6100 ADCCP Programming Manual

Station and Data Capacity on Links

ADCCP Link and Station Management

2–16 069225 Tandem Computers Incorporated

Figure 2-8. ADCCP-to-Token Ring Communication (Option_Two)

Primary Station Token Ring

Controller

SNRM

(T1TIMER starts)

(T1TIMER expires)

To Stations

024

To turn on Option_Two, your application sets the 0 bit of the OPTIONA field of the

configuration block with the (1) SET CONFIGURATION request. See Section 4,

“Writing Applications That Use ADCCP,” for a description of how to set line options,

and Section 6, “Requests and Responses,” for a description of the configuration block

and the (1) SET CONFIGURATION request.

If Option_Two is off, the primary station expects a UA frame in response to a SNRM

frame sent to a secondary station. If the primary station does not receive a DM or UA

frame from the secondary station, the primary station makes only one retry of the

SNRM frame after the T1TIMER expires. If the primary station, receives a DM frame,

your application determines the primary station’s response to a DM frame (usually a

DISC).

Station and Data

Capacity on Links

The LIU buffer space that is available to the ADCCP protocol module limits the

following:

The number of stations that a link can support.

The amount of traffic that the link can sustain.

By considering the various demands on the ADCCP protocol module’s buffer space,

you can make decisions about sizing, tuning, and application design.

The ADCCP protocol module allocates and retains buffers for the following data:

Outgoing frames that have not yet been acknowledged by the remote station.

Incoming frames that the ADCCP protocol has not yet acknowledged to the

remote station (for example, frames that have arrived since the station transmitted

an SREJ frame).

A control block for each station on the link.

Two buffers for trace-related data, if a trace is in progress.