diff --git a/inarp.c b/inarp.c
index 7a71247..46a9e9c 100644
--- a/inarp.c
+++ b/inarp.c
@@ -39,10 +39,10 @@
 							)
 
 struct ARP_DATA {
-	unsigned char src_mac[ETH_ALEN];	//source mac addr
-	unsigned char src_ip[4];	//source ip addr
-	unsigned char dest_mac[ETH_ALEN];	//dest mac addr
-	unsigned char dest_ip[4];	//dest ip 
+	unsigned char src_mac[ETH_ALEN];
+	unsigned char src_ip[4];
+	unsigned char dest_mac[ETH_ALEN];
+	unsigned char dest_ip[4];
 };
 struct ETH_ARP_PACKET {
 	struct ethhdr eh;
@@ -66,41 +66,39 @@
 	struct ethhdr *eh = &eth_arp->eh;
 	struct arphdr *arp = &eth_arp->arp;
 	struct ARP_DATA *arp_data = &eth_arp->arp_data;
-	/*target address */
 	struct sockaddr_ll socket_address;
-	/*prepare sockaddr_ll */
-	/*RAW communication */
+
+	/* Prepare our link-layer address: raw packet interface,
+	 * using the ifindex interface, receiving ARP packets
+	 */
 	socket_address.sll_family = PF_PACKET;
-	/*we don't use a protocoll above ethernet layer
-	   ->just use anything here */
 	socket_address.sll_protocol = htons(ETH_P_ARP);
-	/*index of the network device
-	   see full code later how to retrieve it */
 	socket_address.sll_ifindex = ifindex;
-	/*ARP hardware identifier is ethernet */
 	socket_address.sll_hatype = ARPHRD_ETHER;
-	/*target is another host */
 	socket_address.sll_pkttype = PACKET_OTHERHOST;
-	/*address length */
 	socket_address.sll_halen = ETH_ALEN;
 	memcpy(socket_address.sll_addr, dest_mac, ETH_ALEN);
-	/*set the frame header */
+
+	/* set the frame header */
 	memcpy((void *)eh->h_dest, (void *)dest_mac, ETH_ALEN);
 	memcpy((void *)eh->h_source, (void *)src_mac, ETH_ALEN);
 	eh->h_proto = htons(ETH_P_ARP);
-	/*fill InARP request data for ethernet + ipv4 */
+
+	/* Fill InARP request data for ethernet + ipv4 */
 	arp->ar_hrd = htons(ARPHRD_ETHER);
 	arp->ar_pro = htons(ETH_P_ARP);
 	arp->ar_hln = ETH_ALEN;
 	arp->ar_pln = 4;
 	arp->ar_op = htons(ar_op);
-	//fill arp ethernet mac & ipv4 info
+
+	/* fill arp ethernet mac & ipv4 info */
 	arp_data = (void *)(arp + 1);
-	memcpy(arp_data->src_mac, (void *)src_mac, ETH_ALEN);	//source mac addr
-	memcpy(arp_data->src_ip, src_ip, 4);	//source ip addr
-	memcpy(arp_data->dest_mac, (void *)dest_mac, ETH_ALEN);	//dest mac addr
-	memcpy(arp_data->dest_ip, dest_ip, 4);	//dest ip 
-	/*send the packet */
+	memcpy(arp_data->src_mac, (void *)src_mac, ETH_ALEN);
+	memcpy(arp_data->src_ip, src_ip, 4);
+	memcpy(arp_data->dest_mac, (void *)dest_mac, ETH_ALEN);
+	memcpy(arp_data->dest_ip, dest_ip, 4);
+
+	/* send the packet */
 	send_result = sendto(fd, eth_arp, ETH_ARP_FRAME_LEN, 0,
 			     (struct sockaddr *)&socket_address,
 			     sizeof(socket_address));
@@ -165,7 +163,7 @@
 	}
 }
 
-//return node_id or -1 for error
+/* return node_id or -1 for error */
 int get_node_id_by_mac_address(unsigned char *target_mac_addr)
 {
 	char mac_addr[ETH_ALEN];
@@ -176,11 +174,6 @@
 			break;
 	}
 	if (i != MAX_SERVER_NODE) {
-//              int j;
-//              printf("mac_address for node[%d]:", i+1);
-//              for (j=0; j<6; j++)
-//                      printf("%02x:", 0xff & mac_addr[j]);
-//              printf("\n");
 		return i;
 	} else
 		return -1;
@@ -218,7 +211,7 @@
 {
 	int fd, ret;
 	/*buffer for ethernet frame */
-	static unsigned char buffer[ETH_FRAME_LEN];	/* single packets are usually not bigger than 8192 bytes */
+	static unsigned char buffer[ETH_FRAME_LEN];
 	int send_result = 0;
 	static struct ifreq ifreq_buffer;
 	const char *ifname;
@@ -235,18 +228,16 @@
 		return EXIT_FAILURE;
 	}
 
-	/*our MAC address */
 	static unsigned char src_mac[6];
 	static unsigned char src_ip[4];
 	int ifindex;
-//      int InARP_SERVER;
 
 	if (((fd = socket(AF_PACKET, SOCK_PACKET, htons(ETH_P_ARP)))) == -1) {
-//      if (((fd = socket (AF_PACKET, SOCK_RAW, 0))) == -1) {
 		printf("socket: [%s]\n", strerror(errno));
 		exit(-1);
 	}
-	//local mac address
+
+	/* Query local mac address */
 	memset(&ifreq_buffer, 0x00, sizeof(ifreq_buffer));
 	strcpy(ifreq_buffer.ifr_name, ifname);
 	ret = ioctl(fd, SIOCGIFHWADDR, &ifreq_buffer);
@@ -257,7 +248,8 @@
 	}
 	memcpy(src_mac, ifreq_buffer.ifr_hwaddr.sa_data, ETH_ALEN);
 	show_mac_addr(ifname, src_mac);
-	//interface index
+
+	/* find the ifindex of the interface we're using */
 	memset(&ifreq_buffer, 0x00, sizeof(ifreq_buffer));
 	strcpy(ifreq_buffer.ifr_name, ifname);
 	ret = ioctl(fd, SIOCGIFINDEX, &ifreq_buffer);
@@ -268,30 +260,24 @@
 	}
 	ifindex = ifreq_buffer.ifr_ifindex;
 
-	int length = 0;		/*length of the received frame */
-	static struct ETH_ARP_PACKET *inarp_req = (struct ETH_ARP_PACKET *)buffer;	/* single packets are usually not bigger than 8192 bytes */
-	static struct ETH_ARP_PACKET inarp_resp;	/* single packets are usually not bigger than 8192 bytes */
-	//argv[2]: file name used for storing node ip list
-	//                      line format in file: <node_id> <mac_addr> <ip_addr>
-	//get based address via EMS
-	//set socket as async
-//      fcntl(fd, F_SETFL,O_NONBLOCK|FASYNC);
-	//got based address
+	/* length of the received frame */
+	int length = 0;
+	static struct ETH_ARP_PACKET *inarp_req =
+		(struct ETH_ARP_PACKET *)buffer;
+	static struct ETH_ARP_PACKET inarp_resp;
+
 	while (1) {
-		//get local ip address
+		/* get local ip address */
 		memset(&ifreq_buffer, 0x00, sizeof(ifreq_buffer));
 		strcpy(ifreq_buffer.ifr_name, ifname);
 		ret = ioctl(fd, SIOCGIFADDR, &ifreq_buffer);
 		if (ret == -1) {
-//                      printf("ioctl3: [%s]\n", strerror(errno));
 			sleep(1);
 			continue;
 		}
 
 		if (AF_INET == ifreq_buffer.ifr_addr.sa_family) {
 			memcpy(src_ip, &ifreq_buffer.ifr_addr.sa_data[2], 4);
-//                      show_ip_addr("local", (unsigned char *)&ifreq_buffer.ifr_addr.sa_data[2]);
-			//show_ip_addr("local", src_ip);
 		} else {
 			printf("unknown address family [%d]!\n",
 			       ifreq_buffer.ifr_addr.sa_family);
@@ -304,12 +290,8 @@
 		if (length == -1) {
 			sleep(1);
 		}
-//              printf("length = %d\r\nfd = %d\r\n", length, fd);
 		if (0 == memcmp(src_mac, inarp_req->eh.h_dest, ETH_ALEN)) {
-			if (ntohs(inarp_req->arp.ar_op) == ARPOP_InREQUEST) {	//get a inverse arp request
-//                              printf("[Rsp] InRequest\n");
-				//dump_data("got InARP request packet", buffer, length); 
-				//send inarp response
+			if (ntohs(inarp_req->arp.ar_op) == ARPOP_InREQUEST) {
 
 				printf
 				    ("src mac =%02x:%02x:%02x:%02x:%02x:%02x\r\n",
@@ -348,38 +330,6 @@
 					continue;
 				}
 			}
-//                      } else if (ntohs(inarp_req->arp.ar_op) == ARPOP_InREPLY) {      //get a InARP Response
-//                              int node_id;
-//                              printf("[Rsp] InReply\n");
-//                              node_id = get_node_id_by_mac_address(inarp_req->arp_data.src_mac);
-//                              if (node_id == -1) {
-//                                      //invalid node
-//                                      printf("%02x:%02x:%02x:%02x:%02x:%02x does not belong to this rack.",
-//                                                      inarp_req->arp_data.src_mac[0],
-//                                                      inarp_req->arp_data.src_mac[1],
-//                                                      inarp_req->arp_data.src_mac[2],
-//                                                      inarp_req->arp_data.src_mac[3],
-//                                                      inarp_req->arp_data.src_mac[4],
-//                                                      inarp_req->arp_data.src_mac[5]
-//                                      );
-//                              } else {
-			//valid node id
-//                                      node[node_id].update_time.tv_sec = current_time.tv_sec;
-			//update or remain node's ip
-//                                      if ((0 != memcmp(node[node_id].dest_ip, inarp_req->arp_data.src_ip, 4))) {
-			//ip address is changed.
-//                                              static char ipv4_addr[16];
-//                                              printf("[Rsp] update node[%d] ip @ %u\n", node_id+1, (unsigned)current_time.tv_sec);
-//                                                      show_mac_addr("[Rsp] ", inarp_req->arp_data.src_mac);
-//                                                      show_ip_addr("[Rsp] ", inarp_req->arp_data.src_ip);
-//                                                      memcpy(node[node_id].dest_ip, inarp_req->arp_data.src_ip, 4);
-//                                              sprintf(ipv4_addr, "%d.%d.%d.%d", 
-//                                                                      inarp_req->arp_data.src_ip[0],
-//                                                                      inarp_req->arp_data.src_ip[1],
-//                                                                      inarp_req->arp_data.src_ip[2],
-//                                                                      inarp_req->arp_data.src_ip[3]);
-//                                              printf("[Rsp] update node[%d] ip @ %u\n", node_id+1, (unsigned)current_time.tv_sec);
-//                      }
 			memset(buffer, 0, sizeof(buffer));
 		}
 	}