Network address resolve blocker

• US 6,456,624 B1
• Filed: 10/29/1997
• Issued: 09/24/2002
• Est. Priority Date: 10/29/1997
• Status: Expired due to Term

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Enterasys Networks Incorporated (Extreme Networks, Inc.)
• Inventors: Beaudette, Steven, Eccles, James F.
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US08/960,010
• Time in Patent Office: 1,791 Days
• Field of Search: 370/253, 370/254, 370/255, 370/389, 370/392, 370/400, 370/401, 370/402, 370/403, 370/432, 370/390, 370/475, 370/229, 370/230, 370/231, 370/235, 370/360
• US Class Current: 370/400
• CPC Class Codes: H04L 2012/5685 Addressing issues
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric

Abstract

A switch for selectively precluding the issuance of interswitch resolve packets. When the address of a destination node is not able to be resolved by an interswitch resolve packet, the destination identifier for the packet is stored in an unresolved address table. The unresolved address table includes a destination identifier of the packet, a counter and one or more timers. When the value of the counter reaches a test count value it is determined whether or not the packets have been sent at a rate (indicated by a threshold value) that would unduly degrade the performance of the network. If the resolve packets are unduly loading the network, then the destination identifier is forwarded to a blocked address table. Subsequent issuance of interswitch resolve packets having the destination identifier are selectively filtered to ensure that they do not unduly degrade the performance of the computer network. Some resolve requests are still permitted so that when the node having the destination identifier is subsequently returned to the network, the address may be resolved. With such an arrangement, address resolution may be achieved while maintaining the performance of the computer network.

Claims

1. A method for resolving destination addresses in a switched network system comprising a plurality of switches, the method comprising the steps of:

issuing, at one of the plurality of switches, one interswitch resolve packet to at least one other switch in the network system in response to a packet issued by an associated node for access to a destination when the address of the destination is unknown by the one switch; and

selectively precluding the issuance of additional interswitch resolve packets to the at least one other switch in response to a second packet issued by an associated node for access to the destination in order to enhance performance of the switched network system.

2. The method according to claim 1, wherein the step of selectively precluding includes the steps of:

providing a threshold value for indicating how often interswitch resolve packets may be issued to resolve the destination address; and

issuing interswitch resolve packets to resolve the destination address at a rate no greater than that determined by the threshold value.

3. The method according to claim 2, wherein the step of selectively precluding includes the step of:

designating at least one destination for which interswitch resolve packets are not selectively precluded.

4. The method according to claim 1, including:

providing a test count value and a threshold value; and

when the amount of interswitch resolve packets sent regarding a given destination reaches the test count value, issuing interswitch resolve packets at a rate no greater than that determined by the threshold value.

5. The method according to claim 1, including:

monitoring the rate that interswitch resolve packets are issued for the destination; and

if the rate exceeds a predetermined threshold value, implementing the selectively precluding step.

6. The method according to claim 1, wherein the step of issuing includes a step of examining a directory at the one switch to determine if the address of the destination is known by the one switch.

7. A switch for use in a switched network system, the switch comprising:

a directory for storing addresses of nodes in the network system known to the switch;

means for storing a destination identifier of a packet when the address of the destination is not stored in the directory of any of the switches in the switched network;

means for issuing resolve packets to attempt to resolve the destination address; and

means for selectively precluding the issuance of resolve packets when a rate at which resolve packets have been issued exceeds a threshold value.

8. The switch according to claim 7, wherein the means for selectively precluding includes:

a send value for determining how often resolve packets should be allowed to issue.

9. The switch according to claim 8, wherein the means for selectively precluding includes:

an unblock value for determining when to stop implementing the selectively precluding means.

10. The switch according to claim 7, including:

means for storing destinations for which issuance of resolve packets should not be selectively precluded.

11. The switch according to claim 7, including:

a test count for indicating a number of resolve packets that are permitted to issue before determining whether to selectively preclude issuance of resolve packets;

a threshold value for determining a maximum rate that resolve packets are permitted to issue; and

a count of the number of resolve packets that have been issued.

12. A switch for use in a switched network system, the switch comprising:

a directory for storing addresses of nodes in the network system known to the switch;

means for storing a destination identifier of a packet when the address of the destination is not stored in the directory of any of the switches in the switched network;

means for issuing resolve packets to attempt to resolve the destination address;

means for selectively precluding the issuance of resolve packets when a rate at which resolve packets have been issued exceeds a threshold value;

a test count for indicating a number of resolve packets that are permitted to issue before determining whether to selectively preclude issuance of resolve packets; and

a count of the number of resolve packets that have been issued.