Memory organization in a switching device

• US 20060023719A1
• Filed: 09/15/2005
• Published: 02/02/2006
• Est. Priority Date: 12/16/1996
• Status: Active Grant

• Current Assignee: Bjorn O. Liencres, Dennis C. Ferguson, Hann-Hwan Ju, Nalini Agarwal, Pradeep S. Sindhu, Rasoul Mirzazadeh Oskouy, Raymond Marcelino Manese Lim, Sreeram Veeragandham
• Original Assignee: Bjorn O. Liencres, Dennis C. Ferguson, Hann-Hwan Ju, Nalini Agarwal, Pradeep S. Sindhu, Rasoul Mirzazadeh Oskouy, Raymond Marcelino Manese Lim, Sreeram Veeragandham
• Inventors: Ferguson, Dennis C., Sindhu, Pradeep S., Agarwal, Nalini, Liencres, Bjorn O., Oskouy, Rasoul Mirzazadeh, Veeragandham, Sreeram, Ju, Hann-Hwan, Manese Lim, Raymond Marcelino
• Granted Patent: US 7,545,808 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: G06F 15/167 using a common memory, e.g. mailbox
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/5652 Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
• CPC Class Codes: H04L 2012/5679 Arbitration or scheduling
• CPC Class Codes: H04L 2012/5681 Buffer or queue management
• 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 45/72 Routing based on the source address
• CPC Class Codes: H04L 45/74591 using content-addressable memories [CAM]
• CPC Class Codes: H04L 47/6225 Fixed service order, e.g. Round Robin
• CPC Class Codes: H04L 49/103 using a shared central buffer; using a shared memory
• CPC Class Codes: H04L 49/108 using shared central buffer
• CPC Class Codes: H04L 49/1538 Cell slicing
• CPC Class Codes: H04L 49/203 ATM switching fabrics with multicast or broadcast capabilities
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• CPC Class Codes: H04L 49/252 Store and forward routing
• CPC Class Codes: H04L 49/3072 Packet splitting
• CPC Class Codes: H04L 49/3081 ATM peripheral units, e.g. policing, insertion or extraction
• 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 49/9042 : Separate storage for different parts of the packet, e.g. header and payload
• CPC Class Codes: H04L 49/9047 : including multiple buffers, e.g. buffer pools
• CPC Class Codes: H04L 49/9057 : Arrangements for supporting packet reassembly or resequencing
• CPC Class Codes: H04L 69/22 : Parsing or analysis of headers
• CPC Class Codes: H04L 9/40 : Network security protocols
• CPC Class Codes: H04Q 11/0478 : Provisions for broadband connections

Abstract

A network device switches variable length data units from a source to a destination in a network. An input port receives the variable length data unit and a divider divides the variable length data unit into uniform length data units for temporary storage in the network device. A distributed memory includes a plurality of physically separated memory banks addressable using a single virtual address space and an input switch streams the uniform length data units across the memory banks based on the virtual address space. The network device further includes an output switch for extracting the uniform length data units from the distributed memory by using addresses of the uniform length data units within the virtual address space. The output switch reassembles the uniform length data units to reconstruct the variable length data unit. An output port receives the variable length data unit and transfers the variable length data unit to the destination.

Claims

1-17. -17. (canceled)

18. A network device for switching a variable length data unit from a source to a destination in a network, the network device comprising:

an input port for receiving the variable length data unit;

a divider for dividing the variable length data unit into uniform length data units for temporary storage in the network device;

a distributed memory comprising a plurality of physically separated memory banks addressable using a single virtual address space;

an input switch for streaming the uniform length data units across the memory banks based on the virtual address space;

an output switch for extracting the uniform length data units from the distributed memory by using addresses of the uniform length data units within the virtual address space, the output switch reassembling the uniform length data units to reconstruct the variable length data unit; and

an output port for receiving the variable length data unit and transferring the variable length data unit to the destination.

19. The network device of claim 18, wherein the variable length data unit is a packet.

20. The network device of claim 18, further comprising:

a table to store a relationship between the physically separated memory banks and the virtual address space.

21. The network device of claim 18, wherein each of the physically separated memory banks includes:

a global data area configured to receive the uniform length data units; and

a notification area configured to receive control information relating to the uniform length data units.

22. The network device of claim 21, wherein the distributed memory includes an output queue for storing a notification indicative of the routing of the variable length data unit through the network device.

23. The network device of claim 21, wherein the control information in the notification area includes information used to route the uniform length data units through the network device.

24. The network device of claim 18, wherein the output switch is further configured to stream the uniform length data units across the memory banks in an interleaved manner.

25. The network device of claim 21, wherein the notification area is sized to be ⅕

of a size of the global data area for a given physically separated memory bank.

26. The network device of claim 18, wherein the uniform length data units are each 64 bytes.

27. The network device of claim 18, further including:

logic configured to detect aged variable length data units stored in the virtual address space.

28. A method of routing a variable length data unit through a network device in a system transmitting variable length data units between a source and a destination over a network including the network device, the method comprising:

receiving the variable length data unit;

dividing the variable length data unit into data units of a uniform size;

storing the uniformly sized data units in a distributed memory, the distributed memory including two or more memory banks where consecutive uniformly sized data units from the variable length data unit are stored in consecutive banks of the distributed memory; and

storing linking information in one bank of the distributed memory for uniform data units that are stored throughout the distributed memory, the linking information used for extracting the uniform data units in order for transmission from the network device to the destination.

29. The method of claim 28, wherein the distributed memory is addressable via a single virtual address space.

30. The method of claim 29, further comprising:

storing a relationship between the two or more memory banks and the virtual address space.

31. The method of claim 28, wherein the variable length data unit is a packet.

32. The method of claim 28, wherein the data units of a uniform size are each 64 bytes in length.

33. A network device comprising:

an input port for receiving a variable length data unit;

a divider for dividing the variable length data unit into uniform length data units for temporary storage in the network device;

a distributed memory comprising a plurality of physically separated memory banks;

an input switch for streaming the uniform length data units across the memory banks;

an output switch for extracting the uniform length data units from the distributed memory, the output switch reassembling the uniform length data units to reconstruct the variable length data unit; and

an output port for receiving the reconstructed variable length data unit and transferring the reconstructed variable length data unit.

34. The network device of claim 33, wherein the physically separated memory banks are addressable using a single virtual address space.

35. The network device of claim 33, wherein the variable length data unit is a packet.

36. The network device of claim 33, wherein each of the physically separated memory banks includes:

a global data area configured to receive the uniform length data units; and

a notification area configured to receive control information relating to the uniform length data units.