why connections can continue from master to slave sometimes, and sometimes not ?

["dingji" <dingji@xxxxxxxxxxxxx>]

using linux-2.4.20 kernel with linux-2.4.20-ipvs-1.0.9.patch, 
ipvsadm-1.21-1.rh.9.um.1.i386.rpm

according to Manual-8 there should be three files to configure sync-daemon
/proc/sys/net/ipv4/vs/sync_msg_max_size 
/proc/sys/net/ipv4/vs/sync_frequency 
/proc/sys/net/ipv4/vs/sync_threshold 
but I can only find the last one on my system. 
according to Connection Synchronisation by Horms (Simon Horman), there seems a 
patch for this.
but what's the difference between ip_vs_user_sync_simple and sync-daemon within 
ipvsadm.
and why it seemed to work without the two files, were they set the default 
values?

thanks for any help!