For SNA Server components and applications to communicate with each other, it must be possible to identify a partner within a locality. A partner is an addressable component of a locality; that is, code to which messages can be sent. In an SNA Server system, there is generally only one partner within a locality (such as a link service or the 3270 emulation program); however, separate functions within the local 2.1 node (such as the 3270 and APPC functions) can be considered to be separate partners.