158 results about "Longest prefix match" patented technology

Methods and apparatus are disclosed for generating and using an enhanced tree bitmap data structure in determining a longest prefix match, such as in a router, packet switching system. One implementation organizes the tree bitmap to minimize the number of internal nodes that must be accessed during a lookup operation. A pointer is included in each of the trie or search nodes to the best match so far entry in the leaf or results array which allows direct access to this result without having to parse a corresponding internal node. Moreover, one implementation stores the internal node for a particular level as a first element in its child array. Additionally, one implementation uses a general purpose lookup engine that can traverse multiple tree bitmaps or other data structures simultaneously, and perform complete searches, partial searches, and resume partial searches such as after receiving additional data on which to search.

One embodiment provides a system that receives a packet with a hierarchically structured variable-length identifier (HSVLI). An HSVLI indicates a piece or collection of content and may be hierarchically structured, comprising contiguous components ordered from a most general level to a most specific level. The length of a respective identifier is not fixed. During operation, the system converts the HSVLI into a fixed-length key. Subsequently, the system obtains forwarding information based on one or more longest-prefix matches with a longest-prefix-match lookup engine using the fixed-length key. Next, the system forwards the packet to an output port based on the forwarding information.

The present invention relates to a method and system of performing parallel membership queries to Bloom filters for Longest Prefix Matching, where address prefix memberships are determined in sets of prefixes sorted by prefix length. Hash tables corresponding to each prefix length are probed from the longest to the shortest match in the vector, terminating when a match is found or all of the lengths are searched. The performance, as determined by the number of dependent memory accesses per lookup, is held constant for longer address lengths or additional unique address prefix lengths in the forwarding table given that memory resources scale linearly with the number of prefixes in the forwarding table. For less than 2 Mb of embedded RAM and a commodity SRAM, the present technique achieves average performance of one hash probe per lookup and a worst case of two hash probes and one array access per lookup.

A method and system for determining the best data path in a communication network is presented. A Least Cost Routing path between end users in a multi-network environment, including both public and private networks, is determined based upon a longest prefix match. At network activation time, the numbers or prefixes of numbers of end users attached to the public network (304, 305) are stored in entry node data bases A and C of the private network (303). Assuming an end user terminal U1 calls a target end user U3, an entry node B first checks for a longest prefix match between the called number and numbers already stored into its memory. If this is the first time U3 is called via node B, no match will occur and node B will then broadcast a Query to all nodes in the private network (i.e. Nodes A and C). Only those nodes providing possible access to U3 answer this Query. Node B then determines the longest prefix match with the called number amongst the various query answers, and sets the data path via that node having the longest prefix match.

The invention discloses a routing loop detecting method based on a SDN. The routing loop detecting method comprises the following steps of: obtaining routing table information and routing event information of each node in a network in real time; constructing a real-time topological structure of the network according to the obtained routing table information and routing event information; constructing a multi-routing-form prefix tree matched with the longest prefix by adopting a hierarchical compression method according to the real-time topological structure, and storing a forwarding subnet segment in the routing table of each node; generating a routing next-hop table for each subnet node in the prefix tree in the subnet segment, in which the loop is necessary to judge, and traversing each subnet node of the prefix tree to generate a node forwarding figure; and judging whether the routing loop exists or not according to the node forwarding figure. The invention further discloses a routing loop detecting system based on the SDN. By means of the routing loop detecting method and system based on the SDN, the routing loop detection efficiency and accuracy are increased; and simultaneously, the storage space and the calculation time are reduced.

A device can process commands from a remote device that manages the local device over a content centric network. During operation, the device can receive an Interest for managing a device resource, such that the Interest's name includes a name or a name prefix associated with the device resource, and includes a command for managing the resource. If the device determines that the name prefix corresponds to the local device, the device analyzes the Interest's command to determine a device resource and performs the resource-managing operation on the device resource. If the name prefix does not correspond to the local device, the device performs a longest-prefix-matching lookup using the Interest's name prefix to determine a destination for the Interest. If the Interest's destination corresponds to a component of the local device, the device forwards the Interest to the component or a local agent for the component.

The invention discloses a name routing fast matching search method and device. The device mainly comprises a tree-bitmap and a Blond filter. The tree-bitmap is used for storing the first m layers of name routing, and performing fast longest prefix matching on the first m layers of request content name reaching a router; the Blond filter is used for storing the rest of the prefix of the name routing, and performing longest prefix matching on the rest of the request content name reaching the router. According to the different prefix length of the name routing to be updated, the tree-bitmap and the Blond filter can be updated respectively or simultaneously by the method. According to the invention, the characteristics of fast searching, little required storing of the tree-bitmap and the characteristics of high time efficiency and spatial efficiency are utilized, the routing addressing problem based on the content name in the novel network system is solved, and the requirements of little occupied memory, fast matching speed and fast updating speed of the future network routing are met.

Novel data structures, methods and apparatus for finding the longest prefix match search when searching tables with variable length patterns or prefixes. To find the exact match or the best matching prefix, patterns have to be compared a bit at a time until the exact or first match is found. This requires “n” number of comparisons or memory accesses to identify the closest matching pattern. The trees are built in such a way that the matching result is guaranteed to be a best match, whether it is an exact match or a longest prefix match. Using the trail of all the birds and associated prefix lengths enables determination of the correct prefix result from the trail. By construction, the search tree provides the best matching prefix at or after the first compare during walking of the trail or tree.

A network address associated with a packet is obtained at a search engine of a network device. The search engine includes a plurality of Bloom filters that represent prefixes of respective lengths in the routing table. Respective Bloom filters are applied to respective prefixes of the network address to determine a set of one or more prefixes for which a match potentially exists in the routing table. A number of accesses to the memory are performed using prefixes in set of prefixes, beginning with a longest prefix and continuing in decreasing order of prefix lengths until a matching entry is found in the routing table, and routing information for the packet is retrieved. If the number of performed memory accesses exceeds a threshold, the routing table is adapted to reduce a number of memory accesses to be performed for subsequent packets associated with the network address.

Methods directed to longest prefix matching and systems directed to IP address lookups are presented. The methods and systems relate in particular to IPv6 and comprise finding the longest prefix match (LPM) for an IP address. The method of the invention results in the use of filters to perform LPM. In embodiments of the invention, partial address filtering is used to further reduce filtering requirements. Reducing the number of filtering operations has the advantage of making the LPM algorithm faster and less costly to implement than prior art approaches. Also described is an “ideal offset filter” that extracts a fixed sized sliding window of bits from the IP address being processed.

A method and system is provided for tracking mobile devices combining packet processing technology with Global Positioning System (GPS) technology. A central network system comprising a packet processing subsystem receives transmitted GPS location data from a mobile device transmitting GPS location data, wherein the packet processing subsystem uses a table access scheme to process the GPS location data and produce responsive mapping data, and the central network processing system compares the mapping data to a map and identifies a corresponding map location. Embodiments may also correlate device identification data, tracking table entries, and / or billing zone charges. In some embodiments a look-up key is built responsive to the GPS location data and used to identify map locations. The table access scheme may be a key hashing scheme and, in particular, a longest prefix match type scheme.

A multi-protocol, multi-stage, real-time frame classifier is disclosed. A preliminary multi-protocol frame composition analyzer is provided for performing preliminary multi-protocol frame classification for incoming frames. A parsing instruction generator is provided for processing at least the incoming frame and the preliminary multi-protocol frame classification to provide parsing instructions. A multi-stage parsing engine provides multi-stage parsing of the incoming frame according to the parsing instructions to generate search results presenting information about the incoming frame. An advanced level of data extraction is provided across various frame protocols without imposing a performance penalty. Longest prefix match searches and / or direct lookup searches are supported. Moreover, conditional extractions, instruction branching, multi-stage processing are all performed in real time.

A multi-protocol, multi-stage, real-time frame classifier is disclosed. A preliminary multi-protocol frame composition analyzer is provided for performing preliminary multi-protocol frame classification for incoming frames. A parsing instruction generator is provided for processing at least the incoming frame and the preliminary multi-protocol frame classification to provide parsing instructions. A multi-stage parsing engine provides multi-stage parsing of the incoming frame according to the parsing instructions to generate search results presenting information about the incoming frame. An advanced level of data extraction is provided across various frame protocols without imposing a performance penalty. Longest prefix match searches and / or direct lookup searches are supported. Moreover, conditional extractions, instruction branching, multi-stage processing are all performed in real time.

A router allowing the entry hit probability of the cache to be increased is disclosed. The cache is searched using a different mask for each cache entry. A maximum or optimum cache prefix length is determined as a length of upper bits of the destination address of the received packet which are not masked by a corresponding mask. Alternatively, the cache is searched using longest prefix match (LFM). A cache entry allowing a plurality of destination addresses to be hit can be registered in the cache, resulting in increased cache hit probability.

A lookup unit matrix combines a plurality of lookup units to provide a longest prefix match for a search key longer than the lookup unit's mapper key. A portion of the search key is provided to each of the plurality of lookup units in a single search request issued to the lookup unit matrix. Each lookup unit in the lookup unit matrix performs a multi-level search for the result value based on the portion of the search key forwarded as the mapper key and the result of a multilevel search in the previous lookup unit. The search results in a value corresponding to the search key stored in a single location in one of the lookup units.

One embodiment of the present invention provides a system that resolves conflicts between network service rules for network data traffic in a system where rule patterns with longer prefixes match before rule patterns with shorter prefixes. The system operates by receiving a set of network service rules for network data traffic from multiple network services, wherein network service rules from different network services can possibly conflict. Each of these network service rules specifies: a filter that defines a prefix for a set of packets in the packet flow, and an action list that specifies one or more actions to be applied to the set of packets. Next, the system identifies a conflict between a higher priority rule and a lower priority rule in the set of network service rules. The system resolves this conflict by prepending an action list of the higher priority rule to an action list of a rule with a filter that defines a longer prefix.

Methods and devices for storing binary IP addresses in memory. The longest prefix match problem is converted into a range search problem and the IP addresses corresponding to the different ranges are stored in a tree data structure. The nodes of the tree data structure are created from the bottom leaves up to the root node. The IP addresses are sorted by binary number order and grouped according to the number of common leading or trailing bits per group. For each group, the common leading and / or trailing bits are then removed and the number of bits removed are stored, along with the stripped IP addresses in that group, in a node in the tree data structure.

The present invention relates to a method and system of performing parallel membership queries to Bloom filters for Longest Prefix Matching, where address prefix memberships are determined in sets of prefixes sorted by prefix length. Hash tables corresponding to each prefix length are probed from the longest to the shortest match in the vector, terminating when a match is found or all of the lengths are searched. The performance, as determined by the number of dependent memory accesses per lookup, is held constant for longer address lengths or additional unique address prefix lengths in the forwarding table given that memory resources scale linearly with the number of prefixes in the forwarding table. For less than 2 Mb of embedded RAM and a commodity SRAM, the present technique achieves average performance of one hash probe per lookup and a worst case of two hash probes and one array access per lookup.

A method and apparatus for searching an electronically stored table of information including a plurality of table entries and facilitating high speed searching of a table to provide a longest matching entry. The table searching method uses at least one memory unit having a table of information including a plurality of data entries. The table of information has a plurality of search keys associated with the plurality of data entries and the plurality of search keys form a tree structure based on a prefix length for each of the search keys. The plurality of search keys are expanded such that each of the plurality of search keys has two lowest level search keys associated therewith that cover a lowest level of the tree structure. A binary search of the lowest level search keys is performed based on a search value to determine a longest prefix match. A data entry of the plurality of data entries is output based on said longest prefix match. The method is also applicable to routing data in an internet router where the routing of data packets depends on address information stored in the table of information.

A search engine improves search speed and reduces required memory for a longest prefix matching (LPM) router that routes packets using IP addresses. The search engine includes a first bit vector with set bits corresponding to address ranges. A set bit counter counts the set bits in the bit vector based on a first portion of the address of the a first packet. A first next hop table contains first pointers for each of the set bits. One of the first pointers is selected based on a number of set bits counted by the set bit counter. For longer addresses, the addresses are split into address portions. The search engine includes a trie data structure that has n levels. The n levels of the trie data structure include nodes representing non-overlapping address space.

In an apparatus and method for dispersively processing an IP packet forwarding for supporting a quality of service(QoS), an IP forwarding information base gotten by processing and extracting a routing protocol is dispersed to all input ports of a router on the basis of the QoS in a private network processor for performing a routing protocol process function, so as to dispersively process the IP packet forwarding. The method for dispersively processing the IP packet forwarding for supporting the QoS includes the steps of: a) classifying reception IP packets according to the QoS and storing them at an input-side class queue; b) searching the forwarding information base by using an exact matching table and an LPM (Longest Prefix Matching) search table according to an IP header value of the IP packet stored at the input-side class queue, and gaining forwarding information; c) transferring the IP packet according to the gained forwarding information; d) classifying the transferred IP packets according to the QoS, and storing them at an output-side class queue; and e) outputting the IP packet stored at the output-side class queue according to the QoS, whereby being used in the IP packet forwarding dispersion processing apparatus for supporting the quality of service, etc.

A method for clustering together network IP addresses is disclosed. A number of IP addresses are received and processed to determine which IP addresses share a longest prefix matching. The longest prefix matching process is performed according to radix encoded trie which facilitates on-line clustering of the IP addresses. Client and / or server IP addresses may be clustered in accordance with the teachings herein.

The invention discloses a method and a device for matching a longest prefix. The method comprises the following steps: A, reading a search node; B, determining whether the offset domain of the read search node indicates that an upper node has the matched prefix or not, adding the offset domain of the search node to a pointer pointing to a leaf node array in the upper node if the upper node has the matched prefix, updating the current best matching pointer and executing the step C, and executing the step C if the upper node has no matched prefix; C, determining whether the search node has the leaf node or not while determining corresponding bit matching of branch indication domain and search key words of the search node; D, reading the internal bitmap of the search node while determining that the search node does not have the leaf node, computing the longest matching prefix existing in the search node according to the internal bitmap and the pointer pointing to the leaf node array in the search node, updating the current best matching pointer, and computing the address of the leaf node corresponding to the current best matching pointer. The method can improve the search speed.

A route compression algorithm is applied to route entries of a route table. The route entries are maintained as nodes in a routing tree. The compression algorithm compresses child nodes having a common gateway with their respective parent nodes. The route entries associated with uncompressed nodes are installed into a forwarding table of a routing device that employs longest prefix match (LPM) lookup to forward data packets.

A lookup table including stored data, the lookup table including a Random Access Memory (RAM) for storing the data, wherein the RAM includes a plurality of windows; and a Ternary Content Addressable Memory (TCAM) for storing indices, each index pointing to the windows, and a method for performing a Longest Prefix Match (LPM) including organizing data in such a lookup table, searching according to a lookup key in the TCAM, receiving a match signal from the TCAM including an index pointing to one of the windows, and searching according to the lookup key in the pointed to window.

A method and system is provided for tracking mobile devices combining packet processing technology with Global Positioning System (GPS) technology. A central network system comprising a packet processing subsystem receives transmitted GPS location data from a mobile device transmitting GPS location data, wherein the packet processing subsystem uses a table access scheme to process the GPS location data and produce responsive mapping data, and the central network processing system compares the mapping data to a map and identifies a corresponding map location. Embodiments may also correlate device identification data, tracking table entries, and / or billing zone charges. In some embodiments a look-up key is built responsive to the GPS location data and used to identify map locations. The table access scheme may be a key hashing scheme and, in particular, a longest prefix match type scheme.

A method for clustering together network IP addresses is disclosed. A number of IP addresses are received and processed to determine which IP addresses share a longest prefix matching. The longest prefix matching process is performed according to radix encoded trie which facilitates on-line clustering of the IP addresses. Client and / or server IP addresses may be clustered in accordance with the teachings herein.

A high performance network address processor is provided comprising a longest prefix match lookup engine for receiving a request for data from a designated network destination address. An associated data engine is also provided to couple to the longest prefix match lookup engine for receiving a longest prefix match lookup engine output address from the longest prefix match lookup engine and providing a network address processor data output corresponding to the designated network destination address requested. The high performance network address processor longest prefix match lookup engine comprises a plurality of pipelined lookup tables. Each table provides an index to a given row within the next higher stage lookup table, wherein the last stage, or the last table, in the set of tables comprises an associated data pointer provided as input to the associated data engine. The associated data engine also comprising one or more tables, the associated data engine generating a designated data output associated with the designated network address provided to the high performance NAP.

Methods and apparatus are disclosed for generating and using an enhanced tree bitmap data structure in determining a longest prefix match, such as in a router, packet switching system. One implementation organizes the tree bitmap to minimize the number of internal nodes that must be accessed during a lookup operation. A pointer is included in each of the trie or search nodes to the best match so far entry in the leaf or results array which allows direct access to this result without having to parse a corresponding internal node. Moreover, one implementation stores the internal node for a particular level as a first element in its child array. Additionally, one implementation uses a general purpose lookup engine that can traverse multiple tree bitmaps or other data structures simultaneously, and perform complete searches, partial searches, and resume partial searches such as after receiving additional data on which to search.

Novel data structures, methods and apparatus for finding the longest prefix match search when searching tables with variable length patterns or prefixes. To find the exact match or the best matching prefix, patterns have to be compared a bit at a time until the exact or first: match is found. This requires “n” number of comparisons or memory accesses to identify the closest matching pattern. The trees are built in such a way that the matching result is guaranteed to be a best match, whether it is an exact match or a longest prefix match. Using the trail of all the birds and associated prefix lengths enables determination of the correct prefix result from the trail. By construction, the search tree provides the best matching prefix at or after the first compare during walking of the trail or tree.