diff --git a/core/src/swarm.rs b/core/src/swarm.rs
index 7a3e4be7..29c389c3 100644
--- a/core/src/swarm.rs
+++ b/core/src/swarm.rs
@@ -55,6 +55,8 @@ use futures::prelude::*;
 use smallvec::SmallVec;
 use std::{error, fmt, io, ops::{Deref, DerefMut}};
 
+pub mod toggle;
+
 pub use crate::nodes::raw_swarm::ConnectedPoint;
 
 /// Contains the state of the network, plus the way it should behave.
@@ -389,7 +391,7 @@ pub trait NetworkBehaviour {
     /// Polls for things that swarm should do.
     ///
     /// This API mimics the API of the `Stream` trait.
-    fn poll(&mut self, topology: &mut PollParameters<'_>) -> Async<NetworkBehaviourAction<<<Self::ProtocolsHandler as IntoProtocolsHandler>::Handler as ProtocolsHandler>::InEvent, Self::OutEvent>>;
+    fn poll(&mut self, params: &mut PollParameters<'_>) -> Async<NetworkBehaviourAction<<<Self::ProtocolsHandler as IntoProtocolsHandler>::Handler as ProtocolsHandler>::InEvent, Self::OutEvent>>;
 }
 
 /// Used when deriving `NetworkBehaviour`. When deriving `NetworkBehaviour`, must be implemented
diff --git a/core/src/swarm/toggle.rs b/core/src/swarm/toggle.rs
new file mode 100644
index 00000000..7b83a20b
--- /dev/null
+++ b/core/src/swarm/toggle.rs
@@ -0,0 +1,215 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+use crate::{
+    either::EitherOutput,
+    protocols_handler::{KeepAlive, ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr, IntoProtocolsHandler},
+    swarm::{NetworkBehaviour, NetworkBehaviourAction, NetworkBehaviourEventProcess},
+    upgrade::{InboundUpgrade, OutboundUpgrade, DeniedUpgrade, EitherUpgrade},
+    PeerId, Multiaddr, nodes::ConnectedPoint, swarm::PollParameters,
+};
+use futures::prelude::*;
+use std::error;
+
+/// Implementation of `NetworkBehaviour` that can be either in the disabled or enabled state.
+///
+/// The state can only be chosen at initialization.
+pub struct Toggle<TBehaviour> {
+    inner: Option<TBehaviour>,
+}
+
+impl<TBehaviour> From<Option<TBehaviour>> for Toggle<TBehaviour> {
+    fn from(inner: Option<TBehaviour>) -> Self {
+        Toggle { inner }
+    }
+}
+
+impl<TBehaviour> NetworkBehaviour for Toggle<TBehaviour>
+where
+    TBehaviour: NetworkBehaviour
+{
+    type ProtocolsHandler = ToggleIntoProtoHandler<TBehaviour::ProtocolsHandler>;
+    type OutEvent = TBehaviour::OutEvent;
+
+    fn new_handler(&mut self) -> Self::ProtocolsHandler {
+        ToggleIntoProtoHandler {
+            inner: self.inner.as_mut().map(|i| i.new_handler())
+        }
+    }
+
+    fn addresses_of_peer(&mut self, peer_id: &PeerId) -> Vec<Multiaddr> {
+        self.inner.as_mut().map(|b| b.addresses_of_peer(peer_id)).unwrap_or_else(Vec::new)
+    }
+
+    fn inject_connected(&mut self, peer_id: PeerId, endpoint: ConnectedPoint) {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.inject_connected(peer_id, endpoint)
+        }
+    }
+
+    fn inject_disconnected(&mut self, peer_id: &PeerId, endpoint: ConnectedPoint) {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.inject_disconnected(peer_id, endpoint)
+        }
+    }
+
+    fn inject_replaced(&mut self, peer_id: PeerId, closed_endpoint: ConnectedPoint, new_endpoint: ConnectedPoint) {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.inject_replaced(peer_id, closed_endpoint, new_endpoint)
+        }
+    }
+
+    fn inject_node_event(
+        &mut self,
+        peer_id: PeerId,
+        event: <<Self::ProtocolsHandler as IntoProtocolsHandler>::Handler as ProtocolsHandler>::OutEvent
+    ) {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.inject_node_event(peer_id, event);
+        }
+    }
+
+    fn inject_addr_reach_failure(&mut self, peer_id: Option<&PeerId>, addr: &Multiaddr, error: &dyn error::Error) {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.inject_addr_reach_failure(peer_id, addr, error)
+        }
+    }
+
+    fn inject_dial_failure(&mut self, peer_id: &PeerId) {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.inject_dial_failure(peer_id)
+        }
+    }
+
+    fn poll(&mut self, params: &mut PollParameters<'_>)
+        -> Async<NetworkBehaviourAction<<<Self::ProtocolsHandler as IntoProtocolsHandler>::Handler as ProtocolsHandler>::InEvent, Self::OutEvent>>
+    {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.poll(params)
+        } else {
+            Async::NotReady
+        }
+    }
+}
+
+impl<TEvent, TBehaviour> NetworkBehaviourEventProcess<TEvent> for Toggle<TBehaviour>
+where
+    TBehaviour: NetworkBehaviourEventProcess<TEvent>
+{
+    fn inject_event(&mut self, event: TEvent) {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.inject_event(event);
+        }
+    }
+}
+
+/// Implementation of `IntoProtocolsHandler` that can be in the disabled state.
+pub struct ToggleIntoProtoHandler<TInner> {
+    inner: Option<TInner>,
+}
+
+impl<TInner> IntoProtocolsHandler for ToggleIntoProtoHandler<TInner>
+where
+    TInner: IntoProtocolsHandler
+{
+    type Handler = ToggleProtoHandler<TInner::Handler>;
+
+    fn into_handler(self, remote_peer_id: &PeerId) -> Self::Handler {
+        ToggleProtoHandler {
+            inner: self.inner.map(|h| h.into_handler(remote_peer_id))
+        }
+    }
+}
+
+/// Implementation of `ProtocolsHandler` that can be in the disabled state.
+pub struct ToggleProtoHandler<TInner> {
+    inner: Option<TInner>,
+}
+
+impl<TInner> ProtocolsHandler for ToggleProtoHandler<TInner>
+where
+    TInner: ProtocolsHandler,
+{
+    type InEvent = TInner::InEvent;
+    type OutEvent = TInner::OutEvent;
+    type Error = TInner::Error;
+    type Substream = TInner::Substream;
+    type InboundProtocol = EitherUpgrade<TInner::InboundProtocol, DeniedUpgrade>;
+    type OutboundProtocol = TInner::OutboundProtocol;
+    type OutboundOpenInfo = TInner::OutboundOpenInfo;
+
+    fn listen_protocol(&self) -> Self::InboundProtocol {
+        if let Some(inner) = self.inner.as_ref() {
+            EitherUpgrade::A(inner.listen_protocol())
+        } else {
+            EitherUpgrade::B(DeniedUpgrade)
+        }
+    }
+
+    fn inject_fully_negotiated_inbound(
+        &mut self,
+        out: <Self::InboundProtocol as InboundUpgrade<Self::Substream>>::Output
+    ) {
+        let out = match out {
+            EitherOutput::First(out) => out,
+            EitherOutput::Second(v) => void::unreachable(v),
+        };
+
+        self.inner.as_mut().expect("Can't receive an inbound substream if disabled; QED")
+            .inject_fully_negotiated_inbound(out)
+    }
+
+    fn inject_fully_negotiated_outbound(
+        &mut self,
+        out: <Self::OutboundProtocol as OutboundUpgrade<Self::Substream>>::Output,
+        info: Self::OutboundOpenInfo
+    ) {
+        self.inner.as_mut().expect("Can't receive an outbound substream if disabled; QED")
+            .inject_fully_negotiated_outbound(out, info)
+    }
+
+    fn inject_event(&mut self, event: Self::InEvent) {
+        self.inner.as_mut().expect("Can't receive events if disabled; QED")
+            .inject_event(event)
+    }
+
+    fn inject_dial_upgrade_error(&mut self, info: Self::OutboundOpenInfo, err: ProtocolsHandlerUpgrErr<<Self::OutboundProtocol as OutboundUpgrade<Self::Substream>>::Error>) {
+        self.inner.as_mut().expect("Can't receive an outbound substream if disabled; QED")
+            .inject_dial_upgrade_error(info, err)
+    }
+
+    fn connection_keep_alive(&self) -> KeepAlive {
+        self.inner.as_ref().map(|h| h.connection_keep_alive())
+            .unwrap_or(KeepAlive::Now)
+    }
+
+    fn poll(
+        &mut self,
+    ) -> Poll<
+        ProtocolsHandlerEvent<Self::OutboundProtocol, Self::OutboundOpenInfo, Self::OutEvent>,
+        Self::Error,
+    > {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.poll()
+        } else {
+            Ok(Async::NotReady)
+        }
+    }
+}