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Managing Your SNA Server Gateway


Managing your SNA Server gateway consists of three basic precepts: configuring and maintaining your network, configuring SNA Server, and troubleshooting. The first part deals with specifying your network transport protocols, configuring your routers to pass the appropriate network packets, and maintaining the rest of your physical network. These are readily understood functions of a network Administrator, however, and are not the focus of this chapter. Instead, this chapter is concerned primarily with configuring SNA Server with the SNA Server Administrator and performing basic troubleshooting with the SNA Trace utility.


The actual name for the tool is really SNA Server Admin, which can be found in your Microsoft SNA Server Program Manager group. Rather than call it this, however, I prefer to call it the SNA Server Administrator because this more fully describes its function. For the rest of the chapter, this is how I refer to it.

Using SNA Server Administrator


The SNA Server Administrator is your primary interface to managing your SNA Server domains. The majority of this chapter focuses on how to use the SNA Server Administrator to perform the following tasks:


Configuring a Link Service


The first time you open the SNA Server Administrator, it displays the Servers and Connections window, which lists only the servers, because you haven't created any connections yet (see Figure 40.1). A connection is the basic building block you use to define a linkage between your SNA-compatible mainframe and your SNA Server clients. This process is what the SNA Server Setup program describes as a link service and is what is discussed here. It is not really a difficult process if you have some help from your technical support personnel. If you do not have this help and do not know what addresses, node identification strings, or other salient reference numbers have been assigned for your use, then you can pretty much forget about a working SNA Server configuration. This means that you will need help from your mainframe MIS department and service provider for an X.25/QLLC connection in order to supply the required information.

Figure 40.1. Administering your SNA Server domain with the SNA Server Administrator.

The idea of this discussion is to walk you through the actual process of creating a connection and assigning logical units so that you will understand what information you need to successfully complete your SNA Server configuration. This chapter begins with assigning the properties to your SNA Server that will be used for APPC or AS/400 connections. Then, you'll step through the process of creating connections. Finally, you'll learn how to assign logical units to a connection. Because this discussion includes all the various types of connections and logical units, you might want to skip the parts that do not concern you at this time.

Assigning Server Properties

If your SNA Server installation will be supporting incoming calls; advanced peer-to-peer communications (APPC), which also includes 5250 terminal emulation; or an AS/400 connection, then you must configure the server properties to identify your installation. This is accomplished by selecting the server in the Servers and Connections window and then choosing Services|Properties from the menu. The Server Properties dialog box appears, in which you can assign a comment, network name, and control point name (see Figure 40.2).

Figure 40.2. Assigning server properties to uniquely identify your SNA Server installation.


Alternatively, you can select the server and press Alt+Enter or just double-click on a server to display the Server Properties dialog box.

The comment can contain up to 25 characters, and is used to aid you in identifying your installation when you have more than one SNA Server in your domain. The network name and control point name are the identifiers, which uniquely identify your SNA Server installation on the network. These names are required only for systems using Format 3 XIDs, and define one point of the connection mechanism between SNA Server (the local node) and your SNA-compatible mainframe (the remote node). The remote node names are defined as you create your connections. These values should be supplied by your MIS department, and they vary, depending on how your server is connected to your mainframe.

For an AS/400, the values in the Server Properties dialog box follow:

For a VTAM or NCP connection, you will use these values:


The network name and control point name can contain from one to eight alphanumeric characters. They can include the special characters $, #, and @. The first character must be alphabetic. All lowercase characters are converted to uppercase characters. You cannot use just one name; if you supply one of these names, you must supply both these names.

Click the Addons button to display the SNA Server Additions dialog box. By default, this dialog box only includes the SNA Server Trace options, which you can select to configure the Trace utility. If you have added any third-party software, however, you might be able to configure it here as well.

Creating a Connection

A connection can be considered as the means SNA Server uses to communicate with your SNA-compatible mainframe. It is not used directly by your SNA Server clients. Instead, your SNA Server clients use a logical unit (terminal) that has been assigned to a specific connection. Your clients do not need to know what type of connection they are using, but as the SNA Administrator, you do.

SNA Server supports six types of connections:

SNA Server has some limitations that you should be aware of that may determine how many SNA Server installations you require and how many adapters per server you need to meet your requirements. Table 40.1 summarizes these limitations.

Table 40.1. SNA Server Connection and Session Limitations.

Software/ Hardware Total Connections Total Sessions Note
SNA Server 250 10,000 This includes a maximum of 2,000 clients. A single downstream connection is equivalent to a single client when determining the total number of clients per SNA Server installation.
802.2 250 254
DFT 1 5 Although you can use up to four DFT adapters in a single system, they must all be controlled by a single link service. This can provide you with up to 4 connections with 20 sessions.
SDLC 1 254
X.25/QLLC 250 254 If your adapter does not include a coprocessor, you cannot support a duplex transmission with a DTE speed higher than 9600bps.
Channel 250 254
TwinAx 1 20

The total number of sessions applies to 3270, LUA, and dependent APPC LU-LU sessions. For independent APPC LU sessions, the maximum is 10,000 sessions.

You cannot use multiple 802.2, X.25/QLLC, or channel adapters to increase the number of supported connections.

To create a new connection, follow these steps:

  1. Select the server where you want the connection to be created in the Servers and Connections window. Then choose New Connection from the Services menu or use the shortcut key F2. The Insert Connection dialog box appears.

  2. Select the connection to create. This can be 802.2, SDLC, DFT, X.25, Channel, or TwinAx. Then click the OK button.

  3. In the Connection Properties dialog box, enter the relevant information for your connection type, as described in the following sections.

  4. Click the OK button to accept the connection definition or press Cancel to abort.


The following sections assume that you have already made your choice in the Connection Details dialog box and that the Connection Properties dialog box for your connection type is active.

Creating a DLC 802.2 Connection

Creating a DLC 802.2 connection consists of three parts: defining the connection, assigning the basic settings for the connection, and assigning the advanced settings for the connection. To define the connection, follow these steps:

  1. When the Connection Properties dialog box appears, enter a name for the connection in the Connection Name field (see Figure 40.3). The connection name can be from one to eight alphanumeric characters. The name can include the special characters $, #, and @. All lowercase characters are converted to uppercase characters. The name must be unique and cannot be the reserved name SNASERVR.

    Figure 40.3. Assigning connection properties for an 802.2 connection.

  2. In the Comment field, enter a description for the connection. The description can be a maximum of 25 characters.

  3. In the Link Service field, choose the service the connection will use to communicate with an SNA adapter.


    If no entry is available, you need to use the SNA Server Setup program to install a link service.
  4. In the Remote End section, choose the type of remote system for the connection to use. This can be one of the following:


    When using a Downstream type, be sure to configure the Max BTU setting, as described later in this section, to a value supported by the downstream client.
  5. Choose an entry in the Activation section to specify when to make the connection available. This can be one of the following:

  6. Next, choose the type of connection support to implement in the Allowed Directions section. This can be Incoming Calls, Outgoing Calls, or both. The default is Outgoing Calls.

  7. You now have defined the connection, but you are not finished yet. At this point, you must click the Setup button to configure the basic properties for the connection. This displays the 802.2 Setup dialog box, as shown in Figure 40.4.

Figure 40.4. Configuring the basic properties for an 802.2 connection.

  1. You can configure the following fields in the 802.2 Setup dialog box:


    The network name and control point name can be from one to eight alphanumeric characters. They can include the special characters $, #, and @. The first character must be alphabetic. All lowercase characters are converted to uppercase characters. You cannot use just one name; if you supply one of these names, you must supply both these names.
  2. To specify how often to retry a connection operation, click the Retry Timers button. This displays a dialog box in which you can specify the following choices:

  3. If required, you can configure additional characteristics for the connection by clicking the Advanced button. This expands the dialog box to offer you the following fields:


    Receive ACK Threshold should be less than Unacknowledged Send Limit so that the local system acknowledges received transmissions more frequently than it requires responses from the remote system to sent transmissions.

    If you increase Unacknowledged Send Limit and Receive ACK Threshold, you may achieve greater throughput. You should attempt this only on connections with low error conditions, however, or you may actually decrease throughput.
  4. Click the OK button to accept your connection definition.


Creating a DFT Connection

Creating a DFT connection is much easier than creating some other types of connections. All it requires is the basic definition, which can be accomplished by following these steps:

  1. When the Connection Properties dialog box is displayed, enter a name for the connection in the Connection Name field. The connection name can be from one to eight alphanumeric characters. The name can include the special characters $, #, and @. All lowercase characters are converted to uppercase characters. The name must be unique, and cannot be the reserved name SNASERVR.

  2. In the Comment field, enter a description for the connection. The description can be a maximum of 25 characters.

  3. In the Link Service drop-down list, choose the service the connection will use to communicate with an SNA adapter.


    Even though you can use up to four DFT adapters, you must use only one link service for all of them. If no entry is available, you need to use the SNA Server Setup program to install a link service.
  4. Specify when to make the connection available by choosing an entry in the Activation section. This can be one of the following:


    The Remote End section is preset to Host System, and the Allowed Directions section is preset to Outgoing Calls.
  5. Click the OK button to accept your connection definition.


Creating an SDLC Connection

Creating an SDLC connection also consists of three parts: the first defines the connection, the second assigns the basic settings, and the third assigns the advanced settings for the connection. To create your SDLC connection, follow these steps:

  1. When the Connection Properties dialog box is displayed, enter a name for the connection in the Connection Name field. The connection name can be from one to eight alphanumeric characters. The name can include the special characters $, #, and @. All lowercase characters are converted to uppercase characters. The name must be unique and cannot be the reserved name SNASERVR.

  2. In the Comment field, enter a description for the connection. The description can be a maximum of 25 characters.

  3. In the Link Service drop-down listbox, choose the service the connection will use to communicate with an SNA adapter.


    If no entry is available, you need to use the SNA Server Setup program to install a link service.
  4. In the Remote End section, choose the type of remote system the connection will use. This can be one of the following:


    When using a Downstream system type, be sure to configure the Max BTU setting, as described later in this section, to a value supported by the downstream client.
  5. Specify when to make the connection available by choosing an entry in the Activation group. This can be one of the following:

  6. Next, choose the type of connection support to implement in the Allowed Directions group. This can be Incoming Calls, Outgoing Calls, or both. The default is Outgoing Calls.


    When using multiple SDLC connections for incoming calls, all these connections must use the same encoding (NRZ or NRZI) setting. A DFT connection can be configured only for outgoing calls.
  7. At this point, you have defined the connection; however, before you can use the connection, you must click the Setup button to configure the basic properties for the connection. This displays the SDLC Setup dialog box, and if you choose the Advanced button (as you have here) the dialog box expands.
    You can configure the following fields in this expanded SDLC Setup dialog box:

  8. To specify how often to retry a connection operation, click the Retry Timers button. This displays a dialog box where you can specify the following choices:

  9. Click the OK button to accept your connection definition.


Creating an X.25/QLLC Connection

Creating an X.25/QLLC connection is similar to creating an SDLC connection because it also consists of three parts: defining the connection, assigning the basic settings, and assigning the advanced settings for the connection. To create an X.25/QLLC connection, follow these steps:

  1. When the Connection Properties dialog box is displayed, enter a name for the connection in the Connection Name field. The connection name can be from one to eight alphanumeric characters. The name can include the special characters $, #, and @. All lowercase characters are converted to uppercase characters. The name must be unique and cannot be the reserved name SNASERVR.

  2. In the Comment field, enter a description for the connection. The description can be a maximum of 25 characters.

  3. In the Link Service drop-down listbox, choose the service the connection will use to communicate with an SNA adapter.


    If no entry is available, you need to use the SNA Server Setup program to install a link service.
  4. Choose the type of remote system the connection will use in the Remote End group. This can be one of the following:


    When using a downstream system type, be sure to configure the Max BTU setting, as described later in this section, to a value supported by the downstream client.
  5. Specify when to make the connection available by choosing an entry in the Activation group. This can be one of the following:

  6. Choose the type of connection support to implement in the Allowed Directions group. This can be Incoming Calls, Outgoing Calls, or both. The default is Outgoing Calls.

  7. Select the type of virtual circuit that will be used in the Virtual Circuit Type field. This can be one of the following:

  8. At this point, you have defined the connection; however, before you can use the connection, you must click the Setup button to configure the basic properties for the connection. This displays the X.25 Setup dialog box, and if you click the Advanced button, the dialog box expands.
    You can configure the following fields in the expanded X.25 Setup dialog box:


    User data is a coded string used primarily to specify the protocol to be used. For SNA, this value must be C3, which specifies the QLLC protocol.
  9. To specify how often to retry a connection operation, click the Retry Timers button. This displays a dialog box where you can specify the following choices:

  10. Click the OK button to accept your connection definition.


Creating a Channel Connection

Creating a channel connection also consists of three parts, but there is less information to supply. The first part follows the standard to define the connection, the second assigns the basic settings, and the third assigns the advanced settings for the connection.

To define the connection, follow these steps:

  1. When the Connection Properties dialog box is displayed, enter a name for the connection in the Connection Name field. The connection name can be from one to eight alphanumeric characters. The name can include the special characters $, #, and @. All lowercase characters are converted to uppercase characters. The name must be unique and cannot be the reserved name SNASERVR.

  2. In the Comment field, enter a description for the connection. The description can be a maximum of 25 characters.

  3. In the Link Service drop-down listbox, choose the service the connection will use to communicate with an SNA adapter.


    If no entry is available, you need to use the SNA Server Setup program to install a link service.
  4. Specify when to make the connection available by choosing an entry in the Activation group. This can be one of the following:


    The remote system will be preset to Host System and the Allowed Directions group will be preset to Outgoing Calls.
  5. At this point, you have defined the connection; however, before you can use the connection, you must click the Setup button to configure the basic properties for the connection. This displays the Channel Attached Setup dialog box, and if you click the Advanced button (as you have here) the dialog box expands, as shown in Figure 40.5.
    You can configure the following fields in this dialog box:

    Figure 40.5. Configuring the basic and advanced properties for a channel connection.


    The maximum BTU length should be less than the MAXDATA= value in the VTAM PU definition for a host connection. For a downstream service, this value should be equal to or less than the maximum value supported by the downstream service. For specific values, you should refer to your documentation or just use the default value.
  6. To specify how often to retry a connection operation, click the Retry Timers button to display a dialog box where you can specify the following choices:

  7. Click the OK button to accept your connection definition.


Creating a TwinAx Connection

Creating a TwinAx connection is just like creating a DFT connection in that it only requires the basic definition. You can accomplish this by following these steps:

  1. When the Connection Properties dialog box is displayed, enter a name for the connection in the Connection Name field. The connection name can be from one to eight alphanumeric characters. The name can include the special characters $, #, and @. All lowercase characters are converted to uppercase characters. The name must be unique and cannot be the reserved name SNASERVR.

  2. In the Comment field, enter a description for the connection. The description can be a maximum of 25 characters.

  3. In the Link Service drop-down listbox, choose the service the connection will use to communicate with an SNA adapter.


    If no entry is available, you need to use the SNA Server Setup program to install a link service.
  4. Specify when to make the connection available by choosing an entry in the Activation group. This can be one of the following:


    The remote system is preset to Peer System and the Allowed Directions group is preset to Outgoing Calls.
  5. Click the OK button to accept your connection definition.


Assigning a Logical Unit (LU) to a Connection

Before your clients can actually connect to your SNA-compatible mainframe, you must assign the logical units (LUs) to a connection. This is performed by selecting the connection in the Servers and Connections window and then choosing Services|Assign LU. The Insert LU dialog box appears, where you can select from one of the following:

After you select the appropriate LU type and click the OK button, a New LU Properties dialog box is displayed, where you can define the LU. Each LU has a slightly different dialog box, which is described in the following sections.

Creating a 3270 Logical Unit (LU)

To create a 3270 LU, fill out the following fields in the New 3270 LU Properties dialog box:


If you have several 3270 LUs to create, you can use a shortcut. Along with selecting the 3270 entry in the Insert LU dialog box, enable the Range of LUs checkbox. Then, in the Add LU Range dialog box, enter a name in the Base LU Name field (such as TERM), the starting number in the First LU Number field (01, for example), and the total number of LUs to create in the Number of LUs field (10, for example).

Then click the OK button. This displays the 3270 LU Range Properties dialog box where you should specify a description for the LUs in the Comment field, choose an LU type, and—if the LU type is a 3270 terminal emulation—choose a display mode as well. After you click the OK button, several LUs are created on the selected connection (in this example, these are TERM01 through TERM09).

Creating an Advanced Program-to-Program (APPC) Logical Unit (LU)

There are two types of APPC LUs you can create: an independent APPC LU, which can communicate directly with a peer system and support multiple parallel sessions, or a dependent APPC LU, which requires the support of a host configuration in order to communicate with a transaction program. When creating an APPC LU, keep in mind that you have to create a local and a remote APPC in order to create a link between two transaction programs. The local APPC is created on a server, and the remote APPC is created on a connection.

You should follow a couple of rules for a successful configuration.

For an independent APPC LU, follow these rules:

For a dependent APPC LU, follow these rules:

To create a local APPC LU, fill out the following fields in the New APPC LU Properties dialog box:


If you will be using a remote APPC LU on a DFT connection, you must configure the local APPC LU for a dependent connection.

This name should be obtained from the Administrator of the host or peer APPC LU. For a host connection, the name should be the NETID value in the VTAM Start command for the VTAM system. If the server will communicate with several hosts over several connections, use the subarea name.

For an independent APPC LU, the network name is required. For a dependent APPC LU, the network name is not required, but is recommended because it is used only by local applications.

To specify partners manually, click the Partners button and add the specific partners to create your LU-LU pairs.

To create a remote APPC LU, fill out the following fields in the New APPC LU Properties dialog box:


To specify partners manually, click the Partners button and add the specific partners to create your LU-LU pairs.

If you specify a security key, the session will not be activated unless both APPC LUs have keys that match.

Creating a Logical Unit Application (LUA)

To create an LUA LU, fill out the following fields in the New LUA Properties dialog box:


Creating a Downstream Logical Unit (LU)

To create a downstream LU, fill out the following fields in the New Downstream LU Properties dialog box:


Managing Your Users


Before your users can actually use a connection or logical unit, they must be granted permission to do so. This can be accomplished at the group level or at the user level. As with most other issues relating to security, this is much easier to perform at the group level. The basic series of steps follows:

This last step is the focus of this discussion, and you will be happy to know that it follows the same basic principles as assigning permissions to any other object (such as a directory or file).

The basic steps follow:

  1. Open the Users and Groups window.

  2. Choose New User from the Users menu to display the Add Users and Groups dialog box.

  3. If the default domain, which is where the current SNA Server installation resides, is not the domain in which the group or user accounts reside, choose another from the List Names From field.

  4. In the Names field, select the groups or users and click the Add button.

  5. Click the OK button. This adds the groups or users to the Users and Groups window in the left window.

  6. Select the group or user and choose Assign LUs from the Users menu to display the Assign User LU/Pool Sessions dialog box.

  7. In the Available LU and Pools field, select the LUs and pools to assign to the account and click the OK button.


Before you can assign permission to an LU or LU pool, you must create one. Creating an LU is discussed in the previous sections, and creating an LU pool is discussed in the following section.

Using Logical Unit (LU) Pools


An LU pool is a collection of logical units grouped into a single entity. It is similar to a group account in that it contains multiple user accounts grouped into a single entity. Both offer easier management of resources, but LU pools offer additional benefits as well:

You can create a 3270 terminal/printer, LUA, or downstream pool by opening the LU Pools window and then choosing Pools|New Pool to display the New Pool dialog box. Then enter a unique name for the pool in the Pool Name field, enter a description in the Comment field, and choose the type of pool to create in the LU Type field. If you specified 3270 for the LU type, choose a display mode in the 3270 Display Mode field. Then just click the OK button.

After you create the pool, you have to assign logical units to it. Select the pool and choose Pools|Assign LUs to display the Assign Pool LUs dialog box. This is just a matter of selecting the individual LUs in the Available LUs field and clicking the OK button to assign the LUs to the pool.


Don't forget that before your users can actually use the LU pool, you must assign the appropriate permissions as described in the preceding section.

Managing the SNA Server Services


By default, the SNA Server Services are configured to be inactive at system startup. This means that before your users can use an LU, you have to start the appropriate server or individual connection. This is accomplished by choosing the server or connection in the Servers and Connections window and choosing Services|Start Service. Stopping a server or connection follows the same methodology, but you should choose Services|Stop Service instead.

Any connection configured with On Server Startup activation will be automatically activated when you start the appropriate server. Connections that use the On Demand activation setting are activated as required when a user attempts a connection. Any connection configured with the By Administrator activation requires manually starting or stopping the connection as specified earlier.


You can provide additional fault tolerance and ease of administration by configuring SNA Server to start up when NT Server starts. Just set the SnaServer service to automatic, rather than manual, in the Control Panel Services applet. You can do the same for the NVAlert and NVRunCmd (NetView Alert and Run Command services). Do not configure the SnaNtMn service to Automatic, however, or it will fail to start. SNA Server automatically starts this service for any connection that is configured to use it.

Configuring SNA Administrator


Configuring SNA Server only consists of two choices. You can configure the display options by choosing Options|Preferences, which is pretty self-explanatory, or Options|Server Broadcasts, which requires a bit of discussion. This choice displays the Server Broadcasts dialog box, as shown in Figure 40.6.

Figure 40.6. Configuring SNA Server broadcasts.

In the Select the Client-Server Protocols Which Will Be Used to Send Server Broadcasts Between SNA Servers section, you can choose from the protocols you have installed and configured SNA Server to use. For efficiency, use a single protocol for server broadcasts if you can. If all your installations support TCP/IP, for example, use just TCP/IP. But if you have some servers configured for TCP/IP and some for IPX/SPX, be sure to enable both these protocols so that the installations can communicate between themselves. If you will be using non-TCP/IP protocols over a WAN, you should enable the Route Server Broadcasts over IP Routers checkbox. If you do not, the server broadcasts will fail to propagate across the routers.


Before you do decide to enable the Route Server Broadcasts over IP Routers check with your network administrators (if your company has a separate network administration group) as this option relies on the TCP/IP capability to encapsulate NetBIOS requests. Sometimes, this may not be considered the best option as it can utilize a high percentage of network bandwidth. You network administrators may have a better alternative.

In the SNA Server 2.0 and Comm Server Support group, you should disable the SNA Server 2.0 Servers in the Same Domain checkbox unless you have SNA Server 2.0 installations in the same domain. This option can seriously degrade SNA Server 2.x performance because it requires server broadcasts be sent once a minute. It also uses a significant portion of your network bandwidth that could be used for more productive requirements. If you have any DCA/Microsoft clients, you should enable the DCA/Microsoft Comm Server Client Support checkbox. You also should make sure that you have enabled Microsoft Networking as an available transport protocol because these applications require NetBEUI.

If you are not supporting SNA Server 2.0 installations, you can specify how often SNA Server broadcasts set the time, in seconds, in the Mean Time between Server Broadcasts field. This value ranges from 45 to 65535, with a default of 60. The default is a good choice because broadcast messages are not guaranteed to be received by the client and this will compensate for lost messages. If your network is not error prone, however, and your servers are not overburdened, then you can increase this value and lower the network bandwidth requirement.

Securing SNA Server


Now that you have spent so much time configuring SNA Server, you should spend a little more time to protect your investment. This is very important and should not be overlooked in your effort to provide a service to your network clients. Spend just a little more time to restrict the modifications that are possible to just a few Administrators by following these steps:

  1. Choose Permissions from the Security menu to display the SNA Domain Permissions dialog box.

  2. Click the Remove button to remove the default Everyone group (which has full control of SNA Server Administrator).

  3. Click the Add button to display the Add Users and Groups dialog box.

  4. Choose the group you want to allow full administration of your SNA Server domain (such as Domain Admins) in the Names field. If you want to choose a user account instead of a group account, first click the Show Users button. If the user or group is not in the current domain, choose the correct domain from the List Names From drop-down listbox.


    If you have not already created a group for SNA Server administration, it is a good idea to do so in User Manager for Domains. This group can be assigned permission to administer SNA Server and to limit the damage that could be caused by unfamiliar domain Administrators (Domain Admins).
  5. Choose the access control setting of Full Control in the Type of Access drop-down listbox, and click the OK button.

  6. Click the OK button once again, and you have secured access to your SNA Server domain.


You can further restrict access to groups or users by selecting them and assigning a different type of access. This could be No Access, which prevents them from using SNA Server Administrator; Read, which provides the capability to see the configuration but not change it; Read/Write, which provides the capability to read and modify the configuration but not change permissions; and Full Control, which provides complete access.

It is a good idea to use the Security|Auditing option to enable auditing of your SNA Server configuration if you will be providing access to several users. In this way, you can determine who did what in case of a user error—not so much to assign blame, but instead to determine who needs additional tutoring in their duties.

Using the SNA Trace Utility


If you are encountering problems with SNA Server, you might want to look into the SNA Server Trace utility. This utility is located in your Microsoft SNA Server Program Manager group. It provides two basic options for you:

To use the SNA Server Trace utility, follow these steps:

  1. Launch the SNA Server Trace utility. The SNA Server Trace Options dialog box appears.

  2. In the Service Name drop-down listbox, specify the service to trace.

  3. In the Message Traces group, choose what messages to trace. This varies based on the selected service and may be any of the following:

  4. If you have specified the SNA applications as the selected service, you can trace API messages, which can be any of the following:

  5. If you have a support provider on the line, such as Microsoft Product Service Support, you may need to enable the Internal Tracing option by moving the slider to the requested level. This is not normally useful to Administrators.

  6. To enhance performance, leave the Minimize Disk Access by Buffering Writes checkbox enabled, but if you are attempting to determine the cause of a system crash, disable this option so that the trace logs will be more current (if the system crashes, information in the buffer will be lost).

  7. Repeat these steps for each service to trace.

  8. Click the Apply button and then click the Close button.


Although the trace files might be helpful in some situations, you most likely will require some help from a network guru in order to interpret the data. Most times the information obtained from the trace utility is only used by Microsoft technical support personnel to resolve an otherwise unresolvable problem.

Summary


In this chapter, you explored some of the basic requirements for configuring your SNA Server installations to support your clients' access to your SNA-compatible mainframe. The key feature to remember is that before you can use a link service, you must define the connection, set up the connection, and then configure any advanced properties. After the connection is created, you must assign logical units. And, finally, you must assign permissions to groups or users to access the logical units. Permissions should be based on groups rather than individual users.

You can use Logical Unit pools to offer increased resource efficiency, fault tolerance, and increased performance. And before you walk away from your SNA installation, be sure to safeguard it by assigning specific security to determine just who can use the SNA Server Administrator to configure the installation.

In the next chapter, you will look into optimizing your SNA Server installation. Some of the topics you will consider include how to choose the right server platform and server models. You'll also learn how to configure your base Windows NT Server platform, and then you will look into specific SNA Server configuration choices to improve performance.

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