diff --git a/net/tipc/core.c b/net/tipc/core.c
index 0539a8362858..7f3f693e5125 100644
--- a/net/tipc/core.c
+++ b/net/tipc/core.c
@@ -90,7 +90,7 @@ int tipc_random;
 atomic_t tipc_user_count = ATOMIC_INIT(0);
 
 const char tipc_alphabet[] = 
-	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_";
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_.";
 
 /* configurable TIPC parameters */
 
diff --git a/net/tipc/core.h b/net/tipc/core.h
index d1c3948eb4e8..4638947c2326 100644
--- a/net/tipc/core.h
+++ b/net/tipc/core.h
@@ -275,11 +275,15 @@ static inline void k_term_timer(struct timer_list *timer)
 /*
  * TIPC message buffer code
  *
- * TIPC message buffer headroom leaves room for 14 byte Ethernet header, 
+ * TIPC message buffer headroom reserves space for a link-level header
+ * (in case the message is sent off-node),
  * while ensuring TIPC header is word aligned for quicker access
+ *
+ * The largest header currently supported is 18 bytes, which is used when
+ * the standard 14 byte Ethernet header has 4 added bytes for VLAN info
  */
 
-#define BUF_HEADROOM 16u 
+#define BUF_HEADROOM 20u
 
 struct tipc_skb_cb {
 	void *handle;