[phkamp]

(probably pressing wrong reply link here ?)

Cookies are almost never mentioned in Vary: so all caches have to assume that the precense of cookies means non-cacheable.

[comex]

Hmm. That would indeed be an advantage of a new mechanism.

What I meant about JavaScript is that a server side cookie->session bridge for legacy code would not work in general because corresponding client side code sometimes expects to be able to see the cookies in document.cookie.