+ * considered unreachable. If a value of zero
+ * is present in this field then no changes are to
+ * be made to this parameter.
+ * spp_pathmtu - When Path MTU discovery is disabled the value
+ * specified here will be the "fixed" path mtu.
+ * Note that if the spp_address field is empty
+ * then all associations on this address will
+ * have this fixed path mtu set upon them.
+ *
+ * spp_sackdelay - When delayed sack is enabled, this value specifies
+ * the number of milliseconds that sacks will be delayed
+ * for. This value will apply to all addresses of an
+ * association if the spp_address field is empty. Note
+ * also, that if delayed sack is enabled and this
+ * value is set to 0, no change is made to the last
+ * recorded delayed sack timer value.
+ *
+ * spp_flags - These flags are used to control various features
+ * on an association. The flag field may contain
+ * zero or more of the following options.
+ *
+ * SPP_HB_ENABLE - Enable heartbeats on the
+ * specified address. Note that if the address
+ * field is empty all addresses for the association
+ * have heartbeats enabled upon them.
+ *
+ * SPP_HB_DISABLE - Disable heartbeats on the
+ * speicifed address. Note that if the address
+ * field is empty all addresses for the association
+ * will have their heartbeats disabled. Note also
+ * that SPP_HB_ENABLE and SPP_HB_DISABLE are
+ * mutually exclusive, only one of these two should
+ * be specified. Enabling both fields will have
+ * undetermined results.
+ *
+ * SPP_HB_DEMAND - Request a user initiated heartbeat
+ * to be made immediately.
+ *
+ * SPP_PMTUD_ENABLE - This field will enable PMTU
+ * discovery upon the specified address. Note that
+ * if the address feild is empty then all addresses
+ * on the association are effected.
+ *
+ * SPP_PMTUD_DISABLE - This field will disable PMTU
+ * discovery upon the specified address. Note that
+ * if the address feild is empty then all addresses
+ * on the association are effected. Not also that
+ * SPP_PMTUD_ENABLE and SPP_PMTUD_DISABLE are mutually
+ * exclusive. Enabling both will have undetermined
+ * results.
+ *
+ * SPP_SACKDELAY_ENABLE - Setting this flag turns
+ * on delayed sack. The time specified in spp_sackdelay
+ * is used to specify the sack delay for this address. Note
+ * that if spp_address is empty then all addresses will
+ * enable delayed sack and take on the sack delay
+ * value specified in spp_sackdelay.
+ * SPP_SACKDELAY_DISABLE - Setting this flag turns
+ * off delayed sack. If the spp_address field is blank then
+ * delayed sack is disabled for the entire association. Note
+ * also that this field is mutually exclusive to
+ * SPP_SACKDELAY_ENABLE, setting both will have undefined
+ * results.