Standards Support

The X.25 Recommendations were first specified in 1976, and have subsequently been revised on a number of occastions. It is common to refer to versions of the X.25 Recommendation by the year in which they were issued--for example X.25(1984). The 1980, 1984 and 1988 versions are the most widely used.

Solstice X.25 supports the following features from the 1984 and 1988 X.25 recommendations:

• optional user facilities:

  • extended packet sequence numbering

  • one-way incoming and one-way outgoing logical channels

  • non-standard default packet and window sizes

  • default throughput classes assignment

  • flow control parameter negotiation

  • throughput class negotiation

  • CUG-related facilities

  • bilateral CUG-related facilities

  • fast select and fast select acceptance

  • reverse charging and reverse charging acceptance

  • local charging prevention

  • charging information

  • RPOA selection

  • incoming and outgoing calls barred

  • called line address modified notification

  • call redirection notification

  • call deflection

  • transit delay selection and indication

  • TOA/NPI address format

  • Network User Identifier (NUI)

  • protection

  • priority

• permanent virtual circuits

• two-way logical channels

• called and calling AEF

• expedited data negotiation

• minimum throughput class

• user data on Accept and Clear with Fast Select

• non-X.25 facilities (in Call Request and Call Accepted packets)

• programmable facilities field

• up to 32 bytes of interrupt data

• up to 109 bytes of facilities in Call Request and Call Accepted packets

• DTE-originated cause codes

• MLP

Solstice X.25 does not support:

• on-line facility registration

• the hunt group facility