The following are snippets of Peering Policy Clauses found in the Peering Rules of the Road - A Brief Study of Peering Policies study.  Clauses were categorized and put into rough categories for comparison.

Here are the clauses we categorized as requirements for Prefix Length and aggregation clauses

Excerpts from Peering Polices

Prefix Length

AboveNet will not permit the routes longer than a /24 from its peers. – AboveNet

Routes should be aggregated as much as possible. ATDN will not accept any announcement smaller than /24. – ATDN

Applicant announces a minimum of 1,000 fully aggregated routes or equivalent of 50,000 Class-C networks – tinet

Applicant's network must share a presence with Tinet in at least four regions in Europe and two regions in the US, out of the regions below. These regions must be linked with redundant dedicated IP backbone capacity of OC192 or higher. Applicants are expected to have a significant customer base in any of theregions and thus carry significant domestic traffic in these regions to match this criterion. – tinet

Routes should be aggregated as much as possible. LambdaNet will not accept any announcement smaller than /24. – LambdaNet

# Aggregate routes as much as possible: New Edge Networks will not accept any announcement smaller than /24 – NewEdge

Must provide only IPv4 route advertisements and will not provide route advertisements more specific than a /24 – Charter

A good faith effort should be made to aggregate route announcements as much as practical. – Speakeasy