Hi,if your question is that from PIX501 you need to have 2 IKE IPSec connections? then the answer is yes, u can have upto 10 IKE Peers from the PIX 501

Hiother way is to set the isakmp lifetime to 0 secondsi.e infinite lifetime

hitry setting the isakmp keepalive to 30 secondsso that there is always some traffic 