diff --git a/proto/context.proto b/proto/context.proto
index e403c4a22f2df62f695041c094cc1c6e6a193d5f..49d16229cdac5de84f25cfaa7d196d25184f46f0 100644
--- a/proto/context.proto
+++ b/proto/context.proto
@@ -509,6 +509,7 @@ message Constraint_SLA_Capacity {
 message Constraint_SLA_Availability {
   uint32 num_disjoint_paths = 1;
   bool all_active = 2;
+  float availability = 3; // 0.0 .. 100.0 percentage of availability
 }
 
 enum IsolationLevelEnum {