diff --git a/include/spdk/nvme_spec.h b/include/spdk/nvme_spec.h
index a588d6c1c..d040b5b65 100644
--- a/include/spdk/nvme_spec.h
+++ b/include/spdk/nvme_spec.h
@@ -1465,6 +1465,8 @@ enum spdk_nvme_flush_broadcast {
 	SPDK_NVME_FLUSH_BROADCAST_SUPPORTED		= 3
 };
 
+#define SPDK_NVME_NQN_FIELD_SIZE 256
+
 struct __attribute__((packed)) __attribute__((aligned)) spdk_nvme_ctrlr_data {
 	/* bytes 0-255: controller capabilities and features */
 
@@ -1808,7 +1810,7 @@ struct __attribute__((packed)) __attribute__((aligned)) spdk_nvme_ctrlr_data {
 
 	uint8_t			reserved4[228];
 
-	uint8_t			subnqn[256];
+	uint8_t			subnqn[SPDK_NVME_NQN_FIELD_SIZE];
 
 	uint8_t			reserved5[768];
 
diff --git a/include/spdk/nvmf_fc_spec.h b/include/spdk/nvmf_fc_spec.h
index cf96be017..0a3234249 100644
--- a/include/spdk/nvmf_fc_spec.h
+++ b/include/spdk/nvmf_fc_spec.h
@@ -87,8 +87,6 @@
 
 #define FCNVME_GOOD_RSP_LEN                     12
 #define FCNVME_ASSOC_HOSTID_LEN                 16
-#define FCNVME_ASSOC_HOSTNQN_LEN                256
-#define FCNVME_ASSOC_SUBNQN_LEN                 256
 
 
 typedef uint64_t FCNVME_BE64;
@@ -280,8 +278,8 @@ struct spdk_nvmf_fc_lsdesc_cr_assoc_cmd {
 	FCNVME_BE16  sqsize;
 	FCNVME_BE32  rsvd52;
 	uint8_t hostid[FCNVME_ASSOC_HOSTID_LEN];
-	uint8_t hostnqn[FCNVME_ASSOC_HOSTNQN_LEN];
-	uint8_t subnqn[FCNVME_ASSOC_SUBNQN_LEN];
+	uint8_t hostnqn[SPDK_NVME_NQN_FIELD_SIZE];
+	uint8_t subnqn[SPDK_NVME_NQN_FIELD_SIZE];
 	uint8_t rsvd584[432];
 };
 SPDK_STATIC_ASSERT(sizeof(struct spdk_nvmf_fc_lsdesc_cr_assoc_cmd) == 1016, "size_mismatch");
diff --git a/include/spdk/nvmf_spec.h b/include/spdk/nvmf_spec.h
index 5e4eb44bc..097377f6e 100644
--- a/include/spdk/nvmf_spec.h
+++ b/include/spdk/nvmf_spec.h
@@ -218,8 +218,8 @@ struct spdk_nvmf_fabric_connect_data {
 	uint8_t		hostid[16];
 	uint16_t	cntlid;
 	uint8_t		reserved5[238];
-	uint8_t		subnqn[256];
-	uint8_t		hostnqn[256];
+	uint8_t		subnqn[SPDK_NVME_NQN_FIELD_SIZE];
+	uint8_t		hostnqn[SPDK_NVME_NQN_FIELD_SIZE];
 	uint8_t		reserved6[256];
 };
 SPDK_STATIC_ASSERT(sizeof(struct spdk_nvmf_fabric_connect_data) == 1024, "Incorrect size");