diff --git a/scripts/run-kcp-batch-test.sh b/scripts/run-kcp-batch-test.sh
index 676169b..29c29d7 100755
--- a/scripts/run-kcp-batch-test.sh
+++ b/scripts/run-kcp-batch-test.sh
@@ -6,13 +6,19 @@ script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 repo_dir="$(cd "$script_dir/.." && pwd)"
 script_name="$(basename "$0")"
 
+run_mode="direct"
 server_ssh=""
 peerb_ssh=""
+relay_ssh=""
 server_addr=""
+relay_addr=""
+relay_remote=""
 log_prefix=""
 listen_addr="0.0.0.0:10909"
+relay_listen_addr="0.0.0.0:10909"
 server_workdir="$repo_dir"
 peerb_workdir="$repo_dir"
+relay_workdir="$repo_dir"
 local_workdir="$repo_dir"
 ready_timeout=60
 send_interval=1
@@ -22,24 +28,37 @@ repeat_count=1
 declare -a peerb_files=()
 
 server_started=0
+relay_started=0
 peer_b_started=0
 peer_a_pid=""
 
 usage() {
 	printf 'Usage:\n'
-	printf '  %s --server-ssh <ssh-target> --peerb-ssh <ssh-target> --server-addr <host:port> \\\n' "$script_name"
-	printf '    --log-prefix <prefix> --file <peer-b-path> [--file <peer-b-path> ...] [options]\n'
+	printf '  %s --mode <direct|relay> --server-ssh <ssh-target> --peerb-ssh <ssh-target> \\\n' "$script_name"
+	printf '    --server-addr <ip> --log-prefix <prefix> --file <peer-b-path> [options]\n'
+	printf '\n'
+	printf 'Modes:\n'
+	printf '  direct   peer-a -> hub(server) <- peer-b  (default)\n'
+	printf '  relay    peer-a -> relay(C) -> hub(D) <- peer-b\n'
 	printf '\n'
 	printf 'Required arguments:\n'
-	printf '  --server-ssh <ssh-target>   SSH target for the server machine\n'
+	printf '  --server-ssh <ssh-target>   SSH target for the hub server machine\n'
 	printf '  --peerb-ssh <ssh-target>    SSH target for the peer-b machine\n'
-	printf '  --server-addr <host:port>   Server address used by peer-a and peer-b\n'
+	printf '  --server-addr <ip>          Hub server IP (combined with listen port for peers)\n'
 	printf '  --log-prefix <prefix>       Log directory prefix; logs go under <prefix>logs/\n'
 	printf '  --file <peer-b-path>        Existing file path on peer-b; repeat for multiple files\n'
 	printf '\n'
+	printf 'Relay mode arguments (required when --mode=relay):\n'
+	printf '  --relay-ssh <ssh-target>    SSH target for the relay server machine\n'
+	printf '  --relay-addr <ip>           Relay server IP (combined with relay listen port for peer-a)\n'
+	printf '  --relay-remote <host:port>  Hub address from relay perspective (relay -relay-remote)\n'
+	printf '\n'
 	printf 'Options:\n'
-	printf '  --listen-addr <addr>        Server listen address (default: %s)\n' "$listen_addr"
-	printf '  --server-workdir <dir>      Server-side workdir (default: %s)\n' "$server_workdir"
+	printf '  --mode <direct|relay>       Run mode (default: %s)\n' "$run_mode"
+	printf '  --listen-addr <addr>        Hub server listen address (default: %s)\n' "$listen_addr"
+	printf '  --relay-listen-addr <addr>  Relay server listen address (default: %s)\n' "$relay_listen_addr"
+	printf '  --server-workdir <dir>      Hub server-side workdir (default: %s)\n' "$server_workdir"
+	printf '  --relay-workdir <dir>       Relay server-side workdir (default: %s)\n' "$relay_workdir"
 	printf '  --peerb-workdir <dir>       Peer-b-side workdir (default: %s)\n' "$peerb_workdir"
 	printf '  --local-workdir <dir>       Local peer-a workdir (default: %s)\n' "$local_workdir"
 	printf '  --ready-timeout <seconds>   Startup wait timeout (default: %s)\n' "$ready_timeout"
@@ -48,15 +67,28 @@ usage() {
 	printf '  --drain-wait <seconds>      Wait after the last file before quit (default: %s)\n' "$drain_wait"
 	printf '  -h, --help                  Show this help\n'
 	printf '\n'
-	printf 'Example:\n'
+	printf 'Example (direct mode):\n'
 	printf '  %s \\\n' "$script_name"
+	printf '    --mode direct \\\n'
 	printf '    --server-ssh root@server-host \\\n'
 	printf '    --peerb-ssh root@peer-b-host \\\n'
-	printf '    --server-addr 203.0.113.10:10909 \\\n'
+	printf '    --server-addr 203.0.113.10 \\\n'
 	printf '    --log-prefix case01- \\\n'
 	printf '    --repeat 30 \\\n'
-	printf '    --file /tmp/test125.bin \\\n'
-	printf '    --file /tmp/test5.bin\n'
+	printf '    --file /tmp/test125.bin\n'
+	printf '\n'
+	printf 'Example (relay mode):\n'
+	printf '  %s \\\n' "$script_name"
+	printf '    --mode relay \\\n'
+	printf '    --server-ssh root@hub-host \\\n'
+	printf '    --relay-ssh root@relay-host \\\n'
+	printf '    --peerb-ssh root@peer-b-host \\\n'
+	printf '    --server-addr 152.136.164.246 \\\n'
+	printf '    --relay-addr 139.199.57.110 \\\n'
+	printf '    --relay-remote 172.21.0.13:10909 \\\n'
+	printf '    --log-prefix case01- \\\n'
+	printf '    --repeat 30 \\\n'
+	printf '    --file /tmp/test125.bin\n'
 }
 
 log() {
@@ -217,6 +249,9 @@ clean_log_directories() {
 	remove_local_log_dir
 	remove_remote_log_dir "$server_ssh" "$server_log_dir" "server" "$server_pid_file"
 	remove_remote_log_dir "$peerb_ssh" "$peerb_log_dir" "peer-b"
+	if [[ "$run_mode" == "relay" ]]; then
+		remove_remote_log_dir "$relay_ssh" "$relay_log_dir" "relay" "$relay_pid_file"
+	fi
 }
 
 truncate_local_file() {
@@ -260,11 +295,8 @@ reset_logs_after_probe() {
 }
 
 fetch_remote_peer_b_logs() {
-	log "copying peer-b logs from $peerb_ssh:$peerb_log_dir to $local_log_dir"
-	copy_remote_file_to_local "$peerb_ssh:$peerb_stdout_log" "$local_peer_b_stdout_log"
+	log "copying peer-b latency log from $peerb_ssh:$peerb_latency_log to $local_peer_b_latency_log"
 	copy_remote_file_to_local "$peerb_ssh:$peerb_latency_log" "$local_peer_b_latency_log"
-	copy_remote_file_to_local "$peerb_ssh:$peerb_ts_debug_log" "$local_peer_b_ts_debug_log"
-	copy_remote_file_to_local "$peerb_ssh:$peerb_session_stats_log" "$local_peer_b_session_stats_log"
 }
 
 run_local_latency_summary() {
@@ -308,6 +340,7 @@ start_remote_server() {
 	local script=""
 
 	script="$(cat <<'EOF'
+export PATH="$PATH:/usr/local/go/bin:$HOME/go/bin"
 set -euo pipefail
 
 cd "$SERVER_WORKDIR"
@@ -322,14 +355,14 @@ if [[ -f "$PID_FILE" ]]; then
 fi
 
 : > "$STDOUT_LOG"
-nohup ./kcpserver \
+setsid go run ./cmd/kcpserver/ \
 	-listen "$LISTEN_ADDR" \
 	>>"$STDOUT_LOG" 2>&1 </dev/null &
 echo "$!" > "$PID_FILE"
 EOF
 )"
 
-	log "starting remote kcpserver on $server_ssh"
+	log "starting remote kcpserver (hub) on $server_ssh"
 	run_remote_script "$server_ssh" "$script" \
 		"SERVER_WORKDIR=$server_workdir" \
 		"LOG_DIR=$server_log_dir" \
@@ -341,7 +374,7 @@ EOF
 }
 
 wait_for_remote_server_ready() {
-	local pattern="kcp server listening"
+	local pattern="kcp hub listening"
 	local script=""
 	local start_time="$SECONDS"
 	local status=0
@@ -365,16 +398,17 @@ EOF
 )"
 
 	while (( SECONDS - start_time < ready_timeout )); do
-		if run_remote_script "$server_ssh" "$script" \
+		status=0
+		run_remote_script "$server_ssh" "$script" \
 			"LOG_FILE=$server_stdout_log" \
 			"READY_PATTERN=$pattern" \
-			"PID_FILE=$server_pid_file"; then
-			log "remote server is ready"
-			return 0
-		fi
+			"PID_FILE=$server_pid_file" || status=$?
 
-		status=$?
 		case "$status" in
+			0)
+				log "remote server is ready"
+				return 0
+				;;
 			10)
 				sleep 1
 				;;
@@ -412,12 +446,8 @@ if [[ -z "$pid" ]]; then
 	exit 0
 fi
 
-if ! kill -0 "$pid" 2>/dev/null; then
-	rm -f "$PID_FILE"
-	exit 0
-fi
-
-kill "$pid" 2>/dev/null || true
+# Kill the entire process group (setsid creates a new group with pid == pgid).
+kill -- -"$pid" 2>/dev/null || kill "$pid" 2>/dev/null || true
 for _ in 1 2 3 4 5; do
 	if ! kill -0 "$pid" 2>/dev/null; then
 		rm -f "$PID_FILE"
@@ -426,7 +456,7 @@ for _ in 1 2 3 4 5; do
 	sleep 1
 done
 
-kill -9 "$pid" 2>/dev/null || true
+kill -9 -- -"$pid" 2>/dev/null || kill -9 "$pid" 2>/dev/null || true
 rm -f "$PID_FILE"
 EOF
 )"
@@ -434,21 +464,158 @@ EOF
 	run_remote_script "$server_ssh" "$script" "PID_FILE=$server_pid_file"
 }
 
+start_remote_relay() {
+	local script=""
+
+	script="$(cat <<'EOF'
+export PATH="$PATH:/usr/local/go/bin:$HOME/go/bin"
+set -euo pipefail
+
+cd "$RELAY_WORKDIR"
+mkdir -p "$LOG_DIR"
+
+if [[ -f "$PID_FILE" ]]; then
+	existing_pid="$(<"$PID_FILE")"
+	if [[ -n "$existing_pid" ]] && kill -0 "$existing_pid" 2>/dev/null; then
+		printf >&2 'relay already running with pid %s\n' "$existing_pid"
+		exit 1
+	fi
+fi
+
+: > "$STDOUT_LOG"
+setsid go run ./cmd/kcpserver/ \
+	-mode=relay \
+	-listen "$LISTEN_ADDR" \
+	-relay-remote "$RELAY_REMOTE" \
+	>>"$STDOUT_LOG" 2>&1 </dev/null &
+echo "$!" > "$PID_FILE"
+EOF
+)"
+
+	log "starting remote relay on $relay_ssh"
+	run_remote_script "$relay_ssh" "$script" \
+		"RELAY_WORKDIR=$relay_workdir" \
+		"LOG_DIR=$relay_log_dir" \
+		"PID_FILE=$relay_pid_file" \
+		"STDOUT_LOG=$relay_stdout_log" \
+		"LISTEN_ADDR=$relay_listen_addr" \
+		"RELAY_REMOTE=$relay_remote"
+
+	relay_started=1
+}
+
+wait_for_remote_relay_ready() {
+	local pattern="udp relay listening"
+	local script=""
+	local start_time="$SECONDS"
+	local status=0
+
+	script="$(cat <<'EOF'
+set -euo pipefail
+
+if [[ -f "$LOG_FILE" ]] && grep -Fq -- "$READY_PATTERN" "$LOG_FILE"; then
+	exit 0
+fi
+
+if [[ -f "$PID_FILE" ]]; then
+	pid="$(<"$PID_FILE")"
+	if [[ -n "$pid" ]] && kill -0 "$pid" 2>/dev/null; then
+		exit 10
+	fi
+fi
+
+exit 20
+EOF
+)"
+
+	while (( SECONDS - start_time < ready_timeout )); do
+		status=0
+		run_remote_script "$relay_ssh" "$script" \
+			"LOG_FILE=$relay_stdout_log" \
+			"READY_PATTERN=$pattern" \
+			"PID_FILE=$relay_pid_file" || status=$?
+
+		case "$status" in
+			0)
+				log "remote relay is ready"
+				return 0
+				;;
+			10)
+				sleep 1
+				;;
+			20)
+				log "remote relay exited before readiness"
+				dump_remote_log_head "$relay_ssh" "$relay_stdout_log" "relay"
+				return 1
+				;;
+			*)
+				log "remote relay readiness check failed with status $status"
+				dump_remote_log_head "$relay_ssh" "$relay_stdout_log" "relay"
+				return 1
+				;;
+		esac
+	done
+
+	log "timed out waiting for remote relay readiness after ${ready_timeout}s"
+	dump_remote_log_head "$relay_ssh" "$relay_stdout_log" "relay"
+	return 1
+}
+
+stop_remote_relay() {
+	local script=""
+
+	script="$(cat <<'EOF'
+set -euo pipefail
+
+if [[ ! -f "$PID_FILE" ]]; then
+	exit 0
+fi
+
+pid="$(<"$PID_FILE")"
+if [[ -z "$pid" ]]; then
+	rm -f "$PID_FILE"
+	exit 0
+fi
+
+kill -- -"$pid" 2>/dev/null || kill "$pid" 2>/dev/null || true
+for _ in 1 2 3 4 5; do
+	if ! kill -0 "$pid" 2>/dev/null; then
+		rm -f "$PID_FILE"
+		exit 0
+	fi
+	sleep 1
+done
+
+kill -9 -- -"$pid" 2>/dev/null || kill -9 "$pid" 2>/dev/null || true
+rm -f "$PID_FILE"
+EOF
+)"
+
+	run_remote_script "$relay_ssh" "$script" "PID_FILE=$relay_pid_file"
+}
+
 start_local_peer_a() {
 	log "starting local peer-a"
 	mkdir -p "$local_log_dir" "$local_peer_a_inbox"
 	: > "$local_peer_a_stdout_log"
 
+	local peer_a_args=(
+		-id peer-a
+		-server "$server_connect_addr"
+		-inbox-dir "$local_peer_a_inbox"
+		-latency-log "$local_peer_a_latency_log"
+		-kcp-ts-debug-log "$local_peer_a_ts_debug_log"
+		-kcp-session-stats-log "$local_peer_a_session_stats_log"
+		-interactive=false
+	)
+
+	if [[ "$run_mode" == "relay" ]]; then
+		peer_a_args+=(-relay-via "$relay_connect_addr")
+	fi
+
 	(
 		cd "$local_workdir"
-		exec go run ./cmd/kcppeer \
-			-id peer-a \
-			-server "$server_addr" \
-			-inbox-dir "$local_peer_a_inbox" \
-			-latency-log "$local_peer_a_latency_log" \
-			-kcp-ts-debug-log "$local_peer_a_ts_debug_log" \
-			-kcp-session-stats-log "$local_peer_a_session_stats_log" \
-			-interactive=false \
+		exec go run ./cmd/kcppeer "${peer_a_args[@]}" \
 			>>"$local_peer_a_stdout_log" 2>&1
 	) &
 
@@ -456,7 +623,7 @@ start_local_peer_a() {
 }
 
 wait_for_local_peer_a_ready() {
-	local pattern="connected to $server_addr as peer-a (KCP)"
+	local pattern="opened KCP session as peer-a"
 	local start_time="$SECONDS"
 
 	while (( SECONDS - start_time < ready_timeout )); do
@@ -498,6 +665,7 @@ start_remote_peer_b() {
 	local script=""
 
 	script="$(cat <<'EOF'
+export PATH="$PATH:/usr/local/go/bin:$HOME/go/bin"
 set -euo pipefail
 
 cd "$PEERB_WORKDIR"
@@ -515,7 +683,7 @@ fi
 : > "$COMMAND_FILE"
 
 	peer_b_cmd="$(cat <<'INNER'
-	tail -n +1 -f "$COMMAND_FILE" | exec ./bin/kcppeer \
+	tail -n +1 -f "$COMMAND_FILE" | exec go run ./cmd/kcppeer/ \
 		-id peer-b \
 		-server "$SERVER_ADDR" \
 		-inbox-dir "$INBOX_DIR" \
@@ -525,7 +693,7 @@ fi
 INNER
 )"
 
-nohup bash -lc "$peer_b_cmd" >>"$STDOUT_LOG" 2>&1 </dev/null &
+nohup setsid bash -lc "$peer_b_cmd" >>"$STDOUT_LOG" 2>&1 </dev/null &
 echo "$!" > "$PID_FILE"
 EOF
 )"
@@ -538,7 +706,7 @@ EOF
 		"STDOUT_LOG=$peerb_stdout_log" \
 		"COMMAND_FILE=$peerb_command_file" \
 		"PID_FILE=$peerb_pid_file" \
-		"SERVER_ADDR=$server_addr" \
+		"SERVER_ADDR=$server_connect_addr" \
 		"LATENCY_LOG=$peerb_latency_log" \
 		"TS_DEBUG_LOG=$peerb_ts_debug_log" \
 		"SESSION_STATS_LOG=$peerb_session_stats_log"
@@ -547,7 +715,7 @@ EOF
 }
 
 wait_for_remote_peer_b_ready() {
-	local pattern="connected to $server_addr as peer-b (KCP)"
+	local pattern="opened KCP session as peer-b"
 	local script=""
 	local start_time="$SECONDS"
 	local status=0
@@ -571,16 +739,17 @@ EOF
 )"
 
 	while (( SECONDS - start_time < ready_timeout )); do
-		if run_remote_script "$peerb_ssh" "$script" \
+		status=0
+		run_remote_script "$peerb_ssh" "$script" \
 			"LOG_FILE=$peerb_stdout_log" \
 			"READY_PATTERN=$pattern" \
-			"PID_FILE=$peerb_pid_file"; then
-			log "remote peer-b is ready"
-			return 0
-		fi
+			"PID_FILE=$peerb_pid_file" || status=$?
 
-		status=$?
 		case "$status" in
+			0)
+				log "remote peer-b is ready"
+				return 0
+				;;
 			10)
 				sleep 1
 				;;
@@ -739,7 +908,7 @@ if kill -0 "$pid" 2>/dev/null; then
 		fi
 		sleep 1
 	done
-	kill "$pid" 2>/dev/null || true
+	kill -- -"$pid" 2>/dev/null || kill "$pid" 2>/dev/null || true
 	for _ in 1 2 3 4 5; do
 		if ! kill -0 "$pid" 2>/dev/null; then
 			rm -f "$PID_FILE" "$COMMAND_FILE"
@@ -747,7 +916,7 @@ if kill -0 "$pid" 2>/dev/null; then
 		fi
 		sleep 1
 	done
-	kill -9 "$pid" 2>/dev/null || true
+	kill -9 -- -"$pid" 2>/dev/null || kill -9 "$pid" 2>/dev/null || true
 fi
 
 rm -f "$PID_FILE" "$COMMAND_FILE"
@@ -774,6 +943,11 @@ cleanup() {
 		stop_remote_peer_b || true
 	fi
 
+	if (( relay_started == 1 )); then
+		log "stopping remote relay on $relay_ssh"
+		stop_remote_relay || true
+	fi
+
 	if (( server_started == 1 )); then
 		log "stopping remote server on $server_ssh"
 		stop_remote_server || true
@@ -794,6 +968,11 @@ handle_terminate() {
 
 while [[ $# -gt 0 ]]; do
 	case "$1" in
+		--mode)
+			[[ $# -ge 2 ]] || die "--mode requires a value"
+			run_mode="$2"
+			shift 2
+			;;
 		--server-ssh)
 			[[ $# -ge 2 ]] || die "--server-ssh requires a value"
 			server_ssh="$2"
@@ -804,11 +983,26 @@ while [[ $# -gt 0 ]]; do
 			peerb_ssh="$2"
 			shift 2
 			;;
+		--relay-ssh)
+			[[ $# -ge 2 ]] || die "--relay-ssh requires a value"
+			relay_ssh="$2"
+			shift 2
+			;;
 		--server-addr)
 			[[ $# -ge 2 ]] || die "--server-addr requires a value"
 			server_addr="$2"
 			shift 2
 			;;
+		--relay-addr)
+			[[ $# -ge 2 ]] || die "--relay-addr requires a value"
+			relay_addr="$2"
+			shift 2
+			;;
+		--relay-remote)
+			[[ $# -ge 2 ]] || die "--relay-remote requires a value"
+			relay_remote="$2"
+			shift 2
+			;;
 		--log-prefix)
 			[[ $# -ge 2 ]] || die "--log-prefix requires a value"
 			log_prefix="$2"
@@ -819,11 +1013,21 @@ while [[ $# -gt 0 ]]; do
 			listen_addr="$2"
 			shift 2
 			;;
+		--relay-listen-addr)
+			[[ $# -ge 2 ]] || die "--relay-listen-addr requires a value"
+			relay_listen_addr="$2"
+			shift 2
+			;;
 		--server-workdir)
 			[[ $# -ge 2 ]] || die "--server-workdir requires a value"
 			server_workdir="$2"
 			shift 2
 			;;
+		--relay-workdir)
+			[[ $# -ge 2 ]] || die "--relay-workdir requires a value"
+			relay_workdir="$2"
+			shift 2
+			;;
 		--peerb-workdir)
 			[[ $# -ge 2 ]] || die "--peerb-workdir requires a value"
 			peerb_workdir="$2"
@@ -869,12 +1073,19 @@ while [[ $# -gt 0 ]]; do
 	esac
 done
 
+[[ "$run_mode" == "direct" || "$run_mode" == "relay" ]] || die "--mode must be 'direct' or 'relay', got: $run_mode"
 [[ -n "$server_ssh" ]] || die "--server-ssh is required"
 [[ -n "$peerb_ssh" ]] || die "--peerb-ssh is required"
 [[ -n "$server_addr" ]] || die "--server-addr is required"
 [[ -n "$log_prefix" ]] || die "--log-prefix is required"
 (( ${#peerb_files[@]} > 0 )) || die "at least one --file is required"
 
+if [[ "$run_mode" == "relay" ]]; then
+	[[ -n "$relay_ssh" ]] || die "--relay-ssh is required in relay mode"
+	[[ -n "$relay_addr" ]] || die "--relay-addr is required in relay mode"
+	[[ -n "$relay_remote" ]] || die "--relay-remote is required in relay mode"
+fi
+
 validate_positive_integer "--ready-timeout" "$ready_timeout"
 validate_positive_integer "--repeat" "$repeat_count"
 validate_sleep_value "--send-interval" "$send_interval"
@@ -882,6 +1093,16 @@ validate_sleep_value "--drain-wait" "$drain_wait"
 
 check_local_dependencies
 
+# Extract ports and build peer connection addresses.
+server_port="${listen_addr##*:}"
+server_connect_addr="${server_addr}:${server_port}"
+
+relay_connect_addr=""
+if [[ "$run_mode" == "relay" ]]; then
+	relay_port="${relay_listen_addr##*:}"
+	relay_connect_addr="${relay_addr}:${relay_port}"
+fi
+
 log_dir_name="${log_prefix}logs"
 inbox_dir_name="${log_prefix}inbox"
 
@@ -902,6 +1123,15 @@ server_log_dir="$(join_path "$server_workdir" "$log_dir_name")"
 server_pid_file="$(join_path "$server_log_dir" "server.pid")"
 server_stdout_log="$(join_path "$server_log_dir" "server.stdout.log")"
 
+relay_log_dir=""
+relay_pid_file=""
+relay_stdout_log=""
+if [[ "$run_mode" == "relay" ]]; then
+	relay_log_dir="$(join_path "$relay_workdir" "$log_dir_name")"
+	relay_pid_file="$(join_path "$relay_log_dir" "relay.pid")"
+	relay_stdout_log="$(join_path "$relay_log_dir" "relay.stdout.log")"
+fi
+
 peerb_log_dir="$(join_path "$peerb_workdir" "$log_dir_name")"
 peerb_inbox_dir="$(join_path "$peerb_workdir" "$inbox_dir_name/peer-b")"
 peerb_stdout_log="$(join_path "$peerb_log_dir" "peer-b.stdout.log")"
@@ -919,13 +1149,23 @@ clean_log_directories
 
 mkdir -p "$local_log_dir" "$local_peer_a_inbox"
 
+log "run mode: $run_mode"
 log "local peer-a logs: $local_log_dir"
 log "remote server logs: $server_log_dir"
+if [[ "$run_mode" == "relay" ]]; then
+	log "remote relay logs: $relay_log_dir"
+fi
 log "remote peer-b logs: $peerb_log_dir"
 
 check_remote_peerb_files
 start_remote_server
 wait_for_remote_server_ready
+
+if [[ "$run_mode" == "relay" ]]; then
+	start_remote_relay
+	wait_for_remote_relay_ready
+fi
+
 start_local_peer_a
 start_remote_peer_b
 wait_for_local_peer_a_ready
@@ -940,6 +1180,15 @@ if [[ -n "$peer_a_pid" ]]; then
 	stop_local_peer_a
 fi
 
+if (( relay_started == 1 )); then
+	log "stopping remote relay on $relay_ssh after batch"
+	if stop_remote_relay; then
+		relay_started=0
+	else
+		log "failed to stop remote relay cleanly; cleanup will retry"
+	fi
+fi
+
 if (( server_started == 1 )); then
 	log "stopping remote server on $server_ssh after batch"
 	if stop_remote_server; then