Packet forwarding device equipped with statistics collection device and statistics collection method

• US 20050013300A1
• Filed: 07/07/2004
• Published: 01/20/2005
• Est. Priority Date: 07/11/2003
• Status: Active Grant

• Current Assignee: Alaxala Networks Corporation (Fortinet Inc.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Akahane, Shinichi, Sugai, Kazuo, Tsuchiya, Kazuaki
• Granted Patent: US 7,738,465 B2
• Time in Patent Office: Days
• US Class Current: 370/395.300
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/024 by adaptive sampling
• CPC Class Codes: H04L 43/026 using flow identification
• CPC Class Codes: H04L 43/16 Threshold monitoring

Abstract

A packet forwarding device equipped with a statistics collection device and statistics collection method for high speed ports at a low cost while maintaining the required statistical accuracy for each flow. In order to collect a statistic flow with the required accurate statistic information this device contains a high speed flow table, a flow table made up of many flow entries, a search decision table to decide whether to search the high speed flow table or large volume flow table; and the table to be searched is decided when a packet is received. The accuracy of the statistic information for the flow requiring accurate statistic information is guaranteed by the high speed flow table. Further by setting the large volume flow table and sampling rate as needed, statistic information for many flow entries can be collected with a sufficient flow of sampled statistic information, without lowering packet forwarding performance.

Claims

1. A packet forwarding device equipped with a statistics collection device for collecting statistic information for each one piece of information or combination of multiple information contained in the receive packet header and, a means for transmitting the received packet subjected to the specified processing, wherein

the statistics collection device contains a first table, a second table, and a search table discrimination table for selecting either the first table or the second table based on information contained in the header, and a means for searching the first table, the second table and the search table discrimination table,

the first table and the second table hold at least entries containing one piece of information or combinations of multiple pieces of information contained in the header, and statistic information for collection corresponding to that information, the one piece of information or combinations of multiple pieces of information contained in the header, and information indicating the table corresponding to that information are stored in the search table discrimination table,

when a packet is received, the search table discrimination table is searched based on information contained in the header of that received packet, and the first table or the second table is selected, and

the selected search table is searched and the statistic information to collect is determined, and that statistic information collected.

2. A packet forwarding device according to claim 1,

wherein a protocol value within the IP (Internet Protocol) header, and a source port number or a destination port number within the TCP (Transmission Control Protocol) header or the UDP (User Datagram Protocol) are stored as the discrimination table search keys within the search table discrimination table.

3. A packet forwarding device according to claim 1,

wherein a CAM (Content Addressable Memory) is stored in the first table.

4. A packet forwarding device according to claim 1, comprising a RAM (Random Access Memory) for storing the first table,

wherein the first table is a tree structure comprised of one piece of information or combinations of multiple pieces of information contained in the header, and statistic information corresponding to that information.

5. A packet forwarding device according to claim 1,

wherein the statistics collection device collects one or any one element of information contained in a group comprised of:

a packet count sum matching one or multiple information elements contained in the header of the received packet, the sum of the byte counts of the received packet, the input port number of the received packet, the output port number of the received packet, as well as the time on the statistics collection device that the packet was received, and the time of the first received packet which matches with one element of information or a combination of multiple information elements within the header of the received packet, according to the time the packets were received.

6. A packet forwarding device according to claim 1, comprising:

a sampling rate storage means to store a sampling rate for the second search table, and one element of information or a combination of multiple information elements within the header of the received packet, and

a means to decide whether or not to search the second table based on the sampling rate set in the sampling rate storage means when the selected table is the second table from search results of the search table discrimination table.

7. A packet forwarding device according to claim 6, comprising:

an input interface for holding the multiple communication ports, and a sampling rate storage means formed in the multiple communication ports, and a control means for setting the sampling rate from an external section.

8. A packet forwarding device according to any one of claims claim 6,

wherein the control means contains a means to display the search table discrimination table, and a means to select desired information from the sampling rates stored in the discrimination table, and a means to change the selected information.

9. A packet forwarding device according to claim 1, wherein:

the first table contains the search table discrimination table, the first table contains entries storing identification information for deciding whether or not to search the second table, and

said device searches the first table when a packet is received, and decides whether or not to search the second table according to the identification information values.

10. A packet forwarding device according to claim 1,

wherein the means for searching the first table, the second table, and the search table discrimination table, comprises a first LSI or network processor or microprocessor for searching the first table, and a second LSI or network processor or microprocessor for searching the second table.

11. A packet forwarding device according to claim 10,

wherein the second table, and the second LSI or network processor or microprocessor for searching the all-period second table are implemented on a statistic collection card, and said device comprises a connection means for loading the statistic collection card into the statistics collection device.

12. A packet forwarding device according to claim 6, comprising a function to send the statistic information collected in the first table or the second table to another device connected via a network,

wherein

when sending to another device, said device sends statistic information according to a sampling rate set for one element of information or a combination of multiple information elements within the header.

15. A packet forwarding device according claim 7,

wherein the control means contains a means to display the search table discrimination table, and a means to select desired information from the sampling rates stored in the discrimination table, and a means to change the selected information.

16. A packet forwarding device according to claim 6, wherein:

the first table contains the search table discrimination table,

the first table contains entries storing identification information for deciding whether or not to search the second table, and

said device searches the first table when a packet is received, and decides whether or not to search the second table according to the identification information values.

17. A packet forwarding device according to claim 7, wherein:

the first table contains the search table discrimination table,

the first table contains entries storing identification information for deciding whether or not to search the second table, and

said device searches the first table when a packet is received, and decides whether or not to search the second table according to the identification information values.

18. A packet forwarding device according to claim 8, wherein:

the first table contains the search table discrimination table,

the first table contains entries storing identification information for deciding whether or not to search the second table, and

said device searches the first table when a packet is received, and decides whether or not to search the second table according to the identification information values.

19. A packet forwarding device according to claim 15, wherein:

the first table contains the search table discrimination table,

the first table contains entries storing identification information for deciding whether or not to search the second table, and

said device searches the first table when a packet is received, and decides whether or not to search the second table according to the identification information values.

20. A packet forwarding device according to claim 7, comprising a function to send the statistic information collected in the first table or the second table to another device connected via a network,

wherein

when sending to another device, said device sends statistic information according to a sampling rate set for one element of information or a combination of multiple information elements within the header.

21. A packet forwarding device according to claim 8, comprising a function to send the statistic information collected in the first table or the second table to another device connected via a network,

wherein

when sending to another device, said device sends statistic information according to a sampling rate set for one element of information or a combination of multiple information elements within the header.

22. A packet forwarding device according to claim 15, comprising a function to send the statistic information collected in the first table or the second table to another device connected via a network,

wherein

when sending to another device, said device sends statistic information according to a sampling rate set for one element of information or a combination of multiple information elements within the header.

13. A packet forwarding device comprising a means for receiving a packet, a statistics collection device for collecting statistic information for each one piece of information or combination of multiple information contained in the receive packet header and, a means for transmitting the received packet subjected to the specified processing, wherein

the statistics collection device has a table comprised of entries containing at least one element of information or a combination of multiple information elements within the header and statistic information corresponding to that information, and a means for searching the table based on information contained in the header, and

a storage means for storing statistic collection frequency information for collected statistic information in one element of information or a combination of multiple information elements, and a selection means for selecting the statistic collection frequency information stored in one element of information or a combination of multiple information elements within the header from the storage means based on the header information,

wherein, when a packet is received, said device selects statistic collection frequency information corresponding to information contained in the header of the packet received from the storage means, and decides whether or not to collect statistic information contained in the table, based on the statistic collection frequency information.

14. A packet forwarding device according to claim 13,

wherein the statistics collection device contains one or more tables, a search table discrimination table for selecting which of the one or more tables to search based on information contained in the header, and a means for searching a table, among the one or more tables, and

when a packet is received, searches the search table discrimination table based on information contained in the header of the received packet, and selects a table among the one or more tables for making a search, and

determines the statistic information that must searched and collected from the selected search table and also decides whether or not to search the selected search table, and collects the statistic information when decided to make a search.