diff --git a/daemon/face/face-common.hpp b/daemon/face/face-common.hpp
index 996d7b6..18ca03c 100644
--- a/daemon/face/face-common.hpp
+++ b/daemon/face/face-common.hpp
@@ -47,22 +47,22 @@
 using FaceId = uint64_t;
 
 /// Indicates an invalid FaceId
-constexpr FaceId INVALID_FACEID = ndn::nfd::INVALID_FACE_ID;
+inline constexpr FaceId INVALID_FACEID = ndn::nfd::INVALID_FACE_ID;
 /// Identifies the InternalFace used in management
-constexpr FaceId FACEID_INTERNAL_FACE = 1;
+inline constexpr FaceId FACEID_INTERNAL_FACE = 1;
 /// Identifies a packet comes from the ContentStore
-constexpr FaceId FACEID_CONTENT_STORE = 254;
+inline constexpr FaceId FACEID_CONTENT_STORE = 254;
 /// Identifies the NullFace that drops every packet
-constexpr FaceId FACEID_NULL = 255;
+inline constexpr FaceId FACEID_NULL = 255;
 /// Upper bound of reserved FaceIds
-constexpr FaceId FACEID_RESERVED_MAX = 255;
+inline constexpr FaceId FACEID_RESERVED_MAX = 255;
 
 /**
  * \brief Minimum MTU that may be set.
  *
  * This is done to ensure the NDNLPv2 fragmentation feature functions properly.
  */
-constexpr ssize_t MIN_MTU = 64;
+inline constexpr ssize_t MIN_MTU = 64;
 
 /**
  * \brief Identifies a remote endpoint on the link.
diff --git a/daemon/face/lp-fragmenter.cpp b/daemon/face/lp-fragmenter.cpp
index 0243a48..a9fcf17 100644
--- a/daemon/face/lp-fragmenter.cpp
+++ b/daemon/face/lp-fragmenter.cpp
@@ -41,7 +41,7 @@
 /**
  * \brief Maximum overhead on a single fragment, not counting other NDNLPv2 headers.
  */
-const size_t MAX_SINGLE_FRAG_OVERHEAD =
+constexpr size_t MAX_SINGLE_FRAG_OVERHEAD =
   1 + 9 + // LpPacket TLV-TYPE and TLV-LENGTH
   1 + 1 + 8 + // Sequence TLV
   1 + 9; // Fragment TLV-TYPE and TLV-LENGTH
@@ -49,7 +49,7 @@
 /**
  * \brief Maximum overhead of adding fragmentation to payload, not counting other NDNLPv2 headers.
  */
-const size_t MAX_FRAG_OVERHEAD =
+constexpr size_t MAX_FRAG_OVERHEAD =
   1 + 9 + // LpPacket TLV-TYPE and TLV-LENGTH
   1 + 1 + 8 + // Sequence TLV
   1 + 1 + 8 + // FragIndex TLV
diff --git a/daemon/face/transport.hpp b/daemon/face/transport.hpp
index 1c24c57..0350bf4 100644
--- a/daemon/face/transport.hpp
+++ b/daemon/face/transport.hpp
@@ -89,22 +89,22 @@
 /**
  * \brief Indicates that the transport has no limit on payload size
  */
-constexpr ssize_t MTU_UNLIMITED = -1;
+inline constexpr ssize_t MTU_UNLIMITED = -1;
 
 /**
  * \brief (for internal use) Indicates that the MTU field is unset
  */
-constexpr ssize_t MTU_INVALID = -2;
+inline constexpr ssize_t MTU_INVALID = -2;
 
 /**
  * \brief Indicates that the transport does not support reading the queue capacity/length
  */
-constexpr ssize_t QUEUE_UNSUPPORTED = -1;
+inline constexpr ssize_t QUEUE_UNSUPPORTED = -1;
 
 /**
  * \brief Indicates that the transport was unable to retrieve the queue capacity/length
  */
-constexpr ssize_t QUEUE_ERROR = -2;
+inline constexpr ssize_t QUEUE_ERROR = -2;
 
 /**
  * \brief The lower half of a Face.