Installing and Administering OSI Transport Services

Chapter 1 41

HP OTS/9000 Resources

Addressing Concepts

Figure 1-4

Selector - A selector is a sequence of octets (bytes) used to identify a

SAP. Using the BSD socket analogy, a SAP is the socket, a selector is the

two octet Port ID that is bound (using bind()) to the socket. When a

selector identiﬁes a speciﬁc SAP at a speciﬁc layer, it is referred to as

either a P-selector, S-selector, or T-selector, so it is clear which layer the

selector is associated with.

SAP

ISO

ARPA

Socket

Application

ISO Transport

ISO Network

Application

TCP

XTI

Socket

T-selector

Port ID

NSAP

Data