diff --git a/daemon/call.c b/daemon/call.c
index 54de3542d..5f6c19c7d 100644
--- a/daemon/call.c
+++ b/daemon/call.c
@@ -359,7 +359,7 @@ static int __k_srtp_crypt(struct mediaproxy_srtp *s, struct crypto_context *c) {
 		.hmac		= c->crypto_suite->kernel_hmac,
 		.mki		= c->mki,
 		.mki_len	= c->mki_len,
-		.last_index	= c->s_l,
+		.last_index	= c->last_index,
 		.auth_tag_len	= c->crypto_suite->srtp_auth_tag,
 	};
 	memcpy(s->master_key, c->master_key, c->crypto_suite->master_key_len);
@@ -1071,13 +1071,13 @@ static void callmaster_timer(void *ptr) {
 		update = 0;
 
 		if (sr->other->crypto.out.crypto_suite
-				&& ke->target.encrypt.last_index - sr->other->crypto.out.s_l > 0x4000) {
-			sr->other->crypto.out.s_l = ke->target.encrypt.last_index;
+				&& ke->target.encrypt.last_index - sr->other->crypto.out.last_index > 0x4000) {
+			sr->other->crypto.out.last_index = ke->target.encrypt.last_index;
 			update = 1;
 		}
 		if (sr->crypto.in.crypto_suite
-				&& ke->target.decrypt.last_index - sr->crypto.in.s_l > 0x4000) {
-			sr->crypto.in.s_l = ke->target.decrypt.last_index;
+				&& ke->target.decrypt.last_index - sr->crypto.in.last_index > 0x4000) {
+			sr->crypto.in.last_index = ke->target.decrypt.last_index;
 			update = 1;
 		}
 
diff --git a/daemon/crypto.h b/daemon/crypto.h
index 4e5a2aef1..280484643 100644
--- a/daemon/crypto.h
+++ b/daemon/crypto.h
@@ -55,9 +55,7 @@ struct crypto_context {
 	unsigned int mki_len;
 	unsigned int tag;
 
-	/* from rfc 3711 */
-	u_int32_t roc;
-	u_int64_t s_l;
+	u_int64_t last_index;
 	/* XXX replay list */
 	/* <from, to>? */
 
diff --git a/daemon/rtcp.c b/daemon/rtcp.c
index 446c9e442..0eea8efc1 100644
--- a/daemon/rtcp.c
+++ b/daemon/rtcp.c
@@ -395,11 +395,11 @@ int rtcp_avp2savp(str *s, struct crypto_context *c) {
 	if (check_session_keys(c))
 		return -1;
 
-	if (crypto_encrypt_rtcp(c, rtcp, &payload, c->s_l))
+	if (crypto_encrypt_rtcp(c, rtcp, &payload, c->last_index))
 		return -1;
 
 	idx = (void *) s->s + s->len;
-	*idx = htonl(0x80000000ULL | c->s_l++);
+	*idx = htonl(0x80000000ULL | c->last_index++);
 	s->len += sizeof(*idx);
 
 	to_auth = *s;
diff --git a/daemon/rtp.c b/daemon/rtp.c
index a3ce49901..9fb088f36 100644
--- a/daemon/rtp.c
+++ b/daemon/rtp.c
@@ -96,15 +96,15 @@ static u_int64_t packet_index(struct crypto_context *c, struct rtp_header *rtp)
 
 	seq = ntohs(rtp->seq_num);
 	/* rfc 3711 section 3.3.1 */
-	if (G_UNLIKELY(!c->s_l))
-		c->s_l = seq;
+	if (G_UNLIKELY(!c->last_index))
+		c->last_index = seq;
 
 	/* rfc 3711 appendix A, modified, and sections 3.3 and 3.3.1 */
-	index = ((u_int64_t) c->roc << 16) | seq;
-	diff = index - c->s_l;
+	index = (c->last_index & 0xffffffff0000ULL) | seq;
+	diff = index - c->last_index;
 	if (diff >= 0) {
 		if (diff < 0x8000)
-			c->s_l = index;
+			c->last_index = index;
 		else if (index >= 0x10000)
 			index -= 0x10000;
 	}
@@ -113,8 +113,7 @@ static u_int64_t packet_index(struct crypto_context *c, struct rtp_header *rtp)
 			;
 		else {
 			index += 0x10000;
-			c->roc++;
-			c->s_l = index;
+			c->last_index = index;
 		}
 	}