diff --git a/libknet/handle.c b/libknet/handle.c
index 11f9bc95..9a7e1c3f 100644
--- a/libknet/handle.c
+++ b/libknet/handle.c
@@ -1,452 +1,461 @@
 #include "config.h"
 
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
 #include <pthread.h>
 #include <sys/epoll.h>
 
 #include "libknet-private.h"
 #include "nsscrypto.h"
 
 #define KNET_MAX_EVENTS 8
 #define KNET_PING_TIMERES 200000
 
 static void *_handle_tap_to_links_thread(void *data);
 static void *_handle_recv_from_links_thread(void *data);
 static void *_handle_heartbt_thread(void *data);
 
 knet_handle_t knet_handle_new(const struct knet_handle_cfg *knet_handle_cfg)
 {
 	knet_handle_t knet_h;
 	struct epoll_event ev;
 
 	/*
 	 * validate incoming config request
 	 */
 	if (knet_handle_cfg == NULL) {
 		errno = EINVAL;
 		return NULL;
 	}
 
 	if (knet_handle_cfg->fd <= 0) {
 		errno = EINVAL;
 		return NULL;
 	}
 
 	if ((knet_h = malloc(sizeof(struct knet_handle))) == NULL)
 		return NULL;
 
 	memset(knet_h, 0, sizeof(struct knet_handle));
 
 	if (crypto_init(knet_h, knet_handle_cfg) < 0)
 		goto exit_fail1;
 
 	if ((knet_h->tap_to_links_buf = malloc(KNET_DATABUFSIZE))== NULL)
 		goto exit_fail2;
 
 	memset(knet_h->tap_to_links_buf, 0, KNET_DATABUFSIZE);
 
 	if ((knet_h->recv_from_links_buf = malloc(KNET_DATABUFSIZE))== NULL)
 		goto exit_fail3;
 
 	memset(knet_h->recv_from_links_buf, 0, KNET_DATABUFSIZE);
 
 	if ((knet_h->pingbuf = malloc(KNET_PINGBUFSIZE))== NULL)
 		goto exit_fail4;
 
 	memset(knet_h->pingbuf, 0, KNET_PINGBUFSIZE);
 
 	if (pthread_rwlock_init(&knet_h->list_rwlock, NULL) != 0)
 		goto exit_fail5;
 
 	knet_h->sockfd = knet_handle_cfg->fd;
 	knet_h->tap_to_links_epollfd = epoll_create(KNET_MAX_EVENTS);
 	knet_h->recv_from_links_epollfd = epoll_create(KNET_MAX_EVENTS);
 	knet_h->node_id = knet_handle_cfg->node_id;
 	knet_h->dst_nodeid_offset = knet_handle_cfg->dst_nodeid_offset;
 	knet_h->dst_nodeid_len = knet_handle_cfg->dst_nodeid_len;
 
 	if ((knet_h->tap_to_links_epollfd < 0) ||
 	    (knet_h->recv_from_links_epollfd < 0))
 		goto exit_fail6;
 
 	if ((_fdset_cloexec(knet_h->tap_to_links_epollfd) != 0) ||
 	    (_fdset_cloexec(knet_h->recv_from_links_epollfd != 0)))
 		goto exit_fail6;
 
 	memset(&ev, 0, sizeof(struct epoll_event));
 
 	ev.events = EPOLLIN;
 	ev.data.fd = knet_h->sockfd;
 
 	if (epoll_ctl(knet_h->tap_to_links_epollfd,
 				EPOLL_CTL_ADD, knet_h->sockfd, &ev) != 0)
 		goto exit_fail6;
 
 	if (pthread_create(&knet_h->tap_to_links_thread, 0,
 				_handle_tap_to_links_thread, (void *) knet_h) != 0)
 		goto exit_fail6;
 
 	if (pthread_create(&knet_h->recv_from_links_thread, 0,
 				_handle_recv_from_links_thread, (void *) knet_h) != 0)
 		goto exit_fail7;
 
 	if (pthread_create(&knet_h->heartbt_thread, 0,
 				_handle_heartbt_thread, (void *) knet_h) != 0)
 		goto exit_fail8;
 
 	return knet_h;
 
 exit_fail8:
 	pthread_cancel(knet_h->recv_from_links_thread);
 
 exit_fail7:
 	pthread_cancel(knet_h->tap_to_links_thread);
 
 exit_fail6:
 	if (knet_h->tap_to_links_epollfd >= 0)
 		close(knet_h->tap_to_links_epollfd);
 	if (knet_h->recv_from_links_epollfd >= 0)
 		close(knet_h->recv_from_links_epollfd);
 
 	pthread_rwlock_destroy(&knet_h->list_rwlock);
 
 exit_fail5:
 	free(knet_h->pingbuf);
 
 exit_fail4:
 	free(knet_h->recv_from_links_buf);
 
 exit_fail3:
 	free(knet_h->tap_to_links_buf);
 
 exit_fail2:
 	crypto_fini(knet_h);
 
 exit_fail1:
 	free(knet_h);
 	return NULL;
 }
 
 int knet_handle_free(knet_handle_t knet_h)
 {
 	void *retval;
 
 	if ((knet_h->host_head != NULL) || (knet_h->listener_head != NULL))
 		goto exit_busy;
 
 	pthread_cancel(knet_h->heartbt_thread);
 	pthread_join(knet_h->heartbt_thread, &retval);
 
 	if (retval != PTHREAD_CANCELED)
 		goto exit_busy;
 
 	pthread_cancel(knet_h->tap_to_links_thread);
 	pthread_join(knet_h->tap_to_links_thread, &retval);
 	if (retval != PTHREAD_CANCELED)
 		goto exit_busy;
 
 	pthread_cancel(knet_h->recv_from_links_thread);
 	pthread_join(knet_h->recv_from_links_thread, &retval);
 
 	if (retval != PTHREAD_CANCELED)
 		goto exit_busy;
 
 	close(knet_h->tap_to_links_epollfd);
 	close(knet_h->recv_from_links_epollfd);
 
 	pthread_rwlock_destroy(&knet_h->list_rwlock);
 
 	free(knet_h->tap_to_links_buf);
 	free(knet_h->recv_from_links_buf);
 	free(knet_h->pingbuf);
 
 	crypto_fini(knet_h);
 
 	free(knet_h);
 
 	return 0;
 
  exit_busy:
 	errno = EBUSY;
 	return -EBUSY;
 }
 
 void knet_handle_setfwd(knet_handle_t knet_h, int enabled)
 {
 	knet_h->enabled = (enabled == 1) ? 1 : 0;
 }
 
 void knet_link_timeout(struct knet_link *lnk,
 				time_t interval, time_t timeout, int precision)
 {
 	lnk->ping_interval = interval * 1000; /* microseconds */
 	lnk->pong_timeout = timeout * 1000; /* microseconds */
 	lnk->latency_fix = precision;
 	lnk->latency_exp = precision - \
 				((lnk->ping_interval * precision) / 8000000);
 }
 
 static void _handle_tap_to_links(knet_handle_t knet_h)
 {
 	int j;
 	ssize_t len, snt, outlen;
 	struct knet_host *i;
 
 	len = read(knet_h->sockfd, knet_h->tap_to_links_buf->kf_data,
-					KNET_DATABUFSIZE - KNET_FRAME_SIZE);
+					KNET_DATABUFSIZE - (KNET_FRAME_SIZE + sizeof(seq_num_t)));
 
 	if (len == 0) {
 		/* TODO: disconnection, should never happen! */
 		return;
 	}
 
-	len += KNET_FRAME_SIZE;
+	len += KNET_FRAME_SIZE + sizeof(seq_num_t);
 
 	if (knet_h->enabled != 1) /* data forward is disabled */
 		return;
 
 	/* TODO: packet inspection */
 
 	if (pthread_rwlock_rdlock(&knet_h->list_rwlock) != 0)
 		return;
 
+	/* Use bcast only pckts for now since we have no pckt inspector */
+	knet_h->tap_to_links_buf->kf_seq_num = ++knet_h->bcast_seq_num;
+
 	if (crypto_encrypt_and_sign(knet_h->crypto_instance,
 				    (const unsigned char *)knet_h->tap_to_links_buf,
 				    len,
 				    knet_h->tap_to_links_buf_crypt,
 				    &outlen) < 0)
 		return;
 
 	for (i = knet_h->host_head; i != NULL; i = i->next) {
 		for (j = 0; j < KNET_MAX_LINK; j++) {
-			if (i->link[j].enabled != 1) /* link is disabled */
+			if (i->link[j].ready != 1) /* link is not configured */
+				continue;
+			if (i->link[j].enabled != 1) /* link is not enabled */
 				continue;
 
 			snt = sendto(i->link[j].sock,
 					knet_h->tap_to_links_buf_crypt, outlen, MSG_DONTWAIT,
 					(struct sockaddr *) &i->link[j].address,
 					sizeof(struct sockaddr_storage));
 
-			if ((i->active == 0) && (snt == len))
+			if ((i->active == 0) && (snt == outlen))
 				break;
 		}
 	}
 
 	pthread_rwlock_unlock(&knet_h->list_rwlock);
 }
 
 static void _handle_recv_from_links(knet_handle_t knet_h, int sockfd)
 {
 	ssize_t len, outlen;
 	struct sockaddr_storage address;
 	socklen_t addrlen;
 	struct knet_host *src_host;
 	struct knet_link *src_link;
 	unsigned long long latency_last;
 
 	if (pthread_rwlock_rdlock(&knet_h->list_rwlock) != 0)
 		return;
 
 	addrlen = sizeof(struct sockaddr_storage);
 	len = recvfrom(sockfd, knet_h->recv_from_links_buf, KNET_DATABUFSIZE,
 		MSG_DONTWAIT, (struct sockaddr *) &address, &addrlen);
 
 	if (crypto_authenticate_and_decrypt(knet_h->crypto_instance,
 					    (unsigned char *)knet_h->recv_from_links_buf,
 					    &len) < 0)
 		goto exit_unlock;
 
 	if (len < (KNET_FRAME_SIZE + 1))
 		goto exit_unlock;
 
 	if (ntohl(knet_h->recv_from_links_buf->kf_magic) != KNET_FRAME_MAGIC)
 		goto exit_unlock;
 
 	if (knet_h->recv_from_links_buf->kf_version != KNET_FRAME_VERSION)
 		goto exit_unlock;
 
-	src_host = NULL;
+	knet_h->recv_from_links_buf->kf_node = ntohs(knet_h->recv_from_links_buf->kf_node);
+	src_host = knet_h->host_index[knet_h->recv_from_links_buf->kf_node];
+	if (src_host == NULL) {  /* host not found */
+		goto exit_unlock;
+	}
+
 	src_link = NULL;
 
 	if ((knet_h->recv_from_links_buf->kf_type & KNET_FRAME_PMSK) != 0) {
-		knet_h->recv_from_links_buf->kf_node = ntohs(knet_h->recv_from_links_buf->kf_node);
-		src_host = knet_h->host_index[knet_h->recv_from_links_buf->kf_node];
-
-		if (src_host == NULL)	/* host not found */
-			goto exit_unlock;
-
 		src_link = src_host->link +
 				(knet_h->recv_from_links_buf->kf_link % KNET_MAX_LINK);
 	}
 
 	switch (knet_h->recv_from_links_buf->kf_type) {
 	case KNET_FRAME_DATA:
 		if (knet_h->enabled != 1) /* data forward is disabled */
 			break;
 
+		if (!knet_should_deliver(src_host, 1, knet_h->recv_from_links_buf->kf_seq_num))
+			break;
+
 		write(knet_h->sockfd,
-			knet_h->recv_from_links_buf->kf_data, len - KNET_FRAME_SIZE);
+			knet_h->recv_from_links_buf->kf_data, len - (KNET_FRAME_SIZE + sizeof(seq_num_t)));
+
+		knet_has_been_delivered(src_host, 1, knet_h->recv_from_links_buf->kf_seq_num);
 
 		break;
 	case KNET_FRAME_PING:
 		knet_h->recv_from_links_buf->kf_type = KNET_FRAME_PONG;
 		knet_h->recv_from_links_buf->kf_node = htons(knet_h->node_id);
 
 		if (crypto_encrypt_and_sign(knet_h->crypto_instance,
 					    (const unsigned char *)knet_h->recv_from_links_buf,
 					    len,
 					    knet_h->recv_from_links_buf_crypt,
 					    &outlen) < 0)
 			break;
-					    
 
 		sendto(src_link->sock, knet_h->recv_from_links_buf_crypt, outlen, MSG_DONTWAIT,
 				(struct sockaddr *) &src_link->address,
 				sizeof(struct sockaddr_storage));
 
 		break;
 	case KNET_FRAME_PONG:
 		clock_gettime(CLOCK_MONOTONIC, &src_link->pong_last);
 
 		timespec_diff(knet_h->recv_from_links_buf->kf_time,
 				src_link->pong_last, &latency_last);
 
 		src_link->latency =
 			((src_link->latency * src_link->latency_exp) +
 			((latency_last / 1000llu) *
 				(src_link->latency_fix - src_link->latency_exp))) /
 					src_link->latency_fix;
 
 		if (src_link->latency < src_link->pong_timeout) {
 			if (!src_link->enabled) {
 				src_link->enabled = 1;
 				/* TODO: notify packet inspector */
 			}
 		}
 
 		break;
 	default:
 		goto exit_unlock;
 	}
 
  exit_unlock:
 	pthread_rwlock_unlock(&knet_h->list_rwlock);
 }
 
 static void _handle_check_each(knet_handle_t knet_h, struct knet_link *dst_link)
 {
 	int len;
 	ssize_t outlen;
 	struct timespec clock_now, pong_last;
 	unsigned long long diff_ping;
 
 	/* caching last pong to avoid race conditions */
 	pong_last = dst_link->pong_last;
 
 	if (clock_gettime(CLOCK_MONOTONIC, &clock_now) != 0)
 		return;
 
 	timespec_diff(dst_link->ping_last, clock_now, &diff_ping);
 
 	if (diff_ping >= (dst_link->ping_interval * 1000llu)) {
 		knet_h->pingbuf->kf_time = clock_now;
 		knet_h->pingbuf->kf_link = dst_link->link_id;
 
 		if (crypto_encrypt_and_sign(knet_h->crypto_instance,
 					    (const unsigned char *)knet_h->pingbuf,
 					    KNET_PINGBUFSIZE,
 					    knet_h->pingbuf_crypt,
 					    &outlen) < 0)
 		return;
 
 		len = sendto(dst_link->sock, knet_h->pingbuf_crypt, outlen,
 			MSG_DONTWAIT, (struct sockaddr *) &dst_link->address,
 			sizeof(struct sockaddr_storage));
 
 		if (len == outlen)
 			dst_link->ping_last = clock_now;
 	}
 
 	if (dst_link->enabled == 1) {
 		timespec_diff(pong_last, clock_now, &diff_ping);
 
 		if (diff_ping >= (dst_link->pong_timeout * 1000llu)) {
 			dst_link->enabled = 0; /* TODO: might need write lock */
 			/* TODO: notify packet inspector */
 		}
 	}
 }
 
 static void *_handle_heartbt_thread(void *data)
 {
 	int j;
 	knet_handle_t knet_h;
 	struct knet_host *i;
 
 	knet_h = (knet_handle_t) data;
 
 	/* preparing ping buffer */
 	knet_h->pingbuf->kf_magic = htonl(KNET_FRAME_MAGIC);
 	knet_h->pingbuf->kf_version = KNET_FRAME_VERSION;
 	knet_h->pingbuf->kf_type = KNET_FRAME_PING;
 	knet_h->pingbuf->kf_node = htons(knet_h->node_id);
 
 	while (1) {
 		usleep(KNET_PING_TIMERES);
 
 		if (pthread_rwlock_rdlock(&knet_h->list_rwlock) != 0)
 			continue;
 
 		for (i = knet_h->host_head; i != NULL; i = i->next) {
 			for (j = 0; j < KNET_MAX_LINK; j++) {
 				if (i->link[j].ready != 1) continue;
 				_handle_check_each(knet_h, &i->link[j]);
 			}
 		}
 
 		pthread_rwlock_unlock(&knet_h->list_rwlock);
 	}
 
 	return NULL;
 }
 
 static void *_handle_tap_to_links_thread(void *data)
 {
 	knet_handle_t knet_h;
 	struct epoll_event events[KNET_MAX_EVENTS];
 
 	knet_h = (knet_handle_t) data;
 
 	/* preparing data buffer */
 	knet_h->tap_to_links_buf->kf_magic = htonl(KNET_FRAME_MAGIC);
 	knet_h->tap_to_links_buf->kf_version = KNET_FRAME_VERSION;
 	knet_h->tap_to_links_buf->kf_type = KNET_FRAME_DATA;
+	knet_h->tap_to_links_buf->kf_node = htons(knet_h->node_id);
 
 	while (1) {
 		if (epoll_wait(knet_h->tap_to_links_epollfd, events, KNET_MAX_EVENTS, -1) >= 1)
 			_handle_tap_to_links(knet_h);
 	}
 
 	return NULL;
 
 }
 
 static void *_handle_recv_from_links_thread(void *data)
 {
 	int i, nev;
 	knet_handle_t knet_h = (knet_handle_t) data;
 	struct epoll_event events[KNET_MAX_EVENTS];
 
 	while (1) {
 		nev = epoll_wait(knet_h->recv_from_links_epollfd, events, KNET_MAX_EVENTS, -1);
 
 		for (i = 0; i < nev; i++) {
 			_handle_recv_from_links(knet_h, events[i].data.fd);
 		}
 	}
 
 	return NULL;
 }
diff --git a/libknet/host.c b/libknet/host.c
index fe012f0a..d20ccc80 100644
--- a/libknet/host.c
+++ b/libknet/host.c
@@ -1,150 +1,197 @@
 #include "config.h"
 
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <pthread.h>
 
 #include "libknet-private.h"
 
 int knet_host_get(knet_handle_t knet_h, uint16_t node_id, struct knet_host **host)
 {
 	int ret;
 
 	if ((ret = pthread_rwlock_rdlock(&knet_h->list_rwlock)) != 0)
 		return ret;
 
 	*host = knet_h->host_index[node_id];
 
 	if (*host == NULL) {
 		pthread_rwlock_unlock(&knet_h->list_rwlock);
 		errno = ENOENT;
 		return ENOENT;
 	}
 
 	return 0;
 }
 
 int knet_host_acquire(knet_handle_t knet_h, struct knet_host **host)
 {
 	int ret;
 
 	if ((ret = pthread_rwlock_rdlock(&knet_h->list_rwlock)) != 0)
 		return ret;
 
 	*host = knet_h->host_head;
 
 	return 0;
 }
 
 int knet_host_release(knet_handle_t knet_h, struct knet_host **host)
 {
 	int ret;
 
 	*host = NULL;
 
 	if ((ret = pthread_rwlock_unlock(&knet_h->list_rwlock)) != 0)
 		return ret;
 
 	return 0;
 }
 
 int knet_host_foreach(knet_handle_t knet_h, knet_link_fn_t linkfun, struct knet_host_search *data)
 {
 	int lockstatus;
 	struct knet_host *host;
 
 	lockstatus = pthread_rwlock_rdlock(&knet_h->list_rwlock);
 
 	if ((lockstatus != 0) && (lockstatus != EDEADLK))
 		return lockstatus;
 
 	for (host = knet_h->host_head; host != NULL; host = host->next) {
 		if ((linkfun(knet_h, host, data)) != KNET_HOST_FOREACH_NEXT)
 			break;
 	}
 
 	if (lockstatus == 0)
 		pthread_rwlock_unlock(&knet_h->list_rwlock);
 
 	return 0;
 }
 
 int knet_host_add(knet_handle_t knet_h, uint16_t node_id)
 {
 	int i, ret = 0; /* success */
 	struct knet_host *host;
 
 	if ((ret = pthread_rwlock_wrlock(&knet_h->list_rwlock)) != 0)
 		goto exit_clean;
 
 	if (knet_h->host_index[node_id] != NULL) {
 		errno = ret = EEXIST;
 		goto exit_unlock;
 	}
 
 	if ((host = malloc(sizeof(struct knet_host))) == NULL)
 		goto exit_unlock;
 
 	memset(host, 0, sizeof(struct knet_host));
 
 	host->node_id = node_id;
 
 	for (i = 0; i < KNET_MAX_LINK; i++)
 		host->link[i].link_id = i;
 
 	/* adding new host to the index */
 	knet_h->host_index[node_id] = host;
 
 	/* TODO: keep hosts ordered */
 	/* pushing new host to the front */
 	host->next		= knet_h->host_head;
 	knet_h->host_head	= host;
 
  exit_unlock:
 	pthread_rwlock_unlock(&knet_h->list_rwlock);
 
  exit_clean:
 	return ret;
 }
 
 int knet_host_remove(knet_handle_t knet_h, uint16_t node_id)
 {
 	int ret = 0; /* success */
 	struct knet_host *i, *removed;
 
 	if ((ret = pthread_rwlock_wrlock(&knet_h->list_rwlock)) != 0)
 		goto exit_clean;
 
 	if (knet_h->host_index[node_id] == NULL) {
 		errno = ret = EINVAL;
 		goto exit_unlock;
 	}
 
 	removed = NULL;
 
 	/* removing host from list */
 	if (knet_h->host_head->node_id == node_id) {
 		removed = knet_h->host_head;
 		knet_h->host_head = removed->next;
 	} else {
 		for (i = knet_h->host_head; i->next != NULL; i = i->next) {
 			if (i->next->node_id == node_id) {
 				removed = i->next;
 				i->next = removed->next;
 				break;
 			}
 		}
 	}
 
 	if (removed != NULL) {
 		knet_h->host_index[node_id] = NULL;
 		free(removed);
 	}
 
  exit_unlock:
 	pthread_rwlock_unlock(&knet_h->list_rwlock);
 
  exit_clean:
 	return ret;
 }
+
+/* bcast = 0 -> unicast packet | 1 -> broadcast|mcast */
+
+/* make this bcast/ucast aware */
+int knet_should_deliver(struct knet_host *host, int bcast, seq_num_t seq_num)
+{
+	size_t i, j; /* circular buffer indexes */
+	seq_num_t seq_dist;
+
+	seq_dist = (seq_num < host->bcast_seq_num_rx) ?
+		(SEQ_MAX - seq_num) + host->bcast_seq_num_rx : host->bcast_seq_num_rx - seq_num;
+
+	j = seq_num % KNET_CBUFFER_SIZE;
+
+	if (seq_dist < KNET_CBUFFER_SIZE) { /* seq num is in ring buffer */
+		return (host->bcast_circular_buffer[j] == 0) ? 1 : 0;
+	} else if (seq_dist <= SEQ_MAX - KNET_CBUFFER_SIZE) {
+		memset(host->bcast_circular_buffer, 0, KNET_CBUFFER_SIZE);
+		host->bcast_seq_num_rx = seq_num;
+	}
+
+	/* cleaning up circular buffer */
+	i = (host->bcast_seq_num_rx + 1) % KNET_CBUFFER_SIZE;
+
+	if (i > j) {
+		memset(host->bcast_circular_buffer + i, 0, KNET_CBUFFER_SIZE - i);
+		memset(host->bcast_circular_buffer, 0, j + 1);
+	} else {
+		memset(host->bcast_circular_buffer + i, 0, j - i + 1);
+	}
+
+	host->bcast_seq_num_rx = seq_num;
+
+	return 1;
+}
+
+void knet_has_been_delivered(struct knet_host *host, int bcast, seq_num_t seq_num)
+{
+
+	if (bcast) {
+		host->bcast_circular_buffer[seq_num % KNET_CBUFFER_SIZE] = 1;
+	} else {
+		host->ucast_circular_buffer[seq_num % KNET_CBUFFER_SIZE] = 1;
+	}
+
+	return;
+}
diff --git a/libknet/libknet-private.h b/libknet/libknet-private.h
index 2170bf04..151d60a4 100644
--- a/libknet/libknet-private.h
+++ b/libknet/libknet-private.h
@@ -1,50 +1,51 @@
 #ifndef __KNETHANDLE_H__
 #define __KNETHANDLE_H__
 
 /* NOTE: you shouldn't need to include this header normally, it is provided for
  *       testing purpose only.
  */
 
 #include "libknet.h"
 
 #define KNET_DATABUFSIZE 131072 /* 128k */
 #define KNET_PINGBUFSIZE sizeof(struct knet_frame)
 
 #define timespec_diff(start, end, diff) \
 do { \
 	if (end.tv_sec > start.tv_sec) \
 		*(diff) = ((end.tv_sec - start.tv_sec) * 1000000000llu) \
 					+ end.tv_nsec - start.tv_nsec; \
 	else \
 		*(diff) = end.tv_nsec - start.tv_nsec; \
 } while (0);
 
 struct knet_handle {
 	int sockfd;
 	int tap_to_links_epollfd;
 	int recv_from_links_epollfd;
 	uint16_t node_id;
 	unsigned int enabled:1;
 	struct knet_host *host_head;
 	struct knet_host *host_index[KNET_MAX_HOST];
 	struct knet_listener *listener_head;
 	struct knet_frame *tap_to_links_buf;
 	unsigned char *tap_to_links_buf_crypt;
 	struct knet_frame *recv_from_links_buf;
 	unsigned char *recv_from_links_buf_crypt;
 	struct knet_frame *pingbuf;
 	unsigned char *pingbuf_crypt;
 	pthread_t tap_to_links_thread;
 	pthread_t recv_from_links_thread;
 	pthread_t heartbt_thread;
 	pthread_rwlock_t list_rwlock;
 	struct crypto_instance *crypto_instance;
 	off_t dst_nodeid_offset;
 	size_t dst_nodeid_len;
 	seq_num_t bcast_seq_num;
-	seq_num_t ucast_seq_num;
 };
 
 int _fdset_cloexec(int fd);
+int knet_should_deliver(struct knet_host *host, int bcast, seq_num_t seq_num);
+void knet_has_been_delivered(struct knet_host *host, int bcast, seq_num_t seq_num);
 
 #endif
diff --git a/libknet/libknet.h b/libknet/libknet.h
index 53466a04..6843cef5 100644
--- a/libknet/libknet.h
+++ b/libknet/libknet.h
@@ -1,136 +1,141 @@
 #ifndef __RING_H__
 #define __RING_H__
 
 #include <stdint.h>
 #include <netinet/in.h>
 
 typedef struct knet_handle *knet_handle_t;
 
 #define KNET_RING_DEFPORT 50000
 #define KNET_RING_RCVBUFF 8388608
 
 #define KNET_MAX_HOST 65536
 #define KNET_MAX_LINK 8
 #define KNET_MAX_HOST_LEN 64
 
+#define KNET_CBUFFER_SIZE 4096
+/*
+typedef uint64_t seq_num_t;
+#define SEQ_MAX UINT64_MAX
+*/
+typedef uint16_t seq_num_t;
+#define SEQ_MAX UINT16_MAX
+
 struct knet_link {
 	uint8_t link_id;
 	int sock;
 	char ipaddr[KNET_MAX_HOST_LEN];
 	char port[6];
 	struct sockaddr_storage address;
 	unsigned int ready:1; /* link is configured and ready to be used */
 	unsigned int enabled:1;	/* link is enabled for data */
 	unsigned long long latency; /* average latency computed by fix/exp */
 	unsigned int latency_exp;
 	unsigned int latency_fix;
 	unsigned long long ping_interval;
 	unsigned long long pong_timeout;
 	struct timespec ping_last;
 	struct timespec pong_last;
 };
 
 struct knet_host {
 	uint16_t node_id;
 	char name[KNET_MAX_HOST_LEN];
 	unsigned int active:1; /* data packets are sent to all links */
+	char bcast_circular_buffer[KNET_CBUFFER_SIZE];
+	seq_num_t bcast_seq_num_rx;
+	char ucast_circular_buffer[KNET_CBUFFER_SIZE];
+	seq_num_t ucast_seq_num_tx;
+	seq_num_t ucast_seq_num_rx;
 	struct knet_listener *listener;
 	struct knet_link link[KNET_MAX_LINK];
 	struct knet_host *next;
 };
 
 struct knet_listener {
 	int sock;
 	char ipaddr[KNET_MAX_HOST_LEN];
 	char port[6];
 	struct sockaddr_storage address;
 	struct knet_listener *next;
 };
 
-/* change those to uint8 and UINT8_MAX to test rollover */
-/*
-typedef uint32_t seq_num_t;
-#define SEQ_MAX UINT32_MAX
-*/
-typedef uint16_t seq_num_t;
-#define SEQ_MAX UINT16_MAX
-
 union knet_frame_data {
 	struct {
 		seq_num_t	kfd_seq_num;
 		uint8_t		kfd_data[0];
 	} data;
 	struct {
 		uint8_t		kfd_link;
 		struct timespec	kfd_time;
 	} ping;
 } __attribute__((packed));
 
 struct knet_frame {
 	uint32_t 		kf_magic;
 	uint8_t			kf_version;
 	uint8_t			kf_type;
 	uint16_t		kf_node;
 	union knet_frame_data	kf_payload;
 } __attribute__((packed));
 
 #define kf_seq_num kf_payload.data.kfd_seq_num
 #define kf_data kf_payload.data.kfd_data
 #define kf_link kf_payload.ping.kfd_link
 #define kf_time kf_payload.ping.kfd_time
 
 #define KNET_FRAME_SIZE (sizeof(struct knet_frame) - sizeof(union knet_frame_data))
 
 #define KNET_FRAME_MAGIC 0x12344321
 #define KNET_FRAME_VERSION 0x01
 
 #define KNET_FRAME_DATA 0x00
 #define KNET_FRAME_PING 0x81
 #define KNET_FRAME_PONG 0x82
 #define KNET_FRAME_PMSK 0x80 /* ping/pong packet mask */
 
 #define KNET_MIN_KEY_LEN 1024
 #define KNET_MAX_KEY_LEN 4096
 
 struct knet_handle_cfg {
 	int		fd;
 	uint16_t	node_id;
 	char		*crypto_cipher_type;
 	char		*crypto_hash_type;
 	unsigned char	*private_key;
 	unsigned int	private_key_len;
 	off_t		dst_nodeid_offset; /* destination node_id offset in data packet */
 	size_t		dst_nodeid_len; /* 0 = broadcast to all, 1|2 256/64k nodes, > 2 == 2 */
 };
 
 knet_handle_t knet_handle_new(const struct knet_handle_cfg *knet_handle_cfg);
 void knet_handle_setfwd(knet_handle_t knet_h, int enabled);
 int knet_handle_free(knet_handle_t knet_h);
 
 int knet_host_add(knet_handle_t knet_h, uint16_t node_id);
 int knet_host_acquire(knet_handle_t knet_h, struct knet_host **host);
 int knet_host_get(knet_handle_t knet_h, uint16_t node_id, struct knet_host **host);
 int knet_host_release(knet_handle_t knet_h, struct knet_host **host);
 int knet_host_remove(knet_handle_t knet_h, uint16_t node_id);
 
 void knet_link_timeout(struct knet_link *lnk, time_t interval, time_t timeout, int precision);
 
 #define KNET_HOST_FOREACH_NEXT 0	/* next host */
 #define KNET_HOST_FOREACH_FOUND 1	/* host found, exit loop */
 
 struct knet_host_search {
 	int 			param1;	/* user parameter 1 */
 	void 			*data1;	/* user data pointer 1 */
 	void 			*data2;	/* user data pointer 2 */
 	int 			retval;	/* search return value */
 };
 
 typedef int (*knet_link_fn_t)(knet_handle_t knet_h, struct knet_host *host, struct knet_host_search *data);
 int knet_host_foreach(knet_handle_t knet_h, knet_link_fn_t linkfun, struct knet_host_search *data);
 
 int knet_listener_acquire(knet_handle_t knet_h, struct knet_listener **head, int writelock);
 int knet_listener_release(knet_handle_t knet_h);
 int knet_listener_add(knet_handle_t knet_h, struct knet_listener *listener);
 int knet_listener_remove(knet_handle_t knet_h, struct knet_listener *listener);
 
 #endif