Apparatus and method for forwarding packet data

• US 8,189,589 B2
• Filed: 03/17/2009
• Issued: 05/29/2012
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tanaka, Jun, Tomonaga, Hiroshi, Kuwabara, Takashi, Kurosaki, Hiroshi
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): Haliyur, Venkatesh
• Application Number:
  US12/405,393
• Publication Number:
  US 20090245258A1
• Time in Patent Office: 1,169 Days
• Field of Search: 370328-503
• US Class Current: 370/392
• CPC Class Codes: H04L 41/0659 by isolating or reconfiguring faulty entities
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/557 Error correction, e.g. fault recovery or fault tolerance

Abstract

An apparatus includes an input part, a plurality of output parts, and a switching part. The input part inputs a packet and builds at least one forwarding data block including a predetermined destination identifier and packet data extracted from the inputted packet. The switching part includes a forwarding destination storing section for storing, in association with a predetermined destination identifier, a forwarding destination identifier identifying one of the plurality of output parts, and receives the at least one forwarding data block from the input part, and forwards it to one of the plurality of output parts on the basis of forwarding destination storing section which is updated in response to a change in the operating state of the plurality of output parts.

Claims

1. An apparatus for forwarding packet data, comprising:

a plurality of output parts for outputting a packet, each of the plurality of output parts being defined as one of an output side interface unit and a trunk unit;

an input side interface unit configured to;

input a packet, and

build a sequence of forwarding data blocks each having a header field and a packet data field, the header field including a forwarding destination field and a position indicator, the forwarding destination field storing a first forwarding destination identifier identifying a first output part to which the sequence of forwarding data blocks are to be forwarded when the first output part is in an active state indicating that the first output part is working, the position indicator indicating a relative position of a forwarding data block within the sequence of forwarding data blocks, the packet data field storing a portion of packet data extracted from the packet so that the packet data is restored by combining all of the packet data fields included in the sequence of forwarding data blocks in an order corresponding to the sequence of forwarding data blocks; and

a switch fabric configured to;

store a second forwarding destination identifier in association with the first forwarding destination identifier when the first output part is in an inactive state indicating that the first output part is not working, the second forwarding destination identifier identifying a second output part to which the sequence of forwarding data blocks are to be forwarded when the first output part is in the inactive state;

receive the sequence of forwarding data blocks from the input side interface unit;

perform forwarding destination conversion procedure on the received sequence of forwarding data blocks, the forwarding destination conversion procedure including;

determining whether the first output part is in the active state or not when the switch fabric receives a beginning block of the sequence of forwarding data blocks,

converting, when it is determined that the first output part is in the inactive state, the first forwarding destination identifier stored in the forwarding destination field of each of the sequence of forwarding data blocks into the second forwarding destination identifier so that all the forwarding destination fields of the sequence of forwarding data blocks store the second forwarding destination identifier, and

keeping, when it is determined that the first output part is in the active state, the first forwarding destination identifier stored in the forwarding destination field of each of the sequence of forwarding data blocks so that all the forwarding destination fields of the sequence of forwarding data blocks store the first forwarding destination identifier; and

forward each of the sequence of forwarding data blocks to one of the first and second output parts that is identified by the converted forwarding destination identifier stored in the forwarding destination field of the each of the sequence of forwarding data blocks so that a whole sequence of forwarding data blocks is forwarded to the first output part when the first output part is in the active state at the time of receiving the beginning block of the sequence of forwarding data blocks, and forwarded to the second output part when the first output part is in the inactive state at the time of receiving the beginning block of the sequence of forwarding data blocks.

2. The apparatus of claim 1, wherein

the switch fabric includes first and second forwarding destination tables, the first forwarding destination table storing, in association with the first forwarding destination identifier, the same first forwarding destination identifier, the second destination table storing, in association with the first forwarding destination identifier, the second forwarding destination identifier;

and

the switch fabric performs the forwarding destination conversion procedure on the received sequence of forwarding data blocks by;

selecting the first forwarding destination table when the first output part is in the active state at the time of receiving the beginning block of the sequence of forwarding data blocks;

selecting the second forwarding destination table when the first output part is in the inactive state at the time of receiving the beginning block of the sequence of forwarding data blocks;

obtaining a forwarding destination identifier that is associated with the first forwarding destination identifier in the selected forwarding destination table; and

converting the first forwarding destination identifier stored in the forwarding destination field of each of the sequence of forwarding data blocks into the obtained forwarding destination identifier so that all the forwarding destination fields of the sequence of forwarding data blocks store the obtained forwarding destination identifier.

3. The apparatus of claim 2, wherein

the apparatus includes a plurality of input side interface units, each of the plurality of input side interface units providing a header field of each of the sequence of data blocks with a source identifier identifying the each of the plurality of input side interface units so that all the header fields of the sequence of data blocks include a same source identifier provided by the each of the plurality of input side interface units;

and

upon receiving a plurality of the sequences of forwarding data blocks in parallel from the plurality of input side interface units, the switch fabric performs the forwarding destination conversion procedure in parallel on each of the plurality of the sequences of data blocks with reference to the source identifiers included in the header fields of the each of the plurality of sequences of forwarding data blocks received from the plurality of input side interface units, so that all of the sequence of forwarding data blocks originating from one of the plurality of input side interface units are forwarded to a same one of the plurality of output parts that is identified by the converted forwarding destination identifier stored in the forwarding destination fields of the sequence of forwarding data blocks.

4. The apparatus of claim 1, wherein

the apparatus includes a plurality of the switch fabrics;

the input side interface unit distributes the sequence of forwarding data blocks among the plurality of the switch fabrics; and

each of the plurality of the switch fabrics performs the forwarding destination conversion procedure on at least one forwarding data block received from the input side interface unit, and forwards the at least one forwarding data block to one of the plurality of output parts that is identified by the converted forwarding destination identifier included in the forwarding destination field of the received at least one forwarding data block.

5. The apparatus of claim 2, wherein

the apparatus includes a plurality of the switch fabrics;

the input side interface unit selects one of the first and second forwarding destination tables, and provides all the header fields of the sequence of forwarding data blocks with a table identifier identifying the selected one of the first and second forwarding destination tables, and distributes the sequence of forwarding data blocks among the plurality of switch fabrics; and

each of the plurality of switch fabrics performs the forwarding destination conversion procedure on at least one forwarding data block received from the input side interface unit, by converting the first forwarding destination identifier stored in the header field of the received at least one forwarding data block into the converted forwarding destination identifier that is associated with the first forwarding destination identifier by one of the first and second forwarding destination tables that is identified by the table identifier included in the header field of the received at least one forwarding data block, so that all the sequence of forwarding data blocks including the received at least one forwarding data block are forwarded to a same one of the plurality of output parts that is identified by the converted forwarding destination identifier stored in each of the forwarding destination fields of the sequence of forwarding data blocks.

6. The apparatus of claim 2, wherein

the switch fabric includes first and second forwarding destination tables, both the first and second forwarding destination tables storing, in association with the first forwarding destination identifier, one of the first and second forwarding destination identifiers when no changes are occurring in operating states of the plurality of output parts;

the switch fabric performs the forwarding destination conversion procedure on the sequence of forwarding data blocks by selecting the one of the first and second forwarding destination tables;

the switch fabric updates, in response to a change in an operating state of the plurality of output parts, the other one of the first and second forwarding destination tables that is not being selected so that the other one of the first and second forwarding destination tables stores, in association with the first forwarding destination identifier, the first forwarding destination identifier when the first output part is in the active state, and stores, in association with the first forwarding destination identifier, the second forwarding destination identifier when the first output part is in the inactive state; and

the switch fabric further updates the one of the first and second forwarding destination tables after selecting the other one of the first and second forwarding destination tables so that both the first and second forwarding destination tables store a same one of the first and second forwarding destination identifiers in association with the first forwarding destination identifiers.

7. A method for forwarding packet data within an apparatus including an input side interface unit, a switch fabric, and a plurality of output parts each defined as one of an output side interface unit and a trunk unit, the method comprising:

inputting, by the input side interface unit, a packet;

building, by the input side interface unit, from the inputted packet, a sequence of forwarding data blocks each having a header field and a packet data field, the header field including a forwarding destination field and a position indicator, the forwarding destination field storing a first forwarding destination identifier identifying a first output part to which the sequence of forwarding data blocks are to be forwarded when the first output part is in an active state indicating that the first output part is working, the position indicator indicating a relative position of a forwarding data block within the sequence of forwarding data blocks, the packet data field storing a portion of packet data extracted from the packet so that the packet data is restored by combining all of the packet data fields included in the sequence of forwarding data blocks in an order corresponding to the sequence of forwarding data blocks

storing, by the switch fabric, a second forwarding destination identifier in association with the first forwarding destination identifier when the first output part is in an inactive state indicating that the first output part is not working, the second forwarding destination identifier identifying a second output part to which the sequence of forwarding data blocks are to be forwarded when the first output part is in the inactive state,

receiving, by the switch fabric, the sequence of forwarding data blocks from the input side interface unit;

performing, by the switch fabric, forwarding destination conversion procedure on the received sequence of forwarding data blocks, the forwarding destination conversion procedure including;

determining whether the first output part is in the active state or not when the switch fabric receives a beginning block of the sequence of forwarding data blocks,

converting, when it is determined that the first output part is in the inactive state, the first forwarding destination identifier stored in the forwarding destination field of each of the sequence of forwarding data blocks into the second forwarding destination identifier so that all the forwarding destination fields of the sequence of forwarding data blocks store the second forwarding destination identifier, and

keeping, when it is determined that the first output part is in the active state, the first forwarding destination identifier stored in the forwarding destination field of each of the sequence of forwarding data blocks so that all the forwarding destination fields of the sequence of forwarding data blocks store the first forwarding destination identifier; and

forwarding, by the switch fabric, each of the sequence of forwarding data blocks to one of the first and second output parts that is identified by the converted forwarding destination identifier stored in the forwarding destination field of the each of the sequence of forwarding data blocks so that a whole sequence of forwarding data blocks is forwarded to the first output part when the first output part is in the active state at the time of receiving the beginning block of the sequence of forwarding blocks, and forwarded to the second output part being in the active state when the first output part is in the inactive state at the time of receiving the beginning block of the sequence of forwarding blocks.

8. The method of claim 7, further comprising:

providing the switch fabric with first and second forwarding destination tables, the first forwarding destination table storing, in association with the first forwarding destination identifier, the same first forwarding destination identifier, the second forwarding destination table storing, in association with the first forwarding destination identifier, the second forwarding destination identifier,

wherein

the forwarding destination conversion procedure includes;

selecting the first forwarding destination table when the first output part is in the active state at the time of receiving the beginning block of the sequence of forwarding data blocks;

selecting the second forwarding destination table when the first output part is in the inactive state at the time of receiving the beginning block of the sequence of forwarding data blocks;

obtaining, by the switch fabric, a forwarding destination identifier that is associated with the first forwarding destination identifier in the selected forwarding destination tables; and

converting the first forwarding destination identifier stored in the forwarding destination field of each of the sequence of forwarding data blocks into the obtained forwarding destination identifier so that all the forwarding destination fields of the sequence of forwarding data blocks store the obtained forwarding destination identifier.

9. The method of claim 8, further comprising:

providing the apparatus with a plurality of input side interface units;

inputting, by each of the plurality of input side interface units, the packet;

providing, by the each of the plurality of input side interface units, a header field of each of the sequence of data blocks with a source identifier identifying the each of the plurality of input side interface units so that all the header fields of the sequence of data blocks include the same source identifier provided by the each of the plurality of input side interface units;

performing, upon receiving a plurality of the sequences of forwarding data blocks in parallel from the plurality of input side interface units, the forwarding destination conversion procedure in parallel on each of the plurality of the sequences of forwarding data blocks with reference to a source identifier included in the header fields of each of the plurality of the sequences of forwarding data blocks, so that all the sequence of forwarding data blocks originating from one of the plurality of input side interface units are forwarded to a same one of the plurality of output parts that is identified by the converted forwarding destination identifier stored in the forwarding destination fields of the sequence of forwarding data blocks.

10. The method of claim 7, further comprising:

providing the switch fabric with first and second forwarding destination tables, both the first and second forwarding destination tables storing, in association with the first forwarding destination identifier, one of the first and second forwarding destination identifiers when no changes are occurring in operating states of the plurality of output parts;

performing, by the switch fabric, the forwarding destination conversion procedure on the sequence of forwarding data blocks by selecting one of the first and second forwarding destination tables;

updating, in response to a change in an operating state of the plurality of output parts, the other one of the first and second forwarding destination tables that is not being selected so that the other one of the first and second forwarding destination tables stores, in association with the first forwarding destination identifier, the first forwarding destination identifier when the first output part is in the active state, and stores, in association with the first forwarding destination identifier, the second forwarding destination identifier when the first output part is in the inactive state; and

updating the one of the first and second forwarding destination tables after selecting the other one of the first and second forwarding destination tables, so that both the first and second forwarding destination tables store a same one of the first and second forwarding destination identifiers in association with the first forwarding destination identifiers.