# US 5,351,243 A · Monitor for packets on a communications network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,351,243 A - Document ID: US5351243A - Status: Granted - Kind: A - Application number: 07/814,996 - Filed: 1991-12-27 - Granted: 1994-09-27 - Earliest claimed: 1991-12-27 - Assignees: Digital Equipment Corporation - Inventors: Ramesh S. Kalkunte; Satish L. Rege; Santosh K. Hasani - Web page: https://patentgrep.com/patent/US5351243A ## CPC - H04Q 11/0478: {Provisions for broadband connections} - H04L 2012/5615: {Network termination, e.g. NT1, NT2, PBX} - H04L 2012/5636: {Monitoring or policing, e.g. compliance with allocated rate, corrective actions} - H04L 2012/5652: {Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly} - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A monitor for packets on a local area network includes a set of logic circuits implemented in a computer chip, a memory interacting with the computer chip to provide monitoring data to the logic circuits, logic for receiving a packet from the local area network, and a parser to process bits of the packet as they are received, wherein the parser uses the monitoring data in conjunction with the received bits to provide forwarding data which indicates the type of packet received. The monitor uses the forwarding data to determine whether the received packet is stored in memory, discarded, or forwarded to other host computers in the network. The monitor uses type information from the forwarding data to maintain count information of the different types of packets which may be forwarded to a host computer or a remote monitoring device. ## Claims ### Claim 1 An apparatus for monitoring a plurality of packets on a local area network, wherein the local area network couples a host computer to a plurality of other hose computers with each packet of said plurality of packets comprising a plurality of bit fields including a header field, said header field identifying the source of said packet and the destination of said packet, said apparatus for monitoring packets comprising: a memory containing monitoring data, said monitoring data including a plurality of data category fields identifying a plurality of types of data to be monitored; means, coupled to said local area network and said memory, for receiving at least one of said plurality of packets from said local area network; means for providing forwarding data responsive to said plurality of fields of said packet, said forwarding data including a category field identifying a data type of said received packet and a destination field identifying the destination of said packet; and means, responsive to said data category fields in said memory and said category field of said forwarding data, for monitoring packets on said local area network and for indicating whether said packets on said local area network have fields corresponding to said plurality of data category fields stored in said memory. ### Claim 2 (depends on 1) The apparatus as in claim 1 wherein said means for providing forwarding data and said means for monitoring packets are both included in one application specific integrated circuit (ASIC). ### Claim 3 (depends on 1) The apparatus as in claim 1 wherein said memory further comprises a content addressable memory (CAM). ### Claim 4 (depends on 3) The apparatus as in claim 3 wherein said content addressable memory is a static random access memory chip (SRAM). ### Claim 5 (depends on 1) The apparatus as in claim 1 further comprising: means, responsive to said forwarding data, for storing packets received on said local area network. ### Claim 6 (depends on 5) The apparatus as in claim 5 further comprising: an adapter manager microprocessor; and means for allowing said adapter manager microprocessor to update said monitoring data dynamically while receiving a packet. ### Claim 7 (depends on 1) The apparatus as in claim 1 wherein said means for receiving at least one of said plurality of packets and said means for providing forwarding data operate in parallel. ### Claim 8 (depends on 1) The apparatus as in claim 1 wherein said means for monitoring further comprises means for forwarding said packet to a host computer in response to a said destination field of said forwarding data. ### Claim 9 (depends on 1) The apparatus as in claim 1 wherein said means for monitoring said packet further comprises means for discarding said packet in response to a set condition of a discard field of said forwarding data. ### Claim 10 (depends on 1) The apparatus of claim 1 wherein said mans for monitoring further comprises: means, responsive to said category field of said forwarding data, for maintaining a count of different types of packets received from said local area network. ### Claim 11 (depends on 5) The apparatus as in claim 5 further comprising: means, responsive to said forwarding data, for determining that a particular packet is to be discarded and not stored in packet memory; and means, responsive to a determination that said particular packet is to be discarded, for asserting an electrical signal to prevent storage of said particular packet in said storage means. ### Claim 12 (depends on 10) The apparatus as in claim 10 further comprising: an adapter manager having a microprocessor and an adapter manager memory, said adapter manager to store said count of different types of packets in said adapter manager memory. ### Claim 13 (depends on 12) The apparatus as in claim 12 further comprising: means for one of said host computers to request monitoring information from said adapter manager; and means, responsive to a request from one of said host computers, for allowing said adapter manager to transfer said count of different types of packets to said host computer. ### Claim 14 (depends on 12) The apparatus as in claim 12 further comprising: means for a remote monitoring station to request said count of different types of packets from one of said host computers; means for one of said host computers to request said count of different types of packets from said adapter manager; means for said adapter manager to transfer said count of different types of packets to said host computer; and means for said host computer to transfer said count of different types of packets to said remote monitoring station.