diff --git a/src/lib/dhcpsrv/lease.cc b/src/lib/dhcpsrv/lease.cc
index e9a2c3d11b84bbaa7b1b5c7fa1ea02d838330862..d14c53b273dc60bfa70105f98f365cfe891712b6 100644
--- a/src/lib/dhcpsrv/lease.cc
+++ b/src/lib/dhcpsrv/lease.cc
@@ -343,7 +343,7 @@ Lease4::statesToText(const uint32_t state) {
 
 const std::vector<uint8_t>&
 Lease4::getClientIdVector() const {
-    if(!client_id_) {
+    if (!client_id_) {
         static std::vector<uint8_t> empty_vec;
         return (empty_vec);
     }
diff --git a/src/lib/dhcpsrv/lease.h b/src/lib/dhcpsrv/lease.h
index b603ebeee21f3f674ad9e9230d642ccf2a93942c..0c2c7919038c4d276a2b10deb07683fbd9c5d00a 100644
--- a/src/lib/dhcpsrv/lease.h
+++ b/src/lib/dhcpsrv/lease.h
@@ -660,7 +660,6 @@ typedef boost::shared_ptr<const Lease6> ConstLease6Ptr;
 /// @brief A collection of IPv6 leases.
 typedef std::vector<Lease6Ptr> Lease6Collection;
 
-
 /// @brief A shared pointer to the collection of IPv6 leases.
 typedef boost::shared_ptr<Lease6Collection> Lease6CollectionPtr;
 
diff --git a/src/lib/dhcpsrv/memfile_lease_storage.h b/src/lib/dhcpsrv/memfile_lease_storage.h
index 0fe2a705465118c842aa666338d07bcf3bd5f353..33380b0a6dc60e8d0053f648ecc04b32400d5176 100644
--- a/src/lib/dhcpsrv/memfile_lease_storage.h
+++ b/src/lib/dhcpsrv/memfile_lease_storage.h
@@ -14,6 +14,7 @@
 #include <boost/multi_index/indexed_by.hpp>
 #include <boost/multi_index/member.hpp>
 #include <boost/multi_index/mem_fun.hpp>
+#include <boost/multi_index/hashed_index.hpp>
 #include <boost/multi_index/ordered_index.hpp>
 #include <boost/multi_index_container.hpp>
 #include <boost/multi_index/composite_key.hpp>
@@ -279,6 +280,221 @@ typedef Lease4Storage::index<SubnetIdIndexTag>::type Lease4StorageSubnetIdIndex;
 typedef Lease4Storage::index<HostnameIndexTag>::type Lease4StorageHostnameIndex;
 
 //@}
+
+/// @name Multi index containers holding DHCPv6 lease extended informations
+/// for Bulk Lease Query.
+//@{
+
+/// @brief Lease6 extended informations for Bulk Lease Query.
+class Lease6ExtendedInfo {
+public:
+    /// @brief Constructor.
+    ///
+    /// @param lease_addr Lease address.
+    /// @param link_addr Link address.
+    /// @param id Identifier.
+    Lease6ExtendedInfo(const isc::asiolink::IOAddress& lease_addr,
+                       const isc::asiolink::IOAddress& link_addr,
+                       const std::vector<uint8_t>& id)
+        : lease_addr_(lease_addr), link_addr_(link_addr), id_(id) {
+    }
+
+    /// @brief Lease address.
+    isc::asiolink::IOAddress lease_addr_;
+
+    /// @brief Link address.
+    isc::asiolink::IOAddress link_addr_;
+
+    /// @brief Remote or relay opaque identifier.
+    std::vector<uint8_t> id_;
+};
+
+/// @brief Pointer to a Lease6ExtendedInfo object.
+typedef boost::shared_ptr<Lease6ExtendedInfo> Lease6ExtendedInfoPtr;
+
+/// @brief Tag for indexes by lease address.
+struct LeaseAddressIndexTag { };
+
+/// @brief Tag for indexes by relay id and link address.
+struct RelayIdLinkAddressIndexTag { };
+
+/// @brief Tag for index using relay id.
+struct RelayIdIndexTag { };
+
+/// @brief Tag for indexes by remote id and link address.
+struct RemoteIdLinkAddressIndexTag { };
+
+/// @brief Tag for index using remote id.
+struct RemoteIdIndexTag { };
+
+/// @brief A multi index container holding lease6 extended info for by relay id.
+///
+/// The lease6 extended info may be accessed using different indexes:
+/// - using a composite index: relay id and link address.
+/// - using relay id.
+/// - using lease address.
+///
+/// The choice of binary trees was governed by the fact a large number of
+/// clients can be behind a relay.
+///
+/// Indexes can be accessed using the index number (from 0 to 5) or a
+/// name tag. It is recommended to use the tags to access indexes as
+/// they do not depend on the order of indexes in the container.
+typedef boost::multi_index_container<
+    // It holds pointers to lease6 extended info.
+    Lease6ExtendedInfoPtr,
+    boost::multi_index::indexed_by<
+        // First index is by relay id and link address.
+        boost::multi_index::ordered_non_unique<
+            boost::multi_index::tag<RelayIdLinkAddressIndexTag>,
+            boost::multi_index::composite_key<
+                Lease6ExtendedInfo,
+                boost::multi_index::member<Lease6ExtendedInfo,
+                                           std::vector<uint8_t>,
+                                           &Lease6ExtendedInfo::id_>,
+                boost::multi_index::member<Lease6ExtendedInfo,
+                                           isc::asiolink::IOAddress,
+                                           &Lease6ExtendedInfo::link_addr_>
+            >
+        >,
+
+        // Second index is by relay id.
+        boost::multi_index::ordered_non_unique<
+            boost::multi_index::tag<RelayIdIndexTag>,
+            boost::multi_index::member<Lease6ExtendedInfo,
+                                       std::vector<uint8_t>,
+                                       &Lease6ExtendedInfo::id_>
+        >,
+
+        // Last index is by lease address.
+        boost::multi_index::hashed_non_unique<
+            boost::multi_index::tag<LeaseAddressIndexTag>,
+            boost::multi_index::member<Lease6ExtendedInfo,
+                                       isc::asiolink::IOAddress,
+                                       &Lease6ExtendedInfo::lease_addr_>
+        >
+    >
+> Lease6ExtendedInfoRelayIdTable;
+
+/// @brief A multi index container holding lease6 extended info for by remote id.
+///
+/// The lease6 extended info may be accessed using different indexes:
+/// - using a composite index: remote id and link address.
+/// - using remote id.
+/// - using lease address.
+///
+/// The internal layout of remote id is not used. The choice of hash tables
+/// was governed by the fact a small number of clients should share the same
+/// remote id.
+///
+/// Indexes can be accessed using the index number (from 0 to 5) or a
+/// name tag. It is recommended to use the tags to access indexes as
+/// they do not depend on the order of indexes in the container.
+typedef boost::multi_index_container<
+    // It holds pointers to lease6 extended info.
+    Lease6ExtendedInfoPtr,
+    boost::multi_index::indexed_by<
+        // First index is by remote id and link address.
+        boost::multi_index::hashed_non_unique<
+            boost::multi_index::tag<RemoteIdLinkAddressIndexTag>,
+            boost::multi_index::composite_key<
+                Lease6ExtendedInfo,
+                boost::multi_index::member<Lease6ExtendedInfo,
+                                           std::vector<uint8_t>,
+                                           &Lease6ExtendedInfo::id_>,
+                boost::multi_index::member<Lease6ExtendedInfo,
+                                           isc::asiolink::IOAddress,
+                                           &Lease6ExtendedInfo::link_addr_>
+            >
+        >,
+
+        // Second index is by remote id.
+        boost::multi_index::hashed_non_unique<
+            boost::multi_index::tag<RemoteIdIndexTag>,
+            boost::multi_index::member<Lease6ExtendedInfo,
+                                       std::vector<uint8_t>,
+                                       &Lease6ExtendedInfo::id_>
+        >,
+
+        // Last index is by lease address.
+        boost::multi_index::hashed_non_unique<
+            boost::multi_index::tag<LeaseAddressIndexTag>,
+            boost::multi_index::member<Lease6ExtendedInfo,
+                                       isc::asiolink::IOAddress,
+                                       &Lease6ExtendedInfo::lease_addr_>
+        >
+    >
+> Lease6ExtendedInfoRemoteIdTable;
+
+/// @brief Lease6 extended informations for Bulk Lease Query,
+/// simpler version (2 fields vs 3) for by link address table.
+class Lease6SimpleExtendedInfo {
+public:
+    /// @brief Constructor.
+    ///
+    /// @param lease_addr Lease address.
+    /// @param link_addr Link address.
+    Lease6SimpleExtendedInfo(const isc::asiolink::IOAddress& lease_addr,
+                             const isc::asiolink::IOAddress& link_addr)
+        : lease_addr_(lease_addr), link_addr_(link_addr) {
+    }
+
+    /// @brief Lease address.
+    isc::asiolink::IOAddress lease_addr_;
+
+    /// @brief Link address.
+    isc::asiolink::IOAddress link_addr_;
+};
+
+/// @brief Pointer to a Lease6SimpleExtendedInfo object.
+typedef boost::shared_ptr<Lease6SimpleExtendedInfo> Lease6SimpleExtendedInfoPtr;
+
+/// @brief Tag for indexes by link address.
+struct LinkAddressIndexTag { };
+
+/// @brief A multi index container holding lease6 extended info
+/// for by link address.
+///
+/// The lease6 extended info may be accessed using different indexes:
+/// - using a composite index: link and lease addresses.
+/// - using lease address.
+///
+/// The choice of a binary tree was governed by the fact no hypothesis can
+/// be done on the number of clients.
+///
+/// Indexes can be accessed using the index number (from 0 to 5) or a
+/// name tag. It is recommended to use the tags to access indexes as
+/// they do not depend on the order of indexes in the container.
+typedef boost::multi_index_container<
+    // It holds pointers to lease6 extended info.
+    Lease6SimpleExtendedInfoPtr,
+    boost::multi_index::indexed_by<
+        // First index is by link and lease addresses.
+        boost::multi_index::ordered_non_unique<
+            boost::multi_index::tag<LinkAddressIndexTag>,
+            boost::multi_index::composite_key<
+                Lease6SimpleExtendedInfo,
+                boost::multi_index::member<Lease6SimpleExtendedInfo,
+                                           isc::asiolink::IOAddress,
+                                           &Lease6SimpleExtendedInfo::link_addr_>,
+                boost::multi_index::member<Lease6SimpleExtendedInfo,
+                                           isc::asiolink::IOAddress,
+                                           &Lease6SimpleExtendedInfo::lease_addr_>
+            >
+        >,
+
+        // Last index is by lease address.
+        boost::multi_index::hashed_non_unique<
+            boost::multi_index::tag<LeaseAddressIndexTag>,
+            boost::multi_index::member<Lease6SimpleExtendedInfo,
+                                       isc::asiolink::IOAddress,
+                                       &Lease6SimpleExtendedInfo::lease_addr_>
+        >
+    >
+> Lease6SimpleExtendedInfoLinkAddrTable;
+
+//@}
+
 } // end of isc::dhcp namespace
 } // end of isc namespace