diff --git a/sys/net/crosslayer/net_help/net_help.c b/sys/net/crosslayer/net_help/net_help.c
index 8939e058ab..7ffc29f1cb 100644
--- a/sys/net/crosslayer/net_help/net_help.c
+++ b/sys/net/crosslayer/net_help/net_help.c
@@ -19,7 +19,7 @@
 
 #include "net_help.h"
 
-uint16_t csum(uint16_t sum, uint8_t *buf, uint16_t len)
+uint16_t net_help_csum(uint16_t sum, uint8_t *buf, uint16_t len)
 {
     int count = len >> 1;
 
diff --git a/sys/net/include/net_help.h b/sys/net/include/net_help.h
index 0c4377cf1f..c743ef8110 100644
--- a/sys/net/include/net_help.h
+++ b/sys/net/include/net_help.h
@@ -65,7 +65,20 @@ static inline uint64_t NTOHLL(uint64_t a)
     return byteorder_ntohll(*(network_uint64_t *) &a);
 }
 
-uint16_t csum(uint16_t sum, uint8_t *buf, uint16_t len);
+/**
+ * @brief   Computes the Internet Checksum for *buf* with initial value *init*
+ *
+ * @see <a href="https://tools.ietf.org/html/rfc1071">
+ *          RFC 1071
+ *      </a>
+ *
+ * @param[in] init      Initial value for the checksum (0 in most cases)
+ * @param[in] buf       A byte array to calculate the checksum of
+ * @param[in] buf_len   Length of *buf*
+ *
+ * @return  The Internet Checksum of *buf* with initial value *init*
+ */
+uint16_t net_help_csum(uint16_t init, uint8_t *buf, uint16_t buf_len);
 
 #ifdef __cplusplus
 }
diff --git a/sys/net/network_layer/sixlowpan/icmp.c b/sys/net/network_layer/sixlowpan/icmp.c
index 1490f35cb9..3a8bc8989c 100644
--- a/sys/net/network_layer/sixlowpan/icmp.c
+++ b/sys/net/network_layer/sixlowpan/icmp.c
@@ -1437,8 +1437,8 @@ uint16_t icmpv6_csum(ipv6_hdr_t *ipv6_buf, icmpv6_hdr_t *icmpv6_buf)
     icmpv6_buf->checksum = 0;
     sum = len + IPV6_PROTO_NUM_ICMPV6;
 
-    sum = csum(sum, (uint8_t *)&ipv6_buf->srcaddr, 2 * sizeof(ipv6_addr_t));
-    sum = csum(sum, (uint8_t *)icmpv6_buf, len);
+    sum = net_help_csum(sum, (uint8_t *)&ipv6_buf->srcaddr, 2 * sizeof(ipv6_addr_t));
+    sum = net_help_csum(sum, (uint8_t *)icmpv6_buf, len);
 
     return (sum == 0) ? 0 : ~HTONS(sum);
 }
diff --git a/sys/net/network_layer/sixlowpan/ip.c b/sys/net/network_layer/sixlowpan/ip.c
index c0955827ff..8ad2ccb3d0 100644
--- a/sys/net/network_layer/sixlowpan/ip.c
+++ b/sys/net/network_layer/sixlowpan/ip.c
@@ -820,7 +820,7 @@ uint16_t ipv6_csum(ipv6_hdr_t *ipv6_header, uint8_t *buf, uint16_t len, uint8_t
                            &ipv6_header->destaddr),
           len, buf, proto);
     sum = len + proto;
-    sum = csum(sum, (uint8_t *)&ipv6_header->srcaddr, 2 * sizeof(ipv6_addr_t));
-    sum = csum(sum, buf, len);
+    sum = net_help_csum(sum, (uint8_t *)&ipv6_header->srcaddr, 2 * sizeof(ipv6_addr_t));
+    sum = net_help_csum(sum, buf, len);
     return (sum == 0) ? 0xffff : HTONS(sum);
 }
diff --git a/sys/net/transport_layer/udp/udp.c b/sys/net/transport_layer/udp/udp.c
index 3bf2b48112..230ac61674 100644
--- a/sys/net/transport_layer/udp/udp.c
+++ b/sys/net/transport_layer/udp/udp.c
@@ -43,8 +43,8 @@ uint16_t udp_csum(ipv6_hdr_t *ipv6_header, udp_hdr_t *udp_header)
     uint16_t len = NTOHS(udp_header->length);
 
     sum = len + IPPROTO_UDP;
-    sum = csum(sum, (uint8_t *)&ipv6_header->srcaddr, 2 * sizeof(ipv6_addr_t));
-    sum = csum(sum, (uint8_t *)udp_header, len);
+    sum = net_help_csum(sum, (uint8_t *)&ipv6_header->srcaddr, 2 * sizeof(ipv6_addr_t));
+    sum = net_help_csum(sum, (uint8_t *)udp_header, len);
     return (sum == 0) ? 0xffff : HTONS(sum);
 }