diff --git a/packages/cosmic-swingset/lib/ag-solo/vats/ibc.js b/packages/cosmic-swingset/lib/ag-solo/vats/ibc.js
index 505a9e4716c..8007c325a09 100644
--- a/packages/cosmic-swingset/lib/ag-solo/vats/ibc.js
+++ b/packages/cosmic-swingset/lib/ag-solo/vats/ibc.js
@@ -199,7 +199,11 @@ export function makeIBCProtocolHandler(
       },
       onReceive,
       async onClose(_conn, _reason, _handler) {
-        await callIBCDevice('channelCloseInit', { channelID, portID });
+        const packet = {
+          source_port: portID,
+          source_channel: channelID,
+        };
+        await callIBCDevice('channelCloseInit', { packet });
         usedChannels.delete(channelID);
         usedChannels.delete(rChannelID);
       },
@@ -251,7 +255,10 @@ export function makeIBCProtocolHandler(
     },
     async onBind(_port, localAddr, _protocolHandler) {
       const portID = localAddrToPortID(localAddr);
-      return callIBCDevice('bindPort', { portID });
+      const packet = {
+        source_port: portID,
+      };
+      return callIBCDevice('bindPort', { packet });
     },
     async onConnect(_port, localAddr, remoteAddr, _protocolHandler) {
       console.warn('IBC onConnect', localAddr, remoteAddr);
diff --git a/packages/cosmic-swingset/x/swingset/ibc.go b/packages/cosmic-swingset/x/swingset/ibc.go
index bdadbb33e2a..031c0c26fb0 100644
--- a/packages/cosmic-swingset/x/swingset/ibc.go
+++ b/packages/cosmic-swingset/x/swingset/ibc.go
@@ -23,8 +23,6 @@ type channelHandler struct {
 type channelMessage struct { // comes from swingset's IBC handler
 	Type            string                `json:"type"` // IBC_METHOD
 	Method          string                `json:"method"`
-	PortID          string                `json:"portID"`
-	ChannelID       string                `json:"channelID"`
 	Packet          channeltypes.Packet   `json:"packet"`
 	RelativeTimeout uint64                `json:"relativeTimeout"`
 	Order           channelexported.Order `json:"order"`
@@ -110,13 +108,13 @@ func (ch channelHandler) Receive(ctx *ControllerContext, str string) (ret string
 		}
 
 	case "channelCloseInit":
-		err = ctx.Keeper.ChanCloseInit(ctx.Context, msg.PortID, msg.ChannelID)
+		err = ctx.Keeper.ChanCloseInit(ctx.Context, msg.Packet.SourcePort, msg.Packet.SourceChannel)
 		if err == nil {
 			ret = "true"
 		}
 
 	case "bindPort":
-		err = ctx.Keeper.BindPort(ctx.Context, msg.PortID)
+		err = ctx.Keeper.BindPort(ctx.Context, msg.Packet.SourcePort)
 		if err == nil {
 			ret = "true"
 		}