diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index f94f4570143170d9ec5ccb78add318f667921d7c..b1caa1f057487ea6ee814016a07df1105e0e80ee 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -7417,6 +7417,7 @@ static int sip_answer(struct ast_channel *ast)
 {
 	int res = 0;
 	struct sip_pvt *p = ast_channel_tech_pvt(ast);
+	int oldsdp = FALSE;
 
 	if (!p) {
 		ast_debug(1, "Asked to answer channel %s without tech pvt; ignoring\n",
@@ -7427,10 +7428,14 @@ static int sip_answer(struct ast_channel *ast)
 	if (ast_channel_state(ast) != AST_STATE_UP) {
 		try_suggested_sip_codec(p);
 
+		if (ast_test_flag(&p->flags[0], SIP_PROGRESS_SENT)) {
+			oldsdp = TRUE;
+		}
+
 		ast_setstate(ast, AST_STATE_UP);
 		ast_debug(1, "SIP answering channel: %s\n", ast_channel_name(ast));
 		ast_rtp_instance_update_source(p->rtp);
-		res = transmit_response_with_sdp(p, "200 OK", &p->initreq, XMIT_CRITICAL, FALSE, TRUE);
+		res = transmit_response_with_sdp(p, "200 OK", &p->initreq, XMIT_CRITICAL, oldsdp, TRUE);
 		ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 	}
 	sip_pvt_unlock(p);