Page Redirect after Session expired

Redirect loging page after session expired we can check the session variable and if its null can be redirect.
ex. in page load use this code

protected void page_load(...)
{
if(Session["sesionName"] == null) // cheack session is exist or not
{
page.redirect("login.aspx");// redirect required page
}
}

note :- when we use Globle.aspx file before session expired it session_end method execute. even though we cannot use page redirect withing that method.