Method and apparatus for transmitting a cell and a packet in a network

• US 20040213248A1
• Filed: 03/05/2001
• Published: 10/28/2004
• Est. Priority Date: 08/24/2000
• Status: Abandoned Application

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Okuda, Masato, Tanaka, Jun, Nishimura, Kazuto, Kusayanagi, Michio
• Application Number:
  US09/799,544
• Publication Number:
  US 20040213248A1
• Time in Patent Office: Days
• US Class Current: 370/395.1
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/5665 Interaction of ATM with other protocols
• CPC Class Codes: H04L 49/606 Hybrid ATM switches, e.g. ATM&STM, ATM&Frame Relay or ATM&IP

Abstract

Disclosed is a transmitting apparatus for transmitting a fixed-length cell and a variable-length packet together in one network. A first IF portion of the transmitting apparatus attaches a header corresponding to the protocol of a mixed network to a variable-length packet which arrives from a packet network and transmits it to the mixed network. A second IF portion removes the cell header from a fixed-length cell which arrives from a fixed-length cell network, attaches a header corresponding to the protocol of the mixed network instead, and transmits it to the mixed length. A third IF portion judges whether a data with a header which arrives from the mixed network is a fixed-length cell or a variable-length packet, replaces the header of the mixed network by a cell header if the data is a fixed-length cell and transmits the data to a fixed-length cell network, while removing the header of the mixed network if the data is a variable-length packet, and transmits the data to a packet network.

Claims

1. A method of transmitting a fixed-length cell and a variable-length packet in one network comprising:

attaching a header corresponding to communication protocol in a mixed network in which both of a variable-length packet and a fixed-length cell are transmitted to a variable-length packet, while removing a cell header from a fixed-length cell and attaching a header corresponding to the communication protocol in the mixed network instead; and

transmitting said fixed-length cell and said variable-length packet in the mixed network on the basis of the respective headers.

2. A method of transmitting of a fixed-length cell and a variable-length packet in one network comprising:

attaching a header corresponding to the communication protocol in a mixed network in which both of a variable-length packet and a fixed-length cell are transmitted to a variable-length packet and transmitting said variable-length packet to the mixed network, when said variable-length packet arrives from a packet network;

removing a cell header from a fixed-length cell and adding a header corresponding to the communication protocol in the mixed network instead, and transmitting said fixed-length cell to the mixed network, when said fixed-length cell arrives from a fixed-length cell network;

judging whether data with a header is a fixed-length cell or a variable-length packet when said data arrives from the mixed network, and replacing the header of the mixed network by a cell header and transmitting said data to the fixed-length cell network if said data is a fixed-length cell, while removing the header of the mixed network and transmitting said data to the packet network if said data is a variable-length packet.

3. A method of transmitting a fixed-length cell and a variable-length packet in one network according to claim 2, further comprising:

/

imparting information LI indicating a payload length to the header of said communication protocol, wherein said LI value of said header attached to said fixed-length cell is set at a larger value than a preset value, while said LI value of said header attached to said variable-length packet is set at a packet length not larger than said preset value; and

comparing said LI value of said data with a header which arrives from the mixed network with said preset value, and judging whether said data is a fixed-length cell or a variable-length packet on the basis of the result of the comparison.

4. A method of transmitting a fixed-length cell and a variable-length packet in one network according to claim 2, further comprising:

attaching a code for bit error detection to said variable-length packet, while not attaching a code for bit error detection to said fixed-length cell; and

executing a bit error detection processing by using said code for bit error detection when said variable-length packet with said header is received.

5. A method of transmitting a fixed-length cell and a variable-length packet in one network according to claim 2, further comprising:

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imparting LI (Length Indicator) information indicating a payload length and HEC (Header Error Correction) information which is a cyclic redundancy code for detecting an error in a header to the header of the mixed network; and

detecting, a header error by using said HEC information, and identifying the head of a cell/packet by using said HEC information and said LI information when a variable-length packet with a header or a fixed-length cell with a header is received.

6. A method of transmitting of a fixed-length cell and a variable-length packet in one network according to claim 2, further comprising:

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imparting TTL (Time To Live) information for restricting the time for which a data can exist in the mixed network to the header of the mixed network; and

checking, when a transmitting apparatus receives a data with a header whether or not said TTL value contained in said header is zero, and if said TTL value is zero, discarding data.

7. A method of transmitting a fixed-length cell and a variable-length packet in one network according to claim 3, wherein the range of said packet length is set in advance, and a specific meaning is imparted to said LI value exceeding said range.

8. A method of transmitting a fixed-length cell and a variable-length packet in one network according to claim 7, further comprising:

separating a packet having a length exceeding said preset range into a plurality of packets so that the length of each of the separated packets may satisfy said range;

setting said LI value of each of said separated packets at a value indicating that each packet is a fragmented packet; and

imparting information on fragmentation to said header.

9. A method of transmitting a fixed-length cell and a variable-length packet in one network according to claim 7, further comprising:

subjecting a packet having a length shorter than said preset range to a padding processing,

setting said LI value of said packet subjected to said padding processing at a value indicating that said packet has been subjected to said padding processing; and

imparting information on padding to said header.

10. A method of transmitting a fixed-length cell and a variable-length packet in one network according to claim 7, further comprising:

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sending a message that said packet length is too long to a transmission terminal when a received data is a packet having a length exceeding said preset range.

11. A transmitting apparatus for transmitting a fixed-length cell and a variable-length packet in one network comprising:

a first means for attaching a header corresponding to communication protocol of a mixed network to a variable-length packet which arrives from a packet network and transmitting said variable-length packet to said mixed network;

a second means for removing a cell header from a fixed-length cell which arrives from a fixed-length cell network, attaching a header corresponding to said communication protocol of said mixed network and transmitting said fixed-length cell to said mixed network; and

a third means for judging whether a data with the header of the mixed network which arrives from the mixed network is a fixed-length cell or a variable-length packet, and replacing the header of the mixed network by a cell header and transmitting said data to a fixed-length cell network if said data is a fixed-length cell, while removing said header of the mixed network and transmitting said data to a packet network if said data is a variable-length packet.

12. A transmitting apparatus according to claim 11, further comprising:

a switch for switching said variable-length packet and said fixed-length cell to the respective predetermined routes;

wherein said first means includes a variable-length packet IF portion interface portion for attaching a tag corresponding to a destination address to the variable-length packet, and a mixed IF portion for attaching a header corresponding to said communication protocol of the mixed network to said variable-length packet which is switched by said switch on the basis of said tag, and transmitting said variable-length packet to the mixed network;

said second means includes a fixed-length cell IF portion for attaching a tag corresponding to an connection ID to said fixed-length cell, and a mixed IF portion for attaching a header corresponding to the mixed network to said fixed-length cell which is switched by said switch on the basis of said tag, and transmitting said fixed-length cell to the mixed network; and

said third means includes a judging portion for judging whether said data with said header of the mixed network is a fixed-length cell or a variable-length packet, a fixed-length cell IF portion for replacing said header of the mixed network by said cell header and transmitting said fixed-length cell to said fixed-length cell network, and a variable-length packet IF portion for removing said header of the mixed network from said variable-length packet and transmitting said variable-length packet to said packet network.