Byte

Description

0, 1

Tag 0x2757

2, 3

Length Variable

4

Value[1] User information layer 3 protocol

0x01 Basic mode ISO 1745 [36]

0x02 Recommendation Q.921 (I.441) [3]

0x06 Recommendation X.25 [5], link layer

0x0f Recommendation X.25 Multi link

0x08 Extended LAP-B for half duplex operation (T.71[37])

0x09 HDLC ARM (ISO 4335)[38]

0x0a HDLC NRM (ISO 4335)

0x0b HDLC ABM (ISO 4335)

0x0c LAN logical link control (ISO 8802/2)

0x0d Recommendation X.75 [40]. Single link procedure (SLP).

0x0e Recommendation Q.922

0x0f Core aspects of recommendations Q.922

0x10 User specified

0x11 ISO 7776 DTE-DTE operation.

All the other values are reserved.

5

Value[2] Mode

0x02 Recommendation Q.931

0x06 Recommendation X.25, packet layer

0x07 ISO/IEC 8208 [41]

0x08 CCITT Recommendation X.223

0x09 ISO/IEC 8473 [43]

0x0a Recommendation T.70 [32]

0x0b ISO/IEC TR 9577[82]

0x10 User specified

All the other values are reserved.

Value[3] Optional layer 3 information

This field is user defined.

0xFF is reserved.

Value[4] Default packet size

0x04 Default packet size 16 octets

0x05 Default packet size 32 octets

0x06 Default packet size 64 octets

0x07 Default packet size 128 octets

0x08 Default packet size 256 octets

0x09 Default packet size 512 octets

0x0a Default packet size 1024 octets

0x0b Default packet size 2048 octets

0x0c Default packet size 4096 octets

All the other values are reserved.

Value[5] Packet Window size

1-127

All other values are reserved.