authentication - Is there any better solutions for single sign on (SSO) functionality - PHP -

i working on website application developed on laravel 4.2 framework , website associated websites application related to.

i want implement single sign on (sso) functionality in application.

suppose application : www.example.com

associated websites following :

1. www.testsite1.com
2. www.testsite2.com
3. www.testsite3.com
4. www.testsite4.com

when logged on 1 of websites (my application or associated websites).

after logged, hits rest of websites except (currently logged websites) should not prompt login means should allow enter in application without logging because logged @ 1 application.

same as, when logged on gmail account,and go account (drive,google plus,youtube etc) won't ask login again,it bypass login page application.

is there better , feasible solutions php/laravel ?

may following steps achieve single sign on across different website

1. when user visit www.testsite1.com , redirect user sso server.
2. once user redirected sso server, check if cookie exist, first time there no cookie show login page hosted on sso server.
3. after getting credential user validate user
4. if user valid, generate token token can unique hexadecimal number or hash timestamps.
5. set token cookie on sso server , redirect user original site or success page
6. now when user visit www.testsite2.com or www.testsite3.com, redirect user sso server again
7. once user comes sso, check cookie, if exist , not expire redirect user directly success page without asking login credential again or show login page , follow drill again

as redirecting user on different server, can set cookie there common name 'ssocookie' , every time access same when coming different application. achieve single sign on different domain.