diff --git a/swarmsim/codex/dhttracker.nim b/swarmsim/codex/dhttracker.nim
index d19b438..c43150b 100644
--- a/swarmsim/codex/dhttracker.nim
+++ b/swarmsim/codex/dhttracker.nim
@@ -37,7 +37,7 @@ type
 let RandomShuffler = proc (arr: var seq[PeerDescriptor]) =
   discard arr.nextPermutation()
 
-proc messageType*(T: type DHTTracker): string = "DHTTracker"
+proc protocolId*(T: type DHTTracker): string = "DHTTracker"
 
 proc defaultExpiry*(T: type DHTTracker): Duration = 15.dminutes
 
@@ -53,7 +53,7 @@ proc new*(
     maxPeers: maxPeers,
     shuffler: shuffler,
     peers: initOrderedTable[int, PeerDescriptor](),
-    messageType: DHTTracker.messageType
+    protocolId: DHTTracker.protocolId
   )
 
 proc peers*(self: DHTTracker): seq[PeerDescriptor] = self.peers.values.toSeq()
diff --git a/swarmsim/engine/network.nim b/swarmsim/engine/network.nim
index 11f046e..386379e 100644
--- a/swarmsim/engine/network.nim
+++ b/swarmsim/engine/network.nim
@@ -16,6 +16,9 @@ type
     network: Network
     message: Message
 
+# TODO: use distributions (or trace resampling) instead of a constant for link delay
+# TODO: model link capacity and implement downloads
+
 proc new*(
   T: type Network,
   engine: EventDrivenEngine,
diff --git a/swarmsim/engine/peer.nim b/swarmsim/engine/peer.nim
index 647c15a..e14c127 100644
--- a/swarmsim/engine/peer.nim
+++ b/swarmsim/engine/peer.nim
@@ -21,13 +21,13 @@ proc getProtocol*(self: Peer, protocolId: string): Option[Protocol] =
 
 proc deliver*(self: Peer, message: Message, engine: EventDrivenEngine,
     network: Network): void =
-  self.getProtocol(message.messageType).map(
+  self.getProtocol(message.protocolId).map(
     proc (p: Protocol): void = p.deliver(message, engine, network))
 
 proc initPeer(self: Peer, protocols: seq[Protocol]): Peer =
   # XXX integer indexes or an enum would be better, but this is easier
   for protocol in protocols:
-    self.protocols[protocol.messageType] = protocol
+    self.protocols[protocol.protocolId] = protocol
 
   self
 
diff --git a/swarmsim/engine/protocol.nim b/swarmsim/engine/protocol.nim
index 066b516..87702b9 100644
--- a/swarmsim/engine/protocol.nim
+++ b/swarmsim/engine/protocol.nim
@@ -15,5 +15,5 @@ method uncheckedDeliver(
 
 proc deliver*(self: Protocol, message: Message, engine: EventDrivenEngine,
     network: Network): void =
-  assert(self.messageType == message.messageType)
+  assert(self.protocolId == message.protocolId)
   self.uncheckedDeliver(message, engine, network)
diff --git a/swarmsim/engine/types.nim b/swarmsim/engine/types.nim
index 73547ce..04590e5 100644
--- a/swarmsim/engine/types.nim
+++ b/swarmsim/engine/types.nim
@@ -30,7 +30,7 @@ type
     ## A `Protocol` defines a P2P protocol. It handles messages meant for it,
     ## keeps internal state, and may expose services to other `Protocol`s within
     ## the same `Peer`.
-    messageType*: string ## "Type" of the message accepted by this protocol.
+    protocolId*: string
 
 type
   Peer* = ref object of RootObj
@@ -41,7 +41,7 @@ type
   Message* = ref object of RootObj
     ## A `Message` is a piece of data that is sent over the network. Its meaning
     ## is typically protocol-specific.
-    messageType*: string
+    protocolId*: string
     sender*: Option[Peer] = none(Peer)
     receiver*: Peer
 
diff --git a/tests/codex/tdhttracker.nim b/tests/codex/tdhttracker.nim
index 09c136c..3b0e2eb 100644
--- a/tests/codex/tdhttracker.nim
+++ b/tests/codex/tdhttracker.nim
@@ -13,7 +13,7 @@ import pkg/swarmsim/timeutils
 
 proc getPeerArray(tracker: Peer): seq[PeerDescriptor] =
   DHTTracker(
-      tracker.getProtocol(DHTTracker.messageType).get()).peers
+      tracker.getProtocol(DHTTracker.protocolId).get()).peers
 
 proc getPeerIdArray(tracker: Peer): seq[int] =
   getPeerArray(tracker).map(p => p.peerId)
@@ -22,7 +22,7 @@ proc announcePeer(network: Network, tracker: Peer, peerId: int,
     delay: uint64 = 0) =
   network.send(
     PeerAnnouncement(receiver: tracker,
-      messageType: DHTTracker.messageType, peerId: peerId),
+      protocolId: DHTTracker.protocolId, peerId: peerId),
         delay.some).doAwait()
 
 suite "tracker node":