diff --git a/include/osmocom/sgsn/gprs_sgsn.h b/include/osmocom/sgsn/gprs_sgsn.h
index 33b12dc..5f30889 100644
--- a/include/osmocom/sgsn/gprs_sgsn.h
+++ b/include/osmocom/sgsn/gprs_sgsn.h
@@ -353,6 +353,8 @@
 	int remote_restart_ctr;
 	struct gsn_t *gsn;
 	struct llist_head pdp_list;	/* list of associated pdp ctx (struct sgsn_pdp_ctx*) */
+	struct osmo_timer_list echo_timer;
+	int echo_interval;
 };
 struct sgsn_ggsn_ctx *sgsn_ggsn_ctx_alloc(uint32_t id);
 void sgsn_ggsn_ctx_free(struct sgsn_ggsn_ctx *ggc);
@@ -360,6 +362,8 @@
 struct sgsn_ggsn_ctx *sgsn_ggsn_ctx_by_addr(struct in_addr *addr);
 struct sgsn_ggsn_ctx *sgsn_ggsn_ctx_find_alloc(uint32_t id);
 int sgsn_ggsn_ctx_drop_all_pdp(struct sgsn_ggsn_ctx *ggsn);
+void sgsn_ggsn_ctx_add_pdp(struct sgsn_ggsn_ctx *ggc, struct sgsn_pdp_ctx *pdp);
+void sgsn_ggsn_ctx_remove_pdp(struct sgsn_ggsn_ctx *ggc, struct sgsn_pdp_ctx *pdp);
 
 struct apn_ctx {
 	struct llist_head list;
diff --git a/include/osmocom/sgsn/sgsn.h b/include/osmocom/sgsn/sgsn.h
index 829a8fc..dae9d12 100644
--- a/include/osmocom/sgsn/sgsn.h
+++ b/include/osmocom/sgsn/sgsn.h
@@ -171,6 +171,7 @@
 					 struct tlv_parsed *tp);
 int sgsn_delete_pdp_ctx(struct sgsn_pdp_ctx *pctx);
 void sgsn_pdp_upd_gtp_u(struct sgsn_pdp_ctx *pdp, void *addr, size_t alen);
+void sgsn_ggsn_echo_req(struct sgsn_ggsn_ctx *ggc);
 
 /* gprs_sndcp.c */