General

ISO/IEC ISP 12067 is applicable to interworking units concerned with operating in the Open Systems Interconnection (OSI) environment. It specifies a combination of OSI base standards that collectively provide a relay function for the connection-mode Network Service.

This part of ISO/IEC ISP 12067 defines the RB5 1.1111 profile, which is applicable to an inter-working unit operating between CSMAKD LAN subnetworks and PSDNs using virtual calls over a PSTN leased line permanent access.

Position within the taxonomy

The taxonomy of profiles is detined in ISO/IEC TR 10000-2. This part of ISO/IEC ISP 12067 defines the profile:

• RB51.1111 Relaying the connection-mode Network Service between CSMAKD LAN subnetworks and PSDNs using virtual calls over a PSTN leased line permanent access.

Scenario

Figure 1 illustrates the configuration of systems to which the RR51. 1111 profile is applicable. The figure shows two reference points, but an implementation of this protile may include more attachments to CSMAED LANs and PSDNs, with a reference point at each.

As this profile is a member of the RB group. it is intended that a conforming implementation is capable of interworking with other protiles of the RB group and with end systems implementing profiles from the TB, TC, TD and TE groups or the UB group. provided that suitable relays are in place in the case of those members of these groups which relate to different elements of the subnetwork taxonomy.

This profile specitics the required functions from the supporting protocol stack shown below.