Packet format including unique network identity

• US 5,020,054 A
• Filed: 06/23/1989
• Issued: 05/28/1991
• Est. Priority Date: 06/23/1989
• Status: Expired due to Fees

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.), Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: American Telephone & Telegraph Company (AT&T, Inc.), Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Inventors: May, Carl J. Jr.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Edwards, Christopher O.
• Application Number:
  US07/371,229
• Time in Patent Office: 704 Days
• Field of Search: 370/60, 370/85, 370/94, 370/60.1, 370/85.1, 370/94.1, 370/82, 371/36, 371/49, 371/53
• US Class Current: 370/474
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 49/102 using shared medium, e.g. bus or ring
• 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 9/40 Network security protocols

Abstract

A unique packet transport word, i.e., header, format is employed which eliminates the possiblity of particular packet transport words being mistaken for other transport words used in a private network, public network or otherwise. This is realized by employing a unique network reference code word to compute one or more prescribed parity checks over bits in predetermined bit positions of the transport word. The network reference code word is used to specify the sense, i.e., odd or even, of predetermined ones of the parity check bits being computed which form the one or more prescribed parity checks. Individual ones of such network reference code words are assignable to specific private transport users and, thereby, provide transparency of their transport words in the public or other networks. Additionally, unique network reference code words are assigned to each network layer in a system hierarchy to identify each of the specific network layers and to provide transparency of the lower network layer transport words in the higher network layers.

Claims

1. Apparatus for generating a packet including at least a transport word, i.e., header, comprising:

means for generating said transport word including a predetermined number of groups of bit positions each including a predetermined number of said bit positions, predetermined ones of said transport word bit positions forming an at least one prescribed parity check field;

a source of a reference code word having a number of bits, said reference code word being independent from any information in the transport word;

means for generating an at least first prescribed parity check from bits in a number of predetermined bit positions of said transport word and predetermined ones of said number of bits of said reference code word; and

means for inserting a number of bits representative of said at least first prescribed parity check into a corresponding number of bit positions forming said at least first prescribed parity check field in said transport word.

2. The apparatus as defined in claim 1 wherein said means for generating said at least first prescribed parity check generates a predetermined number of parity check bits forming said at least first parity check by computing parity form said bits in a number of predetermined bit positions of said transport word and wherein each of predetermined ones of said number of reference code word bits defines the sense, i.e., odd or even, of parity being computed to generate a corresponding one of said predetermined number of parity check bits forming said first prescribed parity check.

3. The apparatus as defined in claim 2 wherein said means for generating said at least first prescribed parity check includes means for generating said predetermined number of parity check bits forming said at least first prescribed parity check by computing parity to yield individual ones of said parity check bits from bits in predetermined bit positions in one or more of predetermined ones of said groups of bit positions in said transport word in conjunction with said predetermined ones of said reference code word bits.

4. The apparatus as defined in claim 2 wherein said means for generating said at least first prescribed parity check includes means for generating said predetermined number of parity check bits forming said at least first prescribed parity check by computing parity from bits in predetermined similar bit positions in predetermined ones of said groups of bit positions in said transport word in conjunction with said predetermined ones of said reference code word bits.

5. The apparatus as defined in claim 2 wherein a predetermined number of said transport word bit positions form an at least second prescribed parity check field, and further including means for generating an at least second prescribed parity check from bits in predetermined bit positions of said transport word and means for inserting a number of bits representative of said at least second prescribed parity check in said number of bit positions of said at least second parity check field in said transport word.

6. The apparatus as defined in claim 5 wherein predetermined ones of said reference code word bits are supplied to said means for generating said at least second prescribed parity check, wherein said means for generating said at least second prescribed parity check generates a predetermined number of parity check bits forming said at least second prescribed parity check and wherein each of said supplied predetermined ones of said reference code word bits defines the sense, i.e., odd or even, of parity being computed to generate a corresponding one of said predetermined number of parity check bits forming said at least second prescribed parity check.

7. The apparatus as defined in claim 6 wherein said means for generating said at least second prescribed parity check includes means for generating said predetermined number of parity check bits forming said at least second prescribed parity check by computing parity from bits in predetermined similar bit positions in predetermined ones of said groups of bit positions in said transport word in conjunction with said supplied predetermined ones of said reference code word bits.

8. The apparatus as defined in claim 7 wherein said means for generating said at least first prescribed parity check includes means for generating said predetermined number of parity check bits forming said at least first prescribed parity check by computing individual ones of said parity check bits from bits in predetermined bit positions in one or more of predetermined ones of said groups of bit positions in said transport word in conjunction with said predetermined ones of said reference code word bits.

9. The apparatus as defined in claim 8 wherein predetermined ones of said predetermined similar bit positions in said predetermined ones of said groups of bit positions include said parity check bits which form said at least first prescribed parity check.

10. The apparatus as defined in claim 2 wherein each of said predetermined number of groups of bit positions forms a byte, wherein said means for generating said transport word generates each said byte in parallel and wherein said transport word bit positions form a predetermined number of columns of bit positions and a predetermined number of rows of bit positions.

11. The apparatus as defined in claim 10 wherein said means for generating said at least first prescribed parity check includes means for generating said predetermined number of parity check bits forming said at least first prescribed parity check by computing parity from bits in predetermined bit positions of one or more of predetermined ones of said columns of bit positions in said transport word in conjunction with said predetermined ones of said reference code word bits.

12. The apparatus as defined in claim 11 wherein a predetermined number of said transport word bit positions form an at least second prescribed parity check field, and further including means for generating an at least second prescribed parity check from bits in predetermined bit positions of said transport word and means for inserting a number of bits representative of said at least second prescribed parity check in said number of bit positions of said at least second parity check field in said transport word.

13. The apparatus as defined in claim 12 wherein predetermined ones of said reference code word bits are supplied to said means for generating said at least second prescribed parity check, wherein said means for generating said at least second prescribed parity check generates a predetermined number of parity check bits forming said at least second prescribed parity check and wherein each of said supplied predetermined ones of said reference code word bits defines the sense, i.e., odd or even, of parity being computed to generate a corresponding one of said predetermined number of parity check bits forming said at least second prescribed parity check.

14. The apparatus as defined in claim 13 wherein said means for generating said at least second prescribed parity check includes means for generating said predetermined number of parity check bits forming said at least second prescribed parity check by computing parity from bits in predetermined ones of bit positions of each of a corresponding number of predetermined ones of said rows of bit positions in said transport word in conjunction with said supplied predetermined ones of said reference code word bits.

15. The apparatus as defined in claim 14 wherein said means for generating said transport word generates said transport word to include eight bytes and each byte includes eight bit positions, wherein said means for generating said at least first prescribed parity check generates individual parity check bits by computing parity from bits in the eight bit positions of at least six of said bytes, wherein said means for generating said at least second prescribed parity check generates individual parity check bits by computing parity from bits in each row of bit positions from seven of said bytes and wherein said number of reference code word bits is at least twelve, eight of which are associated on a one-to-one basis with said rows of bit positions and four of which are associated on a one-to-one basis with predetermined ones of said columns of bit positions.

16. The apparatus as defined in claim 1 wherein said reference code word is unique to a particular transport network configuration.

17. The apparatus as defined in claim 1 further including means for interfacing to a transmission facility supplying information to be formatted into said packet.

18. The apparatus as defined in claim 1 further including means for interfacing to a transmission facility to transmit said packet to a remote location.

19. The apparatus as defined in claim 1 further including means for interfacing to apparatus supplying information to be formatted into said packet.

20. The apparatus as defined in claim 19 further including means for interfacing to a packet network node.

21. The apparatus as defined in claim 20 further including means for interfacing to a packet cross-connect switch.

22. Apparatus for generating a packet including at least a transport word, i.e., header, comprising:

means for generating said transport word including a predetermined number of groups of bit positions each including a predetermined number of bit positions, predetermined ones of said transport word bit positions forming a plurality of parity check fields;

a source of a reference code word having a number of bits, said reference code word being independent from any information in the transport word;

means for generating a plurality of prescribed parity checks from bits in predetermined bit positions of said transport word in conjunction with said number of bits of said reference code word, wherein each of said bits from said predetermined bit positions in said transport word is used to compute at least two different parity check bits which form said plurality of prescribed parity checks; and

means for inserting said computed parity check bits into bit positions in said plurality of parity check fields in said transport word.

23. The apparatus as defined in claim 22 wherein said means for generating said plurality of prescribed parity checks includes means for using said number of reference code word bits to determine the sense, i.e., odd or even, of parity being computed to realize predetermined ones of said parity check bits being computed.

24. The apparatus as defined in claim 23 wherein said reference code word is unique to a particular transport network configuration.

25. The apparatus as defined in claim 24 further including means for interfacing to a transmission facility supplying information to be formatted into said packet.