Dear SCO Customer,

The enclosed Support Level Supplement (SLS) PTF3120, the TCP/IP RIP-2 
Supplement, allows subnets to be used in routing policy decisions. This 
enables different subnet masks to be used on physically connected networks 
and allows packets to be successfully routed between different parts of the
network. 

Most computer inter-networks use the same class of addressing, with an 
implicit netmask, depending only on the class of the network address used.
This limits the physical number of connections that can be made to such a 
network, and if physical space is limited it can cause a shortage of network 
addresses to occur. One way to avoid this shortage is to split a network into 
subnets of the same class of addresses. This allows several subnets to be 
used as the primary allocation method for network addresses. The maximum 
number of physical network addresses available within one of these subnets 
can be chosen by careful planning when designing the subnet layout. The 
physical number is limited by the number of bits used in the subnet mask.

A full discussion of the routing choice and setup is beyond the scope of 
this text, however this topic is covered in most reference materials on
network management.



Software Notes and Recommendations
----------------------------------

SLS PTF3120 can be installed on SCO UnixWare Application Server Release 
2.1.0, 2.1.1 and 2.1.2.


Installation Instructions
-------------------------

1. Download the ptf3120.Z and ptf3120.txt files to the /tmp directory
   on your machine.

2. As root, uncompress the file and add the package to your
   system using these commands:

       $ su
       # uncompress /tmp/ptf3120.Z
       # pkgadd -d /tmp/ptf3120


3. Reboot the system after installing this SLS.


Removal Instructions
---------------------

1. As root, remove the package.

   $su
   # pkgrm ptf3120

2. Reboot the system after removing this SLS.


If you have questions regarding this SLS, or the product on which it is
installed, please contact your software supplier.

We appreciate your business.

SCO Support Services