User`s guide

110 DC 900-1317J
ADCCP NRM Programmer’s Guide
6.2 Configuring the Line-Monitor Function
When the Monitor Session for an ICP becomes attached, monitoring is configured for
none of the links. Any subset of them may be configured for monitoring with a Config-
ure Monitor command to the Monitor Session (
usProtCommand field set to
DLI_PROT_START_LINK_TRACE). The set of links to be monitored is specified in the iProt-
Modifier
field, as a bit-mask. For example, links 0 and 2 are specified by setting bits 0 and
2 (i.e., the value 0x0005). Bit positions above the range that represents the actual links
of the ICP are ignored. The
usProtLinkID field, being inapplicable, is not used. The rest
of the Optional Argument fields are set per Figure 3–1 on page 51.
For each link, one of the following four courses of action is taken, depending on that
link’s bit in the mask and its current monitoring state:
• A link which is represented by a ’1’-bit, and which is not currently configured for
monitoring, becomes configured.
• A link which is represented by a ’1’-bit, and which is already configured for mon-
itoring, remains configured.
• A link which is represented by a ’0’-bit, and which is currently configured for
monitoring, becomes not configured. (To cease monitoring on all links while
retaining the Monitor Session, a Configure Monitor command with a 0 bit-mask
may be sent.)
• A link which is represented by a ’0’-bit, and which is already not configured for
monitoring, remains not configured.
The Configure Monitor command is processed independently of whether the Link Ses-
sion for any given link has been established. This means that a link may be configured
for monitoring before its session is opened. Hence the client may choose to open an
ICP’s Monitor Session and configure any subset of the links for monitoring, before any
or all of the Link Sessions are opened. This is handy when it is desirable to observe the
frames that occur at link initialization (SNRMs and the responses to them).