diff --git a/lib/socket.h b/lib/socket.h
index c642bdf9..d3fd7450 100644
--- a/lib/socket.h
+++ b/lib/socket.h
@@ -83,18 +83,23 @@ sk_send_buffer_empty(sock *sk)
 #define SK_TCP_PASSIVE	0	   /* ?  *  -  -  -  ?   -	*/
 #define SK_TCP_ACTIVE	1          /* ?  ?  *  *  -  ?   -	*/
 #define SK_TCP		2
-#define SK_UDP		3          /* ?  ?  -  -  -  ?   ?	*/
-#define SK_IP		5          /* ?  -  -  *  -  ?   ?	*/
+#define SK_UDP		3          /* ?  ?  ?  ?  ?  ?   ?	*/
+#define SK_IP		5          /* ?  -  ?  *  ?  ?   ?	*/
 #define SK_MAGIC	7	   /* Internal use by sysdep code */
 #define SK_UNIX_PASSIVE	8
 #define SK_UNIX		9
 
 /*
- *  Multicast sockets are slightly different from the other ones:
- *  If you want to send packets only, just set the destination
- *  address to the corresponding multicast group and iface to
- *  the interface to be used. If you also want receiving, set
- *  source address to the same multicast group as well.
+ *  For SK_UDP or SK_IP sockets setting DA/DP allows to use sk_send(),
+ *  otherwise sk_send_to() must be used.
+ *
+ *  For SK_IP sockets setting DP specifies protocol number, which is used
+ *  for both receiving and sending.
+ *
+ *  For multicast on SK_UDP or SK_IP sockets set IF and TTL,
+ *  call sk_setup_multicast() to enable multicast on that socket,
+ *  and then use sk_join_group() and sk_leave_group() to manage
+ *  a set of received multicast groups.
  */
 
 #endif
diff --git a/proto/ospf/rt.h b/proto/ospf/rt.h
index d4b85ae2..5020b473 100644
--- a/proto/ospf/rt.h
+++ b/proto/ospf/rt.h
@@ -22,7 +22,7 @@ typedef struct orta
      In OSPFv2, ASBRs from another areas (that we know from rt-summary-lsa),
      have just ORTA_ASBR in options, their real options are unknown */
 #define ORTA_ASBR OPT_RT_E
-#define ORTA_ABR  OPT_RT_V
+#define ORTA_ABR  OPT_RT_B
   struct ospf_area *oa;
   u32 metric1;
   u32 metric2;