Contents
Distributed Link Service

  Configuring a Distributed Link Service

 Making a Link Service Available To Be Distributed


Remote Link Services Example

To provide hot backup using a link service named SNASdlc1 on a server named SNA001 and using a link service named SNADLC3 on a server named SNA002, enter the following in the Remote Link Services box:

\\SNA001\SNASdlc1;\\SNA002\SNADLC3


Configuring a Distributed Link Service

Using Distributed Link Service, an SNA Server can use a link service on another SNA Server as though it were installed on the local SNA Server.

Distributed Link Service:

Allows multiple SNA Servers to share a single adapter (such as a channel adapter).

Supports load balancing across multiple Distributed Link Services.

Supports hot backup because the Distributed Link Service can select alternate remote servers when a remote link fails.

Allows a branch SNA Server that would otherwise connect to the host over a wide-area network link type (such as X.25 or SDLC) to connect instead over TCP/IP. This is especially useful when a routed WAN is the path between the branch and the host.

To configure a Distributed Link Service

1	In the Distributed Link Service Setup dialog box, select the type of link the Distributed Link Service represents. You can specify the link type only when adding a new Distributed Link Service.

2	In the Service Names box, type the names of the remote link services the Distributed Link Service represents. The format of a service name is \\server\servicename, specifying the remote server name and the name of the link service on the remote server. Multiple service names must be of the same link type. If you enter more than one service name, separate the service names with a semicolon (;). Example

The link services specified in the Service Names box do not have to be installed on the remote server, but Distributed Link Service will support active connections only if at least one of the link services is activated and available to be distributed when the connection is activated.

Both the SNA Server running Distributed Link Service and the remote SNA Server providing the actual link service must be running at least one of the following protocols:

TCP/IP

IPX/SPX

Banyan VINES


Making a Link Service Available to Be Distributed

Use the Link Service Configuration dialog box to make link services available to a Distributed Link Service on a remote SNA Server.

To make a link service available to be distributed

In the Link Service Configuration dialog box, select a link service, and then choose Distribute.

Link services that are accessible to Distributed Link Service on other SNA Servers are displayed in the Link Services Installed list box preceded by (D).

The 802.2 Link Service cannot support more than one 802.2 connection to the same MAC address (that is, to the same host) at the same time, whether the connections originate from the local or a remote SNA Server.  The 802.2 protocol specification does not permit two distinct connections to have the same Source MAC, Source SAP, Destination MAC and Destination SAP.  Because of this, you must configure a different 802.2 link service for each SNA Server PU connected to a given host, and each link service must use a different Source SAP value.

When you make an 802 link service available to Distributed Link Service on other SNA Servers, it cannot be used by the local SNA Server, and is not visible in SNA Admin on the local machine.


The name of the link service as shown in the Properties dialog box for the connection using the link service. To view the Properties dialog box for a connection, in SNA Admin, double-click the connection.