Friday, June 12, 2009

Entering Route Strings

A route string describes a connection required between two hosts using one or more SAProuters. Each of these SAProuters then checks its Route Permission Table to see whether the connection between its predecessor and successor is allowed, and if it is, sets it up.

Procedure

The entry of route strings is best illustrated by an example.

The following graphic shows an example of a connection between SAP and a customer system. In this example, an SAP service employee working on sappc wants to log on to a customer application server yourapp that provides or uses the service sapsrv.

This graphic is explained in the accompanying text.

The SAP service employee logs on to the SAP system, and sets up a connection between sappc and yourapp using the SAProuter on sap_rout and the customer's SAProuter your_rout.

your_rout requires password pass_to_app for connections with yourapp.

The route string appears as follows:

/H/sap_rout/H/your_rout/W/pass_to_app/H/yourapp/S/sapsrv

This route string is interpreted by the SAProuters involved in the route as follows:


Host/address

Service/port

Password

Substring 1

/H/sap_rout

/S/

Substring 2

/H/your_rout

/S/

/W/pass_to_app

Substring 3

/H/yourapp

/S/sapsrv


The connection from sappc to the application server is set up in the following steps:

sappc (front end)

Sets up the connection to SAProuter sap_rout according to substring 1 and relays the route information.

sap_rout (SAProuter on SAP side)

Uses the route permission table to check whether route sappc zu your_rout 3299 is allowed, sets up the connection to the customer SAProuter on host your_rout, and passes substring 2 and 3.

your_rout (SAProuter on customer side)

Checks whether route sap_rout to yourapp, sapsrv is permitted. Password pass_to_app is also checked. SAProuter then sets up the connection to the application server.

A SAProuter always checks only the previous host name or the previous IP address and the next substring (/H/.../S/.../W/..) for host name or IP address, service and password. The last substring does not contain a password, since there is no successor in the route.

If the /S/ section is missing, the default port number of the SAProuter is used. If the /W/ section is missing, a password is not used.

With the old password entry, the above route string would appear as follows:

/H/sap_rout/H/your_rout/H/yourapp/S/sapsrv/P/pass_to_app

Note that the host name (which follows the /H/ in the route string) must be at least two characters long.

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