Peering policies can be broadly classified into three types: restrictive, selective and open policy. An ISP applies a policy according to its current status (e.g. Tier 1, Tier 2, …) and its willingness to conclude new peering agreements.

1. Restrictive peering policy: A restrictive policy is typically applied by Tier-1 ISPs. See for example the peering policy of  AT&T or QWEST.
2. Selective peering policy: A selective policy is typically applied by Tier-2 ISPs. See for example the peering policy of BT or Bouygues Telecom.
3. Open peering policy: An open policy is typically applied by small national ISPs (Tier-3 ISPs). See for example the peering policy of NetAccess.