Flexible header protocol for network switch

• US 20020009090A1
• Filed: 06/11/2001
• Published: 01/24/2002
• Est. Priority Date: 06/09/2000
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Kalkunte, Mohan, Ambe, Shekhar
• Granted Patent: US 7,075,939 B2
• Time in Patent Office: Days
• US Class Current: 370/401
• CPC Class Codes: H04L 12/462 LAN interconnection over a bridge based backbone
• 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 45/16 Multipoint routing
• CPC Class Codes: H04L 45/245 Link aggregation, e.g. trunking
• CPC Class Codes: H04L 45/52 Multiprotocol routers
• CPC Class Codes: H04L 45/742 Route cache; Operation thereof
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2458 Modification of priorities while in transit
• CPC Class Codes: H04L 47/266 Stopping or restarting the source, e.g. X-on or X-off
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 49/102 using shared medium, e.g. bus or ring
• CPC Class Codes: H04L 49/109 Integrated on microchip, e.g. switch-on-chip
• CPC Class Codes: H04L 49/15 Interconnection of switching modules
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/3018 Input queuing
• CPC Class Codes: H04L 49/3036 Shared queuing
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/352 Gigabit ethernet switching [GBPS]
• CPC Class Codes: H04L 49/354 for supporting virtual local area networks [VLAN]
• CPC Class Codes: H04L 49/506 : Backpressure
• CPC Class Codes: H04L 49/508 : Head of Line Blocking Avoidance
• CPC Class Codes: H04L 49/602 : Multilayer or multiprotocol switching, e.g. IP switching
• CPC Class Codes: H04L 69/22 : Parsing or analysis of headers
• CPC Class Codes: Y02D 30/50 : in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A data switch for network communications includes a first data port interface which supports at least one data port which transmits and receives data. A second data port interface is also provided supporting at least one data port transmitting and receiving data. A CPU interface is provided, with the CPU interface configured to communicate with a CPU. A common memory is provided, and communicates with the first data port interface and the second data port interface. A memory management unit is provided, and communicates data from the first data port interface and the second data port interface and an common memory. At least two sets of communication channels are provided, with each of the communication channels communicating data and messaging information between the first data port interface, the second data port interface, and the memory management unit. One of the first data port interface and the second data port interface is configured to determine forwarding information from a flexible length header for an incoming data packet received at a port of the one data port interface, and is configured to determine the forwarding information by shifting the information field positions read from the flexible length header.

Claims

1. A network switch for network communications, said network switch comprising:

a first data port interface, said first data port interface supporting at least one data port transmitting and receiving data at a first data rate;

a second data port interface, said second data port interface supporting at least one data port transmitting and receiving data at a second data rate;

a CPU interface, said CPU interface configured to communicate with a CPU;

a memory management unit for communicating data from at least one of said first data port interface and said second data port interface and a memory;

a communication channel, said communication channel for communicating data and messaging information between said first data port interface, said second data port interface, and said memory management unit;

a plurality of lookup tables, said lookup tables including an address resolution lookup table and a VLAN table,

wherein one of said first data port interface and said second data port interface is configured to determine forwarding information from a flexible length header for an incoming data packet received at a port of said one of said first data port interface and said second data port interface, and is configured to determine the forwarding information by shifting the information field positions read from the flexible length header.

2. A network switch as recited in claim 1, wherein one of said first data port interface and said second data port interface is configured to determine an amount of shifting of the information field positions by reading an extended header field of the flexible length header.

3. A network switch as recited in claim 1, wherein the second data rate is greater than the first data rate, the flexible length header of the incoming data packet contains an opcode used to identify a packet type, the incoming data packet arrives at a port of the second data port interface, and the second data port interface is configured to forward the incoming data packet based on the opcode.

4. A network switch as recited in claim 3, wherein said opcode identifies whether the incoming data packet is a unicast packet, a multicast packet, a broadcast packet or resulted in a destination lookup failure.

5. A method of switching data in a network switch, said method comprising:

receiving an incoming data packet at a first port of a switch;

reading a first packet portion, less than a full packet length, to determine particular packet information, said particular packet information including a source address and a destination address;

obtaining an egress port or egress ports based on said particular packet information; and

sending the incoming data packet to the egress port or egress ports;

wherein the incoming data packet has a flexible length header, the first packet portion is read from the flexible length header and the particular packet information is read by shifting the information field positions to account for the flexible length of the flexible length header.

6. A method as recited in claim 5, wherein an amount of shifting of the information field positions is determined by reading an extended header field of the flexible length header.

7. A method as recited in claim 5, wherein the step of receiving the incoming data packet at the first port comprises receiving the incoming data packet at an interconnect port interface, where the interconnect port interface provides communication with ports of at least one other stack-linked network switch, and the flexible length header of the incoming data packet contains an opcode used to identify a packet type, the method further comprises the step of forwarding the incoming data packet based on the opcode.

8. A method as recited in claim 7, wherein said opcode identifies whether the incoming data packet is a unicast packet, a multicast packet, a broadcast packet or resulted in a destination lookup failure.

9. A network switch comprising:

means for receiving an incoming data packet at a first port of the switch;

means for reading a first packet portion, less than a full packet length, to determine particular packet information, said particular packet information including a source address and a destination address;

means for obtaining an egress port or egress ports based on said particular packet information; and

means for sending the incoming data packet to the egress port or egress ports;

wherein the incoming data packet has a flexible length header, the first packet portion is read by the means for reading from the flexible length header and the particular packet information is read by the means for reading by shifting the information field positions to account for the flexible length of the flexible length header.

10. A network switch as recited in claim 9, wherein an amount of shifting of the information field positions by the means for obtaining an egress port or egress ports is determined by reading an extended header field of the flexible length header.

11. A network switch as recited in claim 9, wherein the means for receiving the incoming data packet at the first port comprises means for receiving the incoming data packet at an interconnect port interface, where the interconnect port interface provides communication with ports of at least one other stack-linked network switch, and the flexible length header of the incoming data packet contains an opcode used to identify a packet type, the switch further comprises the means for forwarding the incoming data packet based on the opcode.

12. A network switch as recited in claim 11, wherein said opcode identifies whether the incoming data packet is a unicast packet, a multicast packet, a broadcast packet or resulted in a destination lookup failure.