|Publication number||US5914938 A|
|Application number||US 08/746,963|
|Publication date||22 Jun 1999|
|Filing date||19 Nov 1996|
|Priority date||19 Nov 1996|
|Publication number||08746963, 746963, US 5914938 A, US 5914938A, US-A-5914938, US5914938 A, US5914938A|
|Inventors||David M. Brady, David A. Head, Suryanarayan Ramamurthy, Ahmad Esmaeili|
|Original Assignee||Bay Networks, Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (2), Referenced by (165), Classifications (9), Legal Events (12)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates generally to computer networks and, more particularly, to a method and apparatus for maintaining a forwarding table in a switching node of a computer network.
In recent years, local area networks (LANs) have become a common place in offices and other environments. Now, virtual LANs are beginning to emerge as well. In a basic sense, a switched virtual LAN is a broadcast domain that unites any arbitrary group of LAN segments at wire speed. As is the case with a single physical wire, broadcasts travel to all end-stations in a virtual LAN. A single virtual LAN can connect dozens, or in some cases hundreds, of LAN users. The ability to include multiple physical LAN segments gives virtual LANs a distinct advantage of multiple port routers. In a effort to gain bandwidth for LAN users, network managers often deploy conventional multiple port routers to segment LANs, but each physical segment created by a multiple port router must be treated as a separate logical sub-net. Traffic passing between sub-nets is subjected to additional delay because of processing by the routers.
Virtual LANs minimize this delay problem because they bridge, rather than route, traffic destined for different segments within the same network. Multiple segments per sub-net generally means fewer routing bottlenecks. It also means that end-stations can be assigned to different virtual LANs without having to reconfigure the physical network.
When virtual LANs are used to sub-divide switched traffic into contained areas, Ethernet switching becomes a powerful inter-networking method that greatly reduces the role of the router. Each defined virtual LAN can include several physical segments per local sub-net. With virtual LANs, a network administrator can define user groups regardless of the physical LAN segment to which they are connected. Users assigned to the same virtual LAN communicate at wire speed with low latency and, generally, no routing bottlenecks, regardless of their physical location in the network. Virtual LANs can be extended across multiple switches, with the switches being linked by high speed backbones, such as FDDI, 100 MBPS fast Ethernet, or ATM. Some switches may handle virtual LANs at the data link level (i.e., layer two of the OSI model), leaving layer three (network layer) functions to routers. Other switches may handle virtual LANs at layer three, meaning that they perform basic routing chores themselves.
Ethernet virtual LANs that function at layer two are often defined by software that allows network administrators to group a number switched ports together into a high bandwidth, low latency switched work group. Under the layer two approach, each virtual LAN is assigned a unique number that identifies it for network management purposes. These layer two virtual LANs are based on bridge architecture's that transmit data using media access control (MAC) source and destination addresses. Traffic within virtual LANs is switched according to these addresses and traffic between virtual LANs is handled by a router that imposes filtering, security and traffic management. The router can be either a stand alone unit or a separate card integrated into an Ethernet switch. Either way, the routing is handle by software which is separate from the virtual LAN switching logic.
Once layer two port group virtual LANs are defined, each switch of the network reads incoming frames and learns the MAC addresses associated with each virtual LAN. If an end station sends broadcast or multicast frames, those frames are then forwarded to all ports in that end station's virtual LAN. The ports can be spread across any number of switches connected to the high speed backbone. All LAN segments in a port group are bridged together whether they are separated by the backbone or reside in the same switch.
Supporting layer two virtual LAN port groups on a single switch is a straight forward process. Ethernet switches cache MAC addresses and information about which port each MAC address is connected to. With virtual LAN switches, a virtual LAN number is added to a MAC address and stored in the switch's forwarding table. Armed with this information, switches can direct broadcast to the appropriate ports.
In order to provide rapid access to the forwarding tables, some Ethernet switches use a storage system based on hashing. Hashing is a storage system based on the antithesis of sorting. Instead of keeping the data in an orderly pattern, hashing staggers records throughout a storage space in a pseudorandom function. This pseudorandom function uses the value of a record's key as a search key and outputs an address within the storage space that the data can be placed in. The storage space address is often referred to as a storage bucket.
The function used to generate array indices from search keys is called a hash function and the resulting array is generally referred to as a hash table. Unfortunately, generating appropriate array indices from keys often proves to be difficult. The reason is that if the keys for two different data records hash to the same index value, then collisions will occur. Collisions pose a problem because, over the course of time, the switch will be required to locate stored data records and, if two records have been hashed to the same location in a hash table, one may overwrite the other, resulting in a loss of information. Several techniques for resolving collision problems have been used in the past.
For example, a bounded bucket size approach, where bucket size is limited to a value less than the total number of items being stored in the table, has been used. The benefit of this approach is a guarantee on the maximum search time required to search the table. The consequent problem with such a scheme, however, is the inability of the designer to guarantee storage of all items in the table.
Unbounded bucket size approaches where all items could be stored in one bucket if the selected hash function produced such a result, have also been employed. While such schemes ensure that all items can be stored, search times cannot be guaranteed because the bucket size will vary.
Accordingly, it would be desirable to have an Ethernet switch capable of allowing a guaranteed search time (which is less than the search time required for an unbounded bucket scheme) for each MAC address presented and a guarantee as to the number of entries which can be stored in the MAC address forwarding table.
In one embodiment, the present invention provides a method of locating an entry in a table stored in a computer readable medium. A search key having a first length is presented to a search process. This search value is hashed to generate a bucket identifier having a second length, smaller than the first length. The bucket identifier is then used to address a table stored in a computer readable medium and a pointer is retrieved from an associated storage location. The pointer is used to index a hash bucket containing one or more entries, each of which can be compared to the search key to determine whether any of the entries match the search key. For the case where the table locating method is used in an Ethernet switch, the search keys comprise a virtual LAN identification and media access control address.
In this embodiment, the hash function applied to the search key first segments the search key into a number of equal segments. Each of the segments is multiplied by a corresponding segment of a hash coefficient to create a series of products. These products are summed and the resulting sum is then subjected to a MOD operation with a prime number. The result of the MOD operation is used as the bucket identifier to address the table.
In another embodiment, the present invention provides a computer assisted method of configuring a media access control (MAC) address table for a switching node of a communication network. The MAC address table is made up of a number of hash buckets, each of which have one or more entries. As frames are received at the switching node, a MAC address is identified and, if not already present within the MAC address table, stored as a new entry in one of the hash buckets according to a hash function so long as no overflow of any hash bucket would be created. If a bucket overflow would result from the storing operation, a new hash function is automatically selected so that no hash bucket overflows will result when the new MAC address is stored in a new MAC address table.
The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like numeral indicate similar elements and in which:
FIG. 1 illustrates a computer network utilizing the methods of the present invention and made up of a number of virtual LANs;
FIG. 2 illustrates a network switch node of the computer network shown in FIG. 1;
FIG. 3 is a graphical illustration of the structure of a MAC address table according to one embodiment;
FIG. 4 is a graphical illustration of a hashing process according to the methods of the present invention; and
FIG. 5 is a flow diagram illustrating the process of selecting a new hash function in accordance with the present invention.
A MAC address table search unit is described. In alternative embodiments, the present invention may be applicable to implementations in integrated circuits or chip sets, wireless implementations, switching systems products and transmission system products. For purposes of this application, the term switching systems products shall be taken to mean private branch exchanges (PBXs), central office switching systems that interconnect subscribers, toll/tandem switching systems for interconnecting trunks between switching centers, and broadband core switches found at the center of a service provider's network that may be fed by broadband edge switches or access multiplexers, and associated signaling and support systems and services. The term transmission system products shall be taken to mean products used by services providers to provide interconnection between their subscribers and their networks, such as loop systems, and which provide multiplexing, aggregation and transport between the service provider's switching systems, and associated signaling and support systems and services.
FIG. 1 illustrates a computer system 10 which is made up of a number of virtual LANs 12. Each virtual LAN 12 has a number of end-stations 14. For clarity, only one end-station 14 is labeled in FIG. 1, however, it will be appreciated that each of the end-stations is substantially similar. The end-stations 14 are connected via virtual LAN switches 16. The virtual LAN switches 16 are coupled via a high speed backbone 18. As shown, each of the virtual LAN switches 16 may be connected to other switches within computer system 10 or a virtual LAN switch 16 may be connected to a router 20 which itself is connected to other enterprise networks.
The virtual LAN switches 16 shown in FIG. 1 may create the various virtual LANs 12 at the data link layer (i.e., layer two of the OSI model), leaving layer 3 (i.e., network layer) functions to routers. Alternatively, the virtual LAN switches 16 may handle the virtual LANs 12 at layer 3, and thereby perform basic routing chores.
FIG. 2 further illustrates a virtual LAN switch 16. Each switch 16 includes a number of port cards 22 and a central processor 24. The central processor 24 communicates with each of the port cards 22 via a system bus 26. Each of the port cards 22 supports a number of ports 28. Those skilled in the art will appreciate that each of the ports 28 may handle traffic from a number of end-stations 14 within each of the virtual LANs 12.
As illustrated, each port card 22 includes a port controller 30 and an associated storage device 32. In a preferred embodiment, each port 28 has a dedicated port controller 30 and storage device 32, however, those skilled in the art will appreciate that other configurations may allow a single port controller 30 and storage device 32 to be associated with multiple ports. In one embodiment, the storage device 32 may be a DRAM.
Each port card 22 caches address and other information about each port 28 connected thereto. It will be appreciated that this information may be stored locally in storage devices 32 or, in some cases, may be stored in a central storage device accessable by multiple port controllers 30 via system bus 26. As frames of information are received across ports 28, port controller 30 examines address information within each of frames and compares that information to address information stored in a forwarding table stored in DRAM 32. Based on this comparison, the port controller 30 can determine which port (if any) the incoming frame needs to be switched to and may then pass the frame to the appropriate port card 22 across system bus 26. In some cases, port controller 30 will recognize that the frame is destined for an end-station 14 associated with the port 28 which the port controller 30 controls. In this case, the frame is not forwarded.
As indicated, each frame of information transmitted across computer network 10 contains address and other information. Those skilled in the art will appreciate that a typical Ethernet frame includes a destination address (DA), a source address (SA) and a data field (DATA). The destination address and source address are each 6 bytes (48 bits) long. The DATA is the actual payload being transmitted within the frame. It's length will vary depending upon the associated application. Some Ethernet frames include an additional header portion which specifies a virtual LAN identifier (VLAN ID) which is two bytes (16 bits) in length. Together, the VLAN ID and destination address (DA) uniquely identify an end-station 14 which is to receive a frame.
When a frame having a VLAN ID and a destination address (DA) is received at port controller 30, the port controller 30 can compare the VLAN ID and destination address with those stored in it's forwarding table in order to determine the appropriate routing within switch 16 for the received frame. FIG. 3 further illustrates the manner in which this process is accomplished. As illustrated, DRAM 32 contains a forwarding table which includes a bucket descriptor portion and bucket entry portion. Those skilled in the art will appreciate that the forwarding table has been organized as a hash table. The bucket descriptor portion of the forwarding table contains buckets O to M-1 and the bucket entry portion of the table contains corresponding entries for each of buckets O to M-1 which contain entries. Each bucket O to M-1 may have one or more entries.
An exemplary format of each bucket entry is illustrated in FIG. 3. In general, each bucket entry contains information which corresponds to a port address for the switch 16. Once the appropriate bucket entry has been located, the VLAN ID and destination address search value can be compared with that stored in the bucket entry and, if the two match, the corresponding port routing information can then be used by switch 16 to route the Ethernet frame appropriately.
As further illustrated in FIG. 3, each of the bucket descriptors contain address information. The address information is used as a pointer in order to index the corresponding bucket entries for each of the buckets. The first bit 40 of each of the bucket tables may be used as an empty flag to indicate whether any bucket entries exist for the corresponding bucket. If bucket entries do exist, a 1 may be placed in the first bit position 40. If no bucket entries exist, i.e., indicating a empty bucket, a 0 may be placed in first bit position 40.
As shown in FIG. 3, a search key, made up of the VLAN ID and the destination address retrieved from a received frame, is applied to a universal hash function. Note that for a single VLAN implementation, the VLAN ID may be obtained from processor 24 (which would write a VLAN ID to an appropriate register within port controller 30) rather than from a received frame. Alternatively, a VLAN ID may be obtained from protocol information associated with a received frame or from a VLAN ID header within the received frame itself. The output of the hashing process is a bucket ID value which is used to locate the appropriate bucket descriptor N in the bucket table. From the bucket N, address information is obtained which then can be used by a look-up process to index the appropriate bucket entries for bucket N. Each of the bucket entries corresponding to bucket N can then be compared with the original search key (i.e., the VLAN ID and the destination address) in order to determine whether a match exists. If a match exists, the Ethernet frame corresponding to the search key is routed according to the information contained in the bucket entry.
In addition to DA lookups, SA lookups may also be performed when a frame is received. Such operations allow the hash table to be updated with new values for new end-stations within a network. The SA lookups are performed in the same fashion as the DA lookups described above, except that the search key will be made up of an SA and VLAN ID. If the SA does not correspond to any existing bucket entry in the table, it is added as a new entry using the techniques described below.
The hashing process used with the above described method is further illustrated in FIG. 4. As shown, the 64-bit search value (i.e., the VLAN ID and destination address) is divided into eight segments, each 8 bits in length. Each one of these segments is multiplied by a corresponding 17-bit segment of a 136-bit hash coefficient. The hash coefficient is generated by the central processor 24 of switch 16 and supplied to each of the port controllers 30. The manner in which these hash coefficients are selected is discussed further below. Each one of the products P1-P8 which result from the above multiplication step are then added together to produce a sum. The sum then undergoes a MOD operation in which the divisor is a prime number M, where M equals the number of buckets, in order to produce the bucket ID. If the divisor M is selected to be of the form M=2P -1, where P is an integer and M is a prime number, those skilled in the art will recognize that the MOD circuit may be designed to avoid a divide operation. Instead, as recognized by J. Lawrence Carter and Mark N. Wegmen in "Universal Classes of Hash Functions," 18 Journal of Computer and System Sciences, pp. 143-154 (1979), only one multiply and a few addition, shift and Boolean operations will be required. This may result in increased speed and a fewer number of gates if the above operation is performed in hardware.
The selections of the hash coefficient and the prime number divisor for the MOD operation are governed by the criteria that in one embodiment, a maximum of four compare operations per bucket should be performed when 8K entries are stored in the hash table. That is, after a search key is hashed and a bucket is identified, no more than four buckets entries should exist for each individual bucket in the bucket table. This guarantees that a maximum of four compare operations will need to be performed for each Ethernet frame received over computer network 10. To achieve this result, P is selected so that P=17. It will be appreciated that because the number of buckets M=217 =128K, a total of 8K items may be stored in the hash table with this embodiment, and the vast majority of the 2136 hash functions implemented by the hash algorithm shown in FIG. 4 (where a single hash function is selected by selecting a single value for the Hash Coefficient) will not produce an overflow in the hash table, regardless of the values of the 8K entries. Those skilled in the art will recognize that limiting the number of compare operations in this fashion necessarily allows the switch designer to guarantee a worst-case search time.
To guarantee this criteria, a universal hashing algorithm is used to compute the bucket identifier. This process is illustrated in FIG. 4. Assume that the forwarding table of FIG. 3 is configured to hold 8k entries and that close to this number of entries are currently stored in the table. If a new address and VLAN ID combination is received (and, hence, needs to be stored), a bucket overflow may occur. That is, when the destination address and VLAN ID combination are hashed, they may hash to a bucket which already has four associated bucket entries. In such a case, the switch 16 must change to another hash function, and in particular, a hash function which does not produce a overflow. The manner in which the change is performed is illustrated in FIG. 5.
The selection process 100 begins at step 102 when a potential overflow is recognized. This may correspond to a condition where any hash bucket contains 3 or more entries or another user defined condition. Processor 24 may keep track of such information and update the hash coefficient as appropriate. Then at step 104, the system processor 24 randomly selects a new hash multiplier value but does not yet write that new value to the port controllers 30. Instead, the processor 24 first determines, at step 106, whether the new hash function will produce a potential bucket overflow condition or other conditions necessitating that a new hash function be selected. This is performed by calculating the hash result for each of the addresses that need to be stored in the forwarding table. At step 108, the processor 24 determines whether any potential overflow conditions occurred. If so, the processor 24 repeatedly selects new hash multiplier values until it identifies a good hash function (i.e., one which does not produce potential bucket overflows). Since the probability of a random hash function not producing a bucket overflow is approximately one thousand to one for 8K entries stored in 128K buckets of maximum size 4 (Binomial Distribution), typically the first value chosen will yield a good hash function.
When a new hash function which does not cause any bucket overflows is identified, process 100 moves to step 110 where a new forwarding table is generated using the new hash function. As part of this step, the newly received VLAN ID and address combination are stored as a new bucket entry.
Accordingly, a new MAC address table search unit has been described. Those skilled in the art will appreciate that the present invention has been described with reference to particular embodiments thereof. However, the details of these embodiments may not be required to implement the features of the present invention. Accordingly, the specification and drawings are to be regarded as illustrative only and the present invention is to be limited only in terms of the claims which follow.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US5664184 *||29 Nov 1995||2 Sep 1997||Amalgamated Software Of North America, Inc.||Method and apparatus for implementing Q-trees|
|US5799305 *||2 Nov 1995||25 Aug 1998||Informix Software, Inc.||Method of commitment in a distributed database transaction|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US6084877 *||18 Dec 1997||4 Jul 2000||Advanced Micro Devices, Inc.||Network switch port configured for generating an index key for a network switch routing table using a programmable hash function|
|US6236654 *||18 Dec 1997||22 May 2001||Advanced Micro Devices, Inc.||Method and apparatus for managing learning in an address table in memory|
|US6266705 *||29 Sep 1998||24 Jul 2001||Cisco Systems, Inc.||Look up mechanism and associated hash table for a network switch|
|US6269098 *||18 Dec 1997||31 Jul 2001||Advanced Micro Devices, Inc.||Method and apparatus for scaling number of virtual lans in a switch using an indexing scheme|
|US6269404 *||5 Jan 1999||31 Jul 2001||3Com Corporation||Virtual network architecture for connectionless LAN backbone|
|US6292483 *||18 Dec 1997||18 Sep 2001||Advanced Micro Devices, Inc.||Apparatus and method for generating an index key for a network switch routing table using a programmable hash function|
|US6330557 *||30 Jun 1998||11 Dec 2001||Sun Microsystems, Inc.||Method and system for storing data in a hash table that eliminates the necessity of key storage|
|US6356551 *||18 Dec 1997||12 Mar 2002||Advanced Micro Devices, Inc.||Method and network switch having dual forwarding models with a virtual lan overlay|
|US6457058||12 Jul 2001||24 Sep 2002||Cisco Technology, Inc.||Network switch with hash table look up|
|US6615336 *||12 Jan 2000||2 Sep 2003||Via Technologies, Inc.||Method for performing a medium access control address lookup in a network switch of an ethernet network|
|US6654347 *||22 Oct 1999||25 Nov 2003||Dell Usa L.P.||Site-to-site dynamic virtual local area network|
|US6662208 *||5 Oct 1999||9 Dec 2003||Nortel Networks Limited||System for tracking the history of channel based network devices|
|US6721320 *||18 Dec 1998||13 Apr 2004||Lsi Logic Corporation||Method and apparatus for fibre channel identification and retrieval|
|US6731633 *||25 Apr 2000||4 May 2004||3Com Corporation||Network unit including address hashing|
|US6765877 *||30 Aug 1999||20 Jul 2004||Cisco Technology, Inc.||System and method for detecting unidirectional links|
|US6775281||30 Sep 1999||10 Aug 2004||Mosaid Technologies, Inc.||Method and apparatus for a four-way hash table|
|US6807176 *||30 Aug 2000||19 Oct 2004||Advanced Micro Devices, Inc.||Arrangement for switching data packets in a network switch based on subnet identifier|
|US6816454 *||26 Oct 1998||9 Nov 2004||Marconi Communications, Inc.||Method and system for manipulating the order permanent connections are released|
|US6862287||28 Jun 2002||1 Mar 2005||Mosaid Technologies, Inc.||Method and apparatus for a four-way hash table|
|US6909713||5 Sep 2001||21 Jun 2005||Intel Corporation||Hash-based data frame distribution for web switches|
|US6912223 *||3 Nov 1998||28 Jun 2005||Network Technologies Inc.||Automatic router configuration|
|US6912592 *||5 Jan 2001||28 Jun 2005||Extreme Networks, Inc.||Method and system of aggregate multiple VLANs in a metropolitan area network|
|US6961771||25 Jul 2001||1 Nov 2005||Allied Telesis K.K.||Multi-unit building with secure entry system|
|US6977900 *||26 Aug 2003||20 Dec 2005||Dell Usa L.P.||Site-to-site dynamic virtual local area network|
|US7039764||17 Jan 2002||2 May 2006||Nokia Corporation||Near-perfect, fixed-time searching algorithm using hashing, LRU and cam-based caching|
|US7047254 *||31 Oct 2002||16 May 2006||Hewlett-Packard Development Company, L.P.||Method and apparatus for providing aggregate object identifiers|
|US7065578||20 Mar 2001||20 Jun 2006||At&T Corp.||Service selection in a shared access network using policy routing|
|US7103035 *||14 Jan 2000||5 Sep 2006||Advanced Micro Devices, Inc.||Arrangement for searching network addresses in a network switch using multiple tables based on subnet identifier|
|US7124305||7 Jan 2004||17 Oct 2006||Permabit, Inc.||Data repository and method for promoting network storage of data|
|US7200121||4 Jun 2002||3 Apr 2007||Accton Technology Corporation||Method of setting network configuration and device and system thereof|
|US7277426||24 May 2002||2 Oct 2007||Mosaid Technologies, Inc.||Method and apparatus for reordering entries in a multi probe lookup|
|US7286528||23 Sep 2002||23 Oct 2007||Marvell International Ltd.||Multiple address databases in a switch without the need for extra memory|
|US7287030||7 Jan 2004||23 Oct 2007||Burnside Acquisition, Llc||Data repository and method for promoting network storage of data|
|US7287092 *||11 Aug 2003||23 Oct 2007||Sharp Colin C||Generating a hash for a TCP/IP offload device|
|US7356701||7 Jan 2004||8 Apr 2008||Burnside Acquisition, Llc||Data repository and method for promoting network storage of data|
|US7398283 *||14 Oct 2004||8 Jul 2008||Burnside Acquisition, Llc||Method for providing access control for data items in a data repository in which storage space used by identical content is shared|
|US7406094||17 Apr 2001||29 Jul 2008||Adaptive Networks, Inc.||Power line communication network|
|US7412462 *||16 Feb 2001||12 Aug 2008||Burnside Acquisition, Llc||Data repository and method for promoting network storage of data|
|US7457959||7 Jan 2004||25 Nov 2008||Burnside Acquisition, Llc||Data repository and method for promoting network storage of data|
|US7469243 *||27 Jan 2004||23 Dec 2008||International Business Machines Corporation||Method and device for searching fixed length data|
|US7480251||4 Jun 2004||20 Jan 2009||Cisco Technology, Inc.||System and method for detecting unidirectional links|
|US7506173||17 Jun 2004||17 Mar 2009||Burnside Acquisition, Llc||Data repository and method for promoting network storage of data|
|US7512078 *||15 Oct 2003||31 Mar 2009||Texas Instruments Incorporated||Flexible ethernet bridge|
|US7532576 *||26 Aug 2003||12 May 2009||Dell Products L.P.||Site-to-site dynamic virtual local area network|
|US7577142 *||5 Jan 2001||18 Aug 2009||Cisco Technology, Inc.||Derived VLAN mapping technique|
|US7587617||7 Jan 2004||8 Sep 2009||Burnside Acquisition, Llc||Data repository and method for promoting network storage of data|
|US7657931||7 Jan 2004||2 Feb 2010||Burnside Acquisition, Llc||Data repository and method for promoting network storage of data|
|US7673068||23 Feb 2006||2 Mar 2010||Alcatel Lucent||Method and system for implementing a high availability VLAN|
|US7685096 *||14 Oct 2004||23 Mar 2010||Permabit Technology Corporation||Data repository and method for promoting network storage of data|
|US7693814||6 Apr 2010||Permabit Technology Corporation||Data repository and method for promoting network storage of data|
|US7710901 *||13 Oct 2006||4 May 2010||Nortel Networks Limited||GMPLS control of ethernet|
|US7756012||18 May 2007||13 Jul 2010||Nvidia Corporation||Intelligent failover in a load-balanced network environment|
|US7760619||18 May 2007||20 Jul 2010||Nvidia Corporation||Intelligent failover in a load-balanced networking environment|
|US7765405 *||25 Feb 2005||27 Jul 2010||Microsoft Corporation||Receive side scaling with cryptographically secure hashing|
|US7778253 *||28 Feb 2006||17 Aug 2010||Infineon Technologies Ag||Data switch, and communication system using the data switch|
|US7787369 *||9 Jun 2008||31 Aug 2010||Texas Instruments Incorporated||Flexible Ethernet bridge|
|US7792018 *||18 May 2007||7 Sep 2010||Nvidia Corporation||Intelligent load balancing and failover of network traffic|
|US7830877||15 Aug 2007||9 Nov 2010||Mosaid Technologies Inc.||Congestion level management in a network device|
|US7836198 *||20 Mar 2008||16 Nov 2010||International Business Machines Corporation||Ethernet virtualization using hardware control flow override|
|US7860028 *||9 Jun 2008||28 Dec 2010||Texas Instruments Incorporated||Flexible ethernet bridge|
|US7984180||19 Jul 2011||Solarflare Communications, Inc.||Hashing algorithm for network receive filtering|
|US7990958||28 Feb 2005||2 Aug 2011||SAtech Group, A.B. Limited Liability Company||Method and apparatus for a four-way hash table|
|US7995465||18 May 2007||9 Aug 2011||Nvidia Corporation||Intelligent load balancing and failover of network traffic|
|US7995581||23 Oct 2007||9 Aug 2011||Marvell International Ltd.||Multiple address databases in a switch without the need for extra memory|
|US7996520||19 Sep 2007||9 Aug 2011||Cisco Technology, Inc.||Behavioral classification of communication sessions using active session initiation|
|US8005013 *||12 Jun 2007||23 Aug 2011||Hewlett-Packard Development Company, L.P.||Managing connectivity in a virtual network|
|US8024789 *||25 May 2005||20 Sep 2011||Fujitsu Limited||Communication apparatus, program and method|
|US8040896||25 Nov 2008||18 Oct 2011||At&T Intellectual Property Ii, L.P.||Service selection in a shared access network using virtual networks|
|US8051210 *||15 Oct 2002||1 Nov 2011||Hewlett-Packard Development Company, L.P.||Server with LAN switch that connects ports based on connection information received from first and second LANs|
|US8117443 *||5 Oct 2005||14 Feb 2012||Oracle America, Inc.||Method and apparatus for generating location independent unique identifiers|
|US8131871 *||12 Jan 2006||6 Mar 2012||Cisco Technology, Inc.||Method and system for the automatic reroute of data over a local area network|
|US8134928||15 Dec 2005||13 Mar 2012||Nvidia Corporation||Technique for identifying a failed network interface card within a team of network interface cards|
|US8195832 *||12 Dec 2007||5 Jun 2012||Alcatel Lucent||Facilitating management of layer 2 hardware address table based on packet priority information|
|US8243733||16 Jun 2009||14 Aug 2012||Marvell World Trade Ltd.||Cascaded memory tables for searching|
|US8300647||18 May 2007||30 Oct 2012||Nvidia Corporation||Intelligent load balancing and failover of network traffic|
|US8401013||7 Oct 2010||19 Mar 2013||Mosaid Technologies Incorporated||Congestion management in a network|
|US8432788||18 May 2007||30 Apr 2013||Nvidia Corporation||Intelligent failback in a load-balanced networking environment|
|US8526418||7 Jul 2008||3 Sep 2013||Rpx Corporation||Power line communication network|
|US8554943 *||31 Mar 2006||8 Oct 2013||Emc Corporation||Method and system for reducing packet latency in networks with both low latency and high bandwidths requirements|
|US8588229||8 Aug 2011||19 Nov 2013||Marvell International Ltd.||Multiple address databases in a switch without the need for extra memory|
|US8599853||16 Apr 2010||3 Dec 2013||Wipro Limited||System and method for an exact match search using pointer based pipelined multibit trie traversal technique|
|US8837487||9 Aug 2012||16 Sep 2014||Marvell World Trade Ltd.||Cascaded memory tables for searching|
|US8855121||12 Mar 2013||7 Oct 2014||Conversant Intellectual Property Management Inc.||Congestion management in a network|
|US8931088||26 Mar 2010||6 Jan 2015||Alcatel Lucent||Adaptive distinct counting for network-traffic monitoring and other applications|
|US8959095||16 Jun 2011||17 Feb 2015||Solarflare Communications, Inc.||Hashing algorithm for network receive filtering|
|US9037545||19 Sep 2011||19 May 2015||Hybir Inc.||Group based complete and incremental computer file backup system, process and apparatus|
|US9104676 *||12 Sep 2012||11 Aug 2015||Tencent Technology (Shenzhen) Company Limited||Hash algorithm-based data storage method and system|
|US9117502||6 Feb 2013||25 Aug 2015||Fixnetix Ltd.||System and method for memory management of unique alpha-numeric order identifiers subjected to hashing and truncation for mapping to limited memory space|
|US9146789||21 Mar 2006||29 Sep 2015||Oracle America, Inc.||Method and apparatus for generating and using location-independent distributed object references|
|US9177175||30 Mar 2010||3 Nov 2015||Permabit Technology Corporation||Data repository and method for promoting network storage of data|
|US20010005369 *||5 Jan 2001||28 Jun 2001||Raymond Kloth||Derived vlan mapping technique|
|US20020016855 *||20 Mar 2001||7 Feb 2002||Garrett John W.||Managed access point for service selection in a shared access network|
|US20020019875 *||20 Mar 2001||14 Feb 2002||Garrett John W.||Service selection in a shared access network|
|US20020023171 *||20 Mar 2001||21 Feb 2002||Garrett John W.||Service selection in a shared access network using policy routing|
|US20020023174 *||20 Mar 2001||21 Feb 2002||Garrett John W.||Service selection in a shared access network using dynamic host configuration protocol|
|US20020038296 *||16 Feb 2001||28 Mar 2002||Margolus Norman H.||Data repository and method for promoting network storage of data|
|US20020038419 *||20 Mar 2001||28 Mar 2002||Garrett John W.||Service selection in a shared access network using tunneling|
|US20020145506 *||25 Jul 2001||10 Oct 2002||Takayuki Sato||Multi-unit building with secure entry system|
|US20020159437 *||26 Oct 2001||31 Oct 2002||Foster Michael S.||Method and system for network configuration discovery in a network manager|
|US20030026259 *||28 Jun 2002||6 Feb 2003||Mosaid Technologies, Inc.||Method and apparatus for a four-way hash table|
|US20030189905 *||4 Jun 2002||9 Oct 2003||Accton Technology Corporation||Method of setting network configuration and device and system thereof|
|US20030218978 *||24 May 2002||27 Nov 2003||Mosaid Technologies, Inc.||Method and apparatus for reordering entries in a multi probe lookup|
|US20040047352 *||26 Aug 2003||11 Mar 2004||Dell Usa L.P.||Site-to-site dynamic virtual local area network|
|US20040073712 *||15 Oct 2002||15 Apr 2004||Larson Thane M.||Server with LAN switch that connects ports based on connection information received from first and second LANs|
|US20040075535 *||17 Apr 2001||22 Apr 2004||Propp Michael B||Power line communication network|
|US20040088293 *||31 Oct 2002||6 May 2004||Jeremy Daggett||Method and apparatus for providing aggregate object identifiers|
|US20040139303 *||7 Jan 2004||15 Jul 2004||Permabit, Inc., A Delaware Corporation||Data repository and method for promoting network storage data|
|US20040143578 *||7 Jan 2004||22 Jul 2004||Permabit, Inc., A Delaware Corporation||Data repository and method for promoting network storage of data|
|US20040143743 *||7 Jan 2004||22 Jul 2004||Permabit, Inc., A Delaware Corporation||Data repository and method for promoting network storage of data|
|US20040162808 *||7 Jan 2004||19 Aug 2004||Permabit, Inc., A Delaware Corporation||Data repository and method for promoting network storage of data|
|US20040205056 *||27 Jan 2004||14 Oct 2004||International Business Machines Corporation||Fixed Length Data Search Device, Method for Searching Fixed Length Data, Computer Program, and Computer Readable Recording Medium|
|US20040218538 *||26 Aug 2003||4 Nov 2004||Dell Usa L.P.||Site-to-site dynamic virtual local area network|
|US20040255140 *||17 Jun 2004||16 Dec 2004||Permabit, Inc.||Data repository and method for promoting network storage of data|
|US20050006471 *||3 Jun 2004||13 Jan 2005||Bedell Edwin A.||Card reader/writer devices and methods|
|US20050064331 *||23 Sep 2004||24 Mar 2005||Fuji Photo Film Co., Ltd.||Photosensitive composition and lithographic printing plate precursor using the same|
|US20050083952 *||15 Oct 2003||21 Apr 2005||Texas Instruments Incorporated||Flexible ethernet bridge|
|US20050147113 *||28 Feb 2005||7 Jul 2005||Mosaid Technologies, Inc.||Method and apparatus for a four-way hash table|
|US20050182841 *||11 Aug 2003||18 Aug 2005||Alacritech, Inc.||Generating a hash for a TCP/IP offload device|
|US20050195743 *||22 Sep 2004||8 Sep 2005||P-Cube Ltd.||Real time charging of pre-paid accounts|
|US20050270989 *||11 May 2005||8 Dec 2005||Samsung Electronics Co., Ltd.||Method and apparatus for automatically configuring wireless network device|
|US20060146819 *||28 Feb 2006||6 Jul 2006||Infineon Technologies Ag||Data switch, and communication system using the data switch|
|US20060190721 *||25 May 2005||24 Aug 2006||Fujitsu Limited||Communication apparatus, program and method|
|US20060195698 *||25 Feb 2005||31 Aug 2006||Microsoft Corporation||Receive side scaling with cryptographically secure hashing|
|US20060235995 *||23 Feb 2006||19 Oct 2006||Jagjeet Bhatia||Method and system for implementing a high availability VLAN|
|US20060248079 *||28 Apr 2005||2 Nov 2006||Freescale Semiconductor Incorporated||Method and apparatus for finding a perfect hash function and making minimal hash table for a given set of keys|
|US20070086455 *||13 Oct 2006||19 Apr 2007||Nortel Networks Limited||GMPLS control of ethernet|
|US20070162612 *||12 Jan 2006||12 Jul 2007||Cisco Technology, Inc.||Method and system for the automatic reroute of data over a local area network|
|US20070174381 *||9 Jan 2007||26 Jul 2007||Nec Corporation||Communication system, network for qualification screening/setting, communication device, and network connection method|
|US20080069113 *||28 Nov 2007||20 Mar 2008||Patrick Droz||Method and system for controlling atm traffic using bandwidth allocation technology|
|US20080239952 *||9 Jun 2008||2 Oct 2008||Texas Instruments Incorporated||Flexible ethernet bridge|
|US20080273459 *||9 Jun 2008||6 Nov 2008||Texas Instruments Incorporated||Flexible ethernet bridge|
|US20080285435 *||18 May 2007||20 Nov 2008||Ayaz Abdulla||Intelligent failback in a load-balanced networking environment|
|US20080285441 *||18 May 2007||20 Nov 2008||Ayaz Abdulla||Intelligent load balancing and failover of network traffic|
|US20080285448 *||18 May 2007||20 Nov 2008||Ayaz Abdulla||Intelligent load balancing and failover of network traffic|
|US20080285472 *||18 May 2007||20 Nov 2008||Ayaz Abdulla||Intelligent failover in a load-balanced network environment|
|US20080285552 *||18 May 2007||20 Nov 2008||Ayaz Abdulla||Intelligent failover in a load-balanced networking environment|
|US20080285553 *||18 May 2007||20 Nov 2008||Ayaz Abdulla||Intelligent load balancing and failover of network traffic|
|US20080310421 *||12 Jun 2007||18 Dec 2008||Teisberg Robert R||Managing Connectivity in a Virtual Network|
|US20080317070 *||7 Jul 2008||25 Dec 2008||Adaptive Networks, Inc.||Power line communication network|
|US20090080437 *||25 Nov 2008||26 Mar 2009||Nguyen Han Q||Service selection in a shared access network using virtual networks|
|US20090158006 *||12 Dec 2007||18 Jun 2009||Alcatel Lucent||Facilitating management of layer 2 hardware address table based on packet priority information|
|US20090240346 *||20 Mar 2008||24 Sep 2009||International Business Machines Corporation||Ethernet Virtualization Using Hardware Control Flow Override|
|US20090316700 *||16 Jun 2009||24 Dec 2009||Martin White||Cascaded memory tables for searching|
|US20100185855 *||30 Mar 2010||22 Jul 2010||Margolus Norman H||Data Repository and Method for Promoting Network Storage of Data|
|US20110019546 *||27 Jan 2011||Brown David A||Congestion management in a network|
|US20110239299 *||29 Sep 2011||Alcatel-Lucent Usa Inc.||Adaptive distinct counting for network-traffic monitoring and other applications|
|US20130007008 *||12 Sep 2012||3 Jan 2013||Tencent Technology (Shenzhen) Company Limited||Hash algorithm-based data storage method and system|
|USRE38821 *||12 Jul 2001||11 Oct 2005||Marvell Semiconductor Israel Ltd.||Switching ethernet controller|
|USRE39514||21 Jun 2004||13 Mar 2007||Marvell Semiconductor International Ltd.||Switching ethernet controller|
|USRE43058||1 Sep 2006||3 Jan 2012||Marvell Israel (M.I.S.L) Ltd.||Switching ethernet controller|
|USRE44151||8 Aug 2011||16 Apr 2013||Marvell Israel (M.I.S.L) Ltd.||Switching ethernet controller|
|CN1855873B||12 Apr 2006||12 May 2010||阿尔卡特公司||Method and system for implementing a high availability vlan|
|CN101326791B *||13 Oct 2006||22 Jul 2015||北方电讯网络有限公司||Method and network for controlling Provider Backbone Transport (PBT) with Genreralized Multi-protocol Label Switching (GMPLS)|
|DE10012123B4 *||13 Mar 2000||28 Jan 2010||VIA Technologies, Inc., Hsien-Tien||Verfahren zum Suchen einer MAC-Adresse in einem Netzwerk-Switch|
|EP1249797A2 *||17 Oct 2001||16 Oct 2002||Allied Telesis K. K.||Multi-unit building with secure entry system|
|EP1715630A1 *||15 Mar 2006||25 Oct 2006||Alcatel||Method and system for implementing a high availability VLAN|
|EP1859573A2 *||3 Feb 2006||28 Nov 2007||Exar Corporation||Network address filter including random access memory|
|EP2363996A1 *||13 Oct 2006||7 Sep 2011||Solarflare Communications Inc||Hashing algorithm for determining a default kernel receive queue|
|WO2001047168A2 *||18 Dec 2000||28 Jun 2001||Mitel Semiconductor V N Inc||High speed mac address search engine|
|WO2001080435A2 *||17 Apr 2001||25 Oct 2001||Adaptive Networks Inc||Power line communication network|
|WO2003081460A1 *||26 Mar 2002||2 Oct 2003||Wiral Ltd||Method and system of using fixed-length addresses in message routing|
|WO2003081461A1 *||26 Mar 2002||2 Oct 2003||Wiral Ltd||Search means containing fixed-length addresses generated by a hash function|
|WO2004023732A1 *||6 Sep 2002||18 Mar 2004||Infineon Technologies Ag||Method and apparatus for storing a port identifier in a lan switch|
|WO2007045839A2 *||13 Oct 2006||26 Apr 2007||Level 5 Networks Inc||Hashing algorithm for determining a receive queue|
|WO2011119436A1||18 Mar 2011||29 Sep 2011||Alcatel-Lucent Usa Inc.||Adaptive distinct counting for network-traffic monitoring and other applications|
|U.S. Classification||370/254, 370/401|
|Cooperative Classification||H04L61/00, H04L45/745, H04L29/12009|
|European Classification||H04L45/745, H04L61/00, H04L29/12A|
|10 Mar 1997||AS||Assignment|
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