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So, technically, according to Google, the answer is really ugly. You should canonical to the page level (e.g. "page=2"), but then rel=prev/next to pages 1 and 3 with the same parameters have the current page. So, if you call page 2 with "sort=20" then, "sort=20" should be in the rel=prev/next tags, BUT the canonical should go to page 2 without the "sort=20". Repeat this for every possible parameter, and welcome to Hell. You could just use rel=prev/next with the base URLs, and then rel-canonical to the page level. The other option, though, is to hide these parameters completely. Could you store the results/page option in a cookie, for example (that's what I do on a lot of sites) or leave it default, unless someone changes it? If Google always gets the default, then they'll never see that in the URL. You could also block the sort= parameter in Google Webmaster Tools, although I think combining that with rel=prev/next gets a bit messy.