公开(公告)号：DE69323963D1

公开(公告)日：1999-04-22

申请号：DE69323963

申请日：1993-10-19

Applicant: IBM

Inventor： DERBY JEFFREY HASKELL ,  DRAKE JOHN ELLIS ,  SANDICK HALDON J ,  DOERINGER WILLIBALD A ,  DYKEMAN DOUGLAS H ,  VU KEN VAN

IPC: H04L12/56

Abstract: The process for determining the best communication route from a source end station to a destination end station is distributed over both source and destination network nodes. Network nodes, at the interface between a wide area network (WAN) and each subnetwork, contain access agents to control the communication flow between the wide area network and an end station in the subnetwork. The task of selecting the best route between two end stations is distributed between the access agents at the WAN interface in the first subnetwork, and the access agents at the WAN interface in the second subnetwork. Each access agent at one WAN interface obtains the best route from itself to the end station in its subnetwork. Each access agent at the other WAN interface finds the best route from each access agent at the first WAN interface through itself to the end station in its subnetwork. One designated access agent collects all the best route information. This best route information is concatenated, and the route with the least weight is selected as the best route between end stations.

公开(公告)号：DE69327017T2

公开(公告)日：2000-05-25

申请号：DE69327017

申请日：1993-05-19

Applicant: IBM

Inventor： AUERBACH JOSHUA SETH ,  CHOW CHEE-SENG ,  PETERS MARCIA LAMBERT ,  DRAKE JOHN ELLIS ,  GOPAL PRABANDHAM MADAN ,  HERVATIC ELIZABETH ANNE ,  KAPLAN MARC ADAM

IPC: H04L12/18 ,  H04L12/24

Abstract: In a multicast network communication system, administration of the communication path making up the multicast tree itself has been separated from control and administration of the network. Creation of a multicast distribution tree and control over the membership thereof, is separately controlled independently from the creation and use of the tree transmission path used to communicate among the members of a multicast set. Transmission distribution trees are set up when a transmission request is received and the properties of the transmission path that is required are known. Transmission paths are created and controlled by all nodes in the communications system, each node having necessary control code and processors for responding to requests from set members to transmit a message to groups of users by creating and activating the necessary tree communication path distribution linkages. A distribution tree is created by the Tree Leader by generating a tree address using a random number generator. A tree address correlator is generated utilizing network and node identifiers unique for the network, and a list of subnodes or users connected for each member of the multicast tree set is generated. Using this information, a tree distribution path is computed to cover all of the subnodes required and a tree set up request message is sent by the Tree Leader along a computed path to each involved subnode. Each subnode returns a message indicating whether the tree address is already in use or is available for use. Successfully negotiated tree addresses are marked at the path link initiation and termination points at each node through the network.

公开(公告)号：DE3887572T2

公开(公告)日：1994-08-18

申请号：DE3887572

申请日：1988-05-27

Applicant: IBM

Inventor： ARROWOOD ANDREW HILLIARD ,  BARATZ ALAN EDWARD ,  CHIMENTO PHILIP FRANCIS ,  DRAKE JOHN ELLIS ,  EISENBIES JOHN LAWRENCE ,  GRAY JAMES PEYTON ,  NORSWORTHY KARLA JEAN ,  POSEFSKY DIANE PHYLIS

IPC: H04L29/00 ,  G06F15/16

Abstract: Each network node in a communications network maintains its own copy of the network topology database defining network resources. Each resource record contains a "timer" field which is initially set to a maximum value but which may be decremented on a daily basis. If the timer field is decremented to zero without being reset, the node unilaterally removes the resource record from its copy of the database. The timer field will normally reach zero only for obsolete resource records since each network node responsible for a resource broadcasts a timer-resetting message for the resource (1) each time the resource status changes, (2) when the node first joins or rejoins the network, and (3) on a periodic (weekly) basis regardless of whether conditions (1) or (2) have occurred.

公开(公告)号：DE69327017D1

公开(公告)日：1999-12-23

申请号：DE69327017

申请日：1993-05-19

Applicant: IBM

Inventor： AUERBACH JOSHUA SETH ,  CHOW CHEE-SENG ,  PETERS MARCIA LAMBERT ,  DRAKE JOHN ELLIS ,  GOPAL PRABANDHAM MADAN ,  HERVATIC ELIZABETH ANNE ,  KAPLAN MARC ADAM

IPC: H04L12/18 ,  H04L12/24

Abstract: In a multicast network communication system, administration of the communication path making up the multicast tree itself has been separated from control and administration of the network. Creation of a multicast distribution tree and control over the membership thereof, is separately controlled independently from the creation and use of the tree transmission path used to communicate among the members of a multicast set. Transmission distribution trees are set up when a transmission request is received and the properties of the transmission path that is required are known. Transmission paths are created and controlled by all nodes in the communications system, each node having necessary control code and processors for responding to requests from set members to transmit a message to groups of users by creating and activating the necessary tree communication path distribution linkages. A distribution tree is created by the Tree Leader by generating a tree address using a random number generator. A tree address correlator is generated utilizing network and node identifiers unique for the network, and a list of subnodes or users connected for each member of the multicast tree set is generated. Using this information, a tree distribution path is computed to cover all of the subnodes required and a tree set up request message is sent by the Tree Leader along a computed path to each involved subnode. Each subnode returns a message indicating whether the tree address is already in use or is available for use. Successfully negotiated tree addresses are marked at the path link initiation and termination points at each node through the network.

公开(公告)号：DE68923831T2

公开(公告)日：1996-05-02

申请号：DE68923831

申请日：1989-05-23

Applicant: IBM

Inventor： CITRON ANDREW PAUL ,  DRAKE JOHN ELLIS ,  FERREE MARSHA ELLEN ,  FETVEDT JOHN ENGUM ,  GRAY JAMES PEYTON ,  ORDANIC ZVONIMIR

IPC: H04L29/00 ,  G06F15/16

Abstract: The links in a data communications network following Systems Network Architecture may be categorized as limited resource links if those links are shared access transport facilities, such as a switched telephone network, X.21, X.25 or token ring local area network facilities. In setting up LU-LU sessions between network users, a limited resource session identifier field is set to a specific value if any of the links in the session data path is defined as a limited resource link. In a conversation between two users ends (20, 22), the primary logical unit (32) responds by determining whether the session has been identified as a limited resource session. If it has, the primary logical unit initiates action to deactivate the session without waiting for network control operation action. Allowing the primary logical unit to deactivate a limited resource session assures that the limited resource link or links will not remain allocated needlessly to an unused session.

公开(公告)号：DE68918765T2

公开(公告)日：1995-04-27

申请号：DE68918765

申请日：1989-06-07

Applicant: IBM

Inventor： ARROWOOD ANDREW HILLIARD ,  CLARKE KATHRYN E ,  DRAKE JOHN ELLIS ,  EISENBIES JOHN LAWRENCE ,  GRAY JAMES PEYTON ,  NORSWORTHY KARLA JEAN ,  POZEFSKY DIANE PHYLIS ,  SMETANKA TERENCE DALE

IPC: H04L12/24 ,  H04L12/56

Abstract: In a communications network, each network node can maintain its own list of network resources in a topology database. When the state of a resource "owned" by a particular node changes, that node broadcasts a topology database update (TDU) message to adjacent nodes. Each adjacent node updates its own topology database and rebroadcasts the message. To minimize the amount of information that must be included in TDU messages when two nodes are reconnected after an outage, each node assigns flow reduction sequence numbers (FRSNs) to TDU messages and keeps a record of the FRSN for the last TDU message sent to an adjacent node. The node also records, for each resource in its database, the FRSN of the last TDU message including that resource. When two nodes are reconnected, the sending node includes in the TDU message only those resources having a FRSN greater than the FRSN assigned to the last TDU sent to the adjacent node to which the TDU message is directed.

公开(公告)号：DE69323963T2

公开(公告)日：1999-10-07

申请号：DE69323963

申请日：1993-10-19

Applicant: IBM

Inventor： DERBY JEFFREY HASKELL ,  DRAKE JOHN ELLIS ,  SANDICK HALDON J ,  DOERINGER WILLIBALD A ,  DYKEMAN DOUGLAS H ,  VU KEN VAN

IPC: H04L12/56

Abstract: The process for determining the best communication route from a source end station to a destination end station is distributed over both source and destination network nodes. Network nodes, at the interface between a wide area network (WAN) and each subnetwork, contain access agents to control the communication flow between the wide area network and an end station in the subnetwork. The task of selecting the best route between two end stations is distributed between the access agents at the WAN interface in the first subnetwork, and the access agents at the WAN interface in the second subnetwork. Each access agent at one WAN interface obtains the best route from itself to the end station in its subnetwork. Each access agent at the other WAN interface finds the best route from each access agent at the first WAN interface through itself to the end station in its subnetwork. One designated access agent collects all the best route information. This best route information is concatenated, and the route with the least weight is selected as the best route between end stations.

公开(公告)号：DE68923831D1

公开(公告)日：1995-09-21

申请号：DE68923831

申请日：1989-05-23

Applicant: IBM

Inventor： CITRON ANDREW PAUL ,  DRAKE JOHN ELLIS ,  FERREE MARSHA ELLEN ,  FETVEDT JOHN ENGUM ,  GRAY JAMES PEYTON ,  ORDANIC ZVONIMIR

IPC: H04L29/00 ,  G06F15/16

Abstract: The links in a data communications network following Systems Network Architecture may be categorized as limited resource links if those links are shared access transport facilities, such as a switched telephone network, X.21, X.25 or token ring local area network facilities. In setting up LU-LU sessions between network users, a limited resource session identifier field is set to a specific value if any of the links in the session data path is defined as a limited resource link. In a conversation between two users ends (20, 22), the primary logical unit (32) responds by determining whether the session has been identified as a limited resource session. If it has, the primary logical unit initiates action to deactivate the session without waiting for network control operation action. Allowing the primary logical unit to deactivate a limited resource session assures that the limited resource link or links will not remain allocated needlessly to an unused session.

公开(公告)号：DE3853022T2

公开(公告)日：1995-08-10

申请号：DE3853022

申请日：1988-04-12

Applicant: IBM

Inventor： BARATZ ALAN EDWARD ,  DRAKE JOHN ELLIS ,  GROVER GEORGE ALLAN ,  RAFALOW LEE MARK ,  GRAY JAMES PEYTON ,  POLLARD MELINDA ROSS ,  POZEFSKY DIANE PHYLIS

IPC: G06F13/00 ,  H04L29/00 ,  G06F15/16

Abstract: Method of disseminating information in a computer network wherein, upon activating any link in the network, a first exchange of signals between nodes attached to said link is automatically initiated for providing each of the attached nodes with information indicating the availability of the node at the other end of the link for participating in a predetermined type session. If both nodes are available for participating in a the session, a second exchange of signals between the nodes is initiated for establishing a session. Then a third exchange is automatically initiated for providing the nodes with information needed to make effective use of the session. Upon completion of said third exchange, internal operations are conducted at said nodes designating the session as a predetermined type session and making said session available to transaction programs at the nodes for exchanging additional network state information as needed.

公开(公告)号：DE68918765D1

公开(公告)日：1994-11-17

申请号：DE68918765

申请日：1989-06-07

Applicant: IBM

Inventor： ARROWOOD ANDREW HILLIARD ,  CLARKE KATHRYN E ,  DRAKE JOHN ELLIS ,  EISENBIES JOHN LAWRENCE ,  GRAY JAMES PEYTON ,  NORSWORTHY KARLA JEAN ,  POZEFSKY DIANE PHYLIS ,  SMETANKA TERENCE DALE

IPC: H04L12/24 ,  H04L12/56

Abstract: In a communications network, each network node can maintain its own list of network resources in a topology database. When the state of a resource "owned" by a particular node changes, that node broadcasts a topology database update (TDU) message to adjacent nodes. Each adjacent node updates its own topology database and rebroadcasts the message. To minimize the amount of information that must be included in TDU messages when two nodes are reconnected after an outage, each node assigns flow reduction sequence numbers (FRSNs) to TDU messages and keeps a record of the FRSN for the last TDU message sent to an adjacent node. The node also records, for each resource in its database, the FRSN of the last TDU message including that resource. When two nodes are reconnected, the sending node includes in the TDU message only those resources having a FRSN greater than the FRSN assigned to the last TDU sent to the adjacent node to which the TDU message is directed.