diff --git a/eth/backend.go b/eth/backend.go
index 3fa10086a..c73e76792 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -138,11 +138,12 @@ type Ethereum struct {
 
 	// logger logger.LogSystem
 
-	Mining          bool
-	DataDir         string
-	version         string
-	protocolVersion int
-	networkId       int
+	Mining        bool
+	DataDir       string
+	clientVersion string
+	ethVersionId  int
+	netVersionId  int
+	shhVersionId  int
 }
 
 func New(config *Config) (*Ethereum, error) {
@@ -177,16 +178,16 @@ func New(config *Config) (*Ethereum, error) {
 	servlogger.Infof("Protocol Version: %v, Network Id: %v", config.ProtocolVersion, config.NetworkId)
 
 	eth := &Ethereum{
-		shutdownChan:    make(chan bool),
-		blockDb:         blockDb,
-		stateDb:         stateDb,
-		extraDb:         extraDb,
-		eventMux:        &event.TypeMux{},
-		accountManager:  config.AccountManager,
-		DataDir:         config.DataDir,
-		version:         config.Name, // TODO should separate from Name
-		protocolVersion: config.ProtocolVersion,
-		networkId:       config.NetworkId,
+		shutdownChan:   make(chan bool),
+		blockDb:        blockDb,
+		stateDb:        stateDb,
+		extraDb:        extraDb,
+		eventMux:       &event.TypeMux{},
+		accountManager: config.AccountManager,
+		DataDir:        config.DataDir,
+		clientVersion:  config.Name, // TODO should separate from Name
+		ethVersionId:   config.ProtocolVersion,
+		netVersionId:   config.NetworkId,
 	}
 
 	eth.chainManager = core.NewChainManager(blockDb, stateDb, eth.EventMux())
@@ -195,6 +196,7 @@ func New(config *Config) (*Ethereum, error) {
 	eth.blockProcessor = core.NewBlockProcessor(stateDb, extraDb, eth.pow, eth.txPool, eth.chainManager, eth.EventMux())
 	eth.chainManager.SetProcessor(eth.blockProcessor)
 	eth.whisper = whisper.New()
+	eth.shhVersionId = int(eth.whisper.Version())
 	eth.miner = miner.New(eth, eth.pow, config.MinerThreads)
 
 	hasBlock := eth.chainManager.HasBlock
@@ -324,9 +326,10 @@ func (s *Ethereum) IsListening() bool                    { return true } // Alwa
 func (s *Ethereum) PeerCount() int                       { return s.net.PeerCount() }
 func (s *Ethereum) Peers() []*p2p.Peer                   { return s.net.Peers() }
 func (s *Ethereum) MaxPeers() int                        { return s.net.MaxPeers }
-func (s *Ethereum) Version() string                      { return s.version }
-func (s *Ethereum) ProtocolVersion() int                 { return s.protocolVersion }
-func (s *Ethereum) NetworkId() int                       { return s.networkId }
+func (s *Ethereum) ClientVersion() string                { return s.clientVersion }
+func (s *Ethereum) EthVersion() int                      { return s.ethVersionId }
+func (s *Ethereum) NetVersion() int                      { return s.netVersionId }
+func (s *Ethereum) ShhVersion() int                      { return s.shhVersionId }
 
 // Start the ethereum
 func (s *Ethereum) Start() error {
diff --git a/rpc/api.go b/rpc/api.go
index 4bc199176..aa5b54199 100644
--- a/rpc/api.go
+++ b/rpc/api.go
@@ -49,7 +49,7 @@ func (api *EthereumApi) Close() {
 }
 
 func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) error {
-	// Spec at https://github.com/ethereum/wiki/wiki/Generic-JSON-RPC
+	// Spec at https://github.com/ethereum/wiki/wiki/JSON-RPC
 	rpclogger.Debugf("%s %s", req.Method, req.Params)
 
 	switch req.Method {
@@ -60,14 +60,16 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 		}
 		*reply = common.ToHex(crypto.Sha3(common.FromHex(args.Data)))
 	case "web3_clientVersion":
-		*reply = api.xeth().Backend().Version()
+		*reply = api.xeth().ClientVersion()
 	case "net_version":
-		*reply = string(api.xeth().Backend().ProtocolVersion())
+		*reply = api.xeth().NetworkVersion()
 	case "net_listening":
 		*reply = api.xeth().IsListening()
 	case "net_peerCount":
 		v := api.xeth().PeerCount()
 		*reply = common.ToHex(big.NewInt(int64(v)).Bytes())
+	case "eth_version":
+		*reply = api.xeth().EthVersion()
 	case "eth_coinbase":
 		// TODO handling of empty coinbase due to lack of accounts
 		res := api.xeth().Coinbase()
@@ -84,7 +86,7 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 	case "eth_accounts":
 		*reply = api.xeth().Accounts()
 	case "eth_blockNumber":
-		v := api.xeth().Backend().ChainManager().CurrentBlock().Number()
+		v := api.xeth().CurrentBlock().Number()
 		*reply = common.ToHex(v.Bytes())
 	case "eth_getBalance":
 		args := new(GetBalanceArgs)
@@ -406,6 +408,8 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 
 		res, _ := api.db.Get([]byte(args.Database + args.Key))
 		*reply = common.ToHex(res)
+	case "shh_version":
+		*reply = api.xeth().WhisperVersion()
 	case "shh_post":
 		args := new(WhisperMessageArgs)
 		if err := json.Unmarshal(req.Params, &args); err != nil {
diff --git a/whisper/whisper.go b/whisper/whisper.go
index dbd4fc85f..1d019aea5 100644
--- a/whisper/whisper.go
+++ b/whisper/whisper.go
@@ -16,8 +16,9 @@ import (
 )
 
 const (
-	statusMsg    = 0x0
-	envelopesMsg = 0x01
+	statusMsg      = 0x0
+	envelopesMsg   = 0x01
+	whisperVersion = 0x02
 )
 
 type MessageEvent struct {
@@ -56,7 +57,7 @@ func New() *Whisper {
 	// p2p whisper sub protocol handler
 	whisper.protocol = p2p.Protocol{
 		Name:    "shh",
-		Version: 2,
+		Version: uint(whisperVersion),
 		Length:  2,
 		Run:     whisper.msgHandler,
 	}
@@ -64,6 +65,10 @@ func New() *Whisper {
 	return whisper
 }
 
+func (self *Whisper) Version() uint {
+	return self.protocol.Version
+}
+
 func (self *Whisper) Start() {
 	wlogger.Infoln("Whisper started")
 	go self.update()
diff --git a/xeth/frontend.go b/xeth/frontend.go
new file mode 100644
index 000000000..8deb5c98c
--- /dev/null
+++ b/xeth/frontend.go
@@ -0,0 +1,32 @@
+package xeth
+
+import (
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+// Frontend should be implemented by users of XEth. Its methods are
+// called whenever XEth makes a decision that requires user input.
+type Frontend interface {
+	// UnlockAccount is called when a transaction needs to be signed
+	// but the key corresponding to the transaction's sender is
+	// locked.
+	//
+	// It should unlock the account with the given address and return
+	// true if unlocking succeeded.
+	UnlockAccount(address []byte) bool
+
+	// This is called for all transactions inititated through
+	// Transact. It should prompt the user to confirm the transaction
+	// and return true if the transaction was acknowledged.
+	//
+	// ConfirmTransaction is not used for Call transactions
+	// because they cannot change any state.
+	ConfirmTransaction(tx *types.Transaction) bool
+}
+
+// dummyFrontend is a non-interactive frontend that allows all
+// transactions but cannot not unlock any keys.
+type dummyFrontend struct{}
+
+func (dummyFrontend) UnlockAccount([]byte) bool                  { return false }
+func (dummyFrontend) ConfirmTransaction(*types.Transaction) bool { return true }
diff --git a/xeth/state.go b/xeth/state.go
index b0f2ce019..669cf91e6 100644
--- a/xeth/state.go
+++ b/xeth/state.go
@@ -29,7 +29,7 @@ func (self *State) SafeGet(addr string) *Object {
 func (self *State) safeGet(addr string) *state.StateObject {
 	object := self.state.GetStateObject(common.HexToAddress(addr))
 	if object == nil {
-		object = state.NewStateObject(common.HexToAddress(addr), self.xeth.eth.StateDb())
+		object = state.NewStateObject(common.HexToAddress(addr), self.xeth.backend.StateDb())
 	}
 
 	return object
diff --git a/xeth/xeth.go b/xeth/xeth.go
index 98f5f5b36..36c9979f4 100644
--- a/xeth/xeth.go
+++ b/xeth/xeth.go
@@ -15,12 +15,10 @@ import (
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
-	"github.com/ethereum/go-ethereum/event"
+	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/event/filter"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/miner"
-	"github.com/ethereum/go-ethereum/p2p"
-	"github.com/ethereum/go-ethereum/whisper"
 )
 
 var (
@@ -30,67 +28,13 @@ var (
 	defaultGas       = big.NewInt(90000)          //500000
 )
 
-// to resolve the import cycle
-type Backend interface {
-	BlockProcessor() *core.BlockProcessor
-	ChainManager() *core.ChainManager
-	AccountManager() *accounts.Manager
-	TxPool() *core.TxPool
-	PeerCount() int
-	IsListening() bool
-	Peers() []*p2p.Peer
-	BlockDb() common.Database
-	StateDb() common.Database
-	ExtraDb() common.Database
-	EventMux() *event.TypeMux
-	Whisper() *whisper.Whisper
-	Miner() *miner.Miner
-
-	IsMining() bool
-	StartMining() error
-	StopMining()
-	Version() string
-	ProtocolVersion() int
-	NetworkId() int
-}
-
-// Frontend should be implemented by users of XEth. Its methods are
-// called whenever XEth makes a decision that requires user input.
-type Frontend interface {
-	// UnlockAccount is called when a transaction needs to be signed
-	// but the key corresponding to the transaction's sender is
-	// locked.
-	//
-	// It should unlock the account with the given address and return
-	// true if unlocking succeeded.
-	UnlockAccount(address []byte) bool
-
-	// This is called for all transactions inititated through
-	// Transact. It should prompt the user to confirm the transaction
-	// and return true if the transaction was acknowledged.
-	//
-	// ConfirmTransaction is not used for Call transactions
-	// because they cannot change any state.
-	ConfirmTransaction(tx *types.Transaction) bool
-}
-
-// dummyFrontend is a non-interactive frontend that allows all
-// transactions but cannot not unlock any keys.
-type dummyFrontend struct{}
-
-func (dummyFrontend) UnlockAccount([]byte) bool                  { return false }
-func (dummyFrontend) ConfirmTransaction(*types.Transaction) bool { return true }
-
 type XEth struct {
-	eth            Backend
-	blockProcessor *core.BlockProcessor
-	chainManager   *core.ChainManager
-	accountManager *accounts.Manager
-	state          *State
-	whisper        *Whisper
-
+	backend  *eth.Ethereum
 	frontend Frontend
 
+	state   *State
+	whisper *Whisper
+
 	quit          chan struct{}
 	filterManager *filter.FilterManager
 
@@ -103,33 +47,30 @@ type XEth struct {
 	// regmut   sync.Mutex
 	// register map[string][]*interface{} // TODO improve return type
 
-	// Miner agent
 	agent *miner.RemoteAgent
 }
 
 // New creates an XEth that uses the given frontend.
 // If a nil Frontend is provided, a default frontend which
 // confirms all transactions will be used.
-func New(eth Backend, frontend Frontend) *XEth {
+func New(eth *eth.Ethereum, frontend Frontend) *XEth {
 	xeth := &XEth{
-		eth:            eth,
-		blockProcessor: eth.BlockProcessor(),
-		chainManager:   eth.ChainManager(),
-		accountManager: eth.AccountManager(),
-		whisper:        NewWhisper(eth.Whisper()),
-		quit:           make(chan struct{}),
-		filterManager:  filter.NewFilterManager(eth.EventMux()),
-		frontend:       frontend,
-		logs:           make(map[int]*logFilter),
-		messages:       make(map[int]*whisperFilter),
-		agent:          miner.NewRemoteAgent(),
+		backend:       eth,
+		frontend:      frontend,
+		whisper:       NewWhisper(eth.Whisper()),
+		quit:          make(chan struct{}),
+		filterManager: filter.NewFilterManager(eth.EventMux()),
+		logs:          make(map[int]*logFilter),
+		messages:      make(map[int]*whisperFilter),
+		agent:         miner.NewRemoteAgent(),
 	}
 	eth.Miner().Register(xeth.agent)
 
 	if frontend == nil {
 		xeth.frontend = dummyFrontend{}
 	}
-	xeth.state = NewState(xeth, xeth.chainManager.TransState())
+	xeth.state = NewState(xeth, xeth.backend.ChainManager().TransState())
+
 	go xeth.start()
 	go xeth.filterManager.Start()
 
@@ -175,58 +116,63 @@ func (self *XEth) DefaultGasPrice() *big.Int { return defaultGasPrice }
 func (self *XEth) RemoteMining() *miner.RemoteAgent { return self.agent }
 
 func (self *XEth) AtStateNum(num int64) *XEth {
-	chain := self.Backend().ChainManager()
-	var block *types.Block
-
-	// -1 generally means "latest"
-	// -2 means "pending", which has no blocknum
-	if num < 0 {
-		num = chain.CurrentBlock().Number().Int64()
-	}
-
-	block = chain.GetBlockByNumber(uint64(num))
+	block := self.getBlockByHeight(num)
 
 	var st *state.StateDB
 	if block != nil {
-		st = state.New(block.Root(), self.Backend().StateDb())
+		st = state.New(block.Root(), self.backend.StateDb())
 	} else {
-		st = chain.State()
+		st = self.backend.ChainManager().State()
 	}
-	return self.WithState(st)
+
+	return self.withState(st)
 }
 
-func (self *XEth) Backend() Backend { return self.eth }
-func (self *XEth) WithState(statedb *state.StateDB) *XEth {
+func (self *XEth) withState(statedb *state.StateDB) *XEth {
 	xeth := &XEth{
-		eth:            self.eth,
-		blockProcessor: self.blockProcessor,
-		chainManager:   self.chainManager,
-		whisper:        self.whisper,
+		backend: self.backend,
 	}
 
 	xeth.state = NewState(xeth, statedb)
 	return xeth
 }
+
 func (self *XEth) State() *State { return self.state }
 
 func (self *XEth) Whisper() *Whisper { return self.whisper }
 
+func (self *XEth) getBlockByHeight(height int64) *types.Block {
+	var num uint64
+
+	// -1 means "latest"
+	// -2 means "pending", which has no blocknum
+	if height <= -2 {
+		return &types.Block{}
+	} else if height == -1 {
+		num = self.CurrentBlock().NumberU64()
+	} else {
+		num = uint64(height)
+	}
+
+	return self.backend.ChainManager().GetBlockByNumber(num)
+}
+
 func (self *XEth) BlockByHash(strHash string) *Block {
 	hash := common.HexToHash(strHash)
-	block := self.chainManager.GetBlock(hash)
+	block := self.backend.ChainManager().GetBlock(hash)
 
 	return NewBlock(block)
 }
 
 func (self *XEth) EthBlockByHash(strHash string) *types.Block {
 	hash := common.HexToHash(strHash)
-	block := self.chainManager.GetBlock(hash)
+	block := self.backend.ChainManager().GetBlock(hash)
 
 	return block
 }
 
 func (self *XEth) EthTransactionByHash(hash string) *types.Transaction {
-	data, _ := self.eth.ExtraDb().Get(common.FromHex(hash))
+	data, _ := self.backend.ExtraDb().Get(common.FromHex(hash))
 	if len(data) != 0 {
 		return types.NewTransactionFromBytes(data)
 	}
@@ -234,29 +180,15 @@ func (self *XEth) EthTransactionByHash(hash string) *types.Transaction {
 }
 
 func (self *XEth) BlockByNumber(num int64) *Block {
-	if num == -2 {
-		// "pending" is non-existant
-		return &Block{}
-	}
-
-	if num == -1 {
-		return NewBlock(self.chainManager.CurrentBlock())
-	}
-
-	return NewBlock(self.chainManager.GetBlockByNumber(uint64(num)))
+	return NewBlock(self.getBlockByHeight(num))
 }
 
 func (self *XEth) EthBlockByNumber(num int64) *types.Block {
-	if num == -2 {
-		// "pending" is non-existant
-		return &types.Block{}
-	}
+	return self.getBlockByHeight(num)
+}
 
-	if num == -1 {
-		return self.chainManager.CurrentBlock()
-	}
-
-	return self.chainManager.GetBlockByNumber(uint64(num))
+func (self *XEth) CurrentBlock() *types.Block {
+	return self.backend.ChainManager().CurrentBlock()
 }
 
 func (self *XEth) Block(v interface{}) *Block {
@@ -273,7 +205,7 @@ func (self *XEth) Block(v interface{}) *Block {
 
 func (self *XEth) Accounts() []string {
 	// TODO: check err?
-	accounts, _ := self.eth.AccountManager().Accounts()
+	accounts, _ := self.backend.AccountManager().Accounts()
 	accountAddresses := make([]string, len(accounts))
 	for i, ac := range accounts {
 		accountAddresses[i] = common.ToHex(ac.Address)
@@ -282,31 +214,47 @@ func (self *XEth) Accounts() []string {
 }
 
 func (self *XEth) PeerCount() int {
-	return self.eth.PeerCount()
+	return self.backend.PeerCount()
 }
 
 func (self *XEth) IsMining() bool {
-	return self.eth.IsMining()
+	return self.backend.IsMining()
+}
+
+func (self *XEth) EthVersion() string {
+	return string(self.backend.EthVersion())
+}
+
+func (self *XEth) NetworkVersion() string {
+	return string(self.backend.NetVersion())
+}
+
+func (self *XEth) WhisperVersion() string {
+	return string(self.backend.ShhVersion())
+}
+
+func (self *XEth) ClientVersion() string {
+	return self.backend.ClientVersion()
 }
 
 func (self *XEth) SetMining(shouldmine bool) bool {
-	ismining := self.eth.IsMining()
+	ismining := self.backend.IsMining()
 	if shouldmine && !ismining {
-		err := self.eth.StartMining()
+		err := self.backend.StartMining()
 		return err == nil
 	}
 	if ismining && !shouldmine {
-		self.eth.StopMining()
+		self.backend.StopMining()
 	}
-	return self.eth.IsMining()
+	return self.backend.IsMining()
 }
 
 func (self *XEth) IsListening() bool {
-	return self.eth.IsListening()
+	return self.backend.IsListening()
 }
 
 func (self *XEth) Coinbase() string {
-	cb, _ := self.eth.AccountManager().Coinbase()
+	cb, _ := self.backend.AccountManager().Coinbase()
 	return common.ToHex(cb)
 }
 
@@ -349,7 +297,7 @@ func (self *XEth) SecretToAddress(key string) string {
 
 func (self *XEth) RegisterFilter(args *core.FilterOptions) int {
 	var id int
-	filter := core.NewFilter(self.Backend())
+	filter := core.NewFilter(self.backend)
 	filter.SetOptions(args)
 	filter.LogsCallback = func(logs state.Logs) {
 		self.logMut.Lock()
@@ -375,7 +323,7 @@ func (self *XEth) UninstallFilter(id int) bool {
 
 func (self *XEth) NewFilterString(word string) int {
 	var id int
-	filter := core.NewFilter(self.Backend())
+	filter := core.NewFilter(self.backend)
 
 	switch word {
 	case "pending":
@@ -427,7 +375,7 @@ func (self *XEth) Logs(id int) state.Logs {
 }
 
 func (self *XEth) AllLogs(args *core.FilterOptions) state.Logs {
-	filter := core.NewFilter(self.Backend())
+	filter := core.NewFilter(self.backend)
 	filter.SetOptions(args)
 
 	return filter.Find()
@@ -543,7 +491,7 @@ func (self *XEth) FromNumber(str string) string {
 
 func (self *XEth) PushTx(encodedTx string) (string, error) {
 	tx := types.NewTransactionFromBytes(common.FromHex(encodedTx))
-	err := self.eth.TxPool().Add(tx)
+	err := self.backend.TxPool().Add(tx)
 	if err != nil {
 		return "", err
 	}
@@ -556,7 +504,7 @@ func (self *XEth) PushTx(encodedTx string) (string, error) {
 }
 
 func (self *XEth) Call(fromStr, toStr, valueStr, gasStr, gasPriceStr, dataStr string) (string, error) {
-	statedb := self.State().State() //self.chainManager.TransState()
+	statedb := self.State().State() //self.eth.ChainManager().TransState()
 	msg := callmsg{
 		from:     statedb.GetOrNewStateObject(common.HexToAddress(fromStr)),
 		to:       common.HexToAddress(toStr),
@@ -573,8 +521,8 @@ func (self *XEth) Call(fromStr, toStr, valueStr, gasStr, gasPriceStr, dataStr st
 		msg.gasPrice = defaultGasPrice
 	}
 
-	block := self.chainManager.CurrentBlock()
-	vmenv := core.NewEnv(statedb, self.chainManager, msg, block)
+	block := self.CurrentBlock()
+	vmenv := core.NewEnv(statedb, self.backend.ChainManager(), msg, block)
 
 	res, err := vmenv.Call(msg.from, msg.to, msg.data, msg.gas, msg.gasPrice, msg.value)
 	return common.ToHex(res), err
@@ -635,14 +583,14 @@ func (self *XEth) Transact(fromStr, toStr, valueStr, gasStr, gasPriceStr, codeSt
 		tx = types.NewTransactionMessage(to, value.BigInt(), gas, price, data)
 	}
 
-	state := self.chainManager.TxState()
+	state := self.backend.ChainManager().TxState()
 	nonce := state.NewNonce(from)
 	tx.SetNonce(nonce)
 
 	if err := self.sign(tx, from, false); err != nil {
 		return "", err
 	}
-	if err := self.eth.TxPool().Add(tx); err != nil {
+	if err := self.backend.TxPool().Add(tx); err != nil {
 		return "", err
 	}
 
@@ -656,7 +604,7 @@ func (self *XEth) Transact(fromStr, toStr, valueStr, gasStr, gasPriceStr, codeSt
 }
 
 func (self *XEth) sign(tx *types.Transaction, from common.Address, didUnlock bool) error {
-	sig, err := self.accountManager.Sign(accounts.Account{Address: from.Bytes()}, tx.Hash().Bytes())
+	sig, err := self.backend.AccountManager().Sign(accounts.Account{Address: from.Bytes()}, tx.Hash().Bytes())
 	if err == accounts.ErrLocked {
 		if didUnlock {
 			return fmt.Errorf("sender account still locked after successful unlock")