Clarification required reg., Redhat Cluster Suite

[GVSM Siva Kumar]

Dear Sirs,
	We have recently purchased Redhat Enterprise Linux ES version 3
and Redhat Cluster Suite version 3 to establish a high availability
cluster in Active/Passive configuration with shared storage.

	As per documents available on Redhat's website, it is possible to
establish a heartbeat mechanism over Ethernet. However, our system
integrator feels that this is not possible with RHCS 3 and that heartbeat
mechanism can only be established using a Quorum partition. The SI also
believes that quorum based heartbeat is superior to Ethernet based 
heartbeat mechanism.

	In this regard, can someone please clarify the following.

1) Whether Quorum partition is a superior mechanism for establishing
heartbeat? If so, then in what aspects?
   (Somehow, this looks strange, in an ethernet based heartbeat only
network latencies are involved, which must be negligible with a ethernet
crossover cable. Whereas quorum partition involves two latencies in
writing/reading the quorum partition and the disk access time itself.
Surely, a crossover ethernet based heartbeat must be superior to quorum
partition.) 

2) Is it not possible to establish heartbeat using an ethernet/serial
crossover cable?
	sivakumar