TS Supplement (Includes RFC-1006 Support)

ED-TPDU

TPDUs Used by RFC-1006

5–12 107751 Tandem Computers Incorporated

ED-TPDU Expedited Data (ED) TPDUs, when used with RFC-1006, are different from OSI/TS

ED-TPDUs. The new format of the ED-TPDU is similar to the DT-TPDU; the only

difference is the value of the TPDU code. Figure 5-8 illustrates the RFC-1006 ED-

TPDU.

Figure 5-8. ED-TPDU

Octet

1 2 3 4 to end

ED TPDU-NR EOT

User Data

TPDU Header

075

The length indicator shows the TPDU header length in octets. This value does not

include the length of LI and User data and has the value of 2.

The expedited data code is 0001 0000. This value is in octet 2.

EOT

Bit 8 of octet 3 ( the high order bit, bit mask 1000 0000) indicates the end of an

expedited TSDU. It is always set to 1.

TPDU-NR

TPDU-NR is the expedited TPDU send sequence number and is always set to 0.

User Data

Contains the data of the expedited TSDU. This value can be 1 to 16 octets long.