US20020044526A1 - Network switch with panic mode - Google Patents
Network switch with panic mode Download PDFInfo
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- US20020044526A1 US20020044526A1 US09/973,221 US97322101A US2002044526A1 US 20020044526 A1 US20020044526 A1 US 20020044526A1 US 97322101 A US97322101 A US 97322101A US 2002044526 A1 US2002044526 A1 US 2002044526A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/74—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for increasing reliability, e.g. using redundant or spare channels or apparatus
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/44—Star or tree networks
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/46—Interconnection of networks
- H04L12/4604—LAN interconnection over a backbone network, e.g. Internet, Frame Relay
- H04L12/462—LAN interconnection over a bridge based backbone
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
- H04L69/40—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection
Definitions
- LAN Local Area networks
- LAN's are used to facilitate communications between a number of users. Individual LAN's may be bridged together to allow a large number of users to communicate amongst themselves. These bridged LAN's may be further interconnected with other bridged LAN's using routers to form even larger communications networks.
- FIG. 1 depicts an exemplary interconnected bridged LAN system.
- the numerals 10 , 20 , 30 , etc. are used to identify individual LAN's.
- Bridges between LAN's are designated by the numerals 5 , 15 , 25 and 35 .
- a router between bridged LAN 100 and bridged LAN 200 is identified with the reference numeral 300 .
- a user A is able to communicate with a user B without leaving the LAN 10 .
- the communication is transmitted via bridges 5 and/or 15 .
- the communication must be routed via router 300 to bridged LAN 200 .
- bridges operated at layer 2 of the network model and transparently bridge two LAN's. It is transparent to users A and C that communications between them are ported over bridge 5 because layer 2 bridges do not modify packets, except as necessary to comply with the type of destination LAN.
- the communication must be ported via router 300 which operates at level 3 of the network model.
- LAN network administrators generally attempt to connect together those users who frequently communicate with each other in bridged LAN's. However, if the bridged LAN becomes too large, it becomes unscalable and may experience various well-known problems. Accordingly, routers are used to interconnect bridged LAN's so that the bridged LAN's themselves can be kept to an acceptable size. This results in delays in communications between users which are transmitted via the router 300 . If, for example, in FIG. 1, user E and user A need to communicate frequently, it would be advantageous to interconnect LAN 10 and LAN 50 via a bridge rather than the router 300 . This would require system rewiring, which is costly and may be impracticable under many circumstances, such as, if users A and E will only need to frequently communicate for a limited period of time.
- a switch 37 in bridged LAN 200 provides a redundant communication path between LAN 50 and LAN 60 .
- FIG. 2 depicts another communication system having redundant communications paths.
- the system includes LAN's 305 - 330 .
- LAN 305 is connected to LAN 310 by switch 340 .
- LAN 310 is connected to LAN 315 by a switch 350 .
- This provides a primary communication path between LAN's 305 and 315 . Accordingly, during normal operations communications between users X and Y are directed through switches 340 and 350 along the communication path 410 .
- a redundant path 420 is also shown connecting LAN's 305 and 315 . This path is under the control of switch 360 which also connects LAN 305 with LAN's 320 - 330 .
- Conventional switch 360 includes a switch controller which implements forward processing and spanning tree processing, the latter in accordance with a spanning tree protocol.
- Each of the switches periodically exchange hello messages, typically at a frequency of once per second. It will be recognized by those skilled in the art that data communications are being received by switch 360 at a substantially higher frequency and that tens of thousands, if not hundreds of thousands of data communications packets may be received by the switch 360 every second. Based upon the spanning tree protocol implemented by the switch 360 , data traffic between users X and Y is prohibited by switch 360 from transmission via the redundant communication path 420 as long as the hello messages are periodically received.
- the switch 360 in accordance with the spanning tree protocol, opens the redundant communication path and allows communications between users X and Y to be transmitted via the redundant link 420 . This is intended to ensure that the redundant communication path is only available for transmitting communications between LAN's 305 and 315 when the primary communication path 410 has failed. As those skilled in the art will recognize. if both communication paths 410 and 420 are simultaneously open to traffic, a network loop will be formed which will result in an extreme overloading of the system which is, in turn, likely to bring the network down.
- Conventional switches 340 - 360 may have a threshold capacity over which the switch is unable to forward received traffic. Accordingly, each switch is configured such that when the amount of received traffic exceeds the threshold capacity or limit, the excess traffic may be simply dropped. However, this dropping of traffic may also result in anomalies in the switch 360 monitoring of the hello messages. More particularly, if hello messages are dropped along with excess data communications, the switch 360 will erroneously conclude that the primary communication path 410 is inoperable and therefore open the redundant communication path 420 unnecessarily, thereby causing a network loop which will overload and bring down the system.
- a communications switch for use in transmitting traffic from a first user to a second user in cases where the first and the second users are interconnected by primary and redundant communications paths.
- the switch includes a first port configured to receive periodic hello communications indicative of a proper operation of the primary communications path.
- a switch control monitors the receipt of hello communications, and directs the forwarding of the received data communications up to a threshold capacity or limit.
- the hello communications typically are received at a first frequency, e.g., once per second, and the data communications are received at a second frequency, e.g., tens of thousands per second, which is much greater than the first frequency.
- the switch control drops at least a portion, and preferably all, of the received data communications such that forwarded data communications are at least below, and beneficial well below, the threshold capacity, if not eliminated completely.
- the switch control detects a failure to receive the hello communications and directs the forwarding of communications between the first user and the second user over the redundant communications path responsive thereto.
- the switch control detects the failure to receive successive hello communications, and preferably directs the forwarding of communications over the redundant communications path responsive to a failure to receive a particular number of successive hello communications, for example 15.
- the switch control drops the received data communications responsive to detecting a failure to receive a lesser number of successive hello communications, for example 8, and/or if the received data communications exceed the threshold capacity.
- the switch control operation ensures that hello communications will not be dropped due to the received communications exceeding the threshold capacity, which could result in the switch erroneously concluding that the primary communications path is not operating properly.
- the switch control would direct communications between the first and second users over the redundant communications path causing a network loop and potentially bringing the system or network down. Accordingly, it is preferred that the switch control direct the forwarding communications between the first user and the second user along the redundant path only after it detects a failure to receive a further successive hello communications subsequent to dropping of all of the received data communications.
- a communication system for transmitting traffic from a first user to a second user includes primary and redundant communications paths connecting the first and second users.
- a switch is disposed in the redundant communications path to receive periodic hello communications indicative of a proper operation of the primary communications path and data communications between system users.
- the switch is capable of forwarding received data communications up to a threshold capacity or other limit. If the switch detects a failure to receive a first number of successive hello communications, it will preferably drop all of the received data communications.
- the switch will also forward communications between the first user and the second user along the redundant path responsive to the subsequent detection of a failure to receive a second number of successive hello communications.
- FIG. 1 depicts a prior art LAN configuration.
- FIG. 2 depicts another prior art redundant communication network.
- FIG. 3 depicts a redundant communication network in accordance with the present invention.
- FIG. 4 depicts a communication switch in accordance with the present invention.
- FIG. 5 is a flow chart of the process implemented by the switch depicted in FIG. 4.
- FIG. 3 depicts a redundant network or system similar to the system depicted in FIG. 2 and like components are referenced with identical reference numerals.
- LAN's 305 - 330 are interconnected by switches 340 , 350 and 360 ′.
- Redundant communication paths 410 and 420 interconnect LAN 305 with LAN 315 .
- the primary communication link 410 includes switches 340 and 350 .
- the redundant communication link 420 includes switch 360 ′ connecting LAN 305 , which. for example, could be a high-speed backbone LAN, to LAN's 315 - 330 .
- the switches 340 , 350 and 360 each include spanning tree processing which implements a spanning tree protocol.
- the switches also include forward processing for forwarding received data communications.
- Switches 340 and 360 are shown to be conventional but could, if desired. be configured and programmed in accordance with the present invention, as will be described in detail below with reference to switch 360 ′.
- each of the switches 340 and 350 transmit hello messages to the switch 360 ′ at a frequency of once per second, indicating that the primary communication link is operating to transmit communications between users X and Y.
- switch 360 ′ receives not only the hello messages but also a substantial amount of data traffic for forwarding to LAN's 320 - 330 . So long as the hello messages are received by switch 360 ′ from switches 340 and 350 , switch 360 ′ prohibits communications over the redundant communication link 420 between LAN's 305 and 315 so that a network loop is avoided. It will be recognized that although switch 360 ′ is shown as a dynamic multiported switch, the present invention is equally applicable to conventional bridges and other types of switching or bridging devices.
- the switch 360 ′ maintains a count of any successively missed hello messages. Accordingly, if switch 360 ′ fails to detect fifteen consecutive hello messages from either switch 340 or switch 350 , switch 360 ′ opens the redundant communication path 420 to allow communications between LAN 305 and 315 . If the data traffic received at switch 360 ′ exceeds the capacity of the switch to forward communications to the LAN's 320 - 330 , switch 360 ′, if conventionally configured, would proceed to drop all received traffic exceeding its threshold capacity and continue forwarding data traffic at the fully capacity level.
- the switch 360 ′ would conventionally drop thirty thousand packets of information per second and continue to forward the remaining sixty thousand packets of data traffic.
- switch 360 ′ is programmed to conservatively assess the operability of the primary communication link 410 and to only go into a panic mode if it determines that link 410 has become inoperable.
- FIG. 4 provides a schematic depiction of the switch 360 ′. As indicated, the switch 360 ′ includes a switching device 282 for forwarding communications between LAN 305 and LAN's 315 - 330 .
- the switching device 282 is controlled by the switch control 288 , which includes a control module 284 and memory 286 .
- the control module includes a detector 284 a for detecting traffic received from the LAN's 305 and 315 - 330 , including hello messages from switches 340 and 350 .
- the control module 284 also includes a controller 284 b for controlling the switching device 282 in accordance with instructions received from the processor 284 c , which processes information in accordance with stored programming instructions on the memory 286 .
- These particular components can be implemented in any number of ways as will be well understood by those skilled in the art. It should be recognized that the memory itself may be magnetic, electrical, optical or another type of device capable of storing this necessary instructions and information to allow the control module 284 to operate in the described manner.
- FIG. 5 depicts a flow chart of the steps performed by the switch 360 ′ in accordance with the present invention. It will be understood that the switch 360 ′ may perform numerous other steps in communicating information between LAN 305 and LAN's 315 - 330 which are not shown in the flow chart of FIG. 5 in order to avoid superfluous information which is unnecessary to the skilled artisan's understanding of the present invention.
- switch 360 ′ receives data communications which are forwarded between LAN's 305 and 320 - 330 .
- Switch 360 ′ prohibits the flow of any traffic between LAN 305 and LAN 315 and, hence, the redundant communication link 420 remains closed while communications between LAN's 305 and 315 are transmitted via the primary communication link 410 .
- Detector 284 a of the switch 360 ′ detects data communications and hello messages.
- the switch control processor 284 c operates to monitor the detected hello messages as well as the data traffic as indicated in step 500 .
- the processor 284 c maintains a count of a number of successively missed hello messages from either switch 340 or switch 350 .
- the processor 284 c also maintains information regarding the amount of data traffic received by the switch 360 ′, as indicated in step 505 . So long as hello messages are received and the data communications are below the switch capacity, the controller 284 b , in accordance with the standard forward processing performed on processor 284 c , controls the switching device 282 to forward all received traffic between LAN's 305 and 320 - 330 .
- step 510 the processor 284 c determines if the data traffic detected by detector 284 a exceeds the switch threshold, e.g., sixty thousand packets per second. If not, in step 515 the processor 284 c determines if hello messages are being successively received. If so, the processor 284 c continues with the monitoring at step 500 . If successive hello messages are not being received, the processor 284 c maintains, in conjunction with the memory 286 , a count of the number of successively missed hello messages, as indicated in step 520 .
- the switch threshold e.g., sixty thousand packets per second.
- step 525 the processor 284 c determines if fifteen successive hello messages from either of switches 340 or 350 have not been received. If not, the count of the number of successively missed hello messages continues at step 520 . However, if fifteen successive hello messages have been missed, the processor 284 c instructs the controller 284 b to control the switching device 282 to forward communications between LAN 305 and 315 via the redundant communication path 420 .
- the switch 360 ′ concludes that the primary communication path 410 has become inoperable and begins transmitting communications between LAN 305 and LAN 315 as indicated by step 530 .
- step 510 If, in step 510 , the data communications exceed the threshold of switch 360 ′, e.g., exceed sixty thousand packets per second, the processor 284 c directs the controller 284 b to control the switching device 282 to drop the excess communications traffic as indicated in step 535 .
- the switch 360 ′ does not distinguish between data traffic and hello messages. Accordingly, hello messages as well as data communications may be dropped prior to being detected by the detector 284 a.
- step 540 the controller determines if the successive hello messages are being received one per second. If so, the processor 284 c continues its monitoring function in step 500 . If, however, successive hello messages have been missed, the processor maintains a count of the number of successively missed hello messages as indicated in step 545 .
- step 550 the switch 360 ′ determines if the number of successively missed hello messages equals eight, or some other desired count threshold. If not, the processor 284 c continues to maintain a count of successively missed hello messages, as indicated in step 545 . If, however, the detector 284 a fails to detect eight successive hello messages, the switch 360 ′ goes into a panic mode. In this regard, the processor 284 c directs the controller 284 b to control the switching device 282 to drop all received data communications, as indicated by step 555 .
- any subsequently transmitted hello message should be detected by the detector 284 a thereby stopping the count of missed hello messages prior to the count exceeding the second count threshold of fifteen, as indicated in step 560 , responsive to which the switch 360 ′ opens the redundant communication path 420 .
- the switch can drop packets much faster than it can forward traffic; in particular, it can drop packets as fast as the maximum theoretical rate at which they can be received.
- switch 360 ′ is configured so that the redundant communication link 420 is opened only after the switch 360 ′ has confirmed that a predefined number of successive hello messages have not been received from either of the switches 340 or 350 due to a fault in the primary communication path 410 rather that due to being dropped as part of excess communications traffic received at the switch 360 ′.
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Abstract
A switch is provided for use in a communications system for transmitting traffic from a first user to a second user. The first and the second users are interconnected by a primary communications path and a redundant communications path. The switch includes a first port configured to receive hello communications indicative of a proper operation of the primary communications path and a second port for receiving data communications. A switch control monitors the receipt of the hello communications, directs the forwarding of received data communications up to a threshold capacity and, if the received data communications exceed the threshold capacity, drops at least a portion of the received data communications such that forwarded data communications are below the threshold capacity.
Description
- Local Area networks (LAN's) are used to facilitate communications between a number of users. Individual LAN's may be bridged together to allow a large number of users to communicate amongst themselves. These bridged LAN's may be further interconnected with other bridged LAN's using routers to form even larger communications networks.
- Prior art FIG. 1 depicts an exemplary interconnected bridged LAN system. The
numerals numerals LAN 100 and bridgedLAN 200 is identified with thereference numeral 300. In the prior art bridged LAN system depicted, a user A is able to communicate with a user B without leaving theLAN 10. - If user A desires to communicate with user C in
LAN 20 or user D inLAN 30, the communication is transmitted via bridges 5 and/or 15. If user A desires to communicate with user E, the communication must be routed viarouter 300 to bridged LAN 200. As will be understood by those skilled in the art, bridges operated at layer 2 of the network model and transparently bridge two LAN's. It is transparent to users A and C that communications between them are ported over bridge 5 because layer 2 bridges do not modify packets, except as necessary to comply with the type of destination LAN. However, if user A wishes to communicate with user E, the communication must be ported viarouter 300 which operates at level 3 of the network model. - LAN network administrators generally attempt to connect together those users who frequently communicate with each other in bridged LAN's. However, if the bridged LAN becomes too large, it becomes unscalable and may experience various well-known problems. Accordingly, routers are used to interconnect bridged LAN's so that the bridged LAN's themselves can be kept to an acceptable size. This results in delays in communications between users which are transmitted via the
router 300. If, for example, in FIG. 1, user E and user A need to communicate frequently, it would be advantageous to interconnectLAN 10 andLAN 50 via a bridge rather than therouter 300. This would require system rewiring, which is costly and may be impracticable under many circumstances, such as, if users A and E will only need to frequently communicate for a limited period of time. - It is often beneficial in bridged LAN's and other types of communication systems or networks for redundant communication paths to be provided. Referring again to FIG. 1, a
switch 37 in bridgedLAN 200 provides a redundant communication path betweenLAN 50 andLAN 60. - Prior art FIG. 2 depicts another communication system having redundant communications paths. As shown, the system includes LAN's305-330. LAN 305 is connected to LAN 310 by
switch 340. LAN 310 is connected to LAN 315 by aswitch 350. This provides a primary communication path between LAN's 305 and 315. Accordingly, during normal operations communications between users X and Y are directed throughswitches communication path 410. Aredundant path 420 is also shown connecting LAN's 305 and 315. This path is under the control ofswitch 360 which also connectsLAN 305 with LAN's 320-330.Conventional switch 360 includes a switch controller which implements forward processing and spanning tree processing, the latter in accordance with a spanning tree protocol. - Each of the switches periodically exchange hello messages, typically at a frequency of once per second. It will be recognized by those skilled in the art that data communications are being received by
switch 360 at a substantially higher frequency and that tens of thousands, if not hundreds of thousands of data communications packets may be received by theswitch 360 every second. Based upon the spanning tree protocol implemented by theswitch 360, data traffic between users X and Y is prohibited by switch 360 from transmission via theredundant communication path 420 as long as the hello messages are periodically received. - If a succession of hello messages are not received from either of
switch 340 orswitch 350, for example, fifteen successive hello messages are missed, theswitch 360, in accordance with the spanning tree protocol, opens the redundant communication path and allows communications between users X and Y to be transmitted via theredundant link 420. This is intended to ensure that the redundant communication path is only available for transmitting communications between LAN's 305 and 315 when theprimary communication path 410 has failed. As those skilled in the art will recognize. if bothcommunication paths - Conventional switches340-360 may have a threshold capacity over which the switch is unable to forward received traffic. Accordingly, each switch is configured such that when the amount of received traffic exceeds the threshold capacity or limit, the excess traffic may be simply dropped. However, this dropping of traffic may also result in anomalies in the
switch 360 monitoring of the hello messages. More particularly, if hello messages are dropped along with excess data communications, theswitch 360 will erroneously conclude that theprimary communication path 410 is inoperable and therefore open theredundant communication path 420 unnecessarily, thereby causing a network loop which will overload and bring down the system. - Accordingly, it is an object of the present invention to provide a communications switch which controls a redundant communication link in an enhanced manner.
- It is another object of the present invention to provide a communications switch which routes data traffic over a redundant communications link in such a way that network communications loops are avoided.
- It is a further object of the present invention to provide a communication switch which does not unnecessarily route data traffic over a redundant communications link.
- Additional objects, advantages, novel features of the present invention will become apparent to those skilled in the art from this disclosure, including the following detailed description, as well as by practice of the invention. While the invention is described below with reference to preferred embodiment(s), it should be understood that the invention is not limited thereto. Those of ordinary skill in the art having access to the teachings herein will recognize additional implementations, modifications, and embodiments, as well as other fields of use, which are within the scope of the invention as disclosed and claimed herein and with respect to which the invention could be of significant utility.
- In accordance with the present invention, a communications switch is provided for use in transmitting traffic from a first user to a second user in cases where the first and the second users are interconnected by primary and redundant communications paths. The switch includes a first port configured to receive periodic hello communications indicative of a proper operation of the primary communications path. During normal operations, a switch control monitors the receipt of hello communications, and directs the forwarding of the received data communications up to a threshold capacity or limit. The hello communications typically are received at a first frequency, e.g., once per second, and the data communications are received at a second frequency, e.g., tens of thousands per second, which is much greater than the first frequency. In situations where the received data communications exceed the threshold capacity, the switch control drops at least a portion, and preferably all, of the received data communications such that forwarded data communications are at least below, and beneficial well below, the threshold capacity, if not eliminated completely.
- According to other aspects of the invention, the switch control detects a failure to receive the hello communications and directs the forwarding of communications between the first user and the second user over the redundant communications path responsive thereto. Advantageously, the switch control detects the failure to receive successive hello communications, and preferably directs the forwarding of communications over the redundant communications path responsive to a failure to receive a particular number of successive hello communications, for example 15. The switch control drops the received data communications responsive to detecting a failure to receive a lesser number of successive hello communications, for example 8, and/or if the received data communications exceed the threshold capacity.
- The switch control operation ensures that hello communications will not be dropped due to the received communications exceeding the threshold capacity, which could result in the switch erroneously concluding that the primary communications path is not operating properly. In such a case, the switch control would direct communications between the first and second users over the redundant communications path causing a network loop and potentially bringing the system or network down. Accordingly, it is preferred that the switch control direct the forwarding communications between the first user and the second user along the redundant path only after it detects a failure to receive a further successive hello communications subsequent to dropping of all of the received data communications.
- In accordance with other aspects of the invention, a communication system for transmitting traffic from a first user to a second user includes primary and redundant communications paths connecting the first and second users. A switch is disposed in the redundant communications path to receive periodic hello communications indicative of a proper operation of the primary communications path and data communications between system users. The switch is capable of forwarding received data communications up to a threshold capacity or other limit. If the switch detects a failure to receive a first number of successive hello communications, it will preferably drop all of the received data communications. The switch will also forward communications between the first user and the second user along the redundant path responsive to the subsequent detection of a failure to receive a second number of successive hello communications.
- FIG. 1 depicts a prior art LAN configuration.
- FIG. 2 depicts another prior art redundant communication network.
- FIG. 3 depicts a redundant communication network in accordance with the present invention.
- FIG. 4 depicts a communication switch in accordance with the present invention.
- FIG. 5 is a flow chart of the process implemented by the switch depicted in FIG. 4.
- FIG. 3 depicts a redundant network or system similar to the system depicted in FIG. 2 and like components are referenced with identical reference numerals. As depicted in FIG. 3, LAN's305-330 are interconnected by
switches Redundant communication paths interconnect LAN 305 withLAN 315. Theprimary communication link 410 includesswitches redundant communication link 420 includesswitch 360′ connectingLAN 305, which. for example, could be a high-speed backbone LAN, to LAN's 315-330. - The
switches Switches - During normal operations, communications between users X and Y are transmitted over the
primary communication path 410 viaswitches switches switch 360′ at a frequency of once per second, indicating that the primary communication link is operating to transmit communications between users X and Y. - It will be noted that
switch 360′ receives not only the hello messages but also a substantial amount of data traffic for forwarding to LAN's 320-330. So long as the hello messages are received byswitch 360′ fromswitches redundant communication link 420 between LAN's 305 and 315 so that a network loop is avoided. It will be recognized that althoughswitch 360′ is shown as a dynamic multiported switch, the present invention is equally applicable to conventional bridges and other types of switching or bridging devices. - The
switch 360′ maintains a count of any successively missed hello messages. Accordingly, ifswitch 360′ fails to detect fifteen consecutive hello messages from eitherswitch 340 or switch 350, switch 360′ opens theredundant communication path 420 to allow communications betweenLAN switch 360′ exceeds the capacity of the switch to forward communications to the LAN's 320-330, switch 360′, if conventionally configured, would proceed to drop all received traffic exceeding its threshold capacity and continue forwarding data traffic at the fully capacity level. For example, if theswitch 360′ has a forwarding capacity of sixty thousand packets of information per second and the received traffic between LAN's 305 and 320-330 is ninety thousand packets per second, theswitch 360′ would conventionally drop thirty thousand packets of information per second and continue to forward the remaining sixty thousand packets of data traffic. - As discussed above, this could result in hello messages from
switch 340 and/or switch 350 being dropped. That is, the thirty thousand packets of dropped data could include successive hello messages from either or both ofswitches switch 360′ could be fooled into believing that theprimary communication path 410 is inoperable and, therefore, open up theredundant path 420 between LAN's 305 and 315, resulting in a network loop. - To solve this problem, switch360′ is programmed to conservatively assess the operability of the
primary communication link 410 and to only go into a panic mode if it determines thatlink 410 has become inoperable. FIG. 4 provides a schematic depiction of theswitch 360′. As indicated, theswitch 360′ includes aswitching device 282 for forwarding communications betweenLAN 305 and LAN's 315-330. - The
switching device 282 is controlled by theswitch control 288, which includes acontrol module 284 andmemory 286. The control module includes adetector 284 a for detecting traffic received from the LAN's 305 and 315-330, including hello messages fromswitches control module 284 also includes acontroller 284 b for controlling theswitching device 282 in accordance with instructions received from theprocessor 284 c, which processes information in accordance with stored programming instructions on thememory 286. These particular components can be implemented in any number of ways as will be well understood by those skilled in the art. It should be recognized that the memory itself may be magnetic, electrical, optical or another type of device capable of storing this necessary instructions and information to allow thecontrol module 284 to operate in the described manner. - FIG. 5 depicts a flow chart of the steps performed by the
switch 360′ in accordance with the present invention. It will be understood that theswitch 360′ may perform numerous other steps in communicating information betweenLAN 305 and LAN's 315-330 which are not shown in the flow chart of FIG. 5 in order to avoid superfluous information which is unnecessary to the skilled artisan's understanding of the present invention. - The operation of the
switch 360′ will now be described with reference to FIGS. 3-5. As indicated above, during normal operations switch 360′ receives data communications which are forwarded between LAN's 305 and 320-330. Switch 360′, however, prohibits the flow of any traffic betweenLAN 305 andLAN 315 and, hence, theredundant communication link 420 remains closed while communications between LAN's 305 and 315 are transmitted via theprimary communication link 410. -
Detector 284 a of theswitch 360′ detects data communications and hello messages. Theswitch control processor 284 c operates to monitor the detected hello messages as well as the data traffic as indicated instep 500. In this regard, theprocessor 284 c maintains a count of a number of successively missed hello messages from eitherswitch 340 orswitch 350. Theprocessor 284 c also maintains information regarding the amount of data traffic received by theswitch 360′, as indicated instep 505. So long as hello messages are received and the data communications are below the switch capacity, thecontroller 284 b, in accordance with the standard forward processing performed onprocessor 284 c, controls theswitching device 282 to forward all received traffic between LAN's 305 and 320-330. - In
step 510 theprocessor 284 c determines if the data traffic detected bydetector 284 a exceeds the switch threshold, e.g., sixty thousand packets per second. If not, instep 515 theprocessor 284 c determines if hello messages are being successively received. If so, theprocessor 284 c continues with the monitoring atstep 500. If successive hello messages are not being received, theprocessor 284 c maintains, in conjunction with thememory 286, a count of the number of successively missed hello messages, as indicated instep 520. - In
step 525, theprocessor 284 c determines if fifteen successive hello messages from either ofswitches step 520. However, if fifteen successive hello messages have been missed, theprocessor 284 c instructs thecontroller 284 b to control theswitching device 282 to forward communications betweenLAN redundant communication path 420. Accordingly, oncedetector 284 a has failed to detect fifteen consecutive hello messages, i.e., a period of fifteen seconds has gone by without receiving a hello message from one of eitherswitch 340 or switch 350, theswitch 360′ concludes that theprimary communication path 410 has become inoperable and begins transmitting communications betweenLAN 305 andLAN 315 as indicated bystep 530. - If, in
step 510, the data communications exceed the threshold ofswitch 360′, e.g., exceed sixty thousand packets per second, theprocessor 284 c directs thecontroller 284 b to control theswitching device 282 to drop the excess communications traffic as indicated instep 535. In this regard, theswitch 360′ does not distinguish between data traffic and hello messages. Accordingly, hello messages as well as data communications may be dropped prior to being detected by thedetector 284 a. - In
step 540 the controller determines if the successive hello messages are being received one per second. If so, theprocessor 284 c continues its monitoring function instep 500. If, however, successive hello messages have been missed, the processor maintains a count of the number of successively missed hello messages as indicated instep 545. - In
step 550 theswitch 360′ determines if the number of successively missed hello messages equals eight, or some other desired count threshold. If not, theprocessor 284 c continues to maintain a count of successively missed hello messages, as indicated instep 545. If, however, thedetector 284 a fails to detect eight successive hello messages, theswitch 360′ goes into a panic mode. In this regard, theprocessor 284 c directs thecontroller 284 b to control theswitching device 282 to drop all received data communications, as indicated bystep 555. - Accordingly, if hello messages are being transmitted by
switches switch 360′ but have not been detected because they have been dropped as part of the excessive traffic, by dropping all data traffic any subsequently transmitted hello message should be detected by thedetector 284 a thereby stopping the count of missed hello messages prior to the count exceeding the second count threshold of fifteen, as indicated instep 560, responsive to which theswitch 360′ opens theredundant communication path 420. This is because the switch can drop packets much faster than it can forward traffic; in particular, it can drop packets as fast as the maximum theoretical rate at which they can be received. - Hence, switch360′ is configured so that the
redundant communication link 420 is opened only after theswitch 360′ has confirmed that a predefined number of successive hello messages have not been received from either of theswitches primary communication path 410 rather that due to being dropped as part of excess communications traffic received at theswitch 360′. - It will also be recognized by those skilled in the art that, while the invention has been described above in terms of one or more preferred embodiments, it is not limited thereto. Various features and aspects of the above described invention may be used individually or jointly. Further, although the invention has been described in the context of its implementation in a particular environment and for particular purposes, those skilled in the art will recognize that its usefulness is not limited thereto and that the present invention can be beneficially utilized in any number of environments and implementations. Accordingly, the claims set forth below should be construed in view of the full breadth and spirit of the invention as disclosed herein.
SCHEDULE 1 Issued Patents Pat. No. Issue date Des.308,464 6/12/1990 Des.308,664 6/19/1990 Des.317,750 6/25/1991 Des.336,636 6/22/1993 Des.339,325 9/14/1993 Des.347,624 6/7/1994 RE36,353 10/26/1999 4,380,088 4/12/1983 4,384,363 5/17/1983 4,412,347 10/25/1983 4,568,841 2/4/1986 4,597,078 6/24/1986 4,611,326 9/9/1986 4,621,323 11/4/1986 4,766,386 8/23/1988 4,817,080 3/28/1989 4,823,122 4/18/1989 4,825,435 4/25/1989 4,875,223 10/17/1989 4,875,880 10/24/1989 4,878,219 10/31/1989 4,890,102 12/26/1989 4,924,463 5/8/1990 4,931,791 6/5/1990 4,945,548 7/31/1990 4,970,718 11/13/1990 4,972,161 11/20/1990 4,975,904 12/4/1990 4,975,905 12/4/1990 5,003,556 3/26/1991 5,018,137 5/21/1991 5,018,142 5/21/1991 5,029,164 7/2/1991 5,043,975 8/27/1991 5,058,108 10/15/1991 5,058,109 10/15/1991 5,072,366 12/10/1991 5,084,870 1/28/1992 5,086,469 2/4/1992 5,115,235 5/19/1992 5,119,402 6/2/1992 5,121,382 6/9/1992 5,128,926 7/7/1992 5,129,842 7/14/1992 5,136,716 8/4/1992 5,144,304 9/1/1992 5,148,112 9/15/1992 5,148,353 9/15/1992 5,150,360 9/22/1992 5,151,899 9/29/1992 5,153,876 10/6/1992 5,155,726 10/13/1992 5,167,033 11/24/1992 5,179,554 1/12/1993 5,179,577 1/12/1993 5,185,537 2/9/1993 5,193,151 3/9/1993 5,195,181 3/16/1993 5,202,884 4/13/1993 5,202,999 4/13/1993 5,208,692 5/4/1993 5,210,741 5/11/1993 5,227,778 7/13/1993 5,228,129 7/13/1993 5,235,617 8/10/1993 5,241,632 8/31/1993 5,243,592 9/7/1993 5,247,464 9/21/1993 5,247,524 9/21/1993 5,251,205 10/5/1993 5,255,287 10/19/1993 5,255,375 10/19/1993 5,257,264 10/26/1993 5,265,092 11/23/1993 5,265,216 11/23/1993 5,265,257 11/23/1993 5,267,199 11/30/1993 5,267,237 11/30/1993 5,276,859 1/4/1994 5,276,868 1/4/1994 5,278,829 1/11/1994 5,280,478 1/18/1994 5,280,582 1/18/1994 5,283,571 2/1/1994 5,287,359 2/15/1994 5,289,347 2/22/1994 5,291,491 3/1/1994 5,291,529 3/1/1994 5,293,486 3/8/1994 5,293,487 3/8/1994 5,301,186 4/5/1994 5,303,302 4/12/1994 5,303,391 4/12/1994 5,304,939 4/19/1994 5,305,305 4/19/1994 5,305,306 4/19/1994 5,307,345 4/26/1994 5,307,355 4/26/1994 5,309,437 5/3/1994 5,313,465 5/17/1994 5,313,467 5/17/1994 5,313,641 5/17/1994 5,315,597 5/24/1994 5,321,693 6/14/1994 5,323,394 6/21/1994 5,327,424 7/5/1994 5,327,534 7/5/1994 5,331,636 7/19/1994 5,333,744 8/2/1994 5,335,226 8/2/1994 5,339,307 8/16/1994 5,339,313 8/16/1994 5,341,405 8/23/1994 5,349,343 9/20/1994 5,351,243 9/27/1994 5,353,286 10/4/1994 5,355,124 10/11/1994 5,357,619 10/18/1994 5,361,372 11/1/1994 5,365,658 11/22/1994 5,366,388 11/22/1994 5,367,688 11/22/1994 5,371,868 12/6/1994 5,373,421 12/13/1994 5,377,190 12/27/1994 5,377,327 12/27/1994 5,384,779 1/24/1995 5,386,523 1/31/1995 5,388,099 2/7/1995 5,390,173 2/14/1995 5,390,299 2/14/1995 5,394,401 2/28/1995 5,396,239 3/7/1995 5,398,234 3/14/1995 5,398,242 3/14/1995 5,398,822 3/21/1995 5,400,333 3/21/1995 5,401,193 3/28/1995 5,404,353 4/4/1995 5,404,474 4/4/1995 5,404,536 4/4/1995 5,408,473 4/18/1995 5,408,500 4/18/1995 5,410,535 4/25/1995 5,412,691 5/2/1995 5,414,700 5/9/1995 5,414,704 5/9/1995 5,418,781 5/23/1995 5,418,784 5/23/1995 5,418,967 5/23/1995 5,420,862 5/30/1995 5,420,986 5/30/1995 5,428,611 6/27/1995 5,428,615 6/27/1995 5,428,766 6/27/1995 5,430,727 7/4/1995 5,432,776 7/11/1995 5,432,784 7/11/1995 5,432,788 7/11/1995 5,434,855 7/18/1995 5,434,864 7/18/1995 5,436,903 7/25/1995 5,440,690 8/8/1995 5,440,691 8/8/1995 5,446,734 8/29/1995 5,450,407 9/12/1995 5,452,330 9/19/1995 5,453,983 9/26/1995 5,455,826 10/3/1995 5,455,865 10/3/1995 5,459,713 10/17/1995 5,459,720 10/17/1995 5,465,340 11/7/1995 5,471,632 11/28/1995 5,477,540 12/19/1995 5,481,538 1/2/1996 5,483,526 1/9/1996 5,485,455 1/16/1996 5,485,576 1/16/1996 5,485,586 1/16/1996 5,485,932 1/23/1996 5,489,162 2/6/1996 5,491,692 2/13/1996 5,491,694 2/13/1996 5,491,801 2/13/1996 5,495,232 2/27/1996 5,500,860 3/19/1996 5,509,123 4/16/1996 5,511,076 4/23/1996 5,511,168 4/23/1996 5,515,363 5/7/1996 5,515,513 5/7/1996 5,515,523 5/7/1996 5,517,533 5/14/1996 5,517,617 5/14/1996 5,519,693 5/21/1996 5,519,858 5/21/1996 5,522,042 5/28/1996 5,523,998 6/4/1996 5,524,254 6/4/1996 5,526,355 6/11/1996 5,528,513 6/18/1996 5,535,099 7/9/1996 5,535,209 7/9/1996 5,537,098 7/16/1996 5,537,413 7/15/1996 5,542,076 7/30/1996 5,546,377 8/13/1996 5,546,543 8/13/1996 5,548,762 8/20/1996 5,553,085 9/3/1996 5,553,264 9/3/1996 5,555,405 9/10/1996 5,557,745 9/17/1996 5,568,470 10/22/1996 5,574,860 11/12/1996 5,583,867 12/10/1996 5,590,366 12/31/1996 5,596,575 1/21/1997 5,600,814 2/4/1997 5,602,853 2/11/1997 5,608,726 3/4/1997 5,610,951 3/11/1997 5,613,129 3/18/1997 5,617,409 4/1/1997 5,621,734 4/15/1997 5,631,908 5/20/1997 5,633,867 5/27/1997 5,638,259 6/10/1997 5,644,571 7/1/1997 5,648,959 7/15/1997 5,649,109 7/15/1997 5,649,110 7/15/1997 5,650,997 7/22/1997 5,668,951 9/16/1997 5,675,735 10/7/1997 5,675,742 10/7/1997 5,684,800 11/4/1997 5,724,513 3/3/1998 5,734,659 3/31/1998 5,734,825 3/31/1998 5,740,467 4/14/1998 5,745,697 4/28/1998 5,751,971 5/12/1998 5,781,772 7/14/1998 5,790,546 8/4/1998 5,796,740 8/18/1998 5,796,966 8/18/1998 5,802,061 9/1/1998 5,805,808 9/8/1998 5,809,253 9/15/1998 5,812,771 9/22/1998 5,812,774 9/22/1998 5,822,612 10/13/1998 5,825,772 10/20/1998 5,838,989 11/17/1998 5,844,902 12/1/1998 5,862,206 1/19/1999 5,867,480 2/2/1999 5,870,386 2/9/1999 5,894,517 4/13/1999 5,898,686 4/27/1999 5,898,694 4/27/1999 5,901,045 5/4/1999 5,905,723 5/18/1999 5,910,690 6/8/1999 5,918,040 6/29/1999 5,920,900 7/6/1999 5,922,046 7/13/1999 5,923,851 7/13/1999 5,940,376 8/17/1999 5,941,952 8/24/1999 5,946,308 8/31/1999 5,951,649 9/14/1999 5,953,342 9/14/1999 5,954,301 9/21/1999 5,954,835 9/21/1999 5,956,322 9/21/1999 5,956,335 9/21/1999 5,961,345 10/5/1999 5,963,556 10/5/1999 5,963,719 10/5/1999 5,966,546 10/12/1999 5,968,128 10/19/1999 5,970,229 10/19/1999 5,978,357 11/2/1999 5,987,522 11/16/1999 5,995,995 11/30/1999 5,999,980 12/7/1999 6,000,008 12/7/1999 6,002,675 12/14/1999 6,008,550 12/28/1999 6,014,409 1/11/2000 6,014,659 1/11/2000 6,041,042 3/21/2000 6,044,121 3/28/2000 6,046,982 4/4/2000 6,047,328 4/4/2000 6,061,737 5/9/2000 6,067,557 5/23/2000 6,067,563 5/23/2000 6,072,772 6/6/2000 6,078,949 6/20/2000 6,081,511 6/27/2000 6,085,215 7/4/2000 6,097,705 8/1/2000 6,101,170 8/8/2000 6,112,251 8/29/2000 6,122,281 9/19/2000 6,125,466 9/26/2000 -
SCHEDULE 2 Pending Applications Appln. No. Filing Date 08/323,169 11/30/1994 08/643,899 5/7/1996 08/657,414 6/3/1996 08/670,733 6/24/1996 08/716,056 9/19/1996 08/774,541 12/30/1996 08/779/884 1/6/1997 08/847,344 4/24/1997 08/852,188 5/6/1997 08/960,010 10/29/1997 08/972,267 11/18/1997 08/972,663 11/18/1997 08/974,632 11/19/1997 09/005,740 1/12/1998 09/006,241 1/13/1998 09/006,242 1/13/1998 09/021,245 2/10/1998 09/073,557 5/6/1998 09/082,767 5/21/1998 09/083,062 5/21/1998 09/130,234 8/6/1998 09/174,991 10/19/1998 09/203,107 11/30/1998 09/221,333 12/23/1998 09/243,091 2/2/1999 09/247,820 2/9/1999 09/256,041 2/23/1999 09/257,725 2/25/1999 09/259,946 3/1/1999 09/299,970 4/26/1999 09/332,836 6/14/1999 09/387,317 8/31/99 09/396,077 9/14/1999 09/398,488 9/17/1999 09/411,773 10/4/1999 09/421,021 10/19/1999 09/484,757 1/18/2000 09/578,143 5/24/2000 09/614,236 7/12/2000 09/614,840 7/12/2000 09/628,870 7/24/2000 09/630,703 8/1/2000 09/650,622 8/30/2000
Claims (1)
1. A switch for use in a communications system for transmitting traffic from a first user to a second user, the first and second users being interconnected by a primary communications path and a redundant communications path, comprising:
a first port configured to receive hello communications indicative of a proper operation of the primary communications path;
a second port configured to receive data communications; and
a switch control configured to monitor the receipt of the hello communications, to direct the forwarding of received data communications up to a threshold and, if the received data communications exceed the threshold, to drop at least a portion of the received data communications such that forwarded data communications are below the threshold.
Priority Applications (1)
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---|---|---|---|---|
WO2003079600A2 (en) * | 2002-03-15 | 2003-09-25 | Vitesse Semiconductor Corporation | System and a method for switching data packets or frames using multiple switching elements |
US20080052276A1 (en) * | 2006-08-28 | 2008-02-28 | Assimakis Tzamaloukas | System and method for location-based searches and advertising |
US20080052391A1 (en) * | 2006-08-28 | 2008-02-28 | Seth Rogers | System and method for updating information using limited bandwidth |
US20080059424A1 (en) * | 2006-08-28 | 2008-03-06 | Assimakis Tzamaloukas | System and method for locating-based searches and advertising |
US20090154340A1 (en) * | 2007-12-18 | 2009-06-18 | Motorola, Inc. | Fast ospf inactive router detection |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6301224B1 (en) * | 1998-01-13 | 2001-10-09 | Enterasys Networks, Inc. | Network switch with panic mode |
US6469987B1 (en) | 1998-01-13 | 2002-10-22 | Enterasys Networks, Inc. | Virtual local area network with trunk stations |
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US7173934B2 (en) * | 2001-09-10 | 2007-02-06 | Nortel Networks Limited | System, device, and method for improving communication network reliability using trunk splitting |
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EP1964330B1 (en) * | 2005-12-23 | 2010-08-11 | Telecom Italia S.p.A. | Method for reducing fault detection time in a telecommunication network |
US8004966B2 (en) * | 2008-04-25 | 2011-08-23 | Calix, Inc. | Efficient management of ring networks |
US10356832B2 (en) * | 2015-05-11 | 2019-07-16 | Qualcomm Incorporated | Introduction of powered relay for device-to-device communication |
US11314711B2 (en) * | 2019-01-30 | 2022-04-26 | Hewlett Packard Enterprise Development Lp | Network switch with network analysis data producer-consumer shared memory |
Citations (46)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4823338A (en) * | 1987-08-03 | 1989-04-18 | American Telephone And Telegraph Company | Virtual local area network |
US4845710A (en) * | 1986-12-23 | 1989-07-04 | Oki Electric Industry Co., Ltd. | Dynamic buffer supervising system for a data link access protocol control |
US4933937A (en) * | 1986-11-29 | 1990-06-12 | Kabushiki Kaisha Toshiba | Network adapter for connecting local area network to backbone network |
US4975906A (en) * | 1988-02-15 | 1990-12-04 | Hitachi, Ltd. | Network system |
US5018133A (en) * | 1987-11-18 | 1991-05-21 | Hitachi, Ltd. | Network system comprising a plurality of LANs using hierarchical routing |
US5138615A (en) * | 1989-06-22 | 1992-08-11 | Digital Equipment Corporation | Reconfiguration system and method for high-speed mesh connected local area network |
US5218603A (en) * | 1989-10-19 | 1993-06-08 | Mitsubishi Denki Kabushiki Kaisha | Node unit and communications method for local area network |
US5237661A (en) * | 1989-05-29 | 1993-08-17 | Hitachi, Ltd. | Buffer management method and system therefor using an I/O buffer on main memory and utilizing virtual memory and page fixing |
US5321693A (en) * | 1991-01-25 | 1994-06-14 | Digital Equipment Corporation | Multicast address in a local area network where the local area network has inadequate multicast addressing capability |
US5394402A (en) * | 1993-06-17 | 1995-02-28 | Ascom Timeplex Trading Ag | Hub for segmented virtual local area network with shared media access |
US5473608A (en) * | 1991-04-11 | 1995-12-05 | Galileo International Partnership | Method and apparatus for managing and facilitating communications in a distributed heterogeneous network |
US5473599A (en) * | 1994-04-22 | 1995-12-05 | Cisco Systems, Incorporated | Standby router protocol |
US5594732A (en) * | 1995-03-03 | 1997-01-14 | Intecom, Incorporated | Bridging and signalling subsystems and methods for private and hybrid communications systems including multimedia systems |
US5617421A (en) * | 1994-06-17 | 1997-04-01 | Cisco Systems, Inc. | Extended domain computer network using standard links |
US5619495A (en) * | 1994-09-02 | 1997-04-08 | Mitsubishi Denki Kabushiki Kaisha | Cell switching apparatus and a cell switching system |
US5621734A (en) * | 1984-06-01 | 1997-04-15 | Digital Equipment Corporation | Local area network with server and virtual circuits |
US5636215A (en) * | 1994-12-27 | 1997-06-03 | Mitsubishi Denki Kabushiki Kaisha | Ring type ATM network system |
US5734824A (en) * | 1993-02-10 | 1998-03-31 | Bay Networks, Inc. | Apparatus and method for discovering a topology for local area networks connected via transparent bridges |
US5734865A (en) * | 1995-06-07 | 1998-03-31 | Bull Hn Information Systems Inc. | Virtual local area network well-known port routing mechanism for mult--emulators in an open system environment |
US5752003A (en) * | 1995-07-14 | 1998-05-12 | 3 Com Corporation | Architecture for managing traffic in a virtual LAN environment |
US5751967A (en) * | 1994-07-25 | 1998-05-12 | Bay Networks Group, Inc. | Method and apparatus for automatically configuring a network device to support a virtual network |
US5768257A (en) * | 1996-07-11 | 1998-06-16 | Xylan Corporation | Input buffering/output control for a digital traffic switch |
US5796740A (en) * | 1991-06-14 | 1998-08-18 | Cabletron Systems, Inc. | Router using multiple hop redirect messages to enable bridge like data forwarding |
US5802056A (en) * | 1995-07-12 | 1998-09-01 | Bay Networks, Inc. | Configuration of virtual rings in a token ring local area network |
US5805816A (en) * | 1992-05-12 | 1998-09-08 | Compaq Computer Corp. | Network packet switch using shared memory for repeating and bridging packets at media rate |
US5838677A (en) * | 1995-04-18 | 1998-11-17 | Hitachi, Ltd. | Switching system having means for congestion control by monitoring packets in a shared buffer and by suppressing the reading of packets from input buffers |
US5878232A (en) * | 1996-12-27 | 1999-03-02 | Compaq Computer Corporation | Dynamic reconfiguration of network device's virtual LANs using the root identifiers and root ports determined by a spanning tree procedure |
US5889762A (en) * | 1993-11-30 | 1999-03-30 | Nokia Telecommunications Oy | Control of overload situations in frame relay network which discards the contents of a virtual-channel-specific buffer when said buffer is full |
US5892922A (en) * | 1997-02-28 | 1999-04-06 | 3Com Corporation | Virtual local area network memory access system |
US5949783A (en) * | 1997-09-08 | 1999-09-07 | 3Com Corporation | LAN emulation subsystems for supporting multiple virtual LANS |
US5959989A (en) * | 1997-06-25 | 1999-09-28 | Cisco Technology, Inc. | System for efficient multicast distribution in a virtual local area network environment |
US5959990A (en) * | 1996-03-12 | 1999-09-28 | Bay Networks, Inc. | VLAN frame format |
US5963556A (en) * | 1993-06-23 | 1999-10-05 | Digital Equipment Corporation | Device for partitioning ports of a bridge into groups of different virtual local area networks |
US5963540A (en) * | 1997-12-19 | 1999-10-05 | Holontech Corporation | Router pooling in a network flowswitch |
US5987522A (en) * | 1998-01-13 | 1999-11-16 | Cabletron Systems, Inc. | Privileged virtual local area networks |
US6014380A (en) * | 1997-06-30 | 2000-01-11 | Sun Microsystems, Inc. | Mechanism for packet field replacement in a multi-layer distributed network element |
US6023563A (en) * | 1996-08-20 | 2000-02-08 | Shani; Ron | Networking switch having the network presence of a bridge |
US6047325A (en) * | 1997-10-24 | 2000-04-04 | Jain; Lalit | Network device for supporting construction of virtual local area networks on arbitrary local and wide area computer networks |
US6085238A (en) * | 1996-04-23 | 2000-07-04 | Matsushita Electric Works, Ltd. | Virtual LAN system |
US6111876A (en) * | 1996-03-12 | 2000-08-29 | Nortel Networks Limited | VLAN frame format |
US6112251A (en) * | 1998-01-13 | 2000-08-29 | Cabletron Systems, Inc. | Virtual local network for sending multicast transmissions to trunk stations |
US6128665A (en) * | 1996-12-30 | 2000-10-03 | Cabletron Systems, Inc. | System for broadcasting messages to each of default VLAN ports in subset of ports defined as VLAN ports |
US6157647A (en) * | 1996-11-06 | 2000-12-05 | 3Com Corporation | Direct addressing between VLAN subnets |
US6188691B1 (en) * | 1998-03-16 | 2001-02-13 | 3Com Corporation | Multicast domain virtual local area network |
US6222822B1 (en) * | 1996-04-23 | 2001-04-24 | Cisco Systems, Incorporated | Method for optimizing a digital transmission network operation through transient error monitoring and control and system for implementing said method |
US6301224B1 (en) * | 1998-01-13 | 2001-10-09 | Enterasys Networks, Inc. | Network switch with panic mode |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5088091A (en) | 1989-06-22 | 1992-02-11 | Digital Equipment Corporation | High-speed mesh connected local area network |
US5995486A (en) | 1994-09-17 | 1999-11-30 | International Business Machines Corporation | Flow control method and apparatus for cell-based communication networks |
US5808056A (en) | 1995-10-31 | 1998-09-15 | Merck & Co., Inc. | Process for preparing substituted azetidinones |
US6128655A (en) | 1998-07-10 | 2000-10-03 | International Business Machines Corporation | Distribution mechanism for filtering, formatting and reuse of web based content |
-
1998
- 1998-01-13 US US09/006,241 patent/US6301224B1/en not_active Expired - Lifetime
-
1999
- 1999-01-13 AU AU21049/99A patent/AU736473B2/en not_active Ceased
- 1999-01-13 CA CA002318104A patent/CA2318104C/en not_active Expired - Fee Related
- 1999-01-13 DE DE69917601T patent/DE69917601T2/en not_active Expired - Lifetime
- 1999-01-13 WO PCT/US1999/000154 patent/WO1999037063A1/en active IP Right Grant
- 1999-01-13 EP EP99901323A patent/EP1048149B1/en not_active Expired - Lifetime
-
2001
- 2001-10-09 US US09/973,221 patent/US20020044526A1/en not_active Abandoned
Patent Citations (47)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5621734A (en) * | 1984-06-01 | 1997-04-15 | Digital Equipment Corporation | Local area network with server and virtual circuits |
US4933937A (en) * | 1986-11-29 | 1990-06-12 | Kabushiki Kaisha Toshiba | Network adapter for connecting local area network to backbone network |
US4845710A (en) * | 1986-12-23 | 1989-07-04 | Oki Electric Industry Co., Ltd. | Dynamic buffer supervising system for a data link access protocol control |
US4823338A (en) * | 1987-08-03 | 1989-04-18 | American Telephone And Telegraph Company | Virtual local area network |
US4823338B1 (en) * | 1987-08-03 | 1998-11-10 | At & T Information Systems Inc | Virtual local area network |
US5018133A (en) * | 1987-11-18 | 1991-05-21 | Hitachi, Ltd. | Network system comprising a plurality of LANs using hierarchical routing |
US4975906A (en) * | 1988-02-15 | 1990-12-04 | Hitachi, Ltd. | Network system |
US5237661A (en) * | 1989-05-29 | 1993-08-17 | Hitachi, Ltd. | Buffer management method and system therefor using an I/O buffer on main memory and utilizing virtual memory and page fixing |
US5138615A (en) * | 1989-06-22 | 1992-08-11 | Digital Equipment Corporation | Reconfiguration system and method for high-speed mesh connected local area network |
US5218603A (en) * | 1989-10-19 | 1993-06-08 | Mitsubishi Denki Kabushiki Kaisha | Node unit and communications method for local area network |
US5321693A (en) * | 1991-01-25 | 1994-06-14 | Digital Equipment Corporation | Multicast address in a local area network where the local area network has inadequate multicast addressing capability |
US5473608A (en) * | 1991-04-11 | 1995-12-05 | Galileo International Partnership | Method and apparatus for managing and facilitating communications in a distributed heterogeneous network |
US5796740A (en) * | 1991-06-14 | 1998-08-18 | Cabletron Systems, Inc. | Router using multiple hop redirect messages to enable bridge like data forwarding |
US5805816A (en) * | 1992-05-12 | 1998-09-08 | Compaq Computer Corp. | Network packet switch using shared memory for repeating and bridging packets at media rate |
US5734824A (en) * | 1993-02-10 | 1998-03-31 | Bay Networks, Inc. | Apparatus and method for discovering a topology for local area networks connected via transparent bridges |
US5394402A (en) * | 1993-06-17 | 1995-02-28 | Ascom Timeplex Trading Ag | Hub for segmented virtual local area network with shared media access |
US5963556A (en) * | 1993-06-23 | 1999-10-05 | Digital Equipment Corporation | Device for partitioning ports of a bridge into groups of different virtual local area networks |
US5889762A (en) * | 1993-11-30 | 1999-03-30 | Nokia Telecommunications Oy | Control of overload situations in frame relay network which discards the contents of a virtual-channel-specific buffer when said buffer is full |
US5473599A (en) * | 1994-04-22 | 1995-12-05 | Cisco Systems, Incorporated | Standby router protocol |
US5617421A (en) * | 1994-06-17 | 1997-04-01 | Cisco Systems, Inc. | Extended domain computer network using standard links |
US5751967A (en) * | 1994-07-25 | 1998-05-12 | Bay Networks Group, Inc. | Method and apparatus for automatically configuring a network device to support a virtual network |
US5619495A (en) * | 1994-09-02 | 1997-04-08 | Mitsubishi Denki Kabushiki Kaisha | Cell switching apparatus and a cell switching system |
US5636215A (en) * | 1994-12-27 | 1997-06-03 | Mitsubishi Denki Kabushiki Kaisha | Ring type ATM network system |
US5594732A (en) * | 1995-03-03 | 1997-01-14 | Intecom, Incorporated | Bridging and signalling subsystems and methods for private and hybrid communications systems including multimedia systems |
US5838677A (en) * | 1995-04-18 | 1998-11-17 | Hitachi, Ltd. | Switching system having means for congestion control by monitoring packets in a shared buffer and by suppressing the reading of packets from input buffers |
US5734865A (en) * | 1995-06-07 | 1998-03-31 | Bull Hn Information Systems Inc. | Virtual local area network well-known port routing mechanism for mult--emulators in an open system environment |
US5802056A (en) * | 1995-07-12 | 1998-09-01 | Bay Networks, Inc. | Configuration of virtual rings in a token ring local area network |
US5752003A (en) * | 1995-07-14 | 1998-05-12 | 3 Com Corporation | Architecture for managing traffic in a virtual LAN environment |
US5959990A (en) * | 1996-03-12 | 1999-09-28 | Bay Networks, Inc. | VLAN frame format |
US6111876A (en) * | 1996-03-12 | 2000-08-29 | Nortel Networks Limited | VLAN frame format |
US6222822B1 (en) * | 1996-04-23 | 2001-04-24 | Cisco Systems, Incorporated | Method for optimizing a digital transmission network operation through transient error monitoring and control and system for implementing said method |
US6085238A (en) * | 1996-04-23 | 2000-07-04 | Matsushita Electric Works, Ltd. | Virtual LAN system |
US5768257A (en) * | 1996-07-11 | 1998-06-16 | Xylan Corporation | Input buffering/output control for a digital traffic switch |
US6023563A (en) * | 1996-08-20 | 2000-02-08 | Shani; Ron | Networking switch having the network presence of a bridge |
US6157647A (en) * | 1996-11-06 | 2000-12-05 | 3Com Corporation | Direct addressing between VLAN subnets |
US5878232A (en) * | 1996-12-27 | 1999-03-02 | Compaq Computer Corporation | Dynamic reconfiguration of network device's virtual LANs using the root identifiers and root ports determined by a spanning tree procedure |
US6128665A (en) * | 1996-12-30 | 2000-10-03 | Cabletron Systems, Inc. | System for broadcasting messages to each of default VLAN ports in subset of ports defined as VLAN ports |
US5892922A (en) * | 1997-02-28 | 1999-04-06 | 3Com Corporation | Virtual local area network memory access system |
US5959989A (en) * | 1997-06-25 | 1999-09-28 | Cisco Technology, Inc. | System for efficient multicast distribution in a virtual local area network environment |
US6014380A (en) * | 1997-06-30 | 2000-01-11 | Sun Microsystems, Inc. | Mechanism for packet field replacement in a multi-layer distributed network element |
US5949783A (en) * | 1997-09-08 | 1999-09-07 | 3Com Corporation | LAN emulation subsystems for supporting multiple virtual LANS |
US6047325A (en) * | 1997-10-24 | 2000-04-04 | Jain; Lalit | Network device for supporting construction of virtual local area networks on arbitrary local and wide area computer networks |
US5963540A (en) * | 1997-12-19 | 1999-10-05 | Holontech Corporation | Router pooling in a network flowswitch |
US6112251A (en) * | 1998-01-13 | 2000-08-29 | Cabletron Systems, Inc. | Virtual local network for sending multicast transmissions to trunk stations |
US5987522A (en) * | 1998-01-13 | 1999-11-16 | Cabletron Systems, Inc. | Privileged virtual local area networks |
US6301224B1 (en) * | 1998-01-13 | 2001-10-09 | Enterasys Networks, Inc. | Network switch with panic mode |
US6188691B1 (en) * | 1998-03-16 | 2001-02-13 | 3Com Corporation | Multicast domain virtual local area network |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003079600A2 (en) * | 2002-03-15 | 2003-09-25 | Vitesse Semiconductor Corporation | System and a method for switching data packets or frames using multiple switching elements |
WO2003079600A3 (en) * | 2002-03-15 | 2003-12-24 | Vitesse Semiconductor Corp | System and a method for switching data packets or frames using multiple switching elements |
US20080052276A1 (en) * | 2006-08-28 | 2008-02-28 | Assimakis Tzamaloukas | System and method for location-based searches and advertising |
US20080052391A1 (en) * | 2006-08-28 | 2008-02-28 | Seth Rogers | System and method for updating information using limited bandwidth |
US20080059424A1 (en) * | 2006-08-28 | 2008-03-06 | Assimakis Tzamaloukas | System and method for locating-based searches and advertising |
US20100241352A1 (en) * | 2006-08-28 | 2010-09-23 | Assimakis Tzamaloukas | System and method for location-based searches and advertising |
US7987260B2 (en) * | 2006-08-28 | 2011-07-26 | Dash Navigation, Inc. | System and method for updating information using limited bandwidth |
US8112522B2 (en) * | 2006-08-28 | 2012-02-07 | Dash Navigation, Inc. | System and method for updating information using limited bandwidth |
US8307090B2 (en) | 2006-08-28 | 2012-11-06 | Dash Navigation Inc. | System and method for updating information using limited bandwidth |
US8612437B2 (en) | 2006-08-28 | 2013-12-17 | Blackberry Limited | System and method for location-based searches and advertising |
US20090154340A1 (en) * | 2007-12-18 | 2009-06-18 | Motorola, Inc. | Fast ospf inactive router detection |
US8068409B2 (en) * | 2007-12-18 | 2011-11-29 | Motorola Solutions, Inc. | Fast OSPF inactive router detection |
Also Published As
Publication number | Publication date |
---|---|
DE69917601T2 (en) | 2004-09-30 |
WO1999037063A1 (en) | 1999-07-22 |
EP1048149B1 (en) | 2004-05-26 |
US6301224B1 (en) | 2001-10-09 |
EP1048149A1 (en) | 2000-11-02 |
AU2104999A (en) | 1999-08-02 |
AU736473B2 (en) | 2001-07-26 |
CA2318104A1 (en) | 1999-07-22 |
CA2318104C (en) | 2003-11-11 |
DE69917601D1 (en) | 2004-07-01 |
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