diff --git a/src/vlib/unix/mc_socket.c b/src/vlib/unix/mc_socket.c
index aaf73ae..d4f4a7f 100644
--- a/src/vlib/unix/mc_socket.c
+++ b/src/vlib/unix/mc_socket.c
@@ -165,7 +165,7 @@
   vlib_main_t *vm = msm->mc_main.vlib_main;
   vlib_buffer_t *b;
   uword n_left, n_alloc, n_mtu, i, i_rx;
-  const uword buffer_size = VLIB_BUFFER_DATA_SIZE;
+  const uword buffer_size = vlib_bufer_get_default_size (vm);
   word n_bytes_left;
 
   /* Make sure we have at least a MTU worth of buffers. */
@@ -1011,8 +1011,10 @@
   }
 
   msm->rx_mtu_n_bytes = mtu;
-  msm->rx_mtu_n_buffers = msm->rx_mtu_n_bytes / VLIB_BUFFER_DATA_SIZE;
-  msm->rx_mtu_n_buffers += (msm->rx_mtu_n_bytes % VLIB_BUFFER_DATA_SIZE) != 0;
+  msm->rx_mtu_n_buffers =
+    msm->rx_mtu_n_bytes / vlib_bufer_get_default_size (vm);
+  msm->rx_mtu_n_buffers +=
+    (msm->rx_mtu_n_bytes % vlib_bufer_get_default_size (vm)) != 0;
 
   error = socket_setup (msm);
   if (error)