[Pacemaker] communication channels howto

[lxnf98mm at comcast.net]

The DRBD manual says

It is absolutely vital to configure at least two independent OpenAIS 
communication channels for this functionality to work correctly.

My Google'n has not yielded any results in the how to do this department
I have DRBD configured and working properly with one channel
Where can I find info to add a second channel

Richard