이란 and 이랑, each of words has definitely diffirent meaning.
Koreans use '이란' to ephasize or define the meaning of the words following '이란'.
for example, if we speak '인생이란' then, it means 'Life is...'
이랑 is a conjunction only for nouns.
ex ) 한국인이랑 캐나다인이랑 = korean and canadian
사과랑 배랑 = apple and pear
but the important thing is that we can not use it for joining senteces.