During a Recent  Oracle 11g Rac installation on Solaris, i ran into  the following issue. After installing and configuring oracle clusterware, when we were trying to create the ASM instance, the ASM instance would only stay alive on one node of the cluster. The customer had configured the private interconnect to be a 100 base T connection (As opposed to GiGE). Once the customer re-configured the interconnect to be a GiGE, the ASM instance came up properly. Oracle recommends that you have a GiGE connection for your private interconnect.

Before starting your installation you can check if the interface you are using for the private interconnect, is configured to be a GIGE connection.

On Redhat or Oracle Enterprise Linux

Install the rpm ethtool

ethtool <interfacename> | grep Speed ,will give you the speed of the interface

On Solaris

kstat <interfacename> | grep link_speed  ,will give you the speed of the interface