Installing and Administering OSI Transport Services

76 Chapter 2
Planning Your Network
General X.25 Questions
By default, OTS will also accept call packets with either the OSI or
NULL PID values. Setting the “snet_bind_by_pid” parameter in the
“ots_subnets” file will prevent OTS from accepting CALL requests
using the NULL. If set, OTS will refuse calls with a PID other than
the OSI standard PID.
• What Network layer protocols will be used (CONS, CLNS)?
The Connectionless Network Service (CLNS) has the advantage in
that it can be used with routers and does not require the gateway
facility provided by MSDSG in order to interconnect with CLNS/LAN
subnetworks. However, CLNS does present more overhead because
each packet sent contains addressing information, and Transport
Class 4 must be used.
The Connection-Oriented Network Service (CONS) is currently more
widely used than CLNS/X.25.