HP-UX SNAplus2 R7 APPC Programmer's Guide

APPC Control Verbs

GET_LU_STATUS

Allocate is already waiting), or a ﬁnite value (RECEIVE_ALLOCATE fails unless an incoming Allocate arrives

within the speciﬁed time). For more information, refer to the HP-UX SNAplus2 Administration Guide.

3.3.8 Routing for Incoming Attaches

UNIX

If the application does not specify a dload_id on the RECEIVE_ALLOCATE, it can use the tp_name and lu_alias

parameters of RECEIVE_ALLOCATE to specify the range of incoming Attaches that it will accept. By specifying

a TP name, it indicates that it will accept incoming Attaches from a partner TP only if the partner TP speciﬁed this

TP name on the [MC_]ALLOCATE verb; by using the extended form of RECEIVE_ALLOCATE and specifying

an LU alias, it indicates that it will accept incoming Attaches only if they arrived at a particular SNAplus2 local

LU. In either case, the TP can specify a blank name to indicate that it accepts incoming Attaches for any TP name

or from any local LU.

SNAplus2 matches an incoming Attach to the RECEIVE_ALLOCATE verb in the appropriate TP in the following

order of precedence:

1. A TP that speciﬁes a TP name and an LU alias, both of which match the incoming Attach.

2. A TP that speciﬁes a TP name matching the incoming Attach but does not specify an LU alias.

3. A TP that speciﬁes an LU alias matching the LU that received the incoming Attach but does not specify a TP

name.

4. A TP that does not specify a TP name or an LU alias. Only one TP on each SNAplus2 computer should use

this feature; if two TPs both issue RECEIVE_ALLOCATE verb with no TP name or LU alias, it is not possible

to determine which TP will receive the incoming Attach.

If the TP used a blank TP name, LU alias, or both to accept a range of incoming Attaches, it can check the returned

parameters on this verb to determine the TP name speciﬁed on the incoming Attach, the LU alias of the LU that

received it, or both. This means that you can have a single TP to handle all incoming Attaches, which performs

the appropriate processing for each of several TP names, LUs or both. If this TP receives an incoming Attach

from an unrecognized or unauthorized partner TP, it can reject the new conversation if necessary by issuing the

[MC_]DEALLOCATE verb with an appropriate dealloc_type parameter.

The TP accepting the incoming Attach may be an operator-started TP that has already issued RE-

CEIVE_ALLOCATE, or an automatically started TP listed in the SNAplus2 invokable TP data ﬁle. SNAplus2

uses the TP name, LU alias, or both speciﬁed in this ﬁle to determine whether to start the TP in order to match the

incoming Attach. For more information about the format of this ﬁle, refer to the HP-UX SNAplus2 Administration

Guide. The TP name, LU alias, or both speciﬁed by an automatically started TP on the RECEIVE_ALLOCATE

verb must match those speciﬁed in the ﬁle to ensure that SNAplus2 can route the incoming Attach correctly.

3.4 GET_LU_STATUS

UNIX

This verb is provided for Syncpoint TPs, which need to check whether they have lost communications with their

partner TPs so that they can resynchronize if necessary.