PCM shows the current state of the Physical Connection Management state machine that controls the following features and facilities:
Connection initialization
Maintenance support
This heading is modified to indicate the type of port that is being managed:
PCMS: single-attached station, S-port
PCMA: dual-attached station, A-port
PCMB: dual-attached station, B-port
TABLE 2-3 lists the states that may be returned by pf_stat under the PCM heading.
Table 2-3 pf_stat States Under the PCM Heading
State |
Meaning |
OFF |
PCM is inactive (initial state). |
BREAK |
PCM is starting the connection synchronization phase. |
CONNECT |
PCM is synchronizing the connection end-points prior to the signaling sequence. |
NEXT |
PCM is transmitting PDUs prior to entering SIGNAL state. |
SIGNAL |
PCM is transmitting and receiving signal bits (information) following a NEXT state. |
JOIN |
First state in the sequence leading to a synchronized connection. |
VERIFY |
Second state in the sequence leading to a synchronized connection. |
ACTIVE |
Final state indicating that the port is successfully incorporated in the token path. |
TRACE |
PCM is localizing a stuck beacon condition. |
The normal sequence of PCM states leading to a fully synchronized connection and incorporation of the port into the token path is shown in Figure 2-1. Note that the minimum interval between interrogations is one second and that this is not always fast enough to recover and display the complete sequence of PCM states.