diff --git a/ggsn_tests/GGSN_Tests.ttcn b/ggsn_tests/GGSN_Tests.ttcn
index b802564..28f461c 100644
--- a/ggsn_tests/GGSN_Tests.ttcn
+++ b/ggsn_tests/GGSN_Tests.ttcn
@@ -747,6 +747,18 @@
 		}
 	}
 
+	/* template for an ICMPv6 echo request */
+	template PDU_ICMP tr_ICMPv4_ERQ := {
+		echo := {
+			type_field := 8,
+			code := 0,
+			checksum := ?,
+			identifier := ?,
+			sequence_number := ?,
+			data := ?
+		}
+	}
+
 	/* template for an ICMPv4 echo reply */
 	template PDU_ICMP tr_ICMPv4_ERP(template octetstring data := *) := {
 		echo_reply := {
@@ -910,6 +922,18 @@
 		}
 	}
 
+	/* template for an ICMPv6 echo request */
+	template PDU_ICMPv6 tr_ICMPv6_ERQ := {
+		echoRequest := {
+			typeField := 128,
+			code := 0,
+			checksum := ?,
+			identifier := ?,
+			sequenceNr := ?,
+			data := ?
+		}
+	}
+
 	/* template for receiving/matching an ICMPv6 echo reply */
 	template PDU_ICMPv6 tr_ICMPv6_ERP(template octetstring data := *) := {
 		echoReply := {
@@ -1038,6 +1062,11 @@
 		T_default.stop;
 	}
 
+	/* Wait for ICMPv4 echo request from GTP */
+	function f_wait_icmp4_echo_request(PdpContext ctx) runs on GT_CT {
+		f_wait_icmp4(ctx, tr_ICMPv4_ERQ);
+	}
+
 	/* Wait for ICMPv4 echo reply (or unreachable) from GTP */
 	function f_wait_icmp4_echo_reply(PdpContext ctx) runs on GT_CT {
 		f_wait_icmp4(ctx, (tr_ICMPv4_ERP, tr_ICMPv4_DU));
@@ -1076,6 +1105,11 @@
 		f_wait_icmp6(ctx, tr_ICMPv6_RA(?, 64));
 	}
 
+	/* Wait for ICMPv6 echo request from GTP */
+	function f_wait_icmp6_echo_request(PdpContext ctx) runs on GT_CT {
+		f_wait_icmp6(ctx, tr_ICMPv6_ERQ);
+	}
+
 	/* Wait for ICMPv6 echo reply (or unreachable) from GTP */
 	function f_wait_icmp6_echo_reply(PdpContext ctx) runs on GT_CT {
 		f_wait_icmp6(ctx, (tr_ICMPv6_ERP,tr_ICMPv6_DU));
@@ -1183,6 +1217,37 @@
 		f_pdp_ctx_del(ctx, '1'B);
 	}
 
+	/* Validate if different clients (pdp ctx) can reach one another through GGSN. */
+	testcase TC_pdp6_clients_interact() runs on GT_CT {
+		f_init();
+		var PdpContext ctxA := valueof(t_DefinePDP(f_rnd_imsi('26242'H), '1234'O, c_ApnInet6, valueof(t_EuaIPv6Dyn)));
+		var PdpContext ctxB := valueof(t_DefinePDP(f_rnd_imsi('26242'H), '1234'O, c_ApnInet6, valueof(t_EuaIPv6Dyn)));
+		f_pdp_ctx_act(ctxA);
+		f_send_gtpu(ctxA, f_icmpv6_rs_for_pdp(ctxA));
+		f_wait_rtr_adv(ctxA);
+		f_send_gtpu(ctxA, f_gen_icmpv6_neigh_solicit_for_pdp(ctxA));
+
+		f_pdp_ctx_act(ctxB);
+		f_send_gtpu(ctxB, f_icmpv6_rs_for_pdp(ctxB));
+		f_wait_rtr_adv(ctxB);
+		f_send_gtpu(ctxB, f_gen_icmpv6_neigh_solicit_for_pdp(ctxB));
+
+		var OCT16 addrA_ll := f_ipv6_link_local(ctxA.eua.endUserAddress.endUserAddressIPv6.ipv6_address);
+		var OCT16 addrB_ll := f_ipv6_link_local(ctxB.eua.endUserAddress.endUserAddressIPv6.ipv6_address);
+		var OCT16 addrA_glob := f_ipv6_global(ctxA.eua.endUserAddress.endUserAddressIPv6.ipv6_address);
+		var OCT16 addrB_glob := f_ipv6_global(ctxB.eua.endUserAddress.endUserAddressIPv6.ipv6_address);
+
+		/* Validate if clients can interact using ll addr. */
+		f_send_gtpu(ctxA, f_gen_icmpv6_echo(addrA_ll, addrB_ll));
+		f_wait_gtpu_fail(ctxB);
+
+		/* Validate if clients can interact using global addr. */
+		f_send_gtpu(ctxA, f_gen_icmpv6_echo(addrA_glob, addrB_glob));
+		f_wait_gtpu_fail(ctxB);
+
+		f_pdp_ctx_del(ctxA, '1'B);
+	}
+
 	/* Test PDP context activation for dynamic IPv4 EUA without DNS request */
 	testcase TC_pdp4_act_deact() runs on GT_CT {
 		f_init();
@@ -1263,6 +1328,21 @@
 		f_pdp_ctx_del(ctx, '1'B);
 	}
 
+	/* Validate if different clients (pdp ctx) can reach one another through GGSN. */
+	testcase TC_pdp4_clients_interact() runs on GT_CT {
+		f_init();
+		var PdpContext ctxA := valueof(t_DefinePDP(f_rnd_imsi('26242'H), '1234'O, c_ApnInternet, valueof(t_EuaIPv4Dyn)));
+		var PdpContext ctxB := valueof(t_DefinePDP(f_rnd_imsi('26242'H), '1234'O, c_ApnInternet, valueof(t_EuaIPv4Dyn)));
+		f_pdp_ctx_act(ctxA);
+		f_pdp_ctx_act(ctxB);
+		var OCT4 addrA := ctxA.eua.endUserAddress.endUserAddressIPv4.ipv4_address;
+		var OCT4 addrB := ctxB.eua.endUserAddress.endUserAddressIPv4.ipv4_address;
+		f_send_gtpu(ctxA, f_gen_icmpv4_echo(addrA, addrB));
+		f_wait_icmp4_echo_request(ctxB);
+
+		f_pdp_ctx_del(ctxA, '1'B);
+	}
+
 	testcase TC_echo_req_resp() runs on GT_CT {
 		f_init();
 		f_send_gtpc(ts_GTPC_PING(g_peer_c, g_c_seq_nr));
@@ -1280,11 +1360,13 @@
 		execute(TC_pdp4_act_deact_ipcp());
 		execute(TC_pdp4_act_deact_pcodns());
 		execute(TC_pdp4_act_deact_gtpu_access());
+		execute(TC_pdp4_clients_interact());
 
 		execute(TC_pdp6_act_deact());
 		execute(TC_pdp6_act_deact_pcodns());
 		execute(TC_pdp6_act_deact_icmp6());
 		execute(TC_pdp6_act_deact_gtpu_access());
+		execute(TC_pdp6_clients_interact());
 
 		execute(TC_echo_req_resp());
 	}