ACC X.25 Protocol User's Guide

38 Chapter3
ZX25D X.25 Protocol Driver
Configuration
LCN Assignment Constraints
The Logical Channel Number (LCN) assignment table is used to indicate
which channel numbers to use for PVCs and the different types of SVCs.
The table is always specified from the perspective of the DTE, even if the
link has been configured as a DCE. When assigning the last_pvc,
first_insvc, last_insvc, etc. parameters, the following constraints apply:
• The range of values that may be used for LCNs is 1 to 4095.
• The maximum number of LCNs that can be in use at one time on each
X.25 link is 254 on the Z7200A, Z7400A, and Z7350A interface cards.
On all other ACC cards, up to 1023 LCNs may be used on each X.25
link.
• The PVC L CNs must start at 1.
• The LCN ranges that are assigned for PVCs, one-way incoming SVCs,
two-waySVCs,andone-wayoutgoingSVCsmustnotoverlap.
• The LCN assignment t able specified must agree exactly with the
LCN assignments used for the DXE.
• When defining your Virtual Circuit ZLUs, you must not define more
VCs of a given type than declared in the LCN assignment table.
Configuration Parameters Definition
The following configuration values are currently defined for use in X.25
configuration as a replacement for the POLL and SELECT a ddress
fields. These values are used as a symbolic way of configuring the
associated two 16-bit hexadecimal values.
For example, X25_LINK_DTE_400 canbeusedtosetthePOLLaddress
to 0x800a, and the SELECT address to 0x146a. If a particular desired
configuration value i s not provided b y these values, then two
hexadecimal values can be used instead.
X25_LINK_DTE_400 800Ah 146Ah
X25_LINK_DCE_400 000Ah 146Ah
X25_LINK_DTE_1600 800Ah 486Ah
X25_LINK_DCE_1600 000Ah 486Ah