`established during which a first Switching node monitors the
`traffic over the network to capture portions of the required
`information contained in a defined data packet. Monitoring
`of data traffic during the time window is triggered by a
`predictable event, the occurrence of which is communicated
`to the first Switching node by a hybrid node of the network.
`In addition to providing this "triggering communication,
`the hybrid node also provides the first Switching node with
`the remaining portion of the required information.
`
`23 Claims, 7 Drawing Sheets
`
`902
`
`900
`
`OLUISSUESLOCATEREQUEST TO HYBRIDMODE
`
`S04
`
`HYBRONOISSUESSNIFFING FILTER TODLSWNCOE 1
`
`DLSwNCE EXAMNESDAA TRAFFICTOTECT
`BIND DURING TIME WINDOW
`
`DLSw NODE i CAPTURESMODENAME AND END NODE
`ADRESSES FROMBIND
`
`908
`
`
`
`908
`
`30
`
`COMPARE CAPTURED MODENAME WITHMODENAME OF FILTER
`
`914
`
`912
`
`TIME
`WNBOW
`EXPRED
`
`STOP
`MONITORING
`TRAFFIC
`
`Sonos Ex. 1025, p. 1
` Sonos v. Google
` IPR2021-00964
`
`

`

`U.S. Patent
`
`Sep. 5, 2000
`
`Sheet 1 of 7
`
`6,115,751
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`Sonos Ex. 1025, p. 2
` Sonos v. Google
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`U.S. Patent
`U.S. Patent
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`Sep. 5, 2000
`Sep. 5, 2000
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`Sheet 2 of 7
`Sheet 2 of 7
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`6,115,751
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`Sonosv. Google
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`Sonos Ex. 1025, p. 3
` Sonos v. Google
` IPR2021-00964
`
`

`

`U.S. Patent
`
`Sep. 5, 2000
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`Sheet 3 of 7
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`Sonos Ex. 1025, p. 4
` Sonos v. Google
` IPR2021-00964
`
`

`

`U.S. Patent
`U.S. Patent
`
`Sep. 5, 2000
`Sep. 5, 2000
`
`Sheet 4 of 7
`Sheet 4 of 7
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`6,115,751
`6,115,751
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`Sonos Ex. 1025, p. 5
`Sonosv. Google
`IPR2021-00964
`
`Sonos Ex. 1025, p. 5
` Sonos v. Google
` IPR2021-00964
`
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`U.S. Patent
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`Sep. 5, 2000
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`Sheet 5 of 7
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`6,115,751
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`Sonos Ex. 1025, p. 6
`Sonosv. Google
`IPR2021-00964
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`Sonos Ex. 1025, p. 6
` Sonos v. Google
` IPR2021-00964
`
`
`
`

`

`U.S. Patent
`
`Sep. 5, 2000
`
`Sheet 6 of 7
`
`6,115,751
`
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`
`Sonos Ex. 1025, p. 7
` Sonos v. Google
` IPR2021-00964
`
`

`

`U.S. Patent
`
`Sep. 5, 2000
`
`Sheet 7 of 7
`
`6,115,751
`
`
`
`
`
`
`
`
`
`
`
`
`
`902
`
`OLUISSUES LOCATE REGUEST TO HYERD NODE
`
`90
`4.
`
`HYBRD NODE ISSUES SNIFFING FILTER TO DLSW NODE 1
`
`DLSW NODE 1 EXAMINES DATA TRAFFICTO DETECT
`BIND DURING TIME WINDOW
`
`DLSW NODE 1 CAPTURES MODENAME AND END NODE
`ADDRESSES FROM BIND
`
`COMPARE CAPTURED MODENAME WITH MODENAME OF FILTER
`
`912
`
`TIME
`WINDOW
`EXPRED
`
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`
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`918
`
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`
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`MONITORING
`TRAFFIC
`
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`DLSW NODE 1
`OBTAINS FSID FROM OLU
`
`DLSW NODE 1 SENDS PACKET
`RECOGNIZING FILTER TO DLSW NODE 2
`
`
`
`CENDD
`
`FIG. 9
`
`Sonos Ex. 1025, p. 8
` Sonos v. Google
` IPR2021-00964
`
`

`

`6,115,751
`
`1
`TECHNIQUE FOR CAPTURING
`INFORMATION NEEDED TO IMPLEMENT
`TRANSMISSION PRIORITY ROUTING
`AMONG HETEROGENEOUS NODES OFA
`COMPUTER NETWORK
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`This invention is related to the following U.S. patent
`applications:
`U.S. patent application Ser. No. 08/839,435, titled TECH
`NIOUE FOR MAINTAINING PRIORITIZATION OF
`DATA TRANSFERRED AMONG HETEROGENEOUS
`NODES OF A COMPUTER NETWORK, now U.S. Pat.
`No. 5,991,302; and
`U.S. patent application Ser. No. 08/833,834, titled
`MECHANISM FOR CONVEYING DATA PRIORITIZA
`TION INFORMATION AMONG HETEROGENEOUS
`NODES OF A COMPUTER NETWORK, now U.S. Pat.
`No. 5,940,390, each of which was filed on even date
`herewith and assigned to the assignee of the present inven
`tion; and U.S. patent application Ser. No. 09/354,360, titled
`MECHANISM FOR CONVEYING DATA PRIORITIZA
`TION INFORMATION AMONG HETEROGENEOUS
`25
`NODES OF A COMPUTER NETWORK, filed on Jul 14,
`1999 and assigned to the assignee of the present invention.
`
`15
`
`FIELD OF THE INVENTION
`The invention relates to computer networks and, more
`particularly, to the efficient acquisition of predetermined
`information by nodes of a computer network.
`
`2
`nicate with each other by means of the predefined protocols.
`The lower layers of these architectures are generally stan
`dardized and are typically implemented in hardware and
`firmware, whereas the higher layers are generally imple
`mented in the form of Software running on the Stations
`attached to the network. Examples of Such communications
`architectures include the Systems Network Architecture
`(SNA) developed by International Business Machines Cor
`poration and the Internet communications architecture.
`The Internet architecture is represented by four layers
`which are termed, in ascending interfacing order, the net
`work interface, internetwork, transport and application lay
`ers. These layers are arranged to form a protocol Stack in
`each communicating Station of the network. FIG. 1 illus
`trates a Schematic block diagram of prior art Internet pro
`tocol stacks 125 and 175 used to transmit data between a
`Source station 110 and a destination station 150,
`respectively, of a network 100. As can be seen, the stacks
`125 and 175 are physically connected through a communi
`cations channel 180 at the network interface layers 120 and
`160. For ease of description, the protocol stack 125 will be
`described.
`In general, the lower layers of the communications Stack
`provide internetworking Services and the upper layers,
`which are the users of these Services, collectively provide
`common network application Services. The application layer
`112 provides services suitable for the different types of
`applications using the network, while the lower network
`interface layer 120 of the Internet architecture accepts
`industry Standards defining a flexible network architecture
`oriented to the implementation of LANs.
`Specifically, the network interface layer 120 comprises
`physical and data link Sublayers. The physical layer 126 is
`concerned with the actual transmission of Signals acroSS the
`communication channel and defines the types of cabling,
`plugs and connectors used in connection with the channel.
`The data link layer, on the other hand, is responsible for
`transmission of data from one Station to another and may be
`further divided into two sublayers: Logical Link Control
`(LLC 122) and Media Access Control (MAC 124).
`The MAC sublayer 124 is primarily concerned with
`controlling access to the transmission medium in an orderly
`manner and, to that end, defines procedures by which the
`Stations must abide in order to share the medium. In order for
`multiple Stations to share the same medium and Still
`uniquely identify each other, the MAC sublayer defines a
`hardware or data link address called a MAC address. This
`MAC address is unique for each Station interfacing to a
`LAN. The LLC Sublayer 122 manages communications
`between devices over a Single link of the network and
`provides for environments that need connectionless or
`connection-oriented Services at the data link layer.
`Connection-oriented Services at the data link layer gen
`erally involve three distinct phases: connection
`establishment, data transfer and connection termination.
`During connection establishment, a Single path is estab
`lished between the Source and destination Stations. This
`connection, e.g., an IEEE 802.2 LLC Type 2 or “Data Link
`Control” (DLC) connection as referred hereinafter, is based
`on the use of service access points (SAPs); a SAP is
`generally the address of a port or access point to a higher
`level layer of a Station. Once the connection has been
`established, data is transferred Sequentially over the path
`and, when the DLC connection is no longer needed, the path
`is terminated. The details of Such connection establishment
`and termination are well-known and, thus, will not be
`described herein.
`
`BACKGROUND OF THE INVENTION
`Data communication in a computer network involves the
`eXchange of data between two or more entities intercon
`nected by communication links and Subnetworks. These
`entities are typically Software programs executing on hard
`ware computer platforms, Such as end Stations and interme
`diate Stations. Examples of an intermediate Station may be a
`router or Switch which interconnects the communication
`links and Subnetworks to enable transmission of data
`between the end Stations. A local area network (LAN) is an
`example of a subnetwork that provides relatively short
`distance communication among the interconnected Stations,
`in contrast, a wide area network (WAN) enables long
`distance communication over linkS provided by public or
`private telecommunications facilities.
`Communication Software executing on the end Stations
`correlate and manage data communication with other end
`Stations. The Stations typically communicate by exchanging
`discrete packets or frames of data according to predefined
`protocols. In this context, a protocol consists of a Set of rules
`defining how the Stations interact with each other. In
`addition, network routing Software executing on the routers
`allow expansion of communication to other end Stations.
`Collectively, these hardware and Software components com
`prise a communications network and their interconnections
`are defined by an underlying architecture.
`Modern communications network architectures are typi
`cally organized as a Series of hardware and Software levels
`or “layers” within each station. These layers interact to
`format data for transfer between, e.g., a Source Station and a
`destination Station communicating over the network.
`Specifically, predetermined Services are performed on the
`data as it passes through each layer and the layers commu
`
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`15
`
`3
`The transport layer 114 and the internetwork layer 116 are
`Substantially involved in providing predefined Sets of Ser
`vices to aid in connecting the Source Station to the destina
`tion Station when establishing application-to-application
`communication Sessions. The primary network layer proto
`col of the Internet architecture is the Internet protocol (IP)
`contained within the internetwork layer 116. IP is primarily
`a connectionless network protocol that provides internet
`work routing, fragmentation and reassembly of datagrams
`and that relies on transport protocols for end-to-end reliabil
`ity. An example of Such a transport protocol is the Trans
`mission Control Protocol (TCP) contained within the trans
`port layer 114. Notably, TCP provides connection-oriented
`Services to the upper layer protocols of the Internet archi
`tecture. The term TCP/IP is commonly used to refer to the
`Internet architecture.
`Data transmission over the network 100 therefore consists
`of generating data in, e.g., Sending proceSS 104 executing on
`the Source Station 110, passing that data to the application
`layer 112 and down through the layers of the protocol Stack
`125, where the data are Sequentially formatted as a frame for
`delivery onto the channel 180 as bits. Those frame bits are
`then transmitted over an established connection of channel
`180 to the protocol stack 175 of the destination station 150
`where they are passed up that Stack to a receiving proceSS
`174. Data flow is schematically illustrated by Solid arrows.
`Although actual data transmission occurs vertically
`through the Stacks, each layer is programmed as though Such
`transmission were horizontal. That is, each layer in the
`Source Station 110 is programmed to transmit data to its
`corresponding layer in the destination Station 150, as Sche
`matically shown by dotted arrows. To achieve this effect,
`each layer of the protocol stack 125 in the source station 110
`typically adds information (in the form of a header field) to
`the data frame generated by the Sending proceSS as the frame
`descends the stack. At the destination station 150, the
`various encapsulated headers are Stripped off one-by-one as
`the frame propagates up the layers of the stack 175 until it
`arrives at the receiving process.
`SNA is a mainframe-oriented network architecture that
`also uses a layered approach. The Services included within
`this architecture are generally Similar to those defined in the
`Internet communications architecture. In a SNA network,
`though, applications executing on end Stations typically
`access the network through logical units (LU) of the sta
`tions, accordingly, in a typical SNA network, a communi
`cation Session connects two LUS in a LU-LU Session.
`Activation and deactivation of Such a Session is addressed by
`Advanced Peer to Peer Networking (APPN) functions.
`The APPN functions generally include session establish
`ment and session routing within an APPN network. FIG. 2
`is a schematic block diagram of a prior art APPN network
`200 comprising end stations 202, 212 and 222, 232, which
`are typically configured as end nodes (EN), coupled to token
`ring (TR) subnetworks 204 and 214, respectively. Interme
`diate stations 206 and 216, configured as APPN network
`nodes (NN), are interconnected by a WAN 210 that extends
`the SNA/APPN architecture throughout the network. An
`APPN network node is a full-functioning APPN router node
`having all APPN base service capabilities, including direc
`tory services functions. An APPN end node, on the other
`hand, is capable of performing only a Subset of the functions
`provided by an APPN network node.
`During session establishment, a SNA device (such as EN
`65
`202) requests an optimum route for a Session between two
`LUs; this route is calculated and conveyed to EN 202 by an
`
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`6,115,751
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`4
`intermediate Station functioning as a network node Server
`(e.g., Station 206) via a LOCATE message exchange through
`the network 200. Thereafter, a “set-up’ or BIND message is
`forwarded over the route to initiate the session. The BIND
`includes information pertaining to the partner LU requested
`for the Session. Intermediate Session routing occurs when
`APPN network nodes are present in a session between the
`two devices and forward packets of an LU-LU session over
`the calculated route between those devices. However, when
`the session is between devices (such as EN 202, 212)
`coupled to a shared medium (such as TR 204), network
`nodes (such as APPN NN 206, 216) are not present in the
`Session and Session routing is not necessary.
`In Such a connection network arrangement, a connection
`to a virtual routing node is defined in each of the nodes
`coupled to this portion of the network. The BIND message
`is again used to convey the calculated route to those nodes
`coupled to the network. Thereafter, packets are forwarded
`over the established LU-LU session along the calculated
`route directly between the two APPN end nodes. APPN
`nodes and connection networks are well-known and are, for
`example, described in detail in Systems Network Architec
`ture Advanced Peer to Peer Networking Architecture Ref
`erence IBM Doc SC30-3422 and APPN Networks by Jesper
`Nilausen, printed by John Wiley and Sons, 1994, at pgs
`11-83.
`FIG. 3 is a schematic block diagram of the software
`architecture of a prior art APPN node 300. As noted,
`application 302 executing on an APPN end node, such as EN
`202 of network 200, communicates with another end node,
`such as EN 212, through a LU-LU session; LU 304 within
`each end node functions as both a logical port for the
`application to the network and as an end point of the
`communication Session. The Session generally passes
`through a path control module 312 and a data link control
`(DLC) module 316 of the node, the latter of which connects
`to various network transmission media.
`An intermediate session routing (ISR) module 305 main
`tains a portion of the Session in each “direction' with respect
`to an adjacent node. In response to receiving the BIND
`message during Session establishment, path control 312 and
`ISR 305 are invoked to allocate resources for the session. In
`particular, each node allocates a local form Session identifier
`(LFSID) for each direction of the session; the LFSID is
`thereafter appended to the packets by the node in a trans
`mission header field of a SNA header to identify the session
`context. Collectively, each of these individually-established
`“local Sessions form the logical communication Session
`between the LUs 304 of the end nodes 202, 212.
`When initiating a Session, the application 302 Specifies a
`mode name that is carried within the BIND message and
`distributed to all APPN nodes; the LU304 in each node uses
`the mode name to indicate the Set of required characteristics
`for the Session being established. Specifically, the mode
`name is used by control point (CP) module 308 of each
`APPN node 300 to find a corresponding class of service
`(COS) as defined in a COS table 310. The CP coordinates
`performance of all APPN functions within the node, includ
`ing management of the COS table 310. The COS definition
`in table 310 includes a priority level specified by transmis
`sion priority (TP) information 320 for the packets trans
`ferred over the session; as a result, each APPN node is
`apprised of the priority associated with the packets of a
`LU-LU session. The SNA architecture specifies four (4) TP
`levels: network priority, high priority, medium priority and
`low priority. Path control 312 maintains a plurality of queues
`314, one for each TP level, for transmitting packets onto the
`transmission media via DLC 316.
`
`Sonos Ex. 1025, p. 10
` Sonos v. Google
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`S
`Data link switching (DLSw) is a forwarding mechanism
`for the SNA architecture over an IP backbone network, Such
`as the Internet. ADLSW network is formed when two DLSw
`Switches interconnect the end nodes of the APPN network
`by way of the IP network; the DLSw Switches preferably
`communicate using a Switch-to-Switch protocol (SSP) that
`provides packet "bridging operations at the LLC (i.e.,
`DLC) protocol layer. FIG. 4 is a schematic block diagram of
`a prior art DLSw network 400 comprising DLSw Switches
`406, 416 interconnecting ENs 402, 412 via IP network 410.
`The DLSw forwarding mechanism is also well-known and
`described in detail in Request for Comment (RFC) 1795 by
`Wells & Bartky, 1995 at pgs 1-91.
`According to the DLSw technique, a lower-layer DLC
`connection is established between each EN and DLSw
`15
`Switch; however, these connections terminate at the Switches
`406, 416. In order to provide a complete end-to-end con
`nection between the end nodes, the DLC connections are
`“disposed over a reliable, higher-layer transport
`mechanism, Such as TCP sessions. DLSw Switches can
`establish multiple, parallel TCP sessions using well-known
`port numbers. All packets associated with a particular DLC
`connection typically follow a single, designated TCP Ses
`Sion. Accordingly, SNA data frames originating at a Sending
`EN 402 are transmitted over a particular DLC connection
`along TR 404 to DLSw Switch 406, where they are encap
`Sulated within a designated TCP Session as packets and
`transported over IP network 410. The packets are received
`by DLSw Switch 416, decapsulated to their original frames
`and transmitted over a corresponding DLC connection of TR
`414 to EN 412 in the order received by switch 406 from EN
`402.
`Typically, all packets transmitted by DLSw Switch 406
`over a DLC connection/TCP session flow at the same
`priority level from a single output queue 405 of the Switch
`and arrive at an output queue 415 of DLSw Switch 416 in the
`same order in which they are transmitted. When the Switches
`are configured as bridges to forward packets over a TCP
`Session through the IP network, prioritization is Straightfor
`ward. However, it may be desired to integrate the functions
`of an APPN network node within a DLSw Switch by
`overlaying an APPN layer onto a DLSw layer of the Switch;
`the resulting hybrid node may prioritize the packets at the
`APPN layer in an order governed by the TP information
`levels.
`A problem that arises when deploying a hybrid node in
`such a heterogeneous network is that the TP priority infor
`mation is lost when passing the packets between the APPN
`and DLSw layers, primarily because the TP information is
`not encapsulated within the packets. That is, the APPN layer
`has knowledge of the TP levels associated with the packets
`of a LU-LU Session as a result of its involvement during
`Session establishment; yet that information is not encapsu
`lated within the associated packets and, thus, is not typically
`conveyed beyond the APPN layer. An example of a tagging
`mechanism Suitable for use with the present invention that
`conveys TP levels from the APPN layer to the DLSw layer
`is disclosed in copending and commonly-assigned U.S.
`patent application, titled Technique for Maintaining Priori
`tization of Data Transferred Among Heterogeneous Nodes of
`a Computer Network, filed herewith and incorporated by
`reference as though fully Set forth herein.
`AS described in that commonly-assigned application, the
`APPN protocol layer of the hybrid node assigns a TP level
`to each packet and passes that priority information to the
`DLSW layer of the node via an application programming
`interface extension. The TP level is converted to information
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`that is "tagged' to each packet and the DLSW layer allocates
`each tagged packet to a TCP Session based on the assigned
`TP level. The tagged information is then encapsulated within
`an IP header to enable intermediate routers to maintain the
`order and priority of the packet as it is transmitted outbound
`over the IP network to a receiving DLSw Switch.
`The tagged information within the IP header is not dis
`cernible to the receiving DLSw Switch and, thus, the Switch
`has no knowledge of the TP level associated with the
`outbound packet. When responding to the outbound packet,
`the DLSw Switch cannot select (on the basis of priority) the
`proper TCP Session over which to transmit a corresponding
`inbound packet; accordingly, the Switch arbitrarily chooses
`a Session. If the chosen TCP Session has a lower designated
`priority than the Session carrying the outbound packet,
`network throughput may be negatively impacted.
`A Solution to this problem is disclosed in copending and
`commonly-assigned U.S. patent application, titled Mecha
`nism for Conveying Data Prioritization Information Among
`Heterogeneous Nodes of a Computer Network, filed here
`with and incorporated by reference as though fully set forth
`herein. Here, a packet-recognizing filter is generated by the
`hybrid node and dynamically transmitted to the DLSw
`Switch Over a predefined communication channel of the
`network. The filter contains information, including a LFSID
`classifying the LU-LUSession context of the Specific packet,
`that enables the Switch to assign appropriate TP levels to the
`inbound packets.
`The hybrid node functions as an APPN router node in this
`latter commonly-assigned application and, as a result, it
`allocates the LFSID. However, since a connection network
`arrangement enables a LU-LU Session between end nodes
`without the need for Such a router node, the LFSID is
`assigned by the end node originating the LU-LU Session.
`Although the hybrid node is used to calculate the optimum
`route between the end nodes, it has no knowledge of the
`LFSID and thus cannot provide it to the DLSw Switch. The
`present invention is directed to Solving the problem of
`providing Such information to a Switching node of a hetero
`geneous network.
`SUMMARY OF THE INVENTION
`The invention comprises a technique for efficiently cap
`turing information required to create a filter used by Switch
`ing nodes of a heterogeneous network to implement trans
`mission priority (TP) routing of data traffic over a
`connection network between end nodes of the network. In
`accordance with the inventive technique, a bounded time
`interval, i.e., a time window, is established during which a
`first Switching node monitors the traffic over the network to
`capture portions of the required information contained in a
`defined data packet. Monitoring of data traffic during the
`time window is triggered by a predictable event, the occur
`rence of which is communicated to the first Switching node
`by a hybrid node of the network. In addition to providing this
`“triggering communication, the hybrid node also provides
`the first Switching node with the remaining portion of the
`required information.
`In the illustrative embodiment, the heterogeneous net
`work is preferably a data link Switching (DLSw) network
`and the Switching nodes are DLSw Switches, whereas the
`hybrid node is an advanced peer-to-peer networking (APPN)
`node with DLSw capabilities. The defined data packet is a
`BIND message used to convey an optimum route for a
`logical unit to logical unit (LU-LU) Session between appli
`cations executing on the end nodes of the DLSW network.
`
`Sonos Ex. 1025, p. 11
` Sonos v. Google
` IPR2021-00964
`
`

`

`25
`
`7
`Information needed to create the filter includes a local form
`session identifier (LFSID) and a TP level. The BIND mes
`Sage contains both a mode name that is used to reference the
`TP level and the address of the logical unit originating the
`BIND exchange. Because TP routing occurs over the con
`nection network, the address of the originating logical unit
`(OLU) is needed by the first DLSw node to acquire the
`LFSID. The predictable event is preferably a LOCATE data
`flow between the OLU and the hybrid node.
`Operationally, the OLU issues a LOCATE request to the
`hybrid node, requesting the latter node to locate a destination
`logical unit of an end node by invoking directory Services.
`If the data session path traverses the DLSw connection
`network environment, the hybrid node issues a “sniffing”
`filter to the first DLSw node prior to responding to the
`LOCATE request. Preferably, the Sniffing filter instructs the
`first DLSw node to monitor data traffic over the network for
`the BIND message and, to that end, contains addressing
`information relating to the orginating and destination end
`nodes, along with the TP level associated with a particular
`mode name.
`Upon receiving the filter, the first DLSw node commences
`examination of the data traffic and, in response to recogniz
`ing the BIND message, captures the contents of its mode
`name and its LFSID (contained in the SNA transmission
`header). The node then compares these captured contents
`with the contents of the Sniffing filter (e.g., the addressing
`information and mode name) and if they match, the LFSID
`is recorded. All Subsequent inbound packets having a LFSID
`that matches the captured LFSID are transmitted at the
`specified TP level.
`An advantage of the inventive technique is a reduction in
`overhead of the Switching node, which overhead would
`otherwise be consumed by constantly monitoring network
`traffic for the defined data packet. To that end, the time
`window should be relatively short to ensure that no exces
`Sive overhead is generated.
`BRIEF DESCRIPTION OF THE DRAWINGS
`The above and further advantages of the invention may be
`better understood by referring to the following description in
`conjunction with the accompanying drawings in which like
`reference numbers indicate identical or functionally similar
`elements:
`45
`FIG. 1 is a Schematic block diagram of prior art commu
`nications architecture protocol Stacks, Such as the Internet
`protocol Stack, used to transmit data between Stations of a
`computer network;
`FIG. 2 is a Schematic block diagram of a prior art
`Advanced Peer to Peer Networking (APPN) network includ
`ing APPN nodes;
`FIG. 3 is a schematic block diagram of the software
`architecture a prior art APP