Switch fabric with path redundancy

• US 6,535,510 B2
• Filed: 06/19/2001
• Issued: 03/18/2003
• Est. Priority Date: 06/19/2000
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Tai, Daniel, Cameron, Kevin, Sampath, Srinivas, Pullela, Soma, Kalkunte, Mohan
• Primary Examiner(s): VANDERPUYE, KENNETH N
• Application Number:
  US09/883,212
• Publication Number:
  US 20020027908A1
• Time in Patent Office: 637 Days
• Field of Search: 370/360, 370/428, 370/389, 370/401, 370/327, 370/340, 370/386
• US Class Current: 370/389
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 12/1881 with schedule organisation, e.g. priority, sequence management
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/5651 Priority, marking, classes
• CPC Class Codes: H04L 2012/5665 Interaction of ATM with other protocols
• CPC Class Codes: H04L 2012/5679 Arbitration or scheduling
• CPC Class Codes: H04L 2012/5681 Buffer or queue management
• CPC Class Codes: H04L 2012/5683 for avoiding head of line blocking
• 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 45/245 Link aggregation, e.g. trunking
• CPC Class Codes: H04L 45/54 Organization of routing tables
• CPC Class Codes: H04L 45/745 Address table lookup; Address filtering
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2408 for supporting different services, e.g. a differentiated services [DiffServ] type of service
• CPC Class Codes: H04L 47/2425 for supporting services specification, e.g. SLA
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]
• CPC Class Codes: H04L 47/245 using preemption
• CPC Class Codes: H04L 47/286 Time to live
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/6205 : Arrangements for avoiding head of line blocking
• CPC Class Codes: H04L 47/6215 : Individual queue per QOS, rate or priority
• CPC Class Codes: H04L 47/6225 : Fixed service order, e.g. Round Robin
• CPC Class Codes: H04L 49/101 : using crossbar or matrix
• CPC Class Codes: H04L 49/201 : Multicast operation; Broadcast operation
• CPC Class Codes: H04L 49/203 : ATM switching fabrics with multicast or broadcast capabilities
• CPC Class Codes: H04L 49/205 : Quality of Service based
• CPC Class Codes: H04L 49/25 : Routing or path finding in a switch fabric
• CPC Class Codes: H04L 49/254 : Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/30 : Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/309 : Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/352 : Gigabit ethernet switching [GBPS]
• CPC Class Codes: H04L 49/608 : ATM switches adapted to switch variable length packets, e.g. IP packets
• CPC Class Codes: H04L 49/90 : Buffering arrangements
• CPC Class Codes: H04L 49/901 : using storage descriptor, e.g. read or write pointers
• CPC Class Codes: H04L 49/9094 : Arrangements for simultaneous transmit and receive, e.g. simultaneous reading/writing from/to the storage element
• CPC Class Codes: Y02D 30/50 : in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A method of forwarding data in a network switch fabric is disclosed. An incoming data packet is received at a first port of the fabric and a first packet portion, less than a full packet length, is read to determine particular packet information, the particular packet information including a source address and a destination address. An egress port bitmap is determined based on a lookup in a forwarding table and it is determined if the destination address belongs to a trunk group of trunked ports. The incoming data packet is forwarded based on the egress port bitmap, when the destination address does not belong to the trunk group. When the destination address does belong to the trunk group, a particular trunked port of the trunk group is determined and the incoming data packet is forwarded thereto. More specifically, the particular trunked port of the trunk group may be determined by calculating a hash value based on the source address and the destination value and selecting the particular trunked port based on the hash value. Additionally, a class of service for the incoming data packet is also determined from the particular packet information and a priority for forwarding is set based on the class of service.

Claims

1. A method of forwarding data in a network switch fabric, said method comprising:

receiving an incoming data packet at a first port of the fabric;

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;

determining an egress port bitmap based on a lookup in a forwarding table;

determining if the destination address belongs to a trunk group of trunked ports;

forwarding the incoming data packet based on the egress port bitmap, when the destination address does not belong to the trunk group; and

determining a particular trunked port of the trunk group and forwarding the incoming data packet thereto, when the destination address does belong to the trunk group.

2. A method as recited in claim 1, wherein said step of determining the particular trunked port of the trunk group comprises calculating a hash value based on the source address and the destination address and selecting the particular trunked port based on the hash value.

3. A method as recited in claim 1, wherein said particular packet information includes an opcode value that identifies whether the incoming data packet is a unicast packet, a multicast packet, a broadcast packet or resulted in a destination lookup failure.

4. A method as recited in claim 1, further comprising determining a class of service for the incoming data packet from said particular packet information and setting a priority for forwarding based on the class of service.

5. A network switch fabric forwarding data comprising:

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

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 determining an egress port bitmap based on a lookup in a forwarding table;

means for determining if the destination address belongs to a trunk group of trunked ports;

means for forwarding the incoming data packet based on the egress port bitmap, when the destination address does not belong to the trunk group;

means for determining a particular trunked port of the trunk group; and

means for forwarding the incoming data packet thereto, when the destination address does belong to the trunk group.

6. A network switch fabric as recited in claim 5, wherein said means for determining the particular trunked port of the trunk group comprises means for calculating a hash value based on the source address and the destination address and means for selecting the particular trunked port based on the hash value.

7. A network switch fabric as recited in claim 5, wherein said particular packet information includes an opcode value that identifies whether the incoming data packet is a unicast packet, a multicast packet, a broadcast packet or resulted in a destination lookup failure.

8. A network switch fabric as recited in claim 5, further comprising means for determining a class of service for the incoming data packet from said particular packet information and means for setting a priority for forwarding based on the class of service.