diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 974c51fc02b..0b63ac7f94e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -11,6 +11,8 @@ Release 0.23-PB - Unreleased
 
     HDFS-2518. Add protobuf service for NamenodeProtocol. (suresh)
 
+    HDFS-2520. Add protobuf service for InterDatanodeProtocol. (suresh)
+
   IMPROVEMENTS
 
     HDFS-2018. Move all journal stream management code into one place.
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/proto/InterDatanodeProtocol.proto b/hadoop-hdfs-project/hadoop-hdfs/src/main/proto/InterDatanodeProtocol.proto
new file mode 100644
index 00000000000..9f36e29e0fa
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/proto/InterDatanodeProtocol.proto
@@ -0,0 +1,78 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// This file contains protocol buffers that are used throughout HDFS -- i.e.
+// by the client, server, and data transfer protocols.
+
+option java_package = "org.apache.hadoop.hdfs.protocol.proto";
+option java_outer_classname = "InterDatanodeProtocolProtos";
+option java_generic_services = true;
+option java_generate_equals_and_hash = true;
+
+import "hdfs.proto";
+
+/**
+ * Block with location information and new generation stamp
+ * to be used for recovery.
+ */
+message InitReplicaRecoveryRequestProto {
+  required RecoveringBlockProto block = 1;
+}
+
+/**
+ * Repica recovery information
+ */
+message InitReplicaRecoveryResponseProto {
+  required ReplicaState state = 1; // State fo the replica
+  required BlockProto block = 2;   // block information
+}
+
+/**
+ * Update replica with new generation stamp and length
+ */
+message UpdateReplicaUnderRecoveryRequestProto {
+  required ExtendedBlockProto block = 1; // Block identifier
+  required uint64 recoveryId = 2;        // New genstamp of the replica
+  required uint64 newLength = 3;         // New length of the replica
+}
+
+/**
+ * Response returns updated block information
+ */
+message UpdateReplicaUnderRecoveryResponseProto {
+  required ExtendedBlockProto block = 1; // Updated block information
+}
+
+/**
+ * Protocol used between datanodes for block recovery.
+ *
+ * See the request and response for details of rpc call.
+ */
+service InterDatanodeProtocolService {
+  /**
+   * Initialize recovery of a replica
+   */
+  rpc initReplicaRecovery(InitReplicaRecoveryRequestProto)
+      returns(InitReplicaRecoveryResponseProto);
+
+  /**
+   * Update a replica with new generation stamp and length
+   */
+  rpc updateReplicaUnderRecovery(UpdateReplicaUnderRecoveryRequestProto)
+      returns(UpdateReplicaUnderRecoveryResponseProto);
+}