PACKET FORWARDING DEVICE AND FORWARDING METHOD

• US 20090185561A1
• Filed: 01/15/2009
• Published: 07/23/2009
• Est. Priority Date: 01/17/2008
• Status: Abandoned Application

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: PHILAVONG, MINAXAY
• Application Number:
  US12/354,646
• Publication Number:
  US 20090185561A1
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/54 Organization of routing tables
• CPC Class Codes: H04L 45/741 Routing in networks with a plurality of addressing schemes, e.g. with both IPv4 and IPv6
• CPC Class Codes: H04L 49/90 Buffering arrangements

Abstract

A packet forwarding device that maintains packet sequence before and after packet forwarding is provided. A cache stores forwarding information. A forwarding unit refers to the forwarding information to attempt to determine a forwarding destination of a received packet, sends the packet to a control unit irrespective of whether or not the forwarding destination of the packet could be determined, and in cases in which the forwarding destination of the packet could not be determined, requests the control unit to determine the forwarding destination of the packet. The control unit receives the packet from the forwarding unit, and in cases in which the control unit has been requested by the forwarding unit to determine the forwarding destination of the packet, determines the forwarding destination of the packet, sends the packet to the forwarding destination and stores the forwarding destination as forwarding information in the cache, and in other cases, sends the packet to the forwarding destination determined by the forwarding unit.

Claims

1. A packet forwarding device, comprising:

a cache, a forwarding unit, and a control unit, wherein

said cache is configured to store forwarding information;

said forwarding unit is configured to refer to said forwarding information, to attempt to determine a forwarding destination of a received packet, to send said packet to said control unit regardless of whether or not the forwarding destination of said packet could be determined, and in cases in which the forwarding destination of said packet could not be determined, to request said control unit to determine the forwarding destination of said packet; and

said control unit is configured to receive said packet from said forwarding unit, and in cases in which said forwarding unit has requested determination of the forwarding destination of said packet, to determine the forwarding destination of said packet, to send said packet to said forwarding destination and store said forwarding destination as forwarding information in said cache, and in other cases, to send said packet to the forwarding destination determined by said forwarding unit.

2. The packet forwarding device according to claim 1, wherein

said forwarding unit is configured to add to an internal header of said packet a flag indicating whether or not a forwarding destination of said packet could be determined, and

said control unit is configured to refer to said flag to judge whether or not the forwarding destination of said packet has to be determined.

3. The packet forwarding device according to claim 1, wherein packet sequence is maintained before and after packet forwarding.

4. A router comprising said packet forwarding device according to claim 1.

5. A packet forwarding method, comprising:

receiving a packet by a forwarding unit, and

referring, by said forwarding unit, to forwarding information stored in a cache to attempt to determine a forwarding destination of said packet;

in cases in which said forwarding unit could determine the forwarding destination of said packet, sending said packet from said forwarding unit to a control unit, and

sending said packet from said control unit to the forwarding destination determined by said forwarding unit;

in cases in which said forwarding unit could not determine the forwarding destination of said packet, sending said packet from said forwarding unit to said control unit and requesting by said forwarding unit said control unit to determine the forwarding destination of said packet, and

by said control unit, determining the forwarding destination of said packet, sending said packet to said forwarding destination, and storing said forwarding destination in said cache as forwarding information.

6. The packet forwarding method according to claim 5, comprising

adding, by said forwarding unit, to an internal header of said packet a flag indicating whether or not a forwarding destination of said packet could be determined;

and

referring, by said control unit, to said flag to judge whether or not the forwarding destination of said packet has to be determined.

7. The packet forwarding method according to claim 5 wherein packet sequence is maintained before and after packet forwarding.