+.tp 15
+.BI nsellength " n"
+(ISO only)
+This specifies a trailing number of bytes for a received NSAP
+used for local identification, the remaining leading part of which is
+taken to be the NET (Network Entity Title).
+The default value is 1, which is conformant to US GOSIP.
+When an iso address is set in an ifconfig command,
+it is really the NET which is being specified.
+For example, in US GOSIP, 19 hex digits should be
+specified in the ISO NET to be assigned to the interface.
+There is some evidence that a number different 1 may be useful
+for AFI 37 type addresses.