Corrigendum to X.501 edition 3

ITU - Telecommunication Standardization Sector Temporary Document 2045/Rev.3

STUDY GROUP 7

Geneva, 29 January - 2 February 2001

Question(s): 7/7

SOURCE: RAPPORTEUR Q.7/7

TITLE: DRAFT AMENDMENT 1 TO ITU-T RECOMMENDATION X.85/Y.1321 (2000)

________

SUMMARY

This amendment lengthens the byte count in the LAPS header to conform to IETF standards for byte count in the PPP header. This amendment also makes more precise the description of the LAPS protocol.

Amendment 1 to ITU-T Recommendation X.85/Y.1321 (2000)

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1. In summary, second sentence, replace:

…when the SAPI is set to “11111111”.

with:

…when the Address field is set to “11111111” and the data link is set to operate as the way RFC 2615 defines.

2. In TABLE 1, 7^th row , replace:

…601 304 …

with:

…601 344 …

3. In item b) of TABLE 5, first sentence, replace:

… : 6 for IPv6 ,4 for IPv4 and 255 for PPP….

with:

…: 0021 for Ipv4, 0057 for Ipv6. …

4. In item b) of TABLE 5,second sentence, replace:

When PPP is encapsulated via SAPI, it is noted:….

with:

When the PPP is used to be encapsulated via SAPI for the compatibility with RFC 2615, it is noted: …

5. In item b) of TABLE 5, add a sentence as the subitem (3) following subitem (2):

(3)The data link will be operated as RFC 2615 defines and the Address field is set to “11111111”, the padding field followed information field and the functions of Link Control Protocol and Network Control Protocol will be included.

6. In A.2.1, remove the following sentence:

NOTE - The LAPS shall be encapsulated into a 32-bit word-oriented frame as for the need of providing frame delineation, transparent transferring, and error detection. The frame format of STM-64 or VC-4-64c needs further study.

7. In the title of A.2.3, replace:

The address field shall consist of an single octet as illustrated in Figure A.1. The format of the address field is defined in A.3.2.

with:

The address field shall consist of a single octet as illustrated in Figure A.1 and its value is 0x04 (hexadecimal).

8. In the title of A.2.4, replace:

Control field

with:

Control and SAPI field

9. In A.2.4, add the following sentence to the end of the first paragraph:

For the SAPI field, please refer to A.3.2.

10. In the first sentence of A.2.5, replace:

The information field of a frame, when present, follows the control field (see A.2.4 above) and precedes the frame check sequence (see A.2.7 below).

with:

The information field of a frame, when present, follows the SAPI field and precedes the frame check sequence.

11. In A.2.6, replace:

……A transmitting data link layer entity shall examine the frame content between the opening and closing flag sequences (address, control, information and FCS fields) during transmission; ……

with:

A transmitting data link layer entity shall examine the frame content between the opening and closing flag sequences (address, control, SAPI, information and FCS fields) during transmission;

12. In the 13^th row of A.2.7, replace:

…..on the address, control, and information fields over which the CRC is to be calculated; …..

with:

…..on the address, control, SAPI and information fields over which the CRC is to be calculated; …..

13. In the last paragraph of A.2.7, replace:

The 16-bit FCS is referred to RFC 2615 when the SAPI of LAPS is set to “11111111” for compatibility with RFC 2615. In this case, the length of FCS is changed to the two octets in Figure A.1 and Figure A.4.

with:

The computation of 32-bit FCS and 16-bit FCS is referred to RFC 2615 for compatibility with RFC 2615. In this case of 16-bit FCS, the length of FCS is changed to the two octets in Figure A.1 and Figure A.4.

14. In the last paragraph of A.2.8.3, replace:

…….In this case, bit 1 of the first octet is the high order bit and bit 8 of the 4th octet is the low order bit (see Figure A.4 ), …..

with:

…….In this case, bit 1 of the first octet is the low order bit and bit 8 of the 4th octet is the high order bit (see Figure A.4), ……

15. In A.2.9, remove the following sentence:

f) ends with a sequence of more than six "1" bits.

16. In A.3.2, replace:

The address field format is shown in Figure A.5. The binary sequence is assigned to data link layer Service Access Point Identifier (SAPI) except for 0x7e and 0x7d.

with:

The SAPI field format is shown in Figure A.5. The binary sequence of two bytes is assigned to data link layer Service Access Point Identifier (SAPI).

17. In the last two sentence of A.3.3, replace:

….., LAPS address field can provide more than 250 service access points to be used. The SAPI values are listed in Table A.2.

with:

The SAPI bit order is shown in Figure A.5 and its values are listed in the TABLE A.2.

18. In the first column of TABLE A.2, replace:

with:

0021.

19. In the first column of TABLE A.2, replace:

with:

0057.

20. In TABLE A.2, remove:

the 3rh row:255 PPP based service, please refer to Table 5.

21. In the last row of TABLE A.2, replace:

Reserved for future extension except for 0x7e and 0x7d.

with:

Reserved for future extension.

22. In Figure B.1, replace:

SAPI=4, SAPI=6.

with:

SAPI=0021, SAPI=0057.

23. In the 9^th row of C.1, replace:

When the SAPI of LAPS is set to “11111111” for compatibility with RFC2615, ….

with:

When the LAPS is set to be compatible with RFC2615, …

24. In the first row of TABLE I.1, replace:

Using link address as a set of SAPIs.

with:

Using a set of SAPIs.

25. In the 3^rd row of TABLE I.1, replace:

A single octet length. The all-station address is 0xff, individual station addresses are assigned to Ipv4 (0x04), Ipv6 (0x06), etc. Frame with unrecognized addresses shall be discarded.

with:

A single octet length. The all-station address is 0xff that will be used to be compatible with RFC 2615, the LAPS station addresses is assigned to 0x04. Frame with unrecognized addresses shall be discarded.

26. In the 5th row of TABLE I.1, replace:

unused

with:

Two-octet is used as SAPI

27. The Figure A.1 is changed into the following: