Difference between 301 redirection and rel=canonical ?

[millex]

What is the difference between 301 redirection and rel=canonical tag ?

[sreejasrinivas]

A 301 Redirect signals to the search engine that the page has been moved permanently, remove the page from the index and pass any acquired SEO credit to the new page.
A Canonical Attribute signals to the search engine that the document has multiple versions of the page (or its content). The URL pointed listed in the canonical attribute should be consider the original, the real page: only it should be indexed. The duplicated pages will be kept on the website but should not be indexed by the search engine.

[Intuz]

A 301 redirect means that the page has permanently moved to a new location. The instruction indicates the old location, the new location and that this move or change is permanent. The change can be a change in domain name, web page name, path to a web page on the site or to another site.

Canonical URL used to tell search engines that certain similar URLs are actually one and the same. This is the case where you have products or content that is accessible under multiple URLs, or even on multiple websites. Using a canonical URL, these can exist without harming your rankings.