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`Application Number:
`
`90010416
`
`International
`
`Number:
`
`Title of Invention:
`
`Point-to—Point Internet Protocol
`
`First Named Inventor/Applicant Name:
`
`6108704
`
`Filer:
`
`Michael R Casey
`
`Attorney Docket Number:
`
`2655-0188
`
`Payment information:
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`This Acknowledgement Receipt evidences receipt on the noted date by the USPTO ofthe indicated documents,
`characterized by the applicant, and including page counts, where applicable. It serves as evidence of receipt similar to a
`Post Ca rd, as described in MPEP 503.
`
`New Applications Under 35 U.S.C. 111
`lfa new application is being filed and the application includes the necessary components for a filing date (see 37 CFR
`1.53(b)-(d) and MPEP 506), a Filing Receipt (37 CFR 1.54) will be issued in due course and the date shown on this
`Acknowledgement Receipt will establish the filing date of the application.
`
`National Stage of an International Application under 35 U.S.C. 371
`lfa timely submission to enter the national stage ofan international application is compliant with the conditions of35
`U.S.C. 371 and other applicable requirements a Form PCT/DO/E0/903 indicating acceptance ofthe application as a
`national stage submission under 35 U.S.C. 371 will be issued in addition to the Filing Receipt, in due course.
`
`New International Application Filed with the USPTO as a Receiving Office
`lfa new international application is being filed and the international application includes the necessary components for
`an international filing date(see PCT Article 11 and MPEP 1 B10), a Notification ofthe International Application Number
`and ofthe International Filing Date(Form PCT/R0/105)wi|| be issued in due course, subject to prescriptions concerning
`national security, and the date shown on this Acknowledgement Receipt will establish the international filing date of
`the application.
`
`Page 1509 of 1928
`
`

`
`wow» Er_§ oaaamzmou
`,
`PCT
`INTERNATIONAL APPLICATION PUBLISHED UNDBI '1'HE-PA'I'EN"l' COOPEIATION TREATY (PC?)
`
`
`
`(51) mun-don-I Pm: chsstfiuuon 5 «
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`an [ma-national Puhflcndon um."
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`29 sepmha 1994 (29.o99¢)
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`.‘
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`(21) hm-nnflonnl Appfludon Nnmba-:
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`PCl'l‘IJS94l00(X)4
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`(22) Inunntional Filing Dan:
`
`3 January 1994 (0101.94)
`
`(31) Ddgnatu! Shins: AU. CA. JP. KR. Emopcxn pmzm (AT,
`BE.Cl-l.DB,DK.E§.FR.GB,GR.£B..l'l'.LU.MC.NI..
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`19 March 1993 09.0393)
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`US
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`With ituenmdavnol march report.
`
`no Appflcum acou conromnou [us/us]: 5-too Bayfmnt
`mm. 9.0. Box 58145, Santa Chm. ca 950523145 (Us).
`
`(72) Inventors: N1LA.K.AN'I‘AN. Chanda-a.u-Jdm-an; JT74 Wooaibuk
`Com. San I054; CA9Sll7 (US). LDI. Ly‘, 34852 Win:h(:-
`m Plnca. Fremont. CA 94555 (US). ARUNKUMML N»
`garnj; 3041 Cedar Ridge Court, San Jose. CA 95148 (US).
`SEAMAN. Nfldmll. Iohn; 350 Elan Village Lane, 0206,
`San 106:. CA 95134 (US).
`
`(70 Agent: HAYNES. Mark. A.; I-hynufi. Davis. Suite |70.2l80
`SaudH.i]JRoad.M=n]oPsrk,CA94(n5-6935 (US).
`
`(54) T|'I.|e: SYSTEM FOR REVERSE ADDRfl RESOLUTION FOR REMOTE NEl'WOR.K DEVICE
`
`.5
`
`(57) Abstract
`
`Arcvaumitmurusoluionproanunlfnnuinaaunnmaiandnu netwa-kwhinhanowuesoiznionlogictopmvtdcahiyxczlevcl
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`Page 1510 of 1928
`
`

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`Page1511of1928
`
`

`
`W0 940.2081
`
`PCTIUS94I00O04
`
`SYSTEM FOR REVERSE ADDRESS RESOLUTION
`
`FOR REMOTE NETWORK DEVICE
`
`
`
`The present invention relates to start up protocols for devices in
`
`communication networks; and more particularly to systems which allow a
`
`machine without a configured higher level protocol address to obtain such '
`
`5
`
`address without a unique machine Identifier.
`
`QESCRIEHQN QE BELAIEQ am
`
`A widely accepted series of intematlonei standards describing network
`
`architectures is known as the OSI
`
`reference model.
`
`See, generally,
`
`10
`
`Tannenbaum, , 2nd Ed., 1988, Prentice-Hall. According
`
`to this model, network communications are divided into a plurality of
`
`protocols within layers of the model. Local Area Networks (LANs) operate
`
`using medium access protocols within the lower layers. layers 1 and 2, of the
`
`OSI model, such as the carrier sense multiple access with collision detection
`
`15
`
`CSMA/CD. IEEE Standard 802.3, also known as ETHERNET, and the token
`
`ring access ring method of IEEE Standard 802.5. These two lower layers
`
`are typically broken down into the physical layer and the data link layer. with
`
`the data link layer being further broken down into a media access control
`
`(MAC) layer, and a logical link layer.
`
`20
`
`Systems, such as personal computers, workstations, and mainframe
`
`computers, attached to the LANs each have a distinct lower level protocol
`
`Identifier known as the physical network address or MAC address. LAN
`frames forwarded to a destination system on the network under these lower
`
`;
`
`level protocols contain the destination system MAC address, or other
`
`25
`
`physical network address, as a destination. LAN frames lorwarded irom a
`
`source system on the network contah the source system MAC address, or
`
`other physical network address, as
`
`a
`
`source address.
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`Systems
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`communicate by encapsulating additional protocols (OSI layers 3-7) within
`
`the lower layer LAN frames. These higher level protocols are grouped into
`
`suites such as the TCP/iP protocol suite and the XNS protocol suite. Many
`
`LANs contain groups of end systems that use different higher level protocol
`
`suites. These higher level protocol suites also assign unique higher level
`
`protocol
`
`identifiers to systems which transmit or receive frames in the
`
`network.
`
`For instance. an internet protocol iP address is assigned to each
`
`system operating within an lntemet protocol network. The lntemet protocol
`
`10
`
`address includes a network address portion and a host address portion. The
`
`network address portion identifies a network within which the system resides,
`
`and the host address portion uniquely identifies the system in that network.
`
`Processors routing packets in an lntemet protocol network rely on the
`
`network address portion of the IP address in a frame to find -the local area
`
`15
`
`network of the destination machine. Once the local area network of the
`
`destination is located, the frame Is forwarded to that network where the host
`
`address portion is relied upon to assign a MAC address for the destination
`
`machine to the packet. Thus, higher level protocol address places the
`
`device In a particular network or subnetwork, so that the higher level protocol
`
`can effectively manage the routing of packets among the networks. without
`
`maintaining a table of the unique physical access layer identifiers for all of
`
`the terminals in the network.
`
`in order to communicate in such a network, the machine must first
`
`obtain its higher level protocol address. This address is typically assigned
`
`by a central authority, such as the lntemet Activities Board, or by a network
`
`manager. Normally, a particular machine learns its
`
`IP address by a
`
`configure operation, in which a technblan uses a local tennlnai to configure
`
`the machine.
`
`in a centrally managed network, this could be a cumbersome
`
`task, involving travel of skilled personnel away from the central management
`
`location. However, a reverse address resolution protocol RARP has been
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`developed tor networks such as TCPIIP or SNMP protocols. The HARP
`
`allows a machine without a configured IP address to obtain an IP address
`
`from a remote server. The machine broadcasts a request and waits until an
`
`FlAFlP sewer responds.
`
`In the request, the requesting machine must provide
`
`5
`
`its physical network address (MAC address) to uniquely identify itseii.
`
`allowing the sewer to map it into an IP address.
`
`This RARP protocol works fine, so long as the central manegernent
`
`site is aware of the physical network address of the devices being added to
`
`the network.
`
`in order to find out the physical network address, all of the
`
`'
`
`-
`
`10
`
`system being added to the network must be passed through the central
`
`management site so that the address can be read irom these machines, or
`
`a local technician must read the physical network address from the machine
`
`and telephone the central site. This process makes connecting a new device
`
`to a network difficult. Further, this process of physically reading the physical
`
`15
`
`network address from the box is prone to human errors. Such addresses
`
`are typically very long (MAC addresses are 48 bits long), and can be
`
`misread or typed in erroneously.
`
`It
`
`is desirable to have so-called ‘plug and play‘ network devices.
`
`Such devices can be plugged in and turned on by unsldlled personnel.
`
`20
`
`However, the need to find out the physical network address of the box
`
`detracts from this ability.
`
`Accordingly, it is desirable to provide a technique tor resolving higher
`
`level protocol addresses, without reliance on the lower level protocol
`
`addresses.
`
`25
`
`
`
`1
`
`The present invention provides a reverse address resolution protocol
`
`tor use in a communication network which allows resolution logic to provide
`
`a higher level protocol address, or other lntonnation, to a source oi a request
`
`30
`
`for such address, independent of the physical network address of such
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`source. The protocol according to the present invention is used in a
`
`processor having a plurality of ports, at least one oi such ports connected by
`
`a point-to-point channel to a remote network device. The reverse address
`
`resolution protocol is responsive to a resolution request from the remote
`
`network device across the point-to-point channel to supply the higher level
`
`‘
`
`protocol address based upon the port through which the resolution request
`
`is received, rather than the physical network address of the requesting
`
`device. Thus. a remote device may be coupled to a network, and connected
`
`to a central management site across a point-to-point communication link in
`
`a ‘plug and play‘ mode. The person connecting the device to the remote
`
`network does not need to determine the physical network address of the
`
`device or configure the device with a higher level address protocol. All this
`
`can be handled automatically.
`
`Thus, the present invention can be characterized as an apparatus for
`
`resolving higher level protocol addresses in response to resolution requests
`
`irom a source ol resolution requests in a communication network. The
`
`apparatus comprises a central processor having a plurality ot ports for
`
`connection to the communication network, and resolution logic which is
`
`coupled to the communication network and in communication with the central
`
`processor. The resolution logic provides a higher level protocol identifier in
`
`response to a particular port in the plurality of ports through which the
`
`resolution request is received by the central processor, independent of the
`
`lower level protocol identifier ot the source of the resolution request. The
`resolution logic may be a routine executed by the central processor. or a
`
`routine executed by a network management processor coupled to the
`
`communication network, and in communication with the central processor.
`
`The resolution logic. according to one aspect, includes a resolution
`
`table that is configurable independent of the lower level protocol identifiers,
`
`which assigns higher level protocol identifiers to particular ports of the central
`
`processor through which the resolution requests may be received.
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`-4-
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`The higher level protocol identifier may comprise an intemet protocol
`
`IP address, which includes a network address for the source of the resolution
`
`request. and a host address for the source of the resolution request.
`
`Further, the higher level protocol may be utilized by a network management
`
`5
`
`system, which communicates network-wide, while the lower level protocol
`
`'
`
`comprises a medium access protocol.
`
`The resolution logic, according to the present invention. relies on the -
`
`source of
`
`the resolution request being coupled across a point-to-point
`
`communication channel to the particular port of the processor receiving the
`
`10
`
`request.
`
`in this way. the port serves as a virtual identifier tor the source of
`
`the request.
`
`Thus, the present invention can also be characterized as an apparatus
`
`for connecting a first network and a second network. This apparatus
`
`includes a communication link, a first processor, and a second processor.
`
`15
`
`The first processor has a first interface coupled to the first network and a
`
`second interface coupled to the communication link. The second processor
`
`has a lower level protocol identifier and is coupled to the second network
`
`and to the communication link. Resolution logic is coupled to the first
`
`network to provide a higher level protocol identifier to the second processor
`
`20
`
`in response to a resolution request through the second interface of the first
`
`processor, independent of the lower le_ve| ‘protocol identifier of the second
`
`processor.
`
`in this manner, the first processor can configure the higher level
`
`protocol addresses for devices in the system, independent of the lower level
`
`protocol addresses.
`
`25
`
`According to another aspect of the invention. the first processor
`
`includes resources to provide network services to frames of data in the first
`
`.
`
`and second networks through the first and second interfaces, and the second
`
`processor includes resources to extend the second interface of the first
`
`processor transparently to the second network.
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`The resolution logic may comprise a routine executed by the lirst
`
`processor, or a routine executed by a network management processor
`
`located in the first network.
`
`Accordingly. a technique-which greatly improves the ‘plug and play‘
`
`5
`
`capability of a network-device has been provided. Remote networks may be ‘
`
`set up using this system, without requiring error prone and cumbersome
`
`techniques to acquire the physical network address oi each device being
`
`added to the network.
`
`Other aspects and advantages of the present invention can be seen
`
`10
`
`upon review of the figures, the detailed description, and the claims which
`
`follow.
`
`
`
`Fig.
`
`1
`
`is a schematic diagram of a system including the reverse
`
`15
`
`address resolution logic according to the present invention.
`
`Fig. 2 illustrates a prior art packet exchange sequence for reverse
`
`address resolution over LAN media.
`
`Fig. 3 illustrates a packet exchange sequence over a WAN medium
`
`as extended according to the present invention.
`
`20
`
`Fig. 4 illustrates the resolution request generation process used in the
`
`sequence of Fig. 3.
`
`Fig. 5 illustrates the resolution request response generation process
`
`used in the sequence of Fig. 3.
`
`Fig. 6 illustrates the resolution request response acceptance process
`
`25
`
`used in the sequence of Fig. 3, which results in a request for a subnet mask
`
`in IP networks.
`
`Fig. 7 is a diagram of the subnet mask response generation process
`
`used in the sequence of Fig. 3.
`
`Fig. 8 is a diagram of the subnet mask response acceptance process
`used in the sequence of Fig. 3.
`_
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`Fig. 9 is a schematic diagram illustrating one network environment in
`
`which the present invention may be used.
`
`
`
`5
`
`A detailed description of preferred embodiments oi
`
`the present
`
`'
`
`invention is provided with respect to Figs. 1-9. Fig. 1 illustrates application
`
`of the present invention in a preferred embodiment. Figs. 2-8 Illustrate the -
`
`extended protocol for reverse address resolution used in a preferred
`
`embodiment oi the present invention. Fig. 9 provides an overview of a
`
`10
`
`network in which the present invention may be applied.
`
`Fig.
`
`1 provides a schematic diagram of an apparatus for connecting
`
`a first network 10 to a second network 11 using address resolution logic 25
`
`according to the present invention. The first network 10 includes a first LAN
`
`9 which includes a plurality of end systems and a sewer, and may be
`
`15
`
`interconnected to other LANs using lntennedlate systems (not shown) known
`
`in the art. Coupled to the IAN 9 is a boundary router 12. The boundary
`
`router 12 is an intermediate system in the network which provides network
`
`resources serving higher
`
`level protocol suites which,
`
`in one unique
`
`embodiment, constitute routing resources. As such. the boundary router 12
`
`20
`
`maintains end system directories 13 tor the local LAN 9 and global routing
`
`iniomtation 14 to serve the routing functions according to the higher level
`
`protocol suites. Thus, the end system directories will
`
`include DEC end
`
`system tables, iPX end system tables, IP and system tables, and others to
`
`serve other protocol suites that are operating in the network 10. The
`
`25
`
`boundary router 12 may also be coupled to other portions of the corporate
`
`data network as schematically illustrated at arrow 15.
`
`.
`
`The boundary router 12 inclunbs a local interface 16 which serves the
`
`local LAN 9 providing access to the network resources within the boundary
`
`router to and systems on LAN 9. The boundary router could also have
`
`30
`
`interfaces to other local LANs as well.
`
`in addition. the boundary router 12
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`-7.
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`includes a remote routing interface 17. which provides an interface to the
`
`network resources for and systems in the remote network 11.
`
`In support of
`
`the remote lnteriace 17,
`
`the boundary router maintains and system
`
`directories 18 sewing the higher level protocol suites in the remote network
`
`5
`
`11.
`
`As illustrated schematically by the hatched symbol 19, the remote
`
`network 11 appears to the end systems in the local LAN 9 as it
`
`it were a -
`
`LAN connected locally to the boundary router 12. This appearance is
`
`maintained across a communication link 20, which may use telephone or
`
`10
`
`other dial up lines,
`
`leased lines, satellites. wireless systems. or other
`
`communication media configured as a point-to-point channel, to a routing
`
`adapter 21. which is coupled to the remote network 11. The remote network
`
`11 includes a remote LAN 22 to which a plurality oi end systems and servers
`
`may be connected as known in the art.
`
`in addition, the LAN 22 may be
`
`15
`
`coupled to other LANs In the remote network 11 through intermediate
`
`systems (not shown) as known in the art. The routing adapter 21 provides
`
`resources for extending the remote routing lnteriace 17 transparently to the
`
`remote network 11 across the communication link 20. From the perspective
`
`of the remote network 11.
`
`the routing adapter 21 provides the same
`
`20
`
`functionality as a router, while the routing adapter itseii operates independent
`
`of the higher level protocol suites.
`
`The system thus provides efficient communication between remote
`
`networks, and a corporate network, through a boundary router (e.g., net 11,
`
`routing adaptor 21, link 20, boundary router 12, net 9).
`
`25
`
`The routing adapter 21 includes hardware pertorrnlng physical network
`
`access protocols for connection to the network 22. Also. such hardware is
`
`assigned a physical network address, or MAC address, to uniquely identify
`
`the system for the lower level protocol suites. However,
`
`in order to
`
`participate in the higher level protocol suites managed by the boundary
`
`30
`
`router 12 or elsewhere in the central network 10. an identifier which serves
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`such higher level protocols is needed iorthe routing adapter 21. Thus. the
`
`boundary router 12 includes resolution logic 25 to provide such identifier in
`
`response to the Interface 17 across which a request for such identifier is
`
`received.
`
`5
`
`Figs. 2-8 illustrate the reverse address resolution protocol executed .
`
`by the resolution logic 25 in the boundary router of Fig.
`
`1 according to a
`
`preferred embodiment. in which the higher level protocol address comprises '
`
`an internet protocol IP address, such as used by SNMP (Simple Network
`
`Management Protocol) standard network management sewers.
`
`10
`
`Fig. 2 illustrates the prior art mechanism which is utilized in the
`
`preierred system on ports of the routing adaptor coupled to LAN media. The
`
`structure of Fig. 2 includes a flrst interface 100 corresponding to the RARP
`
`client port of
`
`the routing adapter 21. and a second interiace 101
`
`corresponding to an RARP sewer in the local network 11. The routing
`
`15
`
`adapter includes RARP request generation process 102, an RARP response
`
`acceptance process 103, and an ICMP subnet mask response acceptance
`
`process 104. The resolution logic 25 in the RARP server includes an RARP
`
`response generation process 105. and an ICMP subnet mask response
`generation process 106.
`I
`
`20
`
`Using the industry standard RARP request generation process, as
`
`specified In RFC 903 dated June, 1984. the RARP request generation
`
`process 102 in the client generates an RARP RFC 903 request 107. which
`
`includes the client's MAC address. This request 107 is received at the
`
`sewer interface 101 and the RARP response generation process 105
`
`25
`
`generates a response 103 by accessing a database or other logic which
`
`assigns an IP address based upon the MAC address In the request 107.
`
`The RARP response acceptance process 103 in the client receives the IP
`
`address from the response 103, stores it as appropriate in the client, and
`
`generates an ICMP subnet mask request 109. The sewer 101 receives the
`
`30
`
`request 109 and the ICMP subnet mask response generation process 106
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`supplies a subnet mask response 110 to the client 100. The ICMP subnet
`
`mask response acceptance process 104 then configures the client with the
`
`IP address and the subnet mask. and assigns the address of the sewer 101
`
`as the default gateway address.
`
`Fig. 3 illustrates this process as extended according to the present
`
`invention for reverse address resolution independent of the physical network
`
`address 01 the client.
`
`in this aspect, the interface 120 corresponds to the
`
`routing adapter 21 operating as an HARP client.
`
`The Interface 121
`
`corresponds to the interface 17 of the boundary router 12 operating as an
`
`HARP server. The RAHP sewer 121 need not be located in the boundary
`
`router 12. Rather, it can be located in any in system or intermediate system
`
`coupled to the networks served by the boundary router 12.
`
`in the extended sequence. as illustrated in Fig. 3, the routing adapter
`
`also includes an RAHP request generation process 122 (Hg. 4). an HAHP
`
`response acceptance process 123 (Fig. 6). and an ICMP subnet mask
`
`response acceptance process 124 (Fig. 8).
`
`The HARP sewer in the
`
`boundary router Includes an HARP response generation process 125 (Fig.
`
`5) and an ICMP subnet mask response generation process 126 (Fig. 7).
`
`As in the prior art system, the HARP request generation process 122
`
`in the client 120 generates an FIAHP RFC 903 request 127. Also. the
`
`process 122 generates an extended request 128, which indicates to the
`
`receiver that the address resolution must be conducted independent of the
`
`MAC address.
`
`The HARP response generation process 125 receives both the RFC
`
`903 request 127 and the MAC independent request 123.
`
`It the response can
`
`be served with the RFC 903 request. then the response generation process
`
`125 proceeds that way. However. it the MAC address 01 the client 120 has
`
`not been previously communicated to the response generation process 125,
`
`then the MAC independent request 128 must be utilized.
`
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`The RARP response generation process 125 is coupled to a media
`
`address/IP address database 135 and to a channel number/IF address
`
`database 136. These databases are configured by the network managerto
`
`assign IP addresses throughout the network. The channel number/IF
`
`address database is relied upon when the media address (MAC address) of
`
`A
`
`the client 120 is not available at the time the IP address is configured.
`
`'
`
`in either event. the RARP response generation process 125 generates
`
`an RARP RFC 903 response 129 which includes an IP address. The RARP
`response acceptance proces-3.123 in the client 120 accepts the IP address
`and generates an ICMP subnet mask request 130.
`in the server 121, the
`
`ICMP subnet mask response generation process 126 supplies an ICMP
`
`subnet mask response 131. The client 120 receives that response and
`
`executes the ICMP subnet mask acceptance process 124.
`
`Fig. 4 shows the RARP request generation process corresponding to
`
`block 122 of Fig. 3. This routine loops through all of the interfaces or ports
`
`on the remote node, also called a leaf node. to detennlne its IP address.
`
`The algorithm starts with an interface up message 400. After an interface
`
`up message. the algorithm tests whether the IP address is available in local
`
`storage (step 401).
`
`if the address is availab