Within the Red Hat certification program, the RHCA is considered the most complete (and grueling) certification among the seven major Red Hat certifications. In fact, some equate the prestige of the RHCA to that of the Microsoft Certified Master and possibly the CCIE.
A plumbing fixture like a sink can not function properly without a sink vent. When a drain pipe drains it creates a negative pressure in the sink drain; the negative pressure will pull the water out of the p-trap of the sink that's draining and sewer gases can enter your home if a sink vent is not installed.
For example on a 1 1/2â³ sink drain the vent can not be located more than 5ft away from the trap and the pipe between the trap and the vent can not have bends in excess of 135 degrees. The rules for siphonic fixtures such as a toilet differ. You can have the vent 10ft away and have 225 degrees before the vent.