diff --git a/blockdag/dag.go b/blockdag/dag.go
index 7d26ed5e6..68f061acf 100644
--- a/blockdag/dag.go
+++ b/blockdag/dag.go
@@ -516,8 +516,6 @@ func (dag *BlockDAG) connectBlock(node *blockNode, block *util.Block, fastAdd bo
 		}
 	}
 
-	initialFinalityPoint := dag.lastFinalityPoint
-
 	var finalityPointCandidate *blockNode
 	if !fastAdd {
 		var err error
@@ -537,14 +535,6 @@ func (dag *BlockDAG) connectBlock(node *blockNode, block *util.Block, fastAdd bo
 		dag.lastFinalityPoint = finalityPointCandidate
 	}
 
-	// Scan all accepted transactions and collect any sub-network registry
-	// transactions into subNetworkRegistryTxs. If any sub-network registry
-	// transaction is not well-formed, fail the entire block.
-	subNetworkRegistryTxs, err := validateAndExtractSubNetworkRegistryTxs(acceptedTxsData)
-	if err != nil {
-		return err
-	}
-
 	// Write any block status changes to DB before updating the DAG state.
 	err = dag.index.flushToDB()
 	if err != nil {
@@ -557,7 +547,6 @@ func (dag *BlockDAG) connectBlock(node *blockNode, block *util.Block, fastAdd bo
 		state := &dagState{
 			TipHashes:         dag.TipHashes(),
 			LastFinalityPoint: dag.lastFinalityPoint.hash,
-			LastSubNetworkID:  dag.lastSubNetworkID,
 		}
 		err := dbPutDAGState(dbTx, state)
 		if err != nil {
@@ -578,22 +567,14 @@ func (dag *BlockDAG) connectBlock(node *blockNode, block *util.Block, fastAdd bo
 			return err
 		}
 
-		// Add the pending sub-network in this block to the pending sub-networks
-		// collection.
-		err = dbPutPendingSubNetworkTxs(dbTx, block.Hash(), subNetworkRegistryTxs)
+		// Scan all accepted transactions and register any sub-network registry
+		// transaction. If any sub-network registry transaction is not well-formed,
+		// fail the entire block.
+		err = registerSubNetworks(dbTx, acceptedTxsData)
 		if err != nil {
 			return err
 		}
 
-		// Register all pending sub-networks between the initial finality point and
-		// the new one.
-		if initialFinalityPoint != dag.lastFinalityPoint {
-			err = dag.registerPendingSubNetworks(dbTx, initialFinalityPoint, dag.lastFinalityPoint)
-			if err != nil {
-				return err
-			}
-		}
-
 		// Allow the index manager to call each of the currently active
 		// optional indexes with the block being connected so they can
 		// update themselves accordingly.
@@ -1603,7 +1584,6 @@ func New(config *Config) (*BlockDAG, error) {
 		warningCaches:       newThresholdCaches(vbNumBits),
 		deploymentCaches:    newThresholdCaches(dagconfig.DefinedDeployments),
 		blockCount:          1,
-		lastSubNetworkID:    wire.SubNetworkUnreservedFirst,
 	}
 
 	// Initialize the chain state from the passed database.  When the db
diff --git a/blockdag/dagio.go b/blockdag/dagio.go
index 4be7d33d4..3a916c80f 100644
--- a/blockdag/dagio.go
+++ b/blockdag/dagio.go
@@ -992,9 +992,6 @@ func (dag *BlockDAG) initDAGState() error {
 		// Set the last finality point
 		dag.lastFinalityPoint = dag.index.LookupNode(&state.LastFinalityPoint)
 
-		// Set the last sub-network ID
-		dag.lastSubNetworkID = state.LastSubNetworkID
-
 		return nil
 	})
 }
diff --git a/blockdag/subnetworks.go b/blockdag/subnetworks.go
index 4a90b5285..9544c3771 100644
--- a/blockdag/subnetworks.go
+++ b/blockdag/subnetworks.go
@@ -4,29 +4,57 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
+	"github.com/daglabs/btcd/util"
 
-	"github.com/daglabs/btcd/dagconfig/daghash"
 	"github.com/daglabs/btcd/database"
 	"github.com/daglabs/btcd/util/subnetworkid"
 	"github.com/daglabs/btcd/wire"
 )
 
-// validateAndExtractSubNetworkRegistryTxs filters the given input and extracts a list
-// of valid sub-network registry transactions.
-func validateAndExtractSubNetworkRegistryTxs(txs []*TxWithBlockHash) ([]*wire.MsgTx, error) {
+// registerSubNetworks scans a list of accepted transactions, singles out
+// sub-network registry transactions, validates them, and registers a new
+// sub-network based on it.
+// This function returns an error if one or more transactions are invalid
+func registerSubNetworks(dbTx database.Tx, txs []*TxWithBlockHash) error {
 	validSubNetworkRegistryTxs := make([]*wire.MsgTx, 0)
 	for _, txData := range txs {
 		tx := txData.Tx.MsgTx()
 		if tx.SubNetworkID == wire.SubNetworkRegistry {
 			err := validateSubNetworkRegistryTransaction(tx)
 			if err != nil {
-				return nil, err
+				return err
 			}
 			validSubNetworkRegistryTxs = append(validSubNetworkRegistryTxs, tx)
 		}
+
+		if subnetworkid.Less(&wire.SubNetworkRegistry, &tx.SubNetworkID) {
+			// Transactions are ordered by sub-network, so we can safely assume
+			// that the rest of the transactions will not be sub-network registry
+			// transactions.
+			break
+		}
 	}
 
-	return validSubNetworkRegistryTxs, nil
+	for _, registryTx := range validSubNetworkRegistryTxs {
+		subNetworkID, err := txToSubNetworkID(registryTx)
+		if err != nil {
+			return err
+		}
+		sNet, err := dbGetSubNetwork(dbTx, subNetworkID)
+		if err != nil {
+			return err
+		}
+		if sNet == nil {
+			createdSubNetwork := newSubNetwork(registryTx)
+			err := dbRegisterSubNetwork(dbTx, subNetworkID, createdSubNetwork)
+			if err != nil {
+				return fmt.Errorf("failed registering sub-network"+
+					"for tx '%s': %s", registryTx.TxHash(), err)
+			}
+		}
+	}
+
+	return nil
 }
 
 // validateSubNetworkRegistryTransaction makes sure that a given sub-network registry
@@ -41,66 +69,15 @@ func validateSubNetworkRegistryTransaction(tx *wire.MsgTx) error {
 	return nil
 }
 
-// registerPendingSubNetworks attempts to register all the pending sub-networks that
-// had previously been defined between the initial finality point and the new one.
-// Note: transactions within newFinalityPoint itself are not registered. Instead, they will
-// be registered when the next finality point is chosen; then it will be the
-// initialFinalityPoint.
-func (dag *BlockDAG) registerPendingSubNetworks(dbTx database.Tx, initialFinalityPoint *blockNode, newFinalityPoint *blockNode) error {
-	var stack []*blockNode
-	for currentNode := newFinalityPoint; currentNode != initialFinalityPoint; currentNode = currentNode.selectedParent {
-		stack = append(stack, currentNode)
-	}
-
-	// Register a pending sub-network for all blues. The block itself is not explicitly
-	// registered since it will be one of the blues of the next block.
-	// Note that this means that the very last block in the selected parent chain is not
-	// registered. This is intentional.
-	for i := len(stack) - 1; i >= 0; i-- {
-		currentNode := stack[i]
-		for _, blue := range currentNode.blues {
-			err := dag.registerPendingSubNetworksInBlock(dbTx, blue.hash)
-			if err != nil {
-				return fmt.Errorf("failed to register pending sub-networks: %s", err)
-			}
-		}
-	}
-
-	return nil
+// txToSubNetworkID creates a sub-network ID from a sub-network registry transaction
+func txToSubNetworkID(tx *wire.MsgTx) (*subnetworkid.SubNetworkID, error) {
+	txHash := tx.TxHash()
+	return subnetworkid.New(util.Hash160(txHash[:]))
 }
 
-// registerPendingSubNetworksInBlock attempts to register all the sub-networks
-// that had been defined in a given block.
-func (dag *BlockDAG) registerPendingSubNetworksInBlock(dbTx database.Tx, blockHash daghash.Hash) error {
-	pendingSubNetworkTxs, err := dbGetPendingSubNetworkTxs(dbTx, blockHash)
-	if err != nil {
-		return fmt.Errorf("failed to retrieve pending sub-network txs in block '%s': %s", blockHash, err)
-	}
-	for _, tx := range pendingSubNetworkTxs {
-		if !dbIsRegisteredSubNetworkTx(dbTx, tx.TxHash()) {
-			createdSubNetwork := newSubNetwork(tx)
-			err := dbRegisterSubNetwork(dbTx, dag.lastSubNetworkID, tx.TxHash(), createdSubNetwork)
-			if err != nil {
-				return fmt.Errorf("failed registering sub-network"+
-					"for tx '%s' in block '%s': %s", tx.TxHash(), blockHash, err)
-			}
-
-			dag.lastSubNetworkID++
-		}
-	}
-
-	err = dbRemovePendingSubNetworkTxs(dbTx, blockHash)
-	if err != nil {
-		return fmt.Errorf("failed to remove block '%s'"+
-			"from pending sub-networks: %s", blockHash, err)
-	}
-
-	return nil
-}
-
-// subNetwork returns a registered-and-finalized sub-network. If the sub-network
-// does not exist this method returns an error.
-func (dag *BlockDAG) subNetwork(subNetworkID subnetworkid.SubNetworkID) (*subNetwork, error) {
+// subNetwork returns a registered sub-network. If the sub-network does not exist
+// this method returns an error.
+func (dag *BlockDAG) subNetwork(subNetworkID *subnetworkid.SubNetworkID) (*subNetwork, error) {
 	var sNet *subNetwork
 	var err error
 	dbErr := dag.db.View(func(dbTx database.Tx) error {
@@ -117,213 +94,70 @@ func (dag *BlockDAG) subNetwork(subNetworkID subnetworkid.SubNetworkID) (*subNet
 	return sNet, nil
 }
 
-// GasLimit returns the gas limit of a registered-and-finalized sub-network. If
-// the sub-network does not exist this method returns an error.
-func (dag *BlockDAG) GasLimit(subNetworkID subnetworkid.SubNetworkID) (uint64, error) {
+// GasLimit returns the gas limit of a registered sub-network. If the sub-network does not
+// exist this method returns an error.
+func (dag *BlockDAG) GasLimit(subNetworkID *subnetworkid.SubNetworkID) (uint64, error) {
 	sNet, err := dag.subNetwork(subNetworkID)
 	if err != nil {
 		return 0, err
 	}
+	if sNet == nil {
+		return 0, fmt.Errorf("sub-network '%s' not found", subNetworkID)
+	}
 
 	return sNet.gasLimit, nil
 }
 
-// -----------------------------------------------------------------------------
-// The sub-network registry consists of three buckets:
-// a. The pending sub-network bucket
-// b. The registered transaction bucket
-// c. The sub-network bucket
-//
-// All newly-discovered sub-network registry transactions are stored in the
-// pending sub-network bucket. These transactions are withheld until the
-// blocks that contain them become final.
-//
-// Once the block of a sub-network registry transaction becomes final, all the
-// transactions within that block are retrieved and checked for validity.
-// Valid transactions are then:
-// 1. Assigned a sub-network ID
-// 2. Added to the registered transaction bucket
-// 3. Added to the sub-network bucket
-// -----------------------------------------------------------------------------
-
-// dbPutPendingSubNetworkTxs stores mappings from a block (via its hash) to an
-// array of sub-network transactions.
-func dbPutPendingSubNetworkTxs(dbTx database.Tx, blockHash *daghash.Hash, subNetworkRegistryTxs []*wire.MsgTx) error {
-	// Empty blocks are not written
-	if len(subNetworkRegistryTxs) == 0 {
-		return nil
-	}
-
-	serializedTxs, err := serializeSubNetworkRegistryTxs(subNetworkRegistryTxs)
-	if err != nil {
-		return fmt.Errorf("failed to serialize pending sub-network txs in block '%s': %s", blockHash, err)
-	}
-
-	// Store the serialized transactions
-	bucket := dbTx.Metadata().Bucket(pendingSubNetworksBucketName)
-	err = bucket.Put(blockHash[:], serializedTxs)
-	if err != nil {
-		return fmt.Errorf("failed to write pending sub-network txs in block '%s': %s", blockHash, err)
-	}
-
-	return nil
-}
-
-// dbGetPendingSubNetworkTxs retrieves an array of sub-network transactions,
-// associated with a block's hash, that was previously stored with
-// dbPutPendingSubNetworkTxs.
-// Returns an empty slice if the hash was not previously stored.
-func dbGetPendingSubNetworkTxs(dbTx database.Tx, blockHash daghash.Hash) ([]*wire.MsgTx, error) {
-	bucket := dbTx.Metadata().Bucket(pendingSubNetworksBucketName)
-	serializedTxsBytes := bucket.Get(blockHash[:])
-	if serializedTxsBytes == nil {
-		return []*wire.MsgTx{}, nil
-	}
-
-	txs, err := deserializeSubNetworkRegistryTxs(serializedTxsBytes)
-	if err != nil {
-		return nil, fmt.Errorf("failed to deserialize pending sub-network txs for block '%s': %s", blockHash, err)
-	}
-
-	return txs, nil
-}
-
-// serializeSubNetworkRegistryTxs serializes a slice of MsgTxs by serializing each transaction
-// individually and appending it to one long byte slice.
-func serializeSubNetworkRegistryTxs(subNetworkRegistryTxs []*wire.MsgTx) ([]byte, error) {
-	// Calculate the length in bytes of the serialized transactions
-	serializedTxsLength := uint64(0)
-	for _, tx := range subNetworkRegistryTxs {
-		serializedTxsLength += uint64(tx.SerializeSize())
-	}
-	serializedTxs := bytes.NewBuffer(make([]byte, 0, serializedTxsLength))
-
-	// Write each transaction in the order it appears in
-	for _, tx := range subNetworkRegistryTxs {
-		err := tx.Serialize(serializedTxs)
-		if err != nil {
-			return nil, fmt.Errorf("failed to serialize tx '%s': %s", tx.TxHash(), err)
-		}
-	}
-
-	return serializedTxs.Bytes(), nil
-}
-
-// deserializeSubNetworkRegistryTxs deserializes a byte slice into a slice of MsgTxs.
-func deserializeSubNetworkRegistryTxs(serializedTxsBytes []byte) ([]*wire.MsgTx, error) {
-	serializedTxs := bytes.NewBuffer(serializedTxsBytes)
-
-	// Read each transaction and store it in txs until the end of the buffer
-	txs := make([]*wire.MsgTx, 0)
-	for serializedTxs.Len() > 0 {
-		var tx wire.MsgTx
-		err := tx.Deserialize(serializedTxs)
-		if err != nil {
-			return nil, fmt.Errorf("failed to deserialize pending sub-network txs: %s", err)
-		}
-
-		txs = append(txs, &tx)
-	}
-
-	return txs, nil
-}
-
-// dbRemovePendingSubNetworkTxs deletes an array of sub-network transactions,
-// associated with a block's hash, that was previously stored with
-// dbPutPendingSubNetworkTxs.
-// This function does not return an error if the hash was not previously stored.
-func dbRemovePendingSubNetworkTxs(dbTx database.Tx, blockHash daghash.Hash) error {
-	bucket := dbTx.Metadata().Bucket(pendingSubNetworksBucketName)
-
-	err := bucket.Delete(blockHash[:])
-	if err != nil {
-		return fmt.Errorf("failed to remove pending sub-network txs in block '%s': %s", blockHash, err)
-	}
-
-	return nil
-}
-
-// dbIsRegisteredSubNetworkTx checks whether a sub-network registry transaction
-// had successfully registered a sub-network.
-func dbIsRegisteredSubNetworkTx(dbTx database.Tx, txHash daghash.Hash) bool {
-	bucket := dbTx.Metadata().Bucket(registeredSubNetworkTxsBucketName)
-	subNetworkIDBytes := bucket.Get(txHash[:])
-
-	return subNetworkIDBytes != nil
-}
-
-// dbRegisterSubNetwork stores mappings:
-// a. from the ID of the sub-network to the sub-network data.
-// b. from the hash of a sub-network registry transaction to the sub-network ID.
-func dbRegisterSubNetwork(dbTx database.Tx, subNetworkID uint64, txHash daghash.Hash, network *subNetwork) error {
-	// Serialize the sub-network ID
-	subNetworkIDBytes := make([]byte, 8)
-	byteOrder.PutUint64(subNetworkIDBytes, subNetworkID)
-
+// dbRegisterSubNetwork stores mappings from ID of the sub-network to the sub-network data.
+func dbRegisterSubNetwork(dbTx database.Tx, subNetworkID *subnetworkid.SubNetworkID, network *subNetwork) error {
 	// Serialize the sub-network
 	serializedSubNetwork, err := serializeSubNetwork(network)
 	if err != nil {
-		return fmt.Errorf("failed to serialize sub-netowrk of tx '%s': %s", network.txHash, err)
+		return fmt.Errorf("failed to serialize sub-netowrk '%s': %s", subNetworkID, err)
 	}
 
 	// Store the sub-network
 	subNetworksBucket := dbTx.Metadata().Bucket(subNetworksBucketName)
-	err = subNetworksBucket.Put(subNetworkIDBytes, serializedSubNetwork)
+	err = subNetworksBucket.Put(subNetworkID[:], serializedSubNetwork)
 	if err != nil {
-		return fmt.Errorf("failed to write sub-netowrk of tx '%s': %s", network.txHash, err)
-	}
-
-	// Store the mapping between txHash and subNetworkID
-	registeredSubNetworkTxs := dbTx.Metadata().Bucket(registeredSubNetworkTxsBucketName)
-	err = registeredSubNetworkTxs.Put(txHash[:], subNetworkIDBytes)
-	if err != nil {
-		return fmt.Errorf("failed to put registered sub-networkTx '%s': %s", txHash, err)
+		return fmt.Errorf("failed to write sub-netowrk '%s': %s", subNetworkID, err)
 	}
 
 	return nil
 }
 
-func dbGetSubNetwork(dbTx database.Tx, subNetworkID subnetworkid.SubNetworkID) (*subNetwork, error) {
-	// Get the sub-network
+// dbGetSubNetwork returns the sub-network associated with subNetworkID or nil if the sub-network was not found.
+func dbGetSubNetwork(dbTx database.Tx, subNetworkID *subnetworkid.SubNetworkID) (*subNetwork, error) {
 	bucket := dbTx.Metadata().Bucket(subNetworksBucketName)
 	serializedSubNetwork := bucket.Get(subNetworkID[:])
 	if serializedSubNetwork == nil {
-		return nil, fmt.Errorf("sub-network '%d' not found", subNetworkID)
+		return nil, nil
 	}
 
 	return deserializeSubNetwork(serializedSubNetwork)
 }
 
 type subNetwork struct {
-	txHash   daghash.Hash
 	gasLimit uint64
 }
 
 func newSubNetwork(tx *wire.MsgTx) *subNetwork {
-	txHash := tx.TxHash()
 	gasLimit := binary.LittleEndian.Uint64(tx.Payload[:8])
 
 	return &subNetwork{
-		txHash:   txHash,
 		gasLimit: gasLimit,
 	}
 }
 
 // serializeSubNetwork serializes a subNetwork into the following binary format:
-// | txHash (32 bytes) | gasLimit (8 bytes) |
+// | gasLimit (8 bytes) |
 func serializeSubNetwork(sNet *subNetwork) ([]byte, error) {
-	serializedSNet := bytes.NewBuffer(make([]byte, 0, 40))
-
-	// Write the tx hash
-	err := binary.Write(serializedSNet, byteOrder, sNet.txHash)
-	if err != nil {
-		return nil, fmt.Errorf("failed to serialize sub-network for tx '%s': %s", sNet.txHash, err)
-	}
+	serializedSNet := bytes.NewBuffer(make([]byte, 0, 8))
 
 	// Write the gas limit
-	err = binary.Write(serializedSNet, byteOrder, sNet.gasLimit)
+	err := binary.Write(serializedSNet, byteOrder, sNet.gasLimit)
 	if err != nil {
-		return nil, fmt.Errorf("failed to serialize sub-network for tx '%s': %s", sNet.txHash, err)
+		return nil, fmt.Errorf("failed to serialize sub-network: %s", err)
 	}
 
 	return serializedSNet.Bytes(), nil
@@ -334,22 +168,14 @@ func serializeSubNetwork(sNet *subNetwork) ([]byte, error) {
 func deserializeSubNetwork(serializedSNetBytes []byte) (*subNetwork, error) {
 	serializedSNet := bytes.NewBuffer(serializedSNetBytes)
 
-	// Read the tx hash
-	var txHash daghash.Hash
-	err := binary.Read(serializedSNet, byteOrder, &txHash)
-	if err != nil {
-		return nil, fmt.Errorf("failed to deserialize sub-network: %s", err)
-	}
-
 	// Read the gas limit
 	var gasLimit uint64
-	err = binary.Read(serializedSNet, byteOrder, &gasLimit)
+	err := binary.Read(serializedSNet, byteOrder, &gasLimit)
 	if err != nil {
 		return nil, fmt.Errorf("failed to deserialize sub-network: %s", err)
 	}
 
 	return &subNetwork{
-		txHash:   txHash,
 		gasLimit: gasLimit,
 	}, nil
 }
diff --git a/blockdag/subnetworks_test.go b/blockdag/subnetworks_test.go
index e5fd370b6..8d0d3f34c 100644
--- a/blockdag/subnetworks_test.go
+++ b/blockdag/subnetworks_test.go
@@ -1,23 +1,17 @@
 package blockdag
 
 import (
-	"encoding/binary"
-	"math"
 	"reflect"
 	"testing"
 
 	"github.com/daglabs/btcd/dagconfig"
-	"github.com/daglabs/btcd/wire"
 )
 
-// TestSubNetworkRegistry tests the full sub-network registry flow. In this test:
-// 1. We create a sub-network registry transaction and add its block to the DAG
-// 2. Add 2*finalityInterval so that the sub-network registry transaction becomes final
-// 3. Attempt to retrieve the gas limit of the now-registered sub-network
+// TestSubNetworkRegistry tests the full sub-network registry flow
 func TestSubNetworkRegistry(t *testing.T) {
 	params := dagconfig.SimNetParams
 	params.K = 1
-	dag, teardownFunc, err := DAGSetup("TestFinality", Config{
+	dag, teardownFunc, err := DAGSetup("TestSubNetworkRegistry", Config{
 		DAGParams: &params,
 	})
 	if err != nil {
@@ -25,103 +19,22 @@ func TestSubNetworkRegistry(t *testing.T) {
 	}
 	defer teardownFunc()
 
-	_, err = RegisterSubnetworkForTest(dag, 12345)
-
+	gasLimit := uint64(12345)
+	subNetworkID, err := RegisterSubNetworkForTest(dag, gasLimit)
 	if err != nil {
 		t.Fatalf("could not register network: %s", err)
 	}
-}
-
-func TestSerializeSubNetworkRegistryTxs(t *testing.T) {
-	payload1 := make([]byte, 8)
-	binary.LittleEndian.PutUint64(payload1, uint64(100))
-	tx1 := wire.MsgTx{
-		Version:      1,
-		SubNetworkID: wire.SubNetworkRegistry,
-		Payload:      payload1,
-		TxIn: []*wire.TxIn{
-			{
-				PreviousOutPoint: wire.OutPoint{
-					Hash:  *newHashFromStr("0437cd7f8525ceed2324359c2d0ba26006d92d856a9c20fa0241106ee5a597c9"),
-					Index: 0,
-				},
-				SignatureScript: hexToBytes("47304402204e45e16932b8af514961a1d3a1a25fdf3f4f7732e9d624c6c61548ab5fb8cd410220181522ec8eca07de4860a4acdd12909d831cc56cbbac4622082221a8768d1d0901"),
-				Sequence:        math.MaxUint64,
-			},
-		},
-		TxOut: []*wire.TxOut{{
-			Value:    1000000000,
-			PkScript: hexToBytes("4104ae1a62fe09c5f51b13905f07f06b99a2f7159b2225f374cd378d71302fa28414e7aab37397f554a7df5f142c21c1b7303b8a0626f1baded5c72a704f7e6cd84cac"),
-		}, {
-			Value:    4000000000,
-			PkScript: hexToBytes("410411db93e1dcdb8a016b49840f8c53bc1eb68a382e97b1482ecad7b148a6909a5cb2e0eaddfb84ccf9744464f82e160bfa9b8b64f9d4c03f999b8643f656b412a3ac"),
-		}},
+	limit, err := dag.GasLimit(subNetworkID)
+	if err != nil {
+		t.Fatalf("could not retrieve gas limit: %s", err)
 	}
-
-	payload2 := make([]byte, 8)
-	binary.LittleEndian.PutUint64(payload2, uint64(200))
-	tx2 := wire.MsgTx{
-		Version:      1,
-		SubNetworkID: wire.SubNetworkRegistry,
-		Payload:      payload2,
-		TxIn: []*wire.TxIn{{
-			PreviousOutPoint: wire.OutPoint{
-				Hash:  *newHashFromStr("0437cd7f8525ceed2324359c2d0ba26006d92d856a9c20fa0241106ee5a597c9"),
-				Index: 0,
-			},
-			SignatureScript: hexToBytes("47304402204e45e16932b8af514961a1d3a1a25fdf3f4f7732e9d624c6c61548ab5fb8cd410220181522ec8eca07de4860a4acdd12909d831cc56cbbac4622082221a8768d1d0901"),
-			Sequence:        math.MaxUint64,
-		}},
-		TxOut: []*wire.TxOut{{
-			Value:    5000000,
-			PkScript: hexToBytes("76a914f419b8db4ba65f3b6fcc233acb762ca6f51c23d488ac"),
-		}, {
-			Value:    34400000000,
-			PkScript: hexToBytes("76a914cadf4fc336ab3c6a4610b75f31ba0676b7f663d288ac"),
-		}},
-		LockTime: 0,
-	}
-
-	tests := []struct {
-		name string
-		txs  []*wire.MsgTx
-	}{
-		{
-			name: "empty slice",
-			txs:  []*wire.MsgTx{},
-		},
-		{
-			name: "one transaction",
-			txs:  []*wire.MsgTx{&tx1},
-		},
-		{
-			name: "two transactions",
-			txs:  []*wire.MsgTx{&tx2, &tx1},
-		},
-	}
-
-	for _, test := range tests {
-		serializedTxs, err := serializeSubNetworkRegistryTxs(test.txs)
-		if err != nil {
-			t.Errorf("serialization in test '%s' unexpectedly failed: %s", test.name, err)
-			continue
-		}
-
-		deserializedTxs, err := deserializeSubNetworkRegistryTxs(serializedTxs)
-		if err != nil {
-			t.Errorf("deserialization in test '%s' unexpectedly failed: %s", test.name, err)
-			continue
-		}
-
-		if !reflect.DeepEqual(test.txs, deserializedTxs) {
-			t.Errorf("original txs and deserialized txs are not equal in test '%s'", test.name)
-		}
+	if limit != gasLimit {
+		t.Fatalf("unexpected gas limit. want: %d, got: %d", gasLimit, limit)
 	}
 }
 
 func TestSerializeSubNetwork(t *testing.T) {
 	sNet := &subNetwork{
-		txHash:   *newHashFromStr("0437cd7f8525ceed2324359c2d0ba26006d92d856a9c20fa0241106ee5a597c9"),
 		gasLimit: 1000,
 	}
 
diff --git a/blockdag/test_utils.go b/blockdag/test_utils.go
index 5cb794a6a..a1b4a783a 100644
--- a/blockdag/test_utils.go
+++ b/blockdag/test_utils.go
@@ -3,6 +3,7 @@ package blockdag
 import (
 	"encoding/binary"
 	"fmt"
+	"github.com/daglabs/btcd/util/subnetworkid"
 	"os"
 	"path/filepath"
 	"time"
@@ -143,9 +144,9 @@ func createCoinbaseTxForTest(blockHeight int32, numOutputs uint32, extraNonce in
 	return tx, nil
 }
 
-// RegisterSubnetworkForTest is used to register network on DAG with specified GAS limit.
-func RegisterSubnetworkForTest(dag *BlockDAG, gasLimit uint64) (subNetworkID uint64, err error) {
-	blockTime := time.Unix(dag.genesis.timestamp, 0)
+// RegisterSubNetworkForTest is used to register network on DAG with specified gas limit
+func RegisterSubNetworkForTest(dag *BlockDAG, gasLimit uint64) (*subnetworkid.SubNetworkID, error) {
+	blockTime := time.Unix(dag.selectedTip().timestamp, 0)
 	extraNonce := int64(0)
 
 	buildNextBlock := func(parents blockSet, txs []*wire.MsgTx) (*util.Block, error) {
@@ -180,7 +181,7 @@ func RegisterSubnetworkForTest(dag *BlockDAG, gasLimit uint64) (subNetworkID uin
 		dag.dagLock.Lock()
 		defer dag.dagLock.Unlock()
 
-		err = dag.maybeAcceptBlock(block, BFNone)
+		err := dag.maybeAcceptBlock(block, BFNone)
 		if err != nil {
 			return nil, err
 		}
@@ -188,7 +189,7 @@ func RegisterSubnetworkForTest(dag *BlockDAG, gasLimit uint64) (subNetworkID uin
 		return dag.index.LookupNode(block.Hash()), nil
 	}
 
-	currentNode := dag.genesis
+	currentNode := dag.selectedTip()
 
 	// Create a block with a valid sub-network registry transaction
 	registryTx := wire.NewMsgTx(wire.TxVersion)
@@ -199,34 +200,17 @@ func RegisterSubnetworkForTest(dag *BlockDAG, gasLimit uint64) (subNetworkID uin
 	// Add it to the DAG
 	registryBlock, err := buildNextBlock(setFromSlice(currentNode), []*wire.MsgTx{registryTx})
 	if err != nil {
-		return 0, fmt.Errorf("could not build registry block: %s", err)
+		return nil, fmt.Errorf("could not build registry block: %s", err)
 	}
 	currentNode, err = addBlockToDAG(registryBlock)
 	if err != nil {
-		return 0, fmt.Errorf("could not add registry block to DAG: %s", err)
+		return nil, fmt.Errorf("could not add registry block to DAG: %s", err)
 	}
 
-	// Add 2*finalityInterval to ensure the registry transaction is finalized
-	for currentNode.blueScore < 2*finalityInterval {
-		nextBlock, err := buildNextBlock(setFromSlice(currentNode), []*wire.MsgTx{})
-		if err != nil {
-			return 0, fmt.Errorf("could not create block: %s", err)
-		}
-		currentNode, err = addBlockToDAG(nextBlock)
-		if err != nil {
-			return 0, fmt.Errorf("could not add block to DAG: %s", err)
-		}
-	}
-
-	// Make sure that the sub-network had been successfully registered by trying
-	// to retrieve its gas limit.
-	mostRecentlyRegisteredSubNetworkID := dag.lastSubNetworkID - 1
-	limit, err := dag.GasLimit(mostRecentlyRegisteredSubNetworkID)
+	// Build a sub-network ID from the registry transaction
+	subNetworkID, err := txToSubNetworkID(registryTx)
 	if err != nil {
-		return 0, fmt.Errorf("could not retrieve gas limit: %s", err)
+		return nil, fmt.Errorf("could not build sub-network ID: %s", err)
 	}
-	if limit != gasLimit {
-		return 0, fmt.Errorf("unexpected gas limit. want: %d, got: %d", gasLimit, limit)
-	}
-	return mostRecentlyRegisteredSubNetworkID, nil
+	return subNetworkID, nil
 }
diff --git a/config/config.go b/config/config.go
index 3a68ea936..ae6574053 100644
--- a/config/config.go
+++ b/config/config.go
@@ -754,7 +754,7 @@ func loadConfig() (*Config, []string, error) {
 	}
 
 	if cfg.configFlags.SubNetwork != "" {
-		cfg.SubNetwork, err = subnetworkid.NewIDFromStr(cfg.configFlags.SubNetwork)
+		cfg.SubNetwork, err = subnetworkid.NewFromStr(cfg.configFlags.SubNetwork)
 		if err != nil {
 			return nil, nil, err
 		}
diff --git a/mempool/mempool.go b/mempool/mempool.go
index 9ad5ceab3..35fbb1ff4 100644
--- a/mempool/mempool.go
+++ b/mempool/mempool.go
@@ -659,10 +659,10 @@ func (mp *TxPool) maybeAcceptTransaction(tx *util.Tx, isNew, rateLimit, rejectDu
 
 	// Check that transaction does not overuse GAS
 	msgTx := tx.MsgTx()
-	if msgTx.SubNetworkID == 0 {
+	if msgTx.SubNetworkID == wire.SubNetworkSupportsAll {
 		return nil, nil, txRuleError(wire.RejectInvalid, "Subnetwork 0 is not permited in transaction")
 	} else if msgTx.SubNetworkID != wire.SubNetworkDAGCoin {
-		gasLimit, err := mp.cfg.DAG.GasLimit(msgTx.SubNetworkID)
+		gasLimit, err := mp.cfg.DAG.GasLimit(&msgTx.SubNetworkID)
 		if err != nil {
 			return nil, nil, err
 		}
diff --git a/mempool/mempool_test.go b/mempool/mempool_test.go
index 1756e765d..23115f93e 100644
--- a/mempool/mempool_test.go
+++ b/mempool/mempool_test.go
@@ -9,6 +9,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"github.com/daglabs/btcd/util/subnetworkid"
 	"math"
 	"reflect"
 	"runtime"
@@ -155,11 +156,11 @@ func (p *poolHarness) CreateCoinbaseTx(blockHeight int32, numOutputs uint32) (*u
 	return util.NewTx(tx), nil
 }
 
-// CreateSignedTxForSubnetwork creates a new signed transaction that consumes the provided
+// CreateSignedTxForSubNetwork creates a new signed transaction that consumes the provided
 // inputs and generates the provided number of outputs by evenly splitting the
 // total input amount.  All outputs will be to the payment script associated
 // with the harness and all inputs are assumed to do the same.
-func (p *poolHarness) CreateSignedTxForSubnetwork(inputs []spendableOutpoint, numOutputs uint32, subnetworkID uint64, gas uint64) (*util.Tx, error) {
+func (p *poolHarness) CreateSignedTxForSubNetwork(inputs []spendableOutpoint, numOutputs uint32, subNetworkID *subnetworkid.SubNetworkID, gas uint64) (*util.Tx, error) {
 	// Calculate the total input amount and split it amongst the requested
 	// number of outputs.
 	var totalInput util.Amount
@@ -170,7 +171,7 @@ func (p *poolHarness) CreateSignedTxForSubnetwork(inputs []spendableOutpoint, nu
 	remainder := uint64(totalInput) - amountPerOutput*uint64(numOutputs)
 
 	tx := wire.NewMsgTx(wire.TxVersion)
-	tx.SubNetworkID = subnetworkID
+	tx.SubNetworkID = *subNetworkID
 	tx.Gas = gas
 	for _, input := range inputs {
 		tx.AddTxIn(&wire.TxIn{
@@ -210,7 +211,7 @@ func (p *poolHarness) CreateSignedTxForSubnetwork(inputs []spendableOutpoint, nu
 // total input amount.  All outputs will be to the payment script associated
 // with the harness and all inputs are assumed to do the same.
 func (p *poolHarness) CreateSignedTx(inputs []spendableOutpoint, numOutputs uint32) (*util.Tx, error) {
-	return p.CreateSignedTxForSubnetwork(inputs, numOutputs, wire.SubNetworkDAGCoin, 0)
+	return p.CreateSignedTxForSubNetwork(inputs, numOutputs, &wire.SubNetworkDAGCoin, 0)
 }
 
 // CreateTxChain creates a chain of zero-fee transactions (each subsequent
@@ -1843,13 +1844,13 @@ func TestTransactionGas(t *testing.T) {
 	//	tc := &testContext{t, harness}
 
 	const gasLimit = 10000
-	subnetworkID, err := blockdag.RegisterSubnetworkForTest(harness.txPool.cfg.DAG, gasLimit)
+	subNetworkID, err := blockdag.RegisterSubNetworkForTest(harness.txPool.cfg.DAG, gasLimit)
 	if err != nil {
 		t.Fatalf("unable to register network: %v", err)
 	}
 
 	// Create valid transaction
-	tx, err := harness.CreateSignedTxForSubnetwork(spendableOuts[:1], 1, subnetworkID, gasLimit)
+	tx, err := harness.CreateSignedTxForSubNetwork(spendableOuts[:1], 1, subNetworkID, gasLimit)
 	if err != nil {
 		t.Fatalf("unable to create transaction: %v", err)
 	}
@@ -1859,7 +1860,7 @@ func TestTransactionGas(t *testing.T) {
 	}
 
 	// Create invalid transaction
-	tx, err = harness.CreateSignedTxForSubnetwork(spendableOuts[1:], 1, subnetworkID, gasLimit+1)
+	tx, err = harness.CreateSignedTxForSubNetwork(spendableOuts[1:], 1, subNetworkID, gasLimit+1)
 	if err != nil {
 		t.Fatalf("unable to create transaction: %v", err)
 	}
diff --git a/mining/mining.go b/mining/mining.go
index 79ec6945a..e8ec512af 100644
--- a/mining/mining.go
+++ b/mining/mining.go
@@ -484,23 +484,23 @@ func (g *BlkTmplGenerator) NewBlockTemplate(payToAddress util.Address) (*BlockTe
 		tx := prioItem.tx
 
 		if tx.MsgTx().SubNetworkID != wire.SubNetworkDAGCoin {
-			subnetwork := tx.MsgTx().SubNetworkID
-			gasUsage, ok := gasUsageMap[subnetwork]
+			subNetwork := tx.MsgTx().SubNetworkID
+			gasUsage, ok := gasUsageMap[subNetwork]
 			if !ok {
 				gasUsage = 0
 			}
-			gasLimit, err := g.dag.GasLimit(subnetwork)
+			gasLimit, err := g.dag.GasLimit(&subNetwork)
 			if err != nil {
-				log.Errorf("Cannot get GAS limit for subnetwork %v", subnetwork)
+				log.Errorf("Cannot get GAS limit for subNetwork %v", subNetwork)
 				continue
 			}
 			txGas := tx.MsgTx().Gas
 			if gasLimit-gasUsage < txGas {
-				log.Tracef("Transaction %v (GAS=%v) ignored because gas overusage (GASUsage=%v) in subnetwork %v (GASLimit=%v)",
-					tx.MsgTx().TxHash, txGas, gasUsage, subnetwork, gasLimit)
+				log.Tracef("Transaction %v (GAS=%v) ignored because gas overusage (GASUsage=%v) in subNetwork %v (GASLimit=%v)",
+					tx.MsgTx().TxHash, txGas, gasUsage, subNetwork, gasLimit)
 				continue
 			}
-			gasUsageMap[subnetwork] = gasUsage + txGas
+			gasUsageMap[subNetwork] = gasUsage + txGas
 		}
 
 		// Enforce maximum block size.  Also check for overflow.
diff --git a/wire/msgtx.go b/wire/msgtx.go
index 47543e06b..b5015146f 100644
--- a/wire/msgtx.go
+++ b/wire/msgtx.go
@@ -96,14 +96,6 @@ const (
 	// peers.  Thus, the peak usage of the free list is 12,500 * 512 =
 	// 6,400,000 bytes.
 	freeListMaxItems = 12500
-
-	// SubNetworkReservedFirst and SubnetworkReservedLast mark the range of sub-networks that are reserved for future use
-	// and are currently un-assigned for anything
-	// SubNetworkReservedFirst is the first reserved sub-network
-	SubNetworkReservedFirst = 3
-
-	// SubNetworkUnreservedFirst is the first unreserved sub-network
-	SubNetworkUnreservedFirst = 256
 )
 
 var (