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Chapter 8 - VINES Protocol Support for Applications

Introduction

Applications Summary

Table 8-1. VINES Protocol Support for Applications

Accessing a file service from a DOS workstation
Accessing a PC network printer from a DOS workstation
Connecting to VINES Files from a DOS workstation
Propagating StreetTalk information
Synchronizing network time

Accessing a File Service from a DOS Workstation

1. When the user logs in to the network, the user's profile issues this command:

setdrive h fsapps@eng@development

2. The setdrive client is loaded from the user's VINES Files Service into the DOS workstation over an SPP connection. This connection links the DOS workstation redirector and the VINES Files service.

3. The setdrive client uses NetRPC to communicate with a StreetTalk Service. The client requests the service to return the port address of fsapps@eng@development.

4. Upon receiving the port address, the SETDRIVE client requests the workstation redirector to map the letter h to the requested file service.

5. When the user performs the first operation on the file service, such as a DOS DIR command, the redirector establishes an SPP connection to the file service with the port address.

Accessing a PC Network Printer from a DOS Workstation

1. When the user logs in to the network, the user's profile invokes the following command:

setprint lpt1 on ps@eng@development

2. The SETPRINT client is loaded from the user's VINES Files Service into the DOS workstation over an SPP connection. This connection links the DOS workstation redirector and the VINES Files Service.

3. The SETPRINT client uses NetRPC to communicate with a StreetTalk Service. The client asks the service to return the port address of ps@eng@development.

4. Upon receiving the port address, the SETPRINT client asks the workstation redirector to map lpt1 to the requested print service.

5. When the user submits a print job to the print service, the workstation redirector sends data to the print service with NetRPC. The redirector supplies the port address that was returned by the SETPRINT command.

6. The print job is queued on a disk on the server where the print service runs.

7. The print service sends the data over an SPP connection to the PCPRINT client that runs on the DOS workstation where the PC network printer is connected.

Connecting to VINES Files from a DOS Workstation

1. The redirector issues an unreliable IPC VnsFindSvc broadcast with a hop count of 0 (zero) and a well-known port of 0x0006. This broadcast just travels to all neighbor servers using the VINES Files well-known port. The broadcast messages contain information on the VINES version that the redirector is looking for.

2. If a neighbor server with the appropriate version responds, the redirector establishes an SPP connection with that VINES Files Service.

If more than one neighbor server has the appropriate version, the redirector chooses the first one that responds. Typically, the first responding server has the fastest processor, or the server with the lightest processing load.

3. If no neighbor server with the appropriate version responds, the redirector issues another VnsFindSvc broadcast with a hop count of 1, allowing the broadcast to travel to all servers one hop beyond the local medium.

The broadcast travels over LANs only. The server router for the LAN where the workstation resides filters VINES Files broadcasts so that they do not travel over serial lines or other WAN connections.

4. If a server with the appropriate version responds, the redirector establishes an SPP connection with that VINES Files Service.

If more than one server has the appropriate version, the redirector chooses the first one that responds. Typically, the factors that determine which server responds the fastest depend on the relative processor speeds of the servers and the amount of network traffic between the servers and the workstation.

5. If a server with the appropriate version does not respond, the redirector notifies the user that an appropriate VINES Files version could not be found.

Propagating StreetTalk Information

Whether it is a router
Whether it has already propagated the information

The destination VINES network ID in the VINES IP header is the VINES broadcast address. This address consists of all 0xFs.
The VINES destination port in the IPC short header specifies the StreetTalk well-known port of 0x000F.
The VINES source subnetwork ID in the VINES IP header indicates a server (subnetwork ID of 0x0001).

Do not decrement the hop count.
Check whether the packet was received on the interface that provides the best path to the originator of the packet. The originator is identified by the source VINES internet address in the VINES IP header:

- If the packet was received on the interface that provides the best path, forward the packet on all other attached interfaces.

- If the packet was not received on the interface that provides the best path, the packet has looped back and should be discarded.

Synchronizing Network Time

With zero-hop broadcasts
With the help of other Time Services running on neighboring VINES, ENS for UNIX, and ENS servers that are responsible for propagating and filtering the broadcast

The destination VINES network ID in the VINES IP header is the VINES broadcast address. This address consists of all 0xFs.
The VINES destination port in the IPC short header specifies the Time Service well-known port of 0x0007.
The VINES source subnetwork ID in the VINES IP header indicates a server (subnetwork ID of 0x0001).

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