Добавил:
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
Литература / 802.16-2001+.pdf
Скачиваний:
24
Добавлен:
16.04.2013
Размер:
2.61 Mб
Скачать

AIR INTERFACE FOR FIXED BROADBAND WIRELESS ACCESS SYSTEMS

IEEE Std 802.16-2001

11.1.5 MCA-REQ and MCA-RSP TLV encodings

The type values used shall be those defined in Table 128. The type and length fields shall each be 1 byte in length.

Table 128—Multicast assignment request message encodings

Name

Type

Length

 

Value

(1 byte)

 

(variable-length)

 

 

 

 

 

 

 

 

Multicast CID

1

2

 

 

 

 

 

 

 

Assignment

2

1

0x00

= Leave multicast group

 

 

 

0x01

= Join multicast group

 

 

 

 

reserved

3–255

n

Reserved for future use

 

 

 

 

 

11.2 PKM message encodings

A summary of the TLV encoding format is shown below. The fields are transmitted from left to right.

Type

Length

Value

 

 

 

1 byte

Variable

Length bytes

 

 

 

Type: The Type field is one byte. Values of the PKM Type field are specified in Table 129. Note that Type values between 0 and 127 are defined within the PKM Specification, while values between 128 and 255 are vendor-assigned Attribute Types.

A PKM server shall ignore Attributes with an unknown Type.

A PKM client shall ignore Attributes with an unknown Type.

PKM client and server (i.e., SS and BS) may log receipt of unknown attribute types.

Length: The Length field indicates the length of this attribute’s Value field, in bytes. The length field does not include the Type and Length fields.

Value: The Value field is zero or more bytes and contains information specific to the Attribute. The format and length of the Value field is determined by the Type and Length fields.

Note that a “string” does not require termination by an ASCII NULL because the Attribute already has a length field.

The format of the value field is one of the five data types shown in Table 130.

Copyright © 2002 IEEE. All rights reserved.

279

IEEE Std 802.16-2001

LOCAL AND METROPOLITAN AREA NETWORKS—PART 16:

 

Table 129—PKM Attribute types

 

 

Type

PKM Attribute

 

 

0–5

reserved

 

 

6

Display-String

 

 

7

AUTH-Key

 

 

8

TEK

 

 

9

Key-Lifetime

 

 

10

Key-Sequence-Number

 

 

11

HMAC-Digest

 

 

12

SAID

 

 

13

TEK-Parameters

 

 

14

reserved

 

 

15

CBC-IV

 

 

16

Error-Code

 

 

17

CA-Certificate

 

 

18

SS-Certificate

 

 

19

Security-Capabilities

 

 

20

Cryptographic-Suite

 

 

21

Cryptographic-Suite-List

 

 

22

Version

 

 

23

SA-Descriptor

 

 

24

SA-Type

 

 

25

reserved

 

 

26

reserved

 

 

27

PKM Configuration Settings

 

 

28-255

reserved

 

 

Table 130—Attribute value data types

Data type

Structure

 

 

string

0 – n bytes

 

 

uint8

8-bit unsigned integer

 

 

uint16

16-bit unsigned integer

 

 

uint32

32-bit unsigned integer

 

 

compound

collection of Attributes

 

 

280

Copyright © 2002 IEEE. All rights reserved.

AIR INTERFACE FOR FIXED BROADBAND WIRELESS ACCESS SYSTEMS

IEEE Std 802.16-2001

11.2.1 Display string

Description: This Attribute contains a textual message. It is typically used to explain a failure response and might be logged by the receiver for later retrieval by an SNMP manager. Display strings shall be no longer than 128 bytes. A summary of the Display-String Attribute format is shown below. The fields are transmitted from left to right.

Type

Length

Value (string)

 

 

 

6

0 and 128

A string of characters. There is no requirement that the

 

 

character string be null terminated; the length field

 

 

always identifies the end of the string.

 

 

 

11.2.2 AUTH-Key

Description: The Authorization Key (Auth-Key) is a 20-byte quantity, from which a key encryption key (KEK), and two message authentication keys (one for uplink requests, and a second for downlink replies) are derived. This Attribute contains a 128-byte quantity containing the Authorization Key RSA-encrypted with the SS’s 1024-bit RSA public key. Details of the RSA encryption procedure are given in 7.5. The ciphertext produced by the RSA algorithm shall be the length of the RSA modulus, i.e., 128 bytes.

Type

Length

Value (string)

 

 

 

7

128

128-byte quantity representing an RSA-encrypted Authorization Key.

 

 

 

11.2.3 TEK

Description: This Attribute contains a quantity that is a TEK key, encrypted with a KEK derived from the Authorization Key.

Type

Length

Value (string)

 

 

 

8

8

Encrypted traffic encryption key.

 

 

 

11.2.4 Key lifetime

Description: This attribute contains the lifetime, in seconds, of an Authorization Key or a TEK. It is a 32-bit unsigned quantity representing the number of remaining seconds for which the associated key shall be valid. Note that this attribute can be used as top level attribute (AK) as well as a subattribute (TEK).

Type

Length

Value (uint32)

94 — 32-bit quantity representing key lifetime

A key lifetime of zero indicates that the corresponding Authorization Key or TEK is not valid.

Copyright © 2002 IEEE. All rights reserved.

281

IEEE Std 802.16-2001

LOCAL AND METROPOLITAN AREA NETWORKS—PART 16:

11.2.5 Key-Sequence-Number

Description: This Attribute contains sequence number for a TEK or Authorization Key. The 2 or 4-bit quantity, however, is stored in a single byte, with the high-order 6 or 4 bits set to 0. A summary of the Key-Sequence-Number Attribute format is shown below. Note that this attribute can be used as top level attribute (AK) as well as a subattribute (TEK).

Type

Length

Value (uint8)

 

 

 

10

1

2-bit sequence number (TEK),

 

 

4-bit sequence number (AK)

 

 

 

11.2.6 HMAC digest

Description: This Attribute contains a keyed hash used for message authentication. The HMAC algorithm is defined in IETF RFC 2104.

Type

Length

Value (string)

 

 

 

11

20-bytes

A 160-bit (20 byte) keyed SHA hash

 

 

 

11.2.7 SAID

Description: This Attribute contains a 16-bit SAID used by the Privacy Protocol as the security association identifier.

Type

Length

Value (uint16)

 

 

 

12

2

16-bit quantity representing an SAID

 

 

 

11.2.8 TEK parameters

Description: This Attribute is a compound attribute, consisting of a collection of subattributes. These sub-attributes represent all security parameters relevant to a particular generation of an SAID’s TEK. A summary of the TEK-Parameters Attribute format is shown below.

Type

Length

Value (compound)

 

 

 

13

variable

The Compound field contains the sub-Attributes as

 

 

defined in Table 131

 

 

 

282

Copyright © 2002 IEEE. All rights reserved.

Соседние файлы в папке Литература