diff --git a/.changeset/cuddly-doors-relate.md b/.changeset/cuddly-doors-relate.md
new file mode 100644
index 000000000..28315aef7
--- /dev/null
+++ b/.changeset/cuddly-doors-relate.md
@@ -0,0 +1,6 @@
+---
+"@livekit/protocol": patch
+"github.com/livekit/protocol": patch
+---
+
+Store SDP cid in TrackInfo.
diff --git a/livekit/livekit_models.pb.go b/livekit/livekit_models.pb.go
index 6a1cdbfd1..585a02919 100644
--- a/livekit/livekit_models.pb.go
+++ b/livekit/livekit_models.pb.go
@@ -1972,8 +1972,13 @@ type SimulcastCodecInfo struct {
 	Cid            string                 `protobuf:"bytes,3,opt,name=cid,proto3" json:"cid,omitempty"`
 	Layers         []*VideoLayer          `protobuf:"bytes,4,rep,name=layers,proto3" json:"layers,omitempty"`
 	VideoLayerMode VideoLayer_Mode        `protobuf:"varint,5,opt,name=video_layer_mode,json=videoLayerMode,proto3,enum=livekit.VideoLayer_Mode" json:"video_layer_mode,omitempty"`
-	unknownFields  protoimpl.UnknownFields
-	sizeCache      protoimpl.SizeCache
+	// cid (client side id for track) could be different between
+	// signalling (AddTrackRequest) and SDP offer. This field
+	// will be populated only if it is different to avoid
+	// duplication and keep the representation concise.
+	SdpCid        string `protobuf:"bytes,6,opt,name=sdp_cid,json=sdpCid,proto3" json:"sdp_cid,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
 }
 
 func (x *SimulcastCodecInfo) Reset() {
@@ -2041,6 +2046,13 @@ func (x *SimulcastCodecInfo) GetVideoLayerMode() VideoLayer_Mode {
 	return VideoLayer_MODE_UNUSED
 }
 
+func (x *SimulcastCodecInfo) GetSdpCid() string {
+	if x != nil {
+		return x.SdpCid
+	}
+	return ""
+}
+
 type TrackInfo struct {
 	state protoimpl.MessageState `protogen:"open.v1"`
 	Sid   string                 `protobuf:"bytes,1,opt,name=sid,proto3" json:"sid,omitempty"`
@@ -5423,13 +5435,14 @@ const file_livekit_models_proto_rawDesc = "" +
 	"\x04NONE\x10\x00\x12\a\n" +
 	"\x03GCM\x10\x01\x12\n" +
 	"\n" +
-	"\x06CUSTOM\x10\x02\"\xc6\x01\n" +
+	"\x06CUSTOM\x10\x02\"\xdf\x01\n" +
 	"\x12SimulcastCodecInfo\x12\x1b\n" +
 	"\tmime_type\x18\x01 \x01(\tR\bmimeType\x12\x10\n" +
 	"\x03mid\x18\x02 \x01(\tR\x03mid\x12\x10\n" +
 	"\x03cid\x18\x03 \x01(\tR\x03cid\x12+\n" +
 	"\x06layers\x18\x04 \x03(\v2\x13.livekit.VideoLayerR\x06layers\x12B\n" +
-	"\x10video_layer_mode\x18\x05 \x01(\x0e2\x18.livekit.VideoLayer.ModeR\x0evideoLayerMode\"\xfe\x05\n" +
+	"\x10video_layer_mode\x18\x05 \x01(\x0e2\x18.livekit.VideoLayer.ModeR\x0evideoLayerMode\x12\x17\n" +
+	"\asdp_cid\x18\x06 \x01(\tR\x06sdpCid\"\xfe\x05\n" +
 	"\tTrackInfo\x12\x10\n" +
 	"\x03sid\x18\x01 \x01(\tR\x03sid\x12&\n" +
 	"\x04type\x18\x02 \x01(\x0e2\x12.livekit.TrackTypeR\x04type\x12\x12\n" +
diff --git a/protobufs/livekit_models.proto b/protobufs/livekit_models.proto
index e33093cd6..e876fdfd7 100644
--- a/protobufs/livekit_models.proto
+++ b/protobufs/livekit_models.proto
@@ -202,6 +202,11 @@ message SimulcastCodecInfo {
   string cid = 3;
   repeated VideoLayer layers = 4;
   VideoLayer.Mode video_layer_mode = 5;
+  // cid (client side id for track) could be different between
+  // signalling (AddTrackRequest) and SDP offer. This field
+  // will be populated only if it is different to avoid
+  // duplication and keep the representation concise.
+  string sdp_cid = 6;
 }
 
 message TrackInfo {