diff --git a/Godeps/Godeps.json b/Godeps/Godeps.json
index 38b0ec272..84f4b4c60 100644
--- a/Godeps/Godeps.json
+++ b/Godeps/Godeps.json
@@ -1,6 +1,6 @@
 {
 	"ImportPath": "github.com/jbenet/go-ipfs",
-	"GoVersion": "go1.3",
+	"GoVersion": "devel +ffe33f1f1f17 Tue Nov 25 15:41:33 2014 +1100",
 	"Packages": [
 		"./..."
 	],
diff --git a/exchange/bitswap/bitswap.go b/exchange/bitswap/bitswap.go
index 64f293528..1e0e86b61 100644
--- a/exchange/bitswap/bitswap.go
+++ b/exchange/bitswap/bitswap.go
@@ -15,6 +15,7 @@ import (
 	bsnet "github.com/jbenet/go-ipfs/exchange/bitswap/network"
 	notifications "github.com/jbenet/go-ipfs/exchange/bitswap/notifications"
 	strategy "github.com/jbenet/go-ipfs/exchange/bitswap/strategy"
+	wl "github.com/jbenet/go-ipfs/exchange/bitswap/wantlist"
 	peer "github.com/jbenet/go-ipfs/peer"
 	u "github.com/jbenet/go-ipfs/util"
 	eventlog "github.com/jbenet/go-ipfs/util/eventlog"
@@ -29,6 +30,8 @@ const maxProvidersPerRequest = 3
 const providerRequestTimeout = time.Second * 10
 const hasBlockTimeout = time.Second * 15
 
+const roundTime = time.Second / 2
+
 // New initializes a BitSwap instance that communicates over the
 // provided BitSwapNetwork. This function registers the returned instance as
 // the network delegate.
@@ -41,6 +44,7 @@ func New(parent context.Context, p peer.Peer, network bsnet.BitSwapNetwork, rout
 	notif := notifications.New()
 	go func() {
 		<-ctx.Done()
+		cancelFunc()
 		notif.Shutdown()
 	}()
 
@@ -51,11 +55,12 @@ func New(parent context.Context, p peer.Peer, network bsnet.BitSwapNetwork, rout
 		strategy:      strategy.New(nice),
 		routing:       routing,
 		sender:        network,
-		wantlist:      u.NewKeySet(),
+		wantlist:      wl.NewWantlist(),
 		batchRequests: make(chan []u.Key, 32),
 	}
 	network.SetDelegate(bs)
 	go bs.loop(ctx)
+	go bs.roundWorker(ctx)
 
 	return bs
 }
@@ -85,7 +90,7 @@ type bitswap struct {
 	// TODO(brian): save the strategy's state to the datastore
 	strategy strategy.Strategy
 
-	wantlist u.KeySet
+	wantlist *wl.Wantlist
 
 	// cancelFunc signals cancellation to the bitswap event loop
 	cancelFunc func()
@@ -166,8 +171,8 @@ func (bs *bitswap) sendWantListTo(ctx context.Context, peers <-chan peer.Peer) e
 		panic("Cant send wantlist to nil peerchan")
 	}
 	message := bsmsg.New()
-	for _, wanted := range bs.wantlist.Keys() {
-		message.AddWanted(wanted)
+	for _, wanted := range bs.wantlist.Entries() {
+		message.AddEntry(wanted.Value, wanted.Priority, false)
 	}
 	for peerToQuery := range peers {
 		log.Debug("sending query to: %s", peerToQuery)
@@ -195,9 +200,9 @@ func (bs *bitswap) sendWantListTo(ctx context.Context, peers <-chan peer.Peer) e
 	return nil
 }
 
-func (bs *bitswap) sendWantlistToProviders(ctx context.Context, ks []u.Key) {
+func (bs *bitswap) sendWantlistToProviders(ctx context.Context, wantlist *wl.Wantlist) {
 	wg := sync.WaitGroup{}
-	for _, k := range ks {
+	for _, e := range wantlist.Entries() {
 		wg.Add(1)
 		go func(k u.Key) {
 			child, _ := context.WithTimeout(ctx, providerRequestTimeout)
@@ -208,11 +213,44 @@ func (bs *bitswap) sendWantlistToProviders(ctx context.Context, ks []u.Key) {
 				log.Errorf("error sending wantlist: %s", err)
 			}
 			wg.Done()
-		}(k)
+		}(e.Value)
 	}
 	wg.Wait()
 }
 
+func (bs *bitswap) roundWorker(ctx context.Context) {
+	roundTicker := time.NewTicker(roundTime)
+	bandwidthPerRound := 500000
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-roundTicker.C:
+			alloc, err := bs.strategy.GetAllocation(bandwidthPerRound, bs.blockstore)
+			if err != nil {
+				log.Critical("%s", err)
+			}
+			//log.Errorf("Allocation: %v", alloc)
+			bs.processStrategyAllocation(ctx, alloc)
+		}
+	}
+}
+
+func (bs *bitswap) processStrategyAllocation(ctx context.Context, alloc []*strategy.Task) {
+	for _, t := range alloc {
+		for _, block := range t.Blocks {
+			message := bsmsg.New()
+			message.AddBlock(block)
+			for _, wanted := range bs.wantlist.Entries() {
+				message.AddEntry(wanted.Value, wanted.Priority, false)
+			}
+			if err := bs.send(ctx, t.Peer, message); err != nil {
+				log.Errorf("Message Send Failed: %s", err)
+			}
+		}
+	}
+}
+
 // TODO ensure only one active request per key
 func (bs *bitswap) loop(parent context.Context) {
 
@@ -228,7 +266,7 @@ func (bs *bitswap) loop(parent context.Context) {
 		select {
 		case <-broadcastSignal.C:
 			// Resend unfulfilled wantlist keys
-			bs.sendWantlistToProviders(ctx, bs.wantlist.Keys())
+			bs.sendWantlistToProviders(ctx, bs.wantlist)
 		case ks := <-bs.batchRequests:
 			// TODO: implement batching on len(ks) > X for some X
 			//		i.e. if given 20 keys, fetch first five, then next
@@ -239,7 +277,7 @@ func (bs *bitswap) loop(parent context.Context) {
 				continue
 			}
 			for _, k := range ks {
-				bs.wantlist.Add(k)
+				bs.wantlist.Add(k, 1)
 			}
 			// NB: send want list to providers for the first peer in this list.
 			//		the assumption is made that the providers of the first key in
@@ -277,45 +315,41 @@ func (bs *bitswap) ReceiveMessage(ctx context.Context, p peer.Peer, incoming bsm
 		return nil, nil
 	}
 
-	// Record message bytes in ledger
-	// TODO: this is bad, and could be easily abused.
-	// Should only track *useful* messages in ledger
 	// This call records changes to wantlists, blocks received,
 	// and number of bytes transfered.
 	bs.strategy.MessageReceived(p, incoming)
+	// TODO: this is bad, and could be easily abused.
+	// Should only track *useful* messages in ledger
 
+	var blkeys []u.Key
 	for _, block := range incoming.Blocks() {
+		blkeys = append(blkeys, block.Key())
 		if err := bs.HasBlock(ctx, block); err != nil {
 			log.Error(err)
 		}
 	}
-
-	for _, key := range incoming.Wantlist() {
-		if bs.strategy.ShouldSendBlockToPeer(key, p) {
-			if block, errBlockNotFound := bs.blockstore.Get(key); errBlockNotFound != nil {
-				continue
-			} else {
-				// Create a separate message to send this block in
-				blkmsg := bsmsg.New()
-
-				// TODO: only send this the first time
-				//		no sense in sending our wantlist to the
-				//		same peer multiple times
-				for _, k := range bs.wantlist.Keys() {
-					blkmsg.AddWanted(k)
-				}
-
-				blkmsg.AddBlock(block)
-				bs.send(ctx, p, blkmsg)
-				bs.strategy.BlockSentToPeer(block.Key(), p)
-			}
-		}
+	if len(blkeys) > 0 {
+		bs.cancelBlocks(ctx, blkeys)
 	}
 
 	// TODO: consider changing this function to not return anything
 	return nil, nil
 }
 
+func (bs *bitswap) cancelBlocks(ctx context.Context, bkeys []u.Key) {
+	message := bsmsg.New()
+	message.SetFull(false)
+	for _, k := range bkeys {
+		message.AddEntry(k, 0, true)
+	}
+	for _, p := range bs.strategy.Peers() {
+		err := bs.send(ctx, p, message)
+		if err != nil {
+			log.Errorf("Error sending message: %s", err)
+		}
+	}
+}
+
 func (bs *bitswap) ReceiveError(err error) {
 	log.Errorf("Bitswap ReceiveError: %s", err)
 	// TODO log the network error
@@ -337,8 +371,8 @@ func (bs *bitswap) sendToPeersThatWant(ctx context.Context, block *blocks.Block)
 			if bs.strategy.ShouldSendBlockToPeer(block.Key(), p) {
 				message := bsmsg.New()
 				message.AddBlock(block)
-				for _, wanted := range bs.wantlist.Keys() {
-					message.AddWanted(wanted)
+				for _, wanted := range bs.wantlist.Entries() {
+					message.AddEntry(wanted.Value, wanted.Priority, false)
 				}
 				if err := bs.send(ctx, p, message); err != nil {
 					return err
diff --git a/exchange/bitswap/bitswap_test.go b/exchange/bitswap/bitswap_test.go
index d58ff596a..0e72883cc 100644
--- a/exchange/bitswap/bitswap_test.go
+++ b/exchange/bitswap/bitswap_test.go
@@ -11,6 +11,7 @@ import (
 	blocksutil "github.com/jbenet/go-ipfs/blocks/blocksutil"
 	tn "github.com/jbenet/go-ipfs/exchange/bitswap/testnet"
 	mockrouting "github.com/jbenet/go-ipfs/routing/mock"
+	u "github.com/jbenet/go-ipfs/util"
 	delay "github.com/jbenet/go-ipfs/util/delay"
 	testutil "github.com/jbenet/go-ipfs/util/testutil"
 )
@@ -25,6 +26,7 @@ func TestClose(t *testing.T) {
 	vnet := tn.VirtualNetwork(delay.Fixed(kNetworkDelay))
 	rout := mockrouting.NewServer()
 	sesgen := NewSessionGenerator(vnet, rout)
+	defer sesgen.Stop()
 	bgen := blocksutil.NewBlockGenerator()
 
 	block := bgen.Next()
@@ -39,6 +41,7 @@ func TestGetBlockTimeout(t *testing.T) {
 	net := tn.VirtualNetwork(delay.Fixed(kNetworkDelay))
 	rs := mockrouting.NewServer()
 	g := NewSessionGenerator(net, rs)
+	defer g.Stop()
 
 	self := g.Next()
 
@@ -56,11 +59,13 @@ func TestProviderForKeyButNetworkCannotFind(t *testing.T) {
 	net := tn.VirtualNetwork(delay.Fixed(kNetworkDelay))
 	rs := mockrouting.NewServer()
 	g := NewSessionGenerator(net, rs)
+	defer g.Stop()
 
 	block := blocks.NewBlock([]byte("block"))
 	rs.Client(testutil.NewPeerWithIDString("testing")).Provide(context.Background(), block.Key()) // but not on network
 
 	solo := g.Next()
+	defer solo.Exchange.Close()
 
 	ctx, _ := context.WithTimeout(context.Background(), time.Nanosecond)
 	_, err := solo.Exchange.GetBlock(ctx, block.Key())
@@ -78,8 +83,10 @@ func TestGetBlockFromPeerAfterPeerAnnounces(t *testing.T) {
 	rs := mockrouting.NewServer()
 	block := blocks.NewBlock([]byte("block"))
 	g := NewSessionGenerator(net, rs)
+	defer g.Stop()
 
 	hasBlock := g.Next()
+	defer hasBlock.Exchange.Close()
 
 	if err := hasBlock.Blockstore().Put(block); err != nil {
 		t.Fatal(err)
@@ -89,6 +96,7 @@ func TestGetBlockFromPeerAfterPeerAnnounces(t *testing.T) {
 	}
 
 	wantsBlock := g.Next()
+	defer wantsBlock.Exchange.Close()
 
 	ctx, _ := context.WithTimeout(context.Background(), time.Second)
 	received, err := wantsBlock.Exchange.GetBlock(ctx, block.Key())
@@ -107,7 +115,7 @@ func TestLargeSwarm(t *testing.T) {
 		t.SkipNow()
 	}
 	t.Parallel()
-	numInstances := 5
+	numInstances := 500
 	numBlocks := 2
 	PerformDistributionTest(t, numInstances, numBlocks)
 }
@@ -129,6 +137,7 @@ func PerformDistributionTest(t *testing.T, numInstances, numBlocks int) {
 	net := tn.VirtualNetwork(delay.Fixed(kNetworkDelay))
 	rs := mockrouting.NewServer()
 	sg := NewSessionGenerator(net, rs)
+	defer sg.Stop()
 	bg := blocksutil.NewBlockGenerator()
 
 	t.Log("Test a few nodes trying to get one file with a lot of blocks")
@@ -138,24 +147,29 @@ func PerformDistributionTest(t *testing.T, numInstances, numBlocks int) {
 
 	t.Log("Give the blocks to the first instance")
 
+	var blkeys []u.Key
 	first := instances[0]
 	for _, b := range blocks {
 		first.Blockstore().Put(b)
+		blkeys = append(blkeys, b.Key())
 		first.Exchange.HasBlock(context.Background(), b)
 		rs.Client(first.Peer).Provide(context.Background(), b.Key())
 	}
 
 	t.Log("Distribute!")
 
-	var wg sync.WaitGroup
-
+	wg := sync.WaitGroup{}
 	for _, inst := range instances {
-		for _, b := range blocks {
-			wg.Add(1)
-			// NB: executing getOrFail concurrently puts tremendous pressure on
-			// the goroutine scheduler
-			getOrFail(inst, b, t, &wg)
-		}
+		wg.Add(1)
+		go func(inst Instance) {
+			defer wg.Done()
+			outch, err := inst.Exchange.GetBlocks(context.TODO(), blkeys)
+			if err != nil {
+				t.Fatal(err)
+			}
+			for _ = range outch {
+			}
+		}(inst)
 	}
 	wg.Wait()
 
@@ -189,6 +203,7 @@ func TestSendToWantingPeer(t *testing.T) {
 	net := tn.VirtualNetwork(delay.Fixed(kNetworkDelay))
 	rs := mockrouting.NewServer()
 	sg := NewSessionGenerator(net, rs)
+	defer sg.Stop()
 	bg := blocksutil.NewBlockGenerator()
 
 	me := sg.Next()
@@ -201,7 +216,7 @@ func TestSendToWantingPeer(t *testing.T) {
 
 	alpha := bg.Next()
 
-	const timeout = 100 * time.Millisecond // FIXME don't depend on time
+	const timeout = 1000 * time.Millisecond // FIXME don't depend on time
 
 	t.Logf("Peer %v attempts to get %v. NB: not available\n", w.Peer, alpha.Key())
 	ctx, _ := context.WithTimeout(context.Background(), timeout)
@@ -246,3 +261,33 @@ func TestSendToWantingPeer(t *testing.T) {
 		t.Fatal("Expected to receive alpha from me")
 	}
 }
+
+func TestBasicBitswap(t *testing.T) {
+	net := tn.VirtualNetwork(delay.Fixed(kNetworkDelay))
+	rs := mockrouting.NewServer()
+	sg := NewSessionGenerator(net, rs)
+	bg := blocksutil.NewBlockGenerator()
+
+	t.Log("Test a few nodes trying to get one file with a lot of blocks")
+
+	instances := sg.Instances(2)
+	blocks := bg.Blocks(1)
+	err := instances[0].Exchange.HasBlock(context.TODO(), blocks[0])
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ctx, _ := context.WithTimeout(context.TODO(), time.Second*5)
+	blk, err := instances[1].Exchange.GetBlock(ctx, blocks[0].Key())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Log(blk)
+	for _, inst := range instances {
+		err := inst.Exchange.Close()
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+}
diff --git a/exchange/bitswap/message/internal/pb/message.pb.go b/exchange/bitswap/message/internal/pb/message.pb.go
index f6f8a9bbc..4ddfc56f7 100644
--- a/exchange/bitswap/message/internal/pb/message.pb.go
+++ b/exchange/bitswap/message/internal/pb/message.pb.go
@@ -21,16 +21,16 @@ var _ = proto.Marshal
 var _ = math.Inf
 
 type Message struct {
-	Wantlist         []string `protobuf:"bytes,1,rep,name=wantlist" json:"wantlist,omitempty"`
-	Blocks           [][]byte `protobuf:"bytes,2,rep,name=blocks" json:"blocks,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	Wantlist         *Message_Wantlist `protobuf:"bytes,1,opt,name=wantlist" json:"wantlist,omitempty"`
+	Blocks           [][]byte          `protobuf:"bytes,2,rep,name=blocks" json:"blocks,omitempty"`
+	XXX_unrecognized []byte            `json:"-"`
 }
 
 func (m *Message) Reset()         { *m = Message{} }
 func (m *Message) String() string { return proto.CompactTextString(m) }
 func (*Message) ProtoMessage()    {}
 
-func (m *Message) GetWantlist() []string {
+func (m *Message) GetWantlist() *Message_Wantlist {
 	if m != nil {
 		return m.Wantlist
 	}
@@ -44,5 +44,61 @@ func (m *Message) GetBlocks() [][]byte {
 	return nil
 }
 
+type Message_Wantlist struct {
+	Entries          []*Message_Wantlist_Entry `protobuf:"bytes,1,rep,name=entries" json:"entries,omitempty"`
+	Full             *bool                     `protobuf:"varint,2,opt,name=full" json:"full,omitempty"`
+	XXX_unrecognized []byte                    `json:"-"`
+}
+
+func (m *Message_Wantlist) Reset()         { *m = Message_Wantlist{} }
+func (m *Message_Wantlist) String() string { return proto.CompactTextString(m) }
+func (*Message_Wantlist) ProtoMessage()    {}
+
+func (m *Message_Wantlist) GetEntries() []*Message_Wantlist_Entry {
+	if m != nil {
+		return m.Entries
+	}
+	return nil
+}
+
+func (m *Message_Wantlist) GetFull() bool {
+	if m != nil && m.Full != nil {
+		return *m.Full
+	}
+	return false
+}
+
+type Message_Wantlist_Entry struct {
+	Block            *string `protobuf:"bytes,1,opt,name=block" json:"block,omitempty"`
+	Priority         *int32  `protobuf:"varint,2,opt,name=priority" json:"priority,omitempty"`
+	Cancel           *bool   `protobuf:"varint,3,opt,name=cancel" json:"cancel,omitempty"`
+	XXX_unrecognized []byte  `json:"-"`
+}
+
+func (m *Message_Wantlist_Entry) Reset()         { *m = Message_Wantlist_Entry{} }
+func (m *Message_Wantlist_Entry) String() string { return proto.CompactTextString(m) }
+func (*Message_Wantlist_Entry) ProtoMessage()    {}
+
+func (m *Message_Wantlist_Entry) GetBlock() string {
+	if m != nil && m.Block != nil {
+		return *m.Block
+	}
+	return ""
+}
+
+func (m *Message_Wantlist_Entry) GetPriority() int32 {
+	if m != nil && m.Priority != nil {
+		return *m.Priority
+	}
+	return 0
+}
+
+func (m *Message_Wantlist_Entry) GetCancel() bool {
+	if m != nil && m.Cancel != nil {
+		return *m.Cancel
+	}
+	return false
+}
+
 func init() {
 }
diff --git a/exchange/bitswap/message/internal/pb/message.proto b/exchange/bitswap/message/internal/pb/message.proto
index a8c6c7252..7c44f3a6b 100644
--- a/exchange/bitswap/message/internal/pb/message.proto
+++ b/exchange/bitswap/message/internal/pb/message.proto
@@ -1,6 +1,19 @@
 package bitswap.message.pb;
 
 message Message {
-	repeated string wantlist = 1;
-	repeated bytes blocks = 2;
+
+  message Wantlist {
+
+    message Entry {
+      optional string block = 1; // the block key
+      optional int32 priority = 2; // the priority (normalized). default to 1
+      optional bool cancel = 3;  // whether this revokes an entry
+    }
+
+    repeated Entry entries = 1; // a list of wantlist entries
+    optional bool full = 2;     // whether this is the full wantlist. default to false
+  }
+
+  optional Wantlist wantlist = 1;
+  repeated bytes blocks = 2;
 }
diff --git a/exchange/bitswap/message/message.go b/exchange/bitswap/message/message.go
index 62a39be91..288fc9da7 100644
--- a/exchange/bitswap/message/message.go
+++ b/exchange/bitswap/message/message.go
@@ -9,6 +9,7 @@ import (
 	u "github.com/jbenet/go-ipfs/util"
 
 	ggio "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/gogoprotobuf/io"
+	proto "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/goprotobuf/proto"
 )
 
 // TODO move message.go into the bitswap package
@@ -17,21 +18,21 @@ import (
 type BitSwapMessage interface {
 	// Wantlist returns a slice of unique keys that represent data wanted by
 	// the sender.
-	Wantlist() []u.Key
+	Wantlist() []*Entry
 
 	// Blocks returns a slice of unique blocks
 	Blocks() []*blocks.Block
 
-	// AddWanted adds the key to the Wantlist.
-	//
-	// Insertion order determines priority. That is, earlier insertions are
-	// deemed higher priority than keys inserted later.
-	//
-	// t = 0, msg.AddWanted(A)
-	// t = 1, msg.AddWanted(B)
-	//
-	// implies Priority(A) > Priority(B)
-	AddWanted(u.Key)
+	// AddEntry adds an entry to the Wantlist.
+	AddEntry(u.Key, int, bool)
+
+	// Sets whether or not the contained wantlist represents the entire wantlist
+	// true = full wantlist
+	// false = wantlist 'patch'
+	// default: true
+	SetFull(bool)
+
+	Full() bool
 
 	AddBlock(*blocks.Block)
 	Exportable
@@ -43,23 +44,30 @@ type Exportable interface {
 }
 
 type impl struct {
-	existsInWantlist map[u.Key]struct{}      // map to detect duplicates
-	wantlist         []u.Key                 // slice to preserve ordering
-	blocks           map[u.Key]*blocks.Block // map to detect duplicates
+	full     bool
+	wantlist map[u.Key]*Entry
+	blocks   map[u.Key]*blocks.Block // map to detect duplicates
 }
 
 func New() BitSwapMessage {
 	return &impl{
-		blocks:           make(map[u.Key]*blocks.Block),
-		existsInWantlist: make(map[u.Key]struct{}),
-		wantlist:         make([]u.Key, 0),
+		blocks:   make(map[u.Key]*blocks.Block),
+		wantlist: make(map[u.Key]*Entry),
+		full:     true,
 	}
 }
 
+type Entry struct {
+	Key      u.Key
+	Priority int
+	Cancel   bool
+}
+
 func newMessageFromProto(pbm pb.Message) BitSwapMessage {
 	m := New()
-	for _, s := range pbm.GetWantlist() {
-		m.AddWanted(u.Key(s))
+	m.SetFull(pbm.GetWantlist().GetFull())
+	for _, e := range pbm.GetWantlist().GetEntries() {
+		m.AddEntry(u.Key(e.GetBlock()), int(e.GetPriority()), e.GetCancel())
 	}
 	for _, d := range pbm.GetBlocks() {
 		b := blocks.NewBlock(d)
@@ -68,8 +76,20 @@ func newMessageFromProto(pbm pb.Message) BitSwapMessage {
 	return m
 }
 
-func (m *impl) Wantlist() []u.Key {
-	return m.wantlist
+func (m *impl) SetFull(full bool) {
+	m.full = full
+}
+
+func (m *impl) Full() bool {
+	return m.full
+}
+
+func (m *impl) Wantlist() []*Entry {
+	var out []*Entry
+	for _, e := range m.wantlist {
+		out = append(out, e)
+	}
+	return out
 }
 
 func (m *impl) Blocks() []*blocks.Block {
@@ -80,13 +100,18 @@ func (m *impl) Blocks() []*blocks.Block {
 	return bs
 }
 
-func (m *impl) AddWanted(k u.Key) {
-	_, exists := m.existsInWantlist[k]
+func (m *impl) AddEntry(k u.Key, priority int, cancel bool) {
+	e, exists := m.wantlist[k]
 	if exists {
-		return
+		e.Priority = priority
+		e.Cancel = cancel
+	} else {
+		m.wantlist[k] = &Entry{
+			Key:      k,
+			Priority: priority,
+			Cancel:   cancel,
+		}
 	}
-	m.existsInWantlist[k] = struct{}{}
-	m.wantlist = append(m.wantlist, k)
 }
 
 func (m *impl) AddBlock(b *blocks.Block) {
@@ -106,14 +131,19 @@ func FromNet(r io.Reader) (BitSwapMessage, error) {
 }
 
 func (m *impl) ToProto() *pb.Message {
-	pb := new(pb.Message)
-	for _, k := range m.Wantlist() {
-		pb.Wantlist = append(pb.Wantlist, string(k))
+	pbm := new(pb.Message)
+	pbm.Wantlist = new(pb.Message_Wantlist)
+	for _, e := range m.wantlist {
+		pbm.Wantlist.Entries = append(pbm.Wantlist.Entries, &pb.Message_Wantlist_Entry{
+			Block:    proto.String(string(e.Key)),
+			Priority: proto.Int32(int32(e.Priority)),
+			Cancel:   &e.Cancel,
+		})
 	}
 	for _, b := range m.Blocks() {
-		pb.Blocks = append(pb.Blocks, b.Data)
+		pbm.Blocks = append(pbm.Blocks, b.Data)
 	}
-	return pb
+	return pbm
 }
 
 func (m *impl) ToNet(w io.Writer) error {
diff --git a/exchange/bitswap/message/message_test.go b/exchange/bitswap/message/message_test.go
index 681b60a6f..29eb6eb4e 100644
--- a/exchange/bitswap/message/message_test.go
+++ b/exchange/bitswap/message/message_test.go
@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"testing"
 
+	proto "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/goprotobuf/proto"
+
 	blocks "github.com/jbenet/go-ipfs/blocks"
 	pb "github.com/jbenet/go-ipfs/exchange/bitswap/message/internal/pb"
 	u "github.com/jbenet/go-ipfs/util"
@@ -12,22 +14,26 @@ import (
 func TestAppendWanted(t *testing.T) {
 	const str = "foo"
 	m := New()
-	m.AddWanted(u.Key(str))
+	m.AddEntry(u.Key(str), 1, false)
 
-	if !contains(m.ToProto().GetWantlist(), str) {
+	if !wantlistContains(m.ToProto().GetWantlist(), str) {
 		t.Fail()
 	}
+	m.ToProto().GetWantlist().GetEntries()
 }
 
 func TestNewMessageFromProto(t *testing.T) {
 	const str = "a_key"
 	protoMessage := new(pb.Message)
-	protoMessage.Wantlist = []string{string(str)}
-	if !contains(protoMessage.Wantlist, str) {
+	protoMessage.Wantlist = new(pb.Message_Wantlist)
+	protoMessage.Wantlist.Entries = []*pb.Message_Wantlist_Entry{
+		&pb.Message_Wantlist_Entry{Block: proto.String(str)},
+	}
+	if !wantlistContains(protoMessage.Wantlist, str) {
 		t.Fail()
 	}
 	m := newMessageFromProto(*protoMessage)
-	if !contains(m.ToProto().GetWantlist(), str) {
+	if !wantlistContains(m.ToProto().GetWantlist(), str) {
 		t.Fail()
 	}
 }
@@ -57,7 +63,7 @@ func TestWantlist(t *testing.T) {
 	keystrs := []string{"foo", "bar", "baz", "bat"}
 	m := New()
 	for _, s := range keystrs {
-		m.AddWanted(u.Key(s))
+		m.AddEntry(u.Key(s), 1, false)
 	}
 	exported := m.Wantlist()
 
@@ -65,12 +71,12 @@ func TestWantlist(t *testing.T) {
 		present := false
 		for _, s := range keystrs {
 
-			if s == string(k) {
+			if s == string(k.Key) {
 				present = true
 			}
 		}
 		if !present {
-			t.Logf("%v isn't in original list", string(k))
+			t.Logf("%v isn't in original list", k.Key)
 			t.Fail()
 		}
 	}
@@ -80,19 +86,19 @@ func TestCopyProtoByValue(t *testing.T) {
 	const str = "foo"
 	m := New()
 	protoBeforeAppend := m.ToProto()
-	m.AddWanted(u.Key(str))
-	if contains(protoBeforeAppend.GetWantlist(), str) {
+	m.AddEntry(u.Key(str), 1, false)
+	if wantlistContains(protoBeforeAppend.GetWantlist(), str) {
 		t.Fail()
 	}
 }
 
 func TestToNetFromNetPreservesWantList(t *testing.T) {
 	original := New()
-	original.AddWanted(u.Key("M"))
-	original.AddWanted(u.Key("B"))
-	original.AddWanted(u.Key("D"))
-	original.AddWanted(u.Key("T"))
-	original.AddWanted(u.Key("F"))
+	original.AddEntry(u.Key("M"), 1, false)
+	original.AddEntry(u.Key("B"), 1, false)
+	original.AddEntry(u.Key("D"), 1, false)
+	original.AddEntry(u.Key("T"), 1, false)
+	original.AddEntry(u.Key("F"), 1, false)
 
 	var buf bytes.Buffer
 	if err := original.ToNet(&buf); err != nil {
@@ -106,11 +112,11 @@ func TestToNetFromNetPreservesWantList(t *testing.T) {
 
 	keys := make(map[u.Key]bool)
 	for _, k := range copied.Wantlist() {
-		keys[k] = true
+		keys[k.Key] = true
 	}
 
 	for _, k := range original.Wantlist() {
-		if _, ok := keys[k]; !ok {
+		if _, ok := keys[k.Key]; !ok {
 			t.Fatalf("Key Missing: \"%v\"", k)
 		}
 	}
@@ -146,9 +152,18 @@ func TestToAndFromNetMessage(t *testing.T) {
 	}
 }
 
-func contains(s []string, x string) bool {
-	for _, a := range s {
-		if a == x {
+func wantlistContains(wantlist *pb.Message_Wantlist, x string) bool {
+	for _, e := range wantlist.GetEntries() {
+		if e.GetBlock() == x {
+			return true
+		}
+	}
+	return false
+}
+
+func contains(strs []string, x string) bool {
+	for _, s := range strs {
+		if s == x {
 			return true
 		}
 	}
@@ -159,8 +174,8 @@ func TestDuplicates(t *testing.T) {
 	b := blocks.NewBlock([]byte("foo"))
 	msg := New()
 
-	msg.AddWanted(b.Key())
-	msg.AddWanted(b.Key())
+	msg.AddEntry(b.Key(), 1, false)
+	msg.AddEntry(b.Key(), 1, false)
 	if len(msg.Wantlist()) != 1 {
 		t.Fatal("Duplicate in BitSwapMessage")
 	}
diff --git a/exchange/bitswap/strategy/interface.go b/exchange/bitswap/strategy/interface.go
index 58385f5b7..c74b58c42 100644
--- a/exchange/bitswap/strategy/interface.go
+++ b/exchange/bitswap/strategy/interface.go
@@ -3,6 +3,7 @@ package strategy
 import (
 	"time"
 
+	bstore "github.com/jbenet/go-ipfs/blocks/blockstore"
 	bsmsg "github.com/jbenet/go-ipfs/exchange/bitswap/message"
 	peer "github.com/jbenet/go-ipfs/peer"
 	u "github.com/jbenet/go-ipfs/util"
@@ -34,6 +35,8 @@ type Strategy interface {
 
 	BlockSentToPeer(u.Key, peer.Peer)
 
+	GetAllocation(int, bstore.Blockstore) ([]*Task, error)
+
 	// Values determining bitswap behavioural patterns
 	GetBatchSize() int
 	GetRebroadcastDelay() time.Duration
diff --git a/exchange/bitswap/strategy/ledger.go b/exchange/bitswap/strategy/ledger.go
index 84e92d035..7ce7b73d9 100644
--- a/exchange/bitswap/strategy/ledger.go
+++ b/exchange/bitswap/strategy/ledger.go
@@ -3,6 +3,7 @@ package strategy
 import (
 	"time"
 
+	wl "github.com/jbenet/go-ipfs/exchange/bitswap/wantlist"
 	peer "github.com/jbenet/go-ipfs/peer"
 	u "github.com/jbenet/go-ipfs/util"
 )
@@ -13,7 +14,7 @@ type keySet map[u.Key]struct{}
 
 func newLedger(p peer.Peer, strategy strategyFunc) *ledger {
 	return &ledger{
-		wantList:   keySet{},
+		wantList:   wl.NewWantlist(),
 		Strategy:   strategy,
 		Partner:    p,
 		sentToPeer: make(map[u.Key]time.Time),
@@ -39,7 +40,7 @@ type ledger struct {
 	exchangeCount uint64
 
 	// wantList is a (bounded, small) set of keys that Partner desires.
-	wantList keySet
+	wantList *wl.Wantlist
 
 	// sentToPeer is a set of keys to ensure we dont send duplicate blocks
 	// to a given peer
@@ -65,14 +66,17 @@ func (l *ledger) ReceivedBytes(n int) {
 }
 
 // TODO: this needs to be different. We need timeouts.
-func (l *ledger) Wants(k u.Key) {
+func (l *ledger) Wants(k u.Key, priority int) {
 	log.Debugf("peer %s wants %s", l.Partner, k)
-	l.wantList[k] = struct{}{}
+	l.wantList.Add(k, priority)
+}
+
+func (l *ledger) CancelWant(k u.Key) {
+	l.wantList.Remove(k)
 }
 
 func (l *ledger) WantListContains(k u.Key) bool {
-	_, ok := l.wantList[k]
-	return ok
+	return l.wantList.Contains(k)
 }
 
 func (l *ledger) ExchangeCount() uint64 {
diff --git a/exchange/bitswap/strategy/strategy.go b/exchange/bitswap/strategy/strategy.go
index fe7414caa..b21a3b2b1 100644
--- a/exchange/bitswap/strategy/strategy.go
+++ b/exchange/bitswap/strategy/strategy.go
@@ -5,7 +5,10 @@ import (
 	"sync"
 	"time"
 
+	blocks "github.com/jbenet/go-ipfs/blocks"
+	bstore "github.com/jbenet/go-ipfs/blocks/blockstore"
 	bsmsg "github.com/jbenet/go-ipfs/exchange/bitswap/message"
+	wl "github.com/jbenet/go-ipfs/exchange/bitswap/wantlist"
 	peer "github.com/jbenet/go-ipfs/peer"
 	u "github.com/jbenet/go-ipfs/util"
 )
@@ -77,6 +80,60 @@ func (s *strategist) ShouldSendBlockToPeer(k u.Key, p peer.Peer) bool {
 	return ledger.ShouldSend()
 }
 
+type Task struct {
+	Peer   peer.Peer
+	Blocks []*blocks.Block
+}
+
+func (s *strategist) GetAllocation(bandwidth int, bs bstore.Blockstore) ([]*Task, error) {
+	var tasks []*Task
+
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+	var partners []peer.Peer
+	for _, ledger := range s.ledgerMap {
+		if ledger.ShouldSend() {
+			partners = append(partners, ledger.Partner)
+		}
+	}
+	if len(partners) == 0 {
+		return nil, nil
+	}
+
+	bandwidthPerPeer := bandwidth / len(partners)
+	for _, p := range partners {
+		blksForPeer, err := s.getSendableBlocks(s.ledger(p).wantList, bs, bandwidthPerPeer)
+		if err != nil {
+			return nil, err
+		}
+		tasks = append(tasks, &Task{
+			Peer:   p,
+			Blocks: blksForPeer,
+		})
+	}
+
+	return tasks, nil
+}
+
+func (s *strategist) getSendableBlocks(wantlist *wl.Wantlist, bs bstore.Blockstore, bw int) ([]*blocks.Block, error) {
+	var outblocks []*blocks.Block
+	for _, e := range wantlist.Entries() {
+		block, err := bs.Get(e.Value)
+		if err == u.ErrNotFound {
+			continue
+		}
+		if err != nil {
+			return nil, err
+		}
+		outblocks = append(outblocks, block)
+		bw -= len(block.Data)
+		if bw <= 0 {
+			break
+		}
+	}
+	return outblocks, nil
+}
+
 func (s *strategist) BlockSentToPeer(k u.Key, p peer.Peer) {
 	s.lock.Lock()
 	defer s.lock.Unlock()
@@ -106,8 +163,15 @@ func (s *strategist) MessageReceived(p peer.Peer, m bsmsg.BitSwapMessage) error
 		return errors.New("Strategy received nil message")
 	}
 	l := s.ledger(p)
-	for _, key := range m.Wantlist() {
-		l.Wants(key)
+	if m.Full() {
+		l.wantList = wl.NewWantlist()
+	}
+	for _, e := range m.Wantlist() {
+		if e.Cancel {
+			l.CancelWant(e.Key)
+		} else {
+			l.Wants(e.Key, e.Priority)
+		}
 	}
 	for _, block := range m.Blocks() {
 		// FIXME extract blocks.NumBytes(block) or block.NumBytes() method
@@ -165,5 +229,5 @@ func (s *strategist) GetBatchSize() int {
 }
 
 func (s *strategist) GetRebroadcastDelay() time.Duration {
-	return time.Second * 5
+	return time.Second * 10
 }
diff --git a/exchange/bitswap/strategy/strategy_test.go b/exchange/bitswap/strategy/strategy_test.go
index e063dff68..687ea4d34 100644
--- a/exchange/bitswap/strategy/strategy_test.go
+++ b/exchange/bitswap/strategy/strategy_test.go
@@ -61,7 +61,7 @@ func TestBlockRecordedAsWantedAfterMessageReceived(t *testing.T) {
 	block := blocks.NewBlock([]byte("data wanted by beggar"))
 
 	messageFromBeggarToChooser := message.New()
-	messageFromBeggarToChooser.AddWanted(block.Key())
+	messageFromBeggarToChooser.AddEntry(block.Key(), 1, false)
 
 	chooser.MessageReceived(beggar.Peer, messageFromBeggarToChooser)
 	// for this test, doesn't matter if you record that beggar sent