@@ -214,8 +214,8 @@ func (c *controller) agentSetup(clusterProvider cluster.Provider) error {

 	listen := clusterProvider.GetListenAddress()

 	listenAddr, _, _ := net.SplitHostPort(listen)

-	logrus.Infof("Initializing Libnetwork Agent Listen-Addr=%s Local-addr=%s Adv-addr=%s Data-addr=%s Remote-addr-list=%v",

-		listenAddr, bindAddr, advAddr, dataAddr, remoteAddrList)

+	logrus.Infof("Initializing Libnetwork Agent Listen-Addr=%s Local-addr=%s Adv-addr=%s Data-addr=%s Remote-addr-list=%v MTU=%d",

+		listenAddr, bindAddr, advAddr, dataAddr, remoteAddrList, c.Config().Daemon.NetworkControlPlaneMTU)

 	if advAddr != "" && agent == nil {

 		if err := c.agentInit(listenAddr, bindAddr, advAddr, dataAddr); err != nil {

 			logrus.Errorf("error in agentInit: %v", err)

@@ -286,12 +286,19 @@ func (c *controller) agentInit(listenAddr, bindAddrOrInterface, advertiseAddr, d

 	nodeName := hostname + "-" + stringid.TruncateID(stringid.GenerateRandomID())

 	logrus.Info("Gossip cluster hostname ", nodeName)

-	nDB, err := networkdb.New(&networkdb.Config{

-		BindAddr:      listenAddr,

-		AdvertiseAddr: advertiseAddr,

-		NodeName:      nodeName,

-		Keys:          keys,

-	})

+	netDBConf := networkdb.DefaultConfig()

+	netDBConf.NodeName = nodeName

+	netDBConf.BindAddr = listenAddr

+	netDBConf.AdvertiseAddr = advertiseAddr

+	netDBConf.Keys = keys

+	if c.Config().Daemon.NetworkControlPlaneMTU != 0 {

+		// Consider the MTU remove the IP hdr (IPv4 or IPv6) and the TCP/UDP hdr.

+		// To be on the safe side let's cut 100 bytes

+		netDBConf.PacketBufferSize = (c.Config().Daemon.NetworkControlPlaneMTU - 100)

+		logrus.Debugf("Control plane MTU: %d will initialize NetworkDB with: %d",

+			c.Config().Daemon.NetworkControlPlaneMTU, netDBConf.PacketBufferSize)

+	}

+	nDB, err := networkdb.New(netDBConf)

 	if err != nil {

 		return err

@@ -26,14 +26,15 @@ type Config struct {

 // DaemonCfg represents libnetwork core configuration

 type DaemonCfg struct {

-	Debug           bool

-	Experimental    bool

-	DataDir         string

-	DefaultNetwork  string

-	DefaultDriver   string

-	Labels          []string

-	DriverCfg       map[string]interface{}

-	ClusterProvider cluster.Provider

+	Debug                  bool

+	Experimental           bool

+	DataDir                string

+	DefaultNetwork         string

+	DefaultDriver          string

+	Labels                 []string

+	DriverCfg              map[string]interface{}

+	ClusterProvider        cluster.Provider

+	NetworkControlPlaneMTU int

 }

 // ClusterCfg represents cluster configuration

@@ -221,6 +222,19 @@ func OptionExperimental(exp bool) Option {

 	}

 }

+// OptionNetworkControlPlaneMTU function returns an option setter for control plane MTU

+func OptionNetworkControlPlaneMTU(exp int) Option {

+	return func(c *Config) {

+		logrus.Debugf("Network Control Plane MTU: %d", exp)

+		if exp < 1500 {

+			// if exp == 0 the value won't be used

+			logrus.Warnf("Received a MTU of %d, this value is very low,",

+				"the network control plane can misbehave", exp)

+		}

+		c.Daemon.NetworkControlPlaneMTU = exp

+	}

+}

+

 // ProcessOptions processes options and stores it in config

 func (c *Config) ProcessOptions(options ...Option) {

 	for _, opt := range options {

@@ -232,10 +246,7 @@ func (c *Config) ProcessOptions(options ...Option) {

 // IsValidName validates configuration objects supported by libnetwork

 func IsValidName(name string) bool {

-	if strings.TrimSpace(name) == "" {

-		return false

-	}

-	return true

+	return strings.TrimSpace(name) != ""

 }

 // OptionLocalKVProvider function returns an option setter for kvstore provider

@@ -98,10 +98,14 @@ func (nDB *NetworkDB) RemoveKey(key []byte) {

 }

 func (nDB *NetworkDB) clusterInit() error {

+	nDB.lastStatsTimestamp = time.Now()

+	nDB.lastHealthTimestamp = nDB.lastStatsTimestamp

+

 	config := memberlist.DefaultLANConfig()

 	config.Name = nDB.config.NodeName

 	config.BindAddr = nDB.config.BindAddr

 	config.AdvertiseAddr = nDB.config.AdvertiseAddr

+	config.UDPBufferSize = nDB.config.PacketBufferSize

 	if nDB.config.BindPort != 0 {

 		config.BindPort = nDB.config.BindPort

@@ -199,9 +203,8 @@ func (nDB *NetworkDB) clusterJoin(members []string) error {

 	mlist := nDB.memberlist

 	if _, err := mlist.Join(members); err != nil {

-		// Incase of failure, keep retrying join until it succeeds or the cluster is shutdown.

+		// In case of failure, keep retrying join until it succeeds or the cluster is shutdown.

 		go nDB.retryJoin(members, nDB.stopCh)

-

 		return fmt.Errorf("could not join node to memberlist: %v", err)

 	}

@@ -372,11 +375,21 @@ func (nDB *NetworkDB) gossip() {

 		networkNodes[nid] = nDB.networkNodes[nid]

 	}

+	printStats := time.Since(nDB.lastStatsTimestamp) >= nDB.config.StatsPrintPeriod

+	printHealth := time.Since(nDB.lastHealthTimestamp) >= nDB.config.HealthPrintPeriod

 	nDB.RUnlock()

+	if printHealth {

+		healthScore := nDB.memberlist.GetHealthScore()

+		if healthScore != 0 {

+			logrus.Warnf("NetworkDB stats - healthscore:%d (connectivity issues)", healthScore)

+		}

+		nDB.lastHealthTimestamp = time.Now()

+	}

+

 	for nid, nodes := range networkNodes {

 		mNodes := nDB.mRandomNodes(3, nodes)

-		bytesAvail := udpSendBuf - compoundHeaderOverhead

+		bytesAvail := nDB.config.PacketBufferSize - compoundHeaderOverhead

 		nDB.RLock()

 		network, ok := thisNodeNetworks[nid]

@@ -397,6 +410,14 @@ func (nDB *NetworkDB) gossip() {

 		}

 		msgs := broadcastQ.GetBroadcasts(compoundOverhead, bytesAvail)

+		// Collect stats and print the queue info, note this code is here also to have a view of the queues empty

+		network.qMessagesSent += len(msgs)

+		if printStats {

+			logrus.Infof("NetworkDB stats - Queue net:%s qLen:%d netPeers:%d netMsg/s:%d",

+				nid, broadcastQ.NumQueued(), broadcastQ.NumNodes(), network.qMessagesSent/int((nDB.config.StatsPrintPeriod/time.Second)))

+			network.qMessagesSent = 0

+		}

+

 		if len(msgs) == 0 {

 			continue

 		}

@@ -414,11 +435,15 @@ func (nDB *NetworkDB) gossip() {

 			}

 			// Send the compound message

-			if err := nDB.memberlist.SendToUDP(&mnode.Node, compound); err != nil {

+			if err := nDB.memberlist.SendBestEffort(&mnode.Node, compound); err != nil {

 				logrus.Errorf("Failed to send gossip to %s: %s", mnode.Addr, err)

 			}

 		}

 	}

+	// Reset the stats

+	if printStats {

+		nDB.lastStatsTimestamp = time.Now()

+	}

 }

 func (nDB *NetworkDB) bulkSyncTables() {

@@ -589,7 +614,7 @@ func (nDB *NetworkDB) bulkSyncNode(networks []string, node string, unsolicited b

 	nDB.bulkSyncAckTbl[node] = ch

 	nDB.Unlock()

-	err = nDB.memberlist.SendToTCP(&mnode.Node, buf)

+	err = nDB.memberlist.SendReliable(&mnode.Node, buf)

 	if err != nil {

 		nDB.Lock()

 		delete(nDB.bulkSyncAckTbl, node)

@@ -606,7 +631,7 @@ func (nDB *NetworkDB) bulkSyncNode(networks []string, node string, unsolicited b

 		case <-t.C:

 			logrus.Errorf("Bulk sync to node %s timed out", node)

 		case <-ch:

-			logrus.Debugf("%s: Bulk sync to node %s took %s", nDB.config.NodeName, node, time.Now().Sub(startTime))

+			logrus.Debugf("%s: Bulk sync to node %s took %s", nDB.config.NodeName, node, time.Since(startTime))

 		}

 		t.Stop()

 	}

@@ -3,10 +3,6 @@ package networkdb

 import "github.com/gogo/protobuf/proto"

 const (

-	// Max udp message size chosen to avoid network packet

-	// fragmentation.

-	udpSendBuf = 1400

-

 	// Compound message header overhead 1 byte(message type) + 4

 	// bytes (num messages)

 	compoundHeaderOverhead = 5

@@ -5,6 +5,7 @@ package networkdb

 import (

 	"fmt"

 	"net"

+	"os"

 	"strings"

 	"sync"

 	"time"

@@ -93,6 +94,12 @@ type NetworkDB struct {

 	// bootStrapIP is the list of IPs that can be used to bootstrap

 	// the gossip.

 	bootStrapIP []net.IP

+

+	// lastStatsTimestamp is the last timestamp when the stats got printed

+	lastStatsTimestamp time.Time

+

+	// lastHealthTimestamp is the last timestamp when the health score got printed

+	lastHealthTimestamp time.Time

 }

 // PeerInfo represents the peer (gossip cluster) nodes of a network

@@ -126,6 +133,9 @@ type network struct {

 	// The broadcast queue for table event gossip. This is only

 	// initialized for this node's network attachment entries.

 	tableBroadcasts *memberlist.TransmitLimitedQueue

+

+	// Number of gossip messages sent related to this network during the last stats collection period

+	qMessagesSent int

 }

 // Config represents the configuration of the networdb instance and

@@ -149,6 +159,21 @@ type Config struct {

 	// Keys to be added to the Keyring of the memberlist. Key at index

 	// 0 is the primary key

 	Keys [][]byte

+

+	// PacketBufferSize is the maximum number of bytes that memberlist will

+	// put in a packet (this will be for UDP packets by default with a NetTransport).

+	// A safe value for this is typically 1400 bytes (which is the default). However,

+	// depending on your network's MTU (Maximum Transmission Unit) you may

+	// be able to increase this to get more content into each gossip packet.

+	PacketBufferSize int

+

+	// StatsPrintPeriod the period to use to print queue stats

+	// Default is 5min

+	StatsPrintPeriod time.Duration

+

+	// HealthPrintPeriod the period to use to print the health score

+	// Default is 1min

+	HealthPrintPeriod time.Duration

 }

 // entry defines a table entry

@@ -171,6 +196,18 @@ type entry struct {

 	reapTime time.Duration

 }

+// DefaultConfig returns a NetworkDB config with default values

+func DefaultConfig() *Config {

+	hostname, _ := os.Hostname()

+	return &Config{

+		NodeName:          hostname,

+		BindAddr:          "0.0.0.0",

+		PacketBufferSize:  1400,

+		StatsPrintPeriod:  5 * time.Minute,

+		HealthPrintPeriod: 1 * time.Minute,

+	}

+}

+

 // New creates a new instance of NetworkDB using the Config passed by

 // the caller.

 func New(c *Config) (*NetworkDB, error) {

@@ -200,6 +237,7 @@ func New(c *Config) (*NetworkDB, error) {

 // instances passed by the caller in the form of addr:port

 func (nDB *NetworkDB) Join(members []string) error {

 	nDB.Lock()

+	nDB.bootStrapIP = make([]net.IP, 0, len(members))

 	for _, m := range members {

 		nDB.bootStrapIP = append(nDB.bootStrapIP, net.ParseIP(m))

 	}

@@ -481,9 +519,8 @@ func (nDB *NetworkDB) JoinNetwork(nid string) error {

 	nodeNetworks[nid].tableBroadcasts = &memberlist.TransmitLimitedQueue{

 		NumNodes: func() int {

 			nDB.RLock()

-			num := len(nDB.networkNodes[nid])

-			nDB.RUnlock()

-			return num

+			defer nDB.RUnlock()

+			return len(nDB.networkNodes[nid])

 		},

 		RetransmitMult: 4,

 	}

@@ -30,10 +30,10 @@ func TestMain(m *testing.M) {

 func createNetworkDBInstances(t *testing.T, num int, namePrefix string) []*NetworkDB {

 	var dbs []*NetworkDB

 	for i := 0; i < num; i++ {

-		db, err := New(&Config{

-			NodeName: fmt.Sprintf("%s%d", namePrefix, i+1),

-			BindPort: int(atomic.AddInt32(&dbPort, 1)),

-		})

+		conf := DefaultConfig()

+		conf.NodeName = fmt.Sprintf("%s%d", namePrefix, i+1)

+		conf.BindPort = int(atomic.AddInt32(&dbPort, 1))

+		db, err := New(conf)

 		require.NoError(t, err)

 		if i != 0 {