WiFIX+: A Multicast Solution for based Wireless Mesh Networks

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "WiFIX+: A Multicast Solution for 802.11-based Wireless Mesh Networks"

Transcription

1 WiFIX+: A Multicast Solution for based Wireless Mesh Networks Rui Campos, Carlos Oliveira, José Ruela INESC Porto and Faculdade de Engenharia Universidade do Porto Rua Dr. Roberto Frias, Porto Abstract IEEE is currently one of the main wireless technologies enabling ubiquitous Internet access. With the growing demand for wireless Internet access and the limited radio range, based Wireless Mesh Networks have been proposed as a flexible and cost-effective solution to extend the radio coverage of existing network infrastructures. Many solutions have been proposed to create Wireless Mesh Networks automatically. However, they are either too complex or deal with multicast traffic inefficiently using pure flooding. We propose a simple and efficient solution, called WiFIX+, to forward multicast traffic over based Wireless Mesh Networks. It is based on WiFIX, an existing solution targeted at unicast traffic and extends it with new mechanisms. WiFIX+ was implemented and evaluated in a laboratorial test-bed. The experimental results obtained show that it outperforms IEEE s, the reference solution for based Wireless Mesh Networks, as far as data throughput, delay, and packet loss are concerned. I. INTRODUCTION The Internet has become the global communication infrastructure supporting a myriad of applications and services. These include multicast applications and services such as IPTV and audio/video conferencing, which increasingly require broadband access anytime, anywhere. IEEE is the most common technology used for broadband wireless network access. However, the radio coverage provided by this technology is limited and the installation of many Access Points (APs) connected to a wired infrastructure is required to cover a wide geographical area. This may be a costly solution. In order to overcome the problem, Wireless Mesh Networks (WMNs) have been proposed as a solution. In a WMN the nodes cooperate with each other wirelessly to forward packets between source and destination nodes that are not in radio range, as shown in Fig. 1. WMNs are seen as a flexible, cost-effective solution, with low complexity. Several solutions have been proposed to create WMN automatically. IEEE s [1] is the current IEEE standard targeting based WMNs. It uses pure flooding to deliver multicast traffic. More recently, a new solution, called Wi-Fi Network Infrastructure extension (WiFIX) was proposed [2]. WiFIX deals with unicast traffic more efficiently than s, but has not been optimized for multicast traffic. Specific solutions have been defined to cope with multicast over WMNs [3][4][5][6][7][8][9]. Yet, they introduce too much complexity when it comes to the wired infrastructure extension scenario. In this paper, we propose a new solution, called WiFIX+, which extends WiFIX with new mechanisms to efficiently handle multicast traffic. In addition, it supports terminal mobility without requiring changes to the terminals attaching to the WMN. Our contribution is two-fold. Firstly, we propose a new multicast solution for WMNs. Unlike most of the state of the art solutions, which simply flood multicast traffic over the WMN, WiFIX+ defines a multicast selective forwarding mechanism, where only the nodes that belong to a multicast group receive the corresponding frames. Secondly, as part of WiFIX+, we propose a mobility management mechanism based on a new application of the DHCP snooping technique, usually employed in network access control; it does not require any modification to terminals. The rest of the paper is organized as follows. Section 2 states and illustrates the problem, Section 3 presents some background information required to understand the proposed solution, and Section 4 presents the related work. Section 5 details the WiFIX+ solution and Section 6 describes its implementation under Linux OS. Section 7 deals with the WiFIX+ evaluation and, finally, Section 8 draws the conclusions and points out future work. II. PROBLEM STATEMENT A WMN is used to extend the wired infrastructure to wireless terminals. Terminals shall have access to all applications and services available in the infrastructure, including multicast applications and services, which are the focus herein. From the WMN viewpoint, multicast applications and services consist of multicast flows between the wired infrastructure and the wireless terminals attaching to the WMN; here, we assume that the source of such multicast flows is always located in the wired infrastructure, since this is the major case envisioned for WMNs employed in the infrastructure extension scenario shown in Fig. 1. The problem to solve is then how to route multicast flows across the WMN towards the mobile terminals irrespectively of their location in each moment. Fig. 1 can be used to illustrate the problem using a concrete example. In this scenario, we have a WMN composed of five MAPs (Mesh Access Points). Consider that there is a multicast

2 Multicast Services Current infrastructure Step 1 Step 2 Infrastructure extension UWB WMN MAP2 MAP1 Mobile Terminal 2 MAP3 Wi-Fi Network Mobile Terminal 1 (GMRP), but they are not used in practice. The default behavior of IEEE 802.1D bridges is to process multicast frames as broadcast frames. So, upon receiving a multicast frame an 802.1D bridge simply forwards it to all other ports except the incoming port, like they do to broadcast frames. Yet, this is not the most efficient approach, especially when only a small group of stations requested the corresponding multicast flow. MAP5 MAP4 B. IGMP Snooping Gateway Internet Ethernet Wi-Fi Network Mobile Terminal 2 Figure 1: WiFIX+ reference scenario. flow whose source is in the wired infrastruture network. This flow has to be delivered to the Mobile Terminals (MTs) 1 and 2, according to their current locations. In Step 1, MT1 is connected to MAP3 and MT2 to MAP2. Thus, within the WMN, the traffic has to be delivered to MAP2 and MAP3. In Step 2, MT1 moves to MAP4; therefore, the multicast flow has to be redirected to MAP4, as illustrated in the figure. III. BACKGROUND In this section, we review some important concepts related to WiFIX+, which uses the IEEE 802.1D forwarding mechanism, IGMP snooping to build group tables in order to support selective multicast frame forwarding and DHCP snooping for terminal mobility management. A. IEEE 802.1D Bridges IEEE 802.1D bridges [10] are ubiquitous in Ethernet switched Local Area Networks (LANs). They are also known as learning bridges since they do not define any explicit signalling messages to build and maintain the local forwarding tables. Rather, they learn the path to stations from the source address of data frames passing through. However, the use of this mechanism requires an active topology without loops, i.e. a tree. The Rapid Spanning Tree Protocol (RSTP) [10] has been defined to guarantee that the active topology is loopfree and to ensure proper operation of IEEE 802.1D bridges. RSTP deals with the automatic and dynamic configuration of an active tree network topology while ensuring redundancy. Frame forwarding is based on the analysis of the destination addresses of the frames. When a frame arrives to a bridge port, the bridge looks for the destination address in the forwarding table. If it is not found, a copy of the frame is sent to all ports, except the one it was received from. If it is found, the frame is forwarded only to the specific output port, if different from the input port; otherwise, it is discarded. IEEE 802.1D defines protocols to improve multicast frame forwarding efficiency, the Generic Attribute Registration Protocol (GARP) and the GARP Multicast Registration Protocol The Internet Group Management Protocol (IGMP) is used by IPv4 systems to inform multicast routers about their associations or disassociations to groups. In its third version IGMP defines two types of messages: IGMP Query and IGMP Report. The IGMP Query is sent by multicast routers to inquire stations about their association state to one or more groups. The IGMP Report is sent by stations to multicast routers to report their will to receive multicast traffic related to a certain group. As a consequence of the default operation of IEEE 802.1D bridges, a new technique called IGMP snooping [11] was defined to work on IPv4 networks; a similar technique called Multicast Listener Discovery (MLD) snooping has been defined for IPv6 networks. Thus, switches that implement this technique snoop IGMP messages in order to find out where stations are located in the network. A switch is able to create a Group Table, associating group addresses to ports. Therefore, an incoming multicast frame can be forwarded only to the ports that are associated with the corresponding groups. In IGMPv3, the mechanism to build the group tables can be described as follows: Every switch must maintain a Group Table that associates IP group addresses to ports; When an IGMP Report (Join) message is received, the switch must add a new entry to the Group Table, associating the group address to the incoming port. If it already exists, the switch must update the entry, adding the incoming port; Every entry must have a lifetime parameter to not depend on IGMP Report (Leave) messages to remove the entries. The data forwarding mechanism works according to the following procedure: A data packet with the destination address type X must be forwarded to all ports; A data packet with multicast destination address different from X should be forwarded according to the Group Table; If the data packet destination address is not found in the Group Table, the packet should be forwarded to all ports, except the incoming port. If the network layer protocol is IPv6, the MLD snooping technique will be used. Further details on the operation of IGMP and MLD snooping may be found in [11]. C. DHCP Snooping When a terminal arrives to a new network, it broadcasts a DHCP DISCOVER message. In response, the terminal may

3 receive one or more DHCP OFFER messages. Based on the configuration parameters included in each DHCP OFFER message, the terminal selects one DHCP server. Then, the terminal broadcasts a DHCP REQUEST, in order to inform the selected DHCP server and notify the other servers that their offer was declined. Finally, the chosen DHCP server sends a DHCP ACK message with the configuration parameters, including the IP address assigned to the terminal, the default gateway address, and the DNS server address. DHCP snooping is a technique used by some switches to inspect DHCP messages and, by that means, perform network access control. Snooping switches are able to allow/deny access to a specific terminal, by analyzing the source MAC address of the DHCP message. If the corresponding MAC address is not allowed to have network access, the switch prevents the DHCP procedure from concluding successfully by filtering out the snooped DHCP message. IV. WIFIX WiFIX [2] reuses concepts such as 802.1D bridges and their simple learning mechanism for frame forwarding, and is based on a single-message protocol that enables the self-organization of the WMN. In order to support multi-hop forwarding within a WMN based on legacy IEEE 802.1D bridges, it defines a new encapsulation method, called Ethernet-over (Eo11), which enables the creation of virtual links (Eo11 tunnels) between neighbor MAPs. The Active Topology Creation and Maintenance (ATCM) mechanism is used to create the virtual links; together they form the active tree topology rooted at the master MAP, the device directly connected to the wired infrastructure. ATCM works as follows. The master MAP periodically sends a Topology Refresh (TR) message, which is forwarded by all other MAPs, after changing some parameters (number of hops to the master, parent address, and original address of the frame). Each MAP selects a parent node in the tree rooted at the master MAP. The TR message is employed to both announce the master MAP and notify a node that it has been selected as parent in the tree. IEEE 802.1D bridges are used for packet forwarding on top of the active tree topology; they see the virtual links as common Ethernet links. WiFIX is focused on unicast traffic forwarding. However, it defines a new mechanism to deal with broadcast traffic, where only the nodes with more than one neighbor forward broadcast frames. Yet, it does not specify any particular mechanism to deal with multicast traffic. V. WIFIX+ State of the art solutions described in the literature to cope with multicast traffic in WMNs are inefficient and introduce unnecessary complexity. We propose here a new solution, called WiFIX+, which provides WiFIX with new mechanisms to deal with multicast. In addition, it considers the transport of multicast packets using unicast frames, in order to take advantage of the higher data rates achieved in unicast 1. 1 E.g., in b the data rate for broadcast frames is 1Mbit/s, while the maximum data rate for unicast frames is 11Mbit/s. For that purpose, it is assumed that the MAPs are deployed in a way that enables the use of the maximum unicast data rate; the location of each MAP may be set during the WMN planning phase. WiFIX+ was developed along three evolutionary phases. In the first phase, we considered the simplest mechanism, where multicast traffic is processed as broadcast and the Eo11 tunnels are used to transmit the multicast/broadcast frames. So, multicast traffic is delivered to all nodes, regardless of their association state to groups. Even though this already brings some advantages, it is not the most efficient solution. In the second phase, an improved method was defined, where only the requesting nodes receive multicast traffic for a given group. Finally, in the third phase, we introduced a further improvement to deal with mobility of terminals, which is inherently supported by the first mechanism but not supported by the one designed in the second phase. In what follows, we present the three mechanisms in detail. A. Multicast as Broadcast Taking into account the Eo11 tunnels created by WiFIX, the possibility of sending multicast frames through these tunnels was considered. This approach, called Multicast as Broadcast (MaB), has three main advantages. Firstly, in , broadcast frames are sent with the lowest bit rate defined by the given standard (802.11a/b/g/n). So, if multicast frames are encapsulated in unicast frames, they can be sent using the highest bit rate. Secondly, only one multicast/broadcast frame per link is sent, while in pure flooding every node retransmits once a broadcast frame is received. Thirdly, the use of unicast underneath implicitly guarantees reliability, provided by the IEEE MAC layer. In MaB, when the bridge running in each MAP receives a multicast/broadcast frame, it will send a copy to each port, except the one the frame was received from. Every frame will be encapsulated using the Eo11 header and sent to each neighbor of the node. Thus, frames are not flooded in the network. Instead, they are sent to all nodes over the tree topology. B. Selective Multicast While simple, MaB has the disadvantage of sending multicast frames to all MAPs, regardless of the multicast group membership of the terminals attaching to each MAP. A more efficient solution, called Selective Multicast (SM), was then developed. SM allows the creation of multicast subtrees for each multicast group; each subtree is built upon the spanning tree created by the WiFIX ATCM mechanism by pruning the branches that do not have any terminal associated to the current multicast group. Each multicast packet is only delivered to the terminals requesting it; the spare bandwidth can be used by other flows, unicast and/or multicast, competing for the same network resources. SM can be divided in two stages, learning and forwarding. In the learning stage each MAP constructs group tables based on the IGMP/MLD snooping technique. In the forwarding stage, MAPs look up the group tables created,

4 so that a multicast packet is only forwarded to the ports with terminals associated to the corresponding multicast group. During the learning stage, each MAP examines the IGMP Report messages sent by terminals to multicast routers. The goal is to know from which neighbor a given MAP can reach the terminals that belong to a given group. Using IGMPv3 protocol as reference, the learning process works according to the following rules: When a terminal wants to receive multicast traffic for a given group, it sends an IGMP Report message to multicast routers; Upon receiving an IGMP Report (Join) message, each MAP creates a new entry in the Group Table with the following parameters: group IP address, MAC address of the neighbor the message was received from, and the entry lifetime. If the entry already exists, only the neighbor MAC address list is updated. The lifetime is set to the IGMP Query interval (by default 125 s) and is reset every time an IGMP Report message arrives to the MAP; After updating the Group Table, each MAP forwards the IGMP Report according to the procedure used for multicast frames. Using the learning process, a multicast tree is built for each group. If every MAP supports a terminal that belongs to a given group, the multicast tree coincides with the tree created by ATCM. The multicast forwarding process works as follows: If the destination MAC address corresponds to an IPv4 address such as X, the multicast frame is forwarded to all neighbors except the one the frame was received from; For all other multicast addresses, each MAP looks for an entry in the Group Table corresponding to the group address. If it exists, the MAP forwards the frame only to the neighbors included in that entry; If the Group Table has no entries associated to the multicast IPv4 address of the packet, the multicast frame is dropped. For IPv6, the learning and the forwarding procedures are similar to the ones described above for IPv4. Still, MLD messages are inspected instead and IPv6 addresses are used to identify multicast groups in the Group Table. C. Selective Multicast with Mobility Support Despite its higher efficiency, SM does not support terminal mobility. When a terminal moves to a new MAP, the reacquisition of the multicast flow only occurs when a new IGMP Query sent by a multicast router triggers the terminal to send an IGMP Report that allows the update of the group tables. Thus, the flow reacquisition time is proportional to the period of the IGMP Query messages. So, a further improved mechanism built upon SM was developed. It is called Selective Multicast with Mobility Support (SMob). SMob uses the DHCP snooping technique to speed up the flow reacquisition and avoid changes in the terminals. Upon attaching to a MAP for the first time, a terminal runs a DHCP client to configure IP connectivity automatically. If the terminal moves and re-attaches to the WMN through another MAP, it reruns the DHCP client. Since this time the terminal already has an IP address assigned, the DHCP client tries to keep the same address. It broadcasts a DHCP REQUEST including the IP address it wants to keep. Taking this into account, SMob works as follows: When the DHCP REQUEST message arrives to the new MAP, the MAP adds a new entry in its Mobility Table with the following parameters: MAC address of the terminal, transaction ID of the DHCP message, and the entry lifetime; When a DHCP ACK arrives, the new MAP looks up the Mobility Table using the transaction ID as primary key. If there is an entry matching the transaction ID of the DHCP ACK, the MAP creates a fake IGMP Query message and sends it to the terminal. This message forces the terminal to send an IGMP Report. Note that the fake IGMP Query is sent in unicast, at MAC level, in order to be received only by the terminal that has just attached to the new MAP. Upon the IGMP Query is sent, the new MAP removes the entry from the Mobility Table. All frames that transport DHCP messages are forwarded according to their destination MAC addresses. In practice, some applications upon detecting a link change already send automatically an IGMP Report message. However, this is not a general procedure and is not even defined in the standard [12]. The solution presented herein allows faster multicast flow reacquisition for all applications. VI. WIFIX+ IMPLEMENTATION WiFIX+ was implemented under Linux Operating System (OS). Linux supports 802.1D bridges and provides the tools required to create virtual interfaces, which act as endpoints of the virtual links established between MAPs. Using these tools, WiFIX+ creates and deletes virtual interfaces and performs Eo11 encapsulation. The virtual interfaces act as ports from the Linux bridge 2 viewpoint. Since ATCM used by WiFIX+ enforces a loop free topology, the spanning tree protocol is disabled. The WiFIX+ daemon seats between the virtual interfaces, represented by taps, and the wireless Network Interface Card (NIC). The virtual interfaces are implemented using tap interfaces enabled by the vtun module 3. Taps are virtual interfaces that behave like Layer-2 Ethernet devices for the upper layers. The WiFIX+ operation consists in reading frames from taps, processing and writing on the physical interface, or the reverse sequence in the opposite direction; WiFIX+ accesses the physical interface using a Linux packet socket. A frame that arrives on a tap has an Ethernet header with the original source and destination MAC addresses. WiFIX+ processes the frame according to the type of destination

5 Figure 2: Test-bed used in the experimental tests. MAC address (unicast, multicast, or broadcast), adds the Eo11 header, and sends it to the physical interface. In the opposite direction, when a frame arrives on the physical interface, and if the source MAC address in the Eo11 header corresponds to a neighbor, WiFIX+ removes the Eo11 header and delivers the frame to the tap associated to that neighbor. If the frame does not come from a neighbor, it is silently discarded. Afterwards, the forwarding is done according to the 802.1D bridge mechanism. Besides the taps, the bridge has, at least, the wireless interface used to serve terminals. The multicast/broadcast frame received on a tap is also forwarded to that interface by the bridge. If the frame received on the physical interface corresponds to a TR, it is not forwarded to the taps, because this is a signaling message only processed by WiFIX+. In MaB, multicast/broadcast frames are sent in unicast. When a multicast/broadcast frame arrives on the physical interface, the WiFIX+ daemon removes the Eo11 header and sends the frame to the tap related to the neighbor the frame was received from. Since the destination address is multicast/broadcast, the bridge sends a copy to all interfaces, except the tap the frame is received from. The WiFIX+ daemon verifies the taps, one at a time, encapsulates the frames in unicast and sends them to the neighbor associated to each tap. Thus, a MAP with n neighbors sends n 1 frames. The leaf nodes do not forward any frame. In SM, the IGMP snooping technique is used to improve multicast frame forwarding. Some switches implement this technique. However, the Linux bridge does not. Thus, IGMP snooping was implemented as part of the WiFIX+ daemon, in order to avoid changes to the Linux bridge software. When a multicast frame arrives on the physical interface, WiFIX+ verifies the Ethertype value and if it is equal to 0x800 (IPv4 packet), it inspects the message inside the packet. If this message is an IGMP Report (Join), WiFIX+ adds a new entry to the Group Table with the group IP address, the tap associated to the neighbor the frame was received from, and a lifetime equal to the default IGMP Query period (125 s), for each Group Record included in the IGMP Report (Join). If the IP address already exists in the Group Table, WiFIX+ just adds the tap associated to the neighbor the message was received from and resets the lifetime. If there is no matching, the message is ignored. After the creation of the group tables, the WiFIX+ daemon is able to selectively forward multicast frames. Thus, when a multicast frame arrives to the bridge, it will behave the same way. Nevertheless, this time the WiFIX+ daemon filters out the frames received from the taps according to the Group Table. In SMob, the WiFIX+ daemon uses the DHCP technique to know when a new terminal arrives to a MAP. Upon receiving a broadcast frame on a tap, WiFIX+ verifies the Ethertype field. If it is equal to 0x800, the packet is inspected. If it transports an UDP packet and a DHCP REQUEST message, WiFIX+ adds an entry to the Mobility Table with the transaction ID of the DHCP message, the original source MAC address of the frame, and a lifetime. This entry is kept in the table until a DHCP ACK message arrives on the physical interface. When that happens, WiFIX+ creates the fake IGMP Query message and sends it to the new terminal in unicast, using the MAC address stored in the Mobility Table. In response, the terminal sends an IGMP Report (Join) that allows the MAPs to update their group tables. VII. EVALUATION In this section, we describe the experimental setup, analyze the results and discuss the performance of WiFIX+. A. Experimental Setup The performance of WiFIX+ was evaluated by means of real experiments. Firstly, we compared MaB with IEEE s, then MaB with SM and, finally, MaB with SMob. The metrics used in the evaluation were: throughput, delay, jitter, packet loss ratio, and the multicast flow reacquisition interval. To analyze the performance of IEEE s, we used the opensource implementation open802.11s 4. A test-bed with four machines (MAPs) with Linux OS was built. These machines were all in radio range. To create the topology shown in Fig. 2, we used a technique for filtering TR messages, implemented within the WiFIX+ daemon. Otherwise, due to ATCM, we would get a tree with a parent (master MAP) and three children. We forced this tree topology to ensure that the same active topology was used in all experiments NICs of the four machines were set in ad hoc mode and configured in channel 3, in order to avoid the most used channels (1, 6, and 11). We established a maximum bit rate of 11 Mbit/s, due to the limitations of the ath5 driver required by the open80211s implementation 5. Performance tests were carried out with Iperf 6 and Ping. For all tests, the duration of the flows was set to 120 seconds and ten samples were obtained for each setup. In the master MAP we set a multicast traffic generator, because we intended

6 (a) WiFIX+ (b) IEEE s Figure 3: Throughput: two hops to the master node. to simulate the arrival of traffic to the WMN, coming from the network infrastructure, through this node. B. Experimental Results In order to compare the performance of WiFIX+ and IEEE s, we ran the WiFIX+ daemon in all MAPs and forced the tree topology represented in Fig. 2. In all nodes, except the master MAP, we measured throughput, delay, jitter, and the packet loss ratio. Due to space limitations, here we focus on throughput and delay; the whole set of results on jitter and packet loss can be found in [13]. In the scenario of Fig. 2, the network saturation point measured in MAP3 is about 2.2 Mbit/s, for WiFIX+ MaB, while for s the network saturates at 250 kbit/s; this is a difference of one order of magnitude. This happens because WiFIX+ MaB uses unicast tunnels to send multicast frames and the maximum bit rate defined in the standard can be used (11 Mbit/s). In practice, the maximum bit rate measured for a unicast UDP flow in an ad hoc network with two nodes is about 6 Mbit/s. Considering Fig. 2, for WiFIX+, MAP1 sends two unicast frames and MAP2 retransmits one frame, also in unicast. This is equivalent to a scenario where three nodes compete for the same medium. So, the expected values were obtained, 6Mbit/s 3. For s, the bit rate to send multicast frames is the minimum defined in the standard (1 Mbit/s). In practice, this value is about 800 kbit/s. In IEEE s, all nodes retransmit a multicast frame once, so there are four nodes competing for the same wireless medium. WiFIX+ MaB always transmits one frame less. This is an advantage of WiFIX+ compared to s, together with the use of unicast frames to convey multicast traffic. The plots of Fig. 3 present the throughput measured in MAP4 (two hops to the master MAP) for WiFIX+ MaB and IEEE s. The plot of WiFIX+ MaB shows the higher throughput compared to IEEE s. For IEEE s, the throughput is about 180 kbit/s which is about 30% lower than the value measured in MAP3. This is explained by the high packet loss ratio verified in MAP4 for this solution. Taking into account Fig. 2, this behavior is explained by synchronization in frame forwarding by MAPs 2 and 3, causing frequent collisions. IEEE s does not provide an acknowledgement mechanism for multicast/broadcast frames. So, if there is a collision, the frame is lost and there is no retransmission. Concerning packet delay, the plots of Fig. 4 show the differences between WiFIX+ MaB and IEEE s, for MAP4. We can see that WiFIX+ MaB performs better than IEEE s too. The maximum delay for WiFIX+ is about 300 ms and for IEEE s is about 1 s. The possibility to send traffic at a higher bit rate for WiFIX+ MaB allows the reduction of the delay. Thus, for a given value of offered load, WiFIX+ MaB always introduces a lower packet delay. Multicast applications with real-time requirements, such as video conferencing and radio broadcast over IP, are influenced by packet delay variation. So, the evaluation of network performance concerning jitter 7 is important. For WiFIX+ MaB, with the increase of the offered load, the probability of frame collision also increases, increasing the number of retransmissions. Thus, the packet delay difference between two consecutive packets tends to increase. Besides that, the medium access protocol of networks introduces delay variations. Before initiating a transmission, a node listens to the medium, and if it is free for a given period of time (DIFS, Distributed Inter Frame Space), sends the frame; otherwise, the node will have to wait a random time determined by a random backoff algorithm. In the network saturation zone, the network congestion and the increase of the number of lost frames are responsible for the quick increase of jitter (see Reference [13]). For IEEE s, the behavior is similar to WiFIX+ MaB. In s, for each frame sent by the master MAP, three frames are retransmitted. So, there are four frames to transmit the same information, which increases the competition for the medium. For WiFIX+ MaB, the maximum jitter measured in MAP4 is about 15 ms, while for IEEE s it is about 90 ms. Overall, the jitter in WiFIX+ is much lower than in IEEE s, even for different offered load ranges. The evaluation of the packet loss ratio is important because applications that need multicast traffic forwarding use UDP. This protocol does not support any mechanism to ensure packet delivery, so the number of lost packets is an important 7 In this context this term means packet delay variation.

7 (a) WiFIX+ (b) IEEE s Figure 4: Delay: two hops to the master node. (a) Selective Multicast (b) Multicast as Broadcast Figure 5: Influence of multicast UDP flow in a unicast TCP flow. aspect to consider. The most critical situation is verified for MAP4, with the s solution. Packet loss ratio has an oscillatory behavior even for low values of offered load. The cause of this behavior is the synchronism of MAP2 and MAP3 when sending broadcast frames. So, there are many frames that collide and MAP4 presents packet loss ratio values about 40%, even for low values of offered load. In general, the values of the packet loss ratio for WiFIX+ MaB are smaller than for IEEE s, even for higher values of offered load. Regarding the impact of the number of hops to the master MAP in this metric, MAP4 presents a maximum packet loss ratio that is higher than the value obtained in MAP2. Once MAP2 forwards the frames to MAP4, the value of the packet loss ratio for MAP4, placed two hops away from the master MAP, is affected by the lost frames in the transmission between MAP1 and MAP2 and the transmission between MAP2 and MAP4. So, the higher packet loss ratio measured in MAP4 makes sense. The plots of Fig. 5 allow comparing SM and MaB, concerning the influence of a multicast UDP flow in a unicast TCP flow. The multicast flow bit rate is 1 Mbit/s. When we use MaB, MAP1 sends two frames per multicast frame received, each one at 1 Mbit/s. MAP2 also sends one more frame per multicast frame at the same bit rate. Thus, the unicast TCP flow uses the remaining bandwidth. Therefore, the less multicast frames sent the more bandwidth the unicast TCP flow can use. The influence of the multicast UDP flow is lower, when SM is used. The multicast frames that arrive to MAP2 and MAP3 will be in fact dropped, because these nodes did not request traffic for this group; thus, there is an unnecessary occupation of the network. Using MaB, when the multicast UDP flow is injected, the unicast TCP flow throughput decreases about 1.3 Mbit/s and the average delay is about 540 ms. On the other hand, using SM, the unicast TCP flow throughput decreases about 400 kbit/s and the average delay is about 240 ms. These results show the advantages of using selective multicast forwarding. In order to evaluate SMob, a comparison with MaB was made, concerning the multicast flow reacquisition time. The goal was to analyze the impact of the group tables update time on the total multicast flow reacquisition time. Furthermore, MaB represents the optimal mobility management solution, as a given multicast flow is available in every MAP. Thereby, when a terminal moves, the multicast flow reacquisition time is minimal. In the experimental scenario, the terminal moves from MAP4 to MAP3. In MAP1, we ran the Ping application in order to send 64 bytes multicast packets at 10 ms intervals. In the terminal, we ran an application that invokes the IGMP protocol, allowing the association to a given group. With Wireshark 8, we measured the time when the last packet arrived from MAP4 and the first packet arrived from MAP3. The 8

8 dhclient application of Linux introduces a random time before sending a DHCP Request message, which influences the total multicast flow reacquisition time. This time was subtracted in the calculations, in order to evaluate the sole impact of SMob. The average multicast flow reacquisition times over 10 experiments for each solution was about 210 ms for MaB and 380 ms for SMob. SMob introduces a higher multicast flow reacquisition time than MaB, as expected. This difference is caused by two factors: the DHCP REQUEST and DHCP ACK messages delay and the response time of the terminal to the fake IGMP Query sent by MAP3. However, the observed values for the two mechanisms are the same order of magnitude. Overall, SMob is more advantageous, because it is more efficient in multicast traffic forwarding and does not compromise significantly the multicast flow reacquisition time, compared with MaB. Also, it is important to realize that the average value obtained for SMob is the worst case scenario, when the multicast flow is not being transmitted through the new MAP yet; if that happens, the reacquisition time will be the same as in MaB. C. Discussion In Section VI, we mentioned that the lifetime of Group Table entries was set to 125 s. This value corresponds to the default interval defined in [12] between two IGMP Query messages sent by multicast routers. However, this value is too high and compromises the efficiency of the WiFIX+ SMob solution. To solve this problem, the query interval of multicast routers and the lifetime of the group tables can be reduced. Another solution is to add the terminals MAC addresses to the group tables, associating them to the taps the terminal could be reached from. Thus, upon the arrival of an IGMP Report message, the MAP would verify whether the original source MAC address had already been associated to another tap. If this is true, it means that the terminal has moved from a MAP to a new one. If the MAC address was the only one associated to that tap, the tap could be removed from the corresponding Group Table entry and the traffic would not be forwarded to the corresponding branch anymore. In Section VII, we used different scales in the plots, because WiFIX+ has a much higher limit for throughput than IEEE s. In the first phase, we proved the advantage of using unicast encapsulation in multicast frames. In the second phase, the goal was to show that we could save bandwidth using SM. We injected a new TCP unicast flow and evaluated the influence of an UDP multicast flow using two multicast frame forwarding mechanisms, MaB and SM. Concerning the mobility issue, the major goal in Section VII was to confirm that SMob allows multicast flow reacquisition; however, we also proved that the multicast flow reacquisition time does not increase significantly. Finally, an advantage of WiFIX+ is the fact that it was developed considering an evolutionary approach. So, a specific mechanism can be selected according to the networking context and the specific deployment requirements. VIII. CONCLUSIONS Current solutions for WMNs are either too complex or deal with multicast inefficiently by means of pure flooding. Herein, we proposed a new and simple solution, called WiFIX+, to cope with multicast traffic within WMNs and support mobility of legacy terminals. Experimental results showed that WiFIX+ enables up to one order of magnitude higher throughput and up to one order of magnitude lower delay, when compared to IEEE s. In addition, by using well-known techniques from wired networks, such as IGMP snooping, we showed that the WiFIX+ performance can be further improved. On the other hand, the use of DHCP snooping as a basis for terminal mobility management proved to be a feasible solution. As future work, we shall evaluate the WiFIX+ scalability and the performance improvements obtained for other IEEE variants (IEEE a/g/n). Additionally, we may consider the design of a new mobility management mechanism involving the mobile terminals too, so that the multicast flow reacquisition time is further reduced in the WiFIX+ SMob approach. ACKNOWLEDGMENT The work described in this paper was partially funded by FCT (Fundação para a Ciência e a Tecnologia) under the project PTDC/EEA-TEL/74471/2006 Multicast and Mobility Management in Heterogeneous Access Networks. REFERENCES [1] IEEE P802.11s/D2.0, draft amendment to standard IEEE : Mesh Networking, March 2008, work in progress. [2] Rui Campos, Ricardo Duarte, Filipe Sousa, Manuel Ricardo and José Ruela, Network Infrastructure Extension Using 802.1D-based Wireless Mesh Networks, Wireless Communications And Mobile Computing, January 2010 (on-line version). [3] Sung-Ju Lee, William Su and Mario Gerla, On-Demand Multicast Routing Protocol in Multihop Wireless Mobile Networks, Mobile Networks and Applications 7, [4] J. J. Garcia-Luna-Aceves and Ewerton L. Madruga, A Multicast Routing Protocol for Ad-Hoc Networks, Proc. of IEEE INFOCOM, New York, USA, March [5] Sung-Ju Lee, William Su and Mario Gerla, Ad Hoc Wireless Multicast with Mobility Prediction, Proc. of IEEE ICCCN 99, Boston, USA, October [6] W. A. Shittu, Aisha-Hassan, A. Hashim, F. Anwar and W. Al-Khateeb, A Proposed QoS Multicast Routing Framework for Next-Generation Wireless Mesh Network, IJCSNS, vol 8 No. 9, September, [7] William Su, Sung-Ju Lee and Mario Gerla, Mobility Prediction in Wireless Networks, Proc. of IEEE MILCOM, [8] Hasnaa Moustafa and Houda Labiod, A Multicast On-demand Mesh-based Routing Protocol in Multihop Mobile Wireless Networks, Proc. of IEEE 58th Vehicular Technology Conference, VTC, [9] Pedro M. Ruiz, Franciso J. Galera, Christophe Jelger and Thomas Noel, Efficient Multicast Routing in Wireless Mesh Networks Connected to Internet, Proc. of IEEE SECON 05, Santa Clara, USA, September [10] IEEE 802.1D, IEEE Standard for local and metropolitan area networks., IEEE, June [11] M. Christensen, K. Kimball and F. Solensky, Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Snooping Switches., IETF RFC 4541, May [12] B. Cain, S. Deering, I. Kouvelas, B. Fenner and A. Thyagarajan, Internet Group Management Protocol, Version 3, IETF RFC 3376, October [13] C. Oliveira, Difusão Eficiente de Tráfego Multicast em Redes Emalhadas com Suporte de Mobilidade, University of Porto, 2010, ee05040/docs/dissertacao_carlos_oliveira_vfinal.pdf (in Portuguese).

Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc

Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc (International Journal of Computer Science & Management Studies) Vol. 17, Issue 01 Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc Dr. Khalid Hamid Bilal Khartoum, Sudan dr.khalidbilal@hotmail.com

More information

Study of Different Types of Attacks on Multicast in Mobile Ad Hoc Networks

Study of Different Types of Attacks on Multicast in Mobile Ad Hoc Networks Study of Different Types of Attacks on Multicast in Mobile Ad Hoc Networks Hoang Lan Nguyen and Uyen Trang Nguyen Department of Computer Science and Engineering, York University 47 Keele Street, Toronto,

More information

Behavior Analysis of TCP Traffic in Mobile Ad Hoc Network using Reactive Routing Protocols

Behavior Analysis of TCP Traffic in Mobile Ad Hoc Network using Reactive Routing Protocols Behavior Analysis of TCP Traffic in Mobile Ad Hoc Network using Reactive Routing Protocols Purvi N. Ramanuj Department of Computer Engineering L.D. College of Engineering Ahmedabad Hiteishi M. Diwanji

More information

Objectives. The Role of Redundancy in a Switched Network. Layer 2 Loops. Broadcast Storms. More problems with Layer 2 loops

Objectives. The Role of Redundancy in a Switched Network. Layer 2 Loops. Broadcast Storms. More problems with Layer 2 loops ITE I Chapter 6 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 1 Objectives Implement Spanning Tree Protocols LAN Switching and Wireless Chapter 5 Explain the role of redundancy in a converged

More information

Juniper / Cisco Interoperability Tests. August 2014

Juniper / Cisco Interoperability Tests. August 2014 Juniper / Cisco Interoperability Tests August 2014 Executive Summary Juniper Networks commissioned Network Test to assess interoperability, with an emphasis on data center connectivity, between Juniper

More information

IP Networking Part 6 An Introduction to

IP Networking Part 6 An Introduction to IP Networking Part 6 An Introduction to IP Multicast A webinar to help you prepare for the CBNE Certification Wayne M. Pecena, CPBE, CBNE Texas A&M Information Technology Educational Broadcast Services

More information

CCNA R&S: Introduction to Networks. Chapter 5: Ethernet

CCNA R&S: Introduction to Networks. Chapter 5: Ethernet CCNA R&S: Introduction to Networks Chapter 5: Ethernet 5.0.1.1 Introduction The OSI physical layer provides the means to transport the bits that make up a data link layer frame across the network media.

More information

IP Multicasting. Applications with multiple receivers

IP Multicasting. Applications with multiple receivers IP Multicasting Relates to Lab 10. It covers IP multicasting, including multicast addressing, IGMP, and multicast routing. 1 Applications with multiple receivers Many applications transmit the same data

More information

Lehrstuhl für Informatik 4 Kommunikation und verteilte Systeme. Auxiliary Protocols

Lehrstuhl für Informatik 4 Kommunikation und verteilte Systeme. Auxiliary Protocols Auxiliary Protocols IP serves only for sending packets with well-known addresses. Some questions however remain open, which are handled by auxiliary protocols: Address Resolution Protocol (ARP) Reverse

More information

Extending Networking to Fit the Cloud

Extending Networking to Fit the Cloud VXLAN Extending Networking to Fit the Cloud Kamau WangŨ H Ũ Kamau Wangũhgũ is a Consulting Architect at VMware and a member of the Global Technical Service, Center of Excellence group. Kamau s focus at

More information

SSVVP SIP School VVoIP Professional Certification

SSVVP SIP School VVoIP Professional Certification SSVVP SIP School VVoIP Professional Certification Exam Objectives The SSVVP exam is designed to test your skills and knowledge on the basics of Networking, Voice over IP and Video over IP. Everything that

More information

Introduction to IP Multicast Routing

Introduction to IP Multicast Routing Introduction to IP Multicast Routing by Chuck Semeria and Tom Maufer Abstract The first part of this paper describes the benefits of multicasting, the Multicast Backbone (MBONE), Class D addressing, and

More information

William Stallings Data and Computer Communications. Chapter 15 Internetwork Protocols

William Stallings Data and Computer Communications. Chapter 15 Internetwork Protocols William Stallings Data and Computer Communications Chapter 15 Internetwork Protocols Internetworking Terms (1) Communications Network Facility that provides data transfer service An internet Collection

More information

Introduction to IP v6

Introduction to IP v6 IP v 1-3: defined and replaced Introduction to IP v6 IP v4 - current version; 20 years old IP v5 - streams protocol IP v6 - replacement for IP v4 During developments it was called IPng - Next Generation

More information

Implementation of a Lightweight Service Advertisement and Discovery Protocol for Mobile Ad hoc Networks

Implementation of a Lightweight Service Advertisement and Discovery Protocol for Mobile Ad hoc Networks Implementation of a Lightweight Advertisement and Discovery Protocol for Mobile Ad hoc Networks Wenbin Ma * Department of Electrical and Computer Engineering 19 Memorial Drive West, Lehigh University Bethlehem,

More information

Efficient Video Distribution Networks with.multicast: IGMP Querier and PIM-DM

Efficient Video Distribution Networks with.multicast: IGMP Querier and PIM-DM Efficient Video Distribution Networks with.multicast: IGMP Querier and PIM-DM A Dell technical white paper Version 1.1 Victor Teeter Network Solutions Engineer This document is for informational purposes

More information

An Experimental Performance Analysis of MAC Multicast in 802.11b Networks for VoIP Traffic

An Experimental Performance Analysis of MAC Multicast in 802.11b Networks for VoIP Traffic An Experimental Performance Analysis of MAC Multicast in 82.11b Networks for VoIP Traffic Martin Kappes DoCoMo Euro-Labs Landsberger Str. 312, 8687 Munich, Germany kappes@docomolab-euro.com Keywords: IEEE

More information

A Comparison Study of Qos Using Different Routing Algorithms In Mobile Ad Hoc Networks

A Comparison Study of Qos Using Different Routing Algorithms In Mobile Ad Hoc Networks A Comparison Study of Qos Using Different Routing Algorithms In Mobile Ad Hoc Networks T.Chandrasekhar 1, J.S.Chakravarthi 2, K.Sravya 3 Professor, Dept. of Electronics and Communication Engg., GIET Engg.

More information

Internet Protocol: IP packet headers. vendredi 18 octobre 13

Internet Protocol: IP packet headers. vendredi 18 octobre 13 Internet Protocol: IP packet headers 1 IPv4 header V L TOS Total Length Identification F Frag TTL Proto Checksum Options Source address Destination address Data (payload) Padding V: Version (IPv4 ; IPv6)

More information

VXLAN: Scaling Data Center Capacity. White Paper

VXLAN: Scaling Data Center Capacity. White Paper VXLAN: Scaling Data Center Capacity White Paper Virtual Extensible LAN (VXLAN) Overview This document provides an overview of how VXLAN works. It also provides criteria to help determine when and where

More information

CROSS LAYER BASED MULTIPATH ROUTING FOR LOAD BALANCING

CROSS LAYER BASED MULTIPATH ROUTING FOR LOAD BALANCING CHAPTER 6 CROSS LAYER BASED MULTIPATH ROUTING FOR LOAD BALANCING 6.1 INTRODUCTION The technical challenges in WMNs are load balancing, optimal routing, fairness, network auto-configuration and mobility

More information

Network Simulation Traffic, Paths and Impairment

Network Simulation Traffic, Paths and Impairment Network Simulation Traffic, Paths and Impairment Summary Network simulation software and hardware appliances can emulate networks and network hardware. Wide Area Network (WAN) emulation, by simulating

More information

6.1. Why do LANs tend to use broadcast networks? Why not use networks consisting of multiplexers and switches?

6.1. Why do LANs tend to use broadcast networks? Why not use networks consisting of multiplexers and switches? TUTORIAL 2 (EKT 332) 6.1. Why do LANs tend to use broadcast networks? Why not use networks consisting of multiplexers and switches? Why broadcast network? -The computers in a LAN are separated by a short

More information

Network Considerations for IPTV

Network Considerations for IPTV Network Considerations for IPTV This document provides an overview of the various methods and techniques for distributing live and prerecorded digital video across local area networks. It also offers some

More information

Networking 4 Voice and Video over IP (VVoIP)

Networking 4 Voice and Video over IP (VVoIP) Networking 4 Voice and Video over IP (VVoIP) Course Objectives This course will give delegates a good understanding of LANs, WANs and VVoIP (Voice and Video over IP). It is aimed at those who want to move

More information

TECHNICAL NOTE. GoFree WIFI-1 web interface settings. Revision Comment Author Date 0.0a First release James Zhang 10/09/2012

TECHNICAL NOTE. GoFree WIFI-1 web interface settings. Revision Comment Author Date 0.0a First release James Zhang 10/09/2012 TECHNICAL NOTE GoFree WIFI-1 web interface settings Revision Comment Author Date 0.0a First release James Zhang 10/09/2012 1/14 Web interface settings under admin mode Figure 1: web interface admin log

More information

CHAPTER 10 IP MULTICAST

CHAPTER 10 IP MULTICAST CHAPTER 10 IP MULTICAST This chapter is about IP multicast, the network layer mechanisms in the Internet to support applications where data is sent from a sender to multiple receivers. The first section

More information

Data Networking and Architecture. Delegates should have some basic knowledge of Internet Protocol and Data Networking principles.

Data Networking and Architecture. Delegates should have some basic knowledge of Internet Protocol and Data Networking principles. Data Networking and Architecture The course focuses on theoretical principles and practical implementation of selected Data Networking protocols and standards. Physical network architecture is described

More information

APPLICATION NOTE 210 PROVIDER BACKBONE BRIDGE WITH TRAFFIC ENGINEERING: A CARRIER ETHERNET TECHNOLOGY OVERVIEW

APPLICATION NOTE 210 PROVIDER BACKBONE BRIDGE WITH TRAFFIC ENGINEERING: A CARRIER ETHERNET TECHNOLOGY OVERVIEW PROVIDER BACKBONE BRIDGE WITH TRAFFIC ENGINEERING: A CARRIER ETHERNET TECHNOLOGY OVERVIEW By Thierno Diallo, Product Specialist Originally designed as a local-area network (LAN) communication protocol,

More information

packet retransmitting based on dynamic route table technology, as shown in fig. 2 and 3.

packet retransmitting based on dynamic route table technology, as shown in fig. 2 and 3. Implementation of an Emulation Environment for Large Scale Network Security Experiments Cui Yimin, Liu Li, Jin Qi, Kuang Xiaohui National Key Laboratory of Science and Technology on Information System

More information

CHAPTER 10 LAN REDUNDANCY. Scaling Networks

CHAPTER 10 LAN REDUNDANCY. Scaling Networks CHAPTER 10 LAN REDUNDANCY Scaling Networks CHAPTER 10 10.0 Introduction 10.1 Spanning Tree Concepts 10.2 Varieties of Spanning Tree Protocols 10.3 Spanning Tree Configuration 10.4 First-Hop Redundancy

More information

Transport and Network Layer

Transport and Network Layer Transport and Network Layer 1 Introduction Responsible for moving messages from end-to-end in a network Closely tied together TCP/IP: most commonly used protocol o Used in Internet o Compatible with a

More information

SBSCET, Firozpur (Punjab), India

SBSCET, Firozpur (Punjab), India Volume 3, Issue 9, September 2013 ISSN: 2277 128X International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: www.ijarcsse.com Layer Based

More information

CHAPTER MANAGED SWITCH SOFTWARE MONITORING. In This Chapter...

CHAPTER MANAGED SWITCH SOFTWARE MONITORING. In This Chapter... MANAGED SWITCH SOFTWARE MONITORING CHAPTER 23 In This Chapter... System Information.................................................3 2 Port and Power Status...............................................3

More information

Definition. A Historical Example

Definition. A Historical Example Overlay Networks This lecture contains slides created by Ion Stoica (UC Berkeley). Slides used with permission from author. All rights remain with author. Definition Network defines addressing, routing,

More information

Wave Relay System and General Project Details

Wave Relay System and General Project Details Wave Relay System and General Project Details Wave Relay System Provides seamless multi-hop connectivity Operates at layer 2 of networking stack Seamless bridging Emulates a wired switch over the wireless

More information

Advanced Computer Networks

Advanced Computer Networks Introduction to Mobile Ad hoc Networks (MANETs) Advanced Computer Networks Outline Ad hoc networks Differences to other networks Applications Research areas Routing Other research areas Enabling Technologies

More information

Final for ECE374 05/06/13 Solution!!

Final for ECE374 05/06/13 Solution!! 1 Final for ECE374 05/06/13 Solution!! Instructions: Put your name and student number on each sheet of paper! The exam is closed book. You have 90 minutes to complete the exam. Be a smart exam taker -

More information

Scaling 10Gb/s Clustering at Wire-Speed

Scaling 10Gb/s Clustering at Wire-Speed Scaling 10Gb/s Clustering at Wire-Speed InfiniBand offers cost-effective wire-speed scaling with deterministic performance Mellanox Technologies Inc. 2900 Stender Way, Santa Clara, CA 95054 Tel: 408-970-3400

More information

A New Approach to Developing High-Availability Server

A New Approach to Developing High-Availability Server A New Approach to Developing High-Availability Server James T. Yu, Ph.D. School of Computer Science, Telecommunications, and Information Systems DePaul University jyu@cs.depaul.edu ABSTRACT This paper

More information

Analysis of IP Network for different Quality of Service

Analysis of IP Network for different Quality of Service 2009 International Symposium on Computing, Communication, and Control (ISCCC 2009) Proc.of CSIT vol.1 (2011) (2011) IACSIT Press, Singapore Analysis of IP Network for different Quality of Service Ajith

More information

Detecting rogue systems

Detecting rogue systems Product Guide Revision A McAfee Rogue System Detection 4.7.1 For use with epolicy Orchestrator 4.6.3-5.0.0 Software Detecting rogue systems Unprotected systems, referred to as rogue systems, are often

More information

DSR: The Dynamic Source Routing Protocol for Multi-Hop Wireless Ad Hoc Networks

DSR: The Dynamic Source Routing Protocol for Multi-Hop Wireless Ad Hoc Networks DSR: The Dynamic Source Routing Protocol for Multi-Hop Wireless Ad Hoc Networks David B. Johnson David A. Maltz Josh Broch Computer Science Department Carnegie Mellon University Pittsburgh, PA 15213-3891

More information

Monitoring Mobile Flows in Emerging IPv6 Access Networks Concepts and First Prototype

Monitoring Mobile Flows in Emerging IPv6 Access Networks Concepts and First Prototype Monitoring Mobile Flows in Emerging IPv6 Access Networks Concepts and First Prototype Pedro Marques 1,2, Helder Castro 1,2, and Manuel Ricardo 1,2 1. FEUP - Fac. Eng. Univ. Porto, Rua Dr. Roberto Frias,

More information

About Firewall Protection

About Firewall Protection 1. This guide describes how to configure basic firewall rules in the UTM to protect your network. The firewall then can provide secure, encrypted communications between your local network and a remote

More information

The necessity of multicast for IPTV streaming

The necessity of multicast for IPTV streaming The necessity of multicast for IPTV streaming ARIANIT MARAJ, ADRIAN SHEHU Telecommunication Department Faculty of Information Technology, Polytechnic University of Tirana Tirana, Republic of Albania arianit.maraj@ptkonline.com,

More information

Review: Lecture 1 - Internet History

Review: Lecture 1 - Internet History Review: Lecture 1 - Internet History late 60's ARPANET, NCP 1977 first internet 1980's The Internet collection of networks communicating using the TCP/IP protocols 1 Review: Lecture 1 - Administration

More information

CS 5480/6480: Computer Networks Spring 2012 Homework 4 Solutions Due by 1:25 PM on April 11 th 2012

CS 5480/6480: Computer Networks Spring 2012 Homework 4 Solutions Due by 1:25 PM on April 11 th 2012 CS 5480/6480: Computer Networks Spring 2012 Homework 4 Solutions Due by 1:25 PM on April 11 th 2012 Important: The solutions to the homework problems from the course book have been provided by the authors.

More information

SONICWALL SWITCHING NSA 2400MX IN SONICOS ENHANCED

SONICWALL SWITCHING NSA 2400MX IN SONICOS ENHANCED You can read the recommendations in the user, the technical or the installation for SONICWALL SWITCHING NSA 2400MX IN SONICOS ENHANCED 5.7. You'll find the answers to all your questions on the SONICWALL

More information

SSVP SIP School VoIP Professional Certification

SSVP SIP School VoIP Professional Certification SSVP SIP School VoIP Professional Certification Exam Objectives The SSVP exam is designed to test your skills and knowledge on the basics of Networking and Voice over IP. Everything that you need to cover

More information

The ABCs of Spanning Tree Protocol

The ABCs of Spanning Tree Protocol The ABCs of Spanning Tree Protocol INTRODUCTION In an industrial automation application that relies heavily on the health of the Ethernet network that attaches all the controllers and computers together,

More information

enetworks TM IP Quality of Service B.1 Overview of IP Prioritization

enetworks TM IP Quality of Service B.1 Overview of IP Prioritization encor! enetworks TM Version A, March 2008 2010 Encore Networks, Inc. All rights reserved. IP Quality of Service The IP Quality of Service (QoS) feature allows you to assign packets a level of priority

More information

Throughput Analysis of WEP Security in Ad Hoc Sensor Networks

Throughput Analysis of WEP Security in Ad Hoc Sensor Networks Throughput Analysis of WEP Security in Ad Hoc Sensor Networks Mohammad Saleh and Iyad Al Khatib iitc Stockholm, Sweden {mohsaleh, iyad}@iitc.se ABSTRACT This paper presents a performance investigation

More information

Tomás P. de Miguel DIT-UPM. dit UPM

Tomás P. de Miguel DIT-UPM. dit UPM Tomás P. de Miguel DIT- 15 12 Internet Mobile Market Phone.com 15 12 in Millions 9 6 3 9 6 3 0 1996 1997 1998 1999 2000 2001 0 Wireless Internet E-mail subscribers 2 (January 2001) Mobility The ability

More information

LAN Switching. 15-441 Computer Networking. Switched Network Advantages. Hubs (more) Hubs. Bridges/Switches, 802.11, PPP. Interconnecting LANs

LAN Switching. 15-441 Computer Networking. Switched Network Advantages. Hubs (more) Hubs. Bridges/Switches, 802.11, PPP. Interconnecting LANs LAN Switching 15-441 Computer Networking Bridges/Switches, 802.11, PPP Extend reach of a single shared medium Connect two or more segments by copying data frames between them Switches only copy data when

More information

What is VLAN Routing?

What is VLAN Routing? Application Note #38 February 2004 What is VLAN Routing? This Application Notes relates to the following Dell product(s): 6024 and 6024F 33xx Abstract Virtual LANs (VLANs) offer a method of dividing one

More information

Quality of Service Analysis of site to site for IPSec VPNs for realtime multimedia traffic.

Quality of Service Analysis of site to site for IPSec VPNs for realtime multimedia traffic. Quality of Service Analysis of site to site for IPSec VPNs for realtime multimedia traffic. A Network and Data Link Layer infrastructure Design to Improve QoS in Voice and video Traffic Jesús Arturo Pérez,

More information

FORTH-ICS / TR-375 March 2006. Experimental Evaluation of QoS Features in WiFi Multimedia (WMM)

FORTH-ICS / TR-375 March 2006. Experimental Evaluation of QoS Features in WiFi Multimedia (WMM) FORTH-ICS / TR-375 March 26 Experimental Evaluation of QoS Features in WiFi Multimedia (WMM) Vasilios A. Siris 1 and George Stamatakis 1 Abstract We investigate the operation and performance of WMM (WiFi

More information

IP and Mobility. Requirements to a Mobile IP. Terminology in Mobile IP

IP and Mobility. Requirements to a Mobile IP. Terminology in Mobile IP IP and Mobility Chapter 2 Technical Basics: Layer Methods for Medium Access: Layer 2 Chapter Wireless Networks: Bluetooth, WLAN, WirelessMAN, WirelessWAN Mobile Telecommunication Networks: GSM, GPRS, UMTS

More information

hp ProLiant network adapter teaming

hp ProLiant network adapter teaming hp networking june 2003 hp ProLiant network adapter teaming technical white paper table of contents introduction 2 executive summary 2 overview of network addressing 2 layer 2 vs. layer 3 addressing 2

More information

Network Test 3 Study Guide

Network Test 3 Study Guide Name: Class: Date: Network Test 3 Study Guide Multiple Choice Identify the choice that best completes the statement or answers the question. 1. When a frame is received, which component reads the source

More information

Wireless Mesh Networks under FreeBSD

Wireless Mesh Networks under FreeBSD Wireless Networks under FreeBSD Rui Paulo rpaulo@freebsd.org The FreeBSD Project AsiaBSDCon 2010 - Tokyo, Japan Abstract With the advent of low cost wireless chipsets, wireless mesh networks became much

More information

Management Software. Web Browser User s Guide AT-S106. For the AT-GS950/48 Gigabit Ethernet Smart Switch. Version 1.0.0. 613-001339 Rev.

Management Software. Web Browser User s Guide AT-S106. For the AT-GS950/48 Gigabit Ethernet Smart Switch. Version 1.0.0. 613-001339 Rev. Management Software AT-S106 Web Browser User s Guide For the AT-GS950/48 Gigabit Ethernet Smart Switch Version 1.0.0 613-001339 Rev. A Copyright 2010 Allied Telesis, Inc. All rights reserved. No part of

More information

IP Networking. Overview. Networks Impact Daily Life. IP Networking - Part 1. How Networks Impact Daily Life. How Networks Impact Daily Life

IP Networking. Overview. Networks Impact Daily Life. IP Networking - Part 1. How Networks Impact Daily Life. How Networks Impact Daily Life Overview Dipl.-Ing. Peter Schrotter Institute of Communication Networks and Satellite Communications Graz University of Technology, Austria Fundamentals of Communicating over the Network Application Layer

More information

Advanced VSAT Solutions Bridge Point-to-Multipoint (BPM) Overview

Advanced VSAT Solutions Bridge Point-to-Multipoint (BPM) Overview 2114 West 7 th Street Tempe, AZ 85281 USA Voice +1.480.333.2200 E-mail sales@comtechefdata.com Web www.comtechefdata.com Advanced VSAT Solutions Bridge Point-to-Multipoint (BPM) Overview January 2014 2014

More information

Efficient Network Management (236635) Final Project

Efficient Network Management (236635) Final Project Efficient Network Management (36635) Final Project Project Title: SNMP Agent for large data transfer Team: Kfir Karmon (ID 3797696) Tsachi Sharfman (ID 97399). Problem Description One of the weaknesses

More information

QoS Switching. Two Related Areas to Cover (1) Switched IP Forwarding (2) 802.1Q (Virtual LANs) and 802.1p (GARP/Priorities)

QoS Switching. Two Related Areas to Cover (1) Switched IP Forwarding (2) 802.1Q (Virtual LANs) and 802.1p (GARP/Priorities) QoS Switching H. T. Kung Division of Engineering and Applied Sciences Harvard University November 4, 1998 1of40 Two Related Areas to Cover (1) Switched IP Forwarding (2) 802.1Q (Virtual LANs) and 802.1p

More information

Virtual Local Area Networks

Virtual Local Area Networks Virtual Local Area Networks Suba Varadarajan, varadarajan.5@osu.edu This paper describes virtual local area networks (VLAN's), their uses and how they work in accordance with the 802.1Q standard. Other

More information

Comparison of RIP, EIGRP, OSPF, IGRP Routing Protocols in Wireless Local Area Network (WLAN) By Using OPNET Simulator Tool - A Practical Approach

Comparison of RIP, EIGRP, OSPF, IGRP Routing Protocols in Wireless Local Area Network (WLAN) By Using OPNET Simulator Tool - A Practical Approach Comparison of RIP, EIGRP, OSPF, IGRP Routing Protocols in Wireless Local Area Network (WLAN) By Using OPNET Simulator Tool - A Practical Approach U. Dillibabau 1, Akshay 2, M. Lorate Shiny 3 UG Scholars,

More information

A Transport Protocol for Multimedia Wireless Sensor Networks

A Transport Protocol for Multimedia Wireless Sensor Networks A Transport Protocol for Multimedia Wireless Sensor Networks Duarte Meneses, António Grilo, Paulo Rogério Pereira 1 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks Introduction Wireless

More information

Optimizing Enterprise Network Bandwidth For Security Applications. Improving Performance Using Antaira s Management Features

Optimizing Enterprise Network Bandwidth For Security Applications. Improving Performance Using Antaira s Management Features Optimizing Enterprise Network Bandwidth For Security Applications Improving Performance Using Antaira s Management Features By: Brian Roth, Product Marketing Engineer April 1, 2014 April 2014 Optimizing

More information

Introduction to LAN Protocols

Introduction to LAN Protocols CHAPTER 2 Chapter Goals Learn about different LAN protocols. Understand the different methods used to deal with media contention. Learn about different LAN topologies. This chapter introduces the various

More information

Performance Evaluation of Wired and Wireless Local Area Networks

Performance Evaluation of Wired and Wireless Local Area Networks International Journal of Engineering Research and Development ISSN: 2278-067X, Volume 1, Issue 11 (July 2012), PP.43-48 www.ijerd.com Performance Evaluation of Wired and Wireless Local Area Networks Prof.

More information

Performance Analysis of AQM Schemes in Wired and Wireless Networks based on TCP flow

Performance Analysis of AQM Schemes in Wired and Wireless Networks based on TCP flow International Journal of Soft Computing and Engineering (IJSCE) Performance Analysis of AQM Schemes in Wired and Wireless Networks based on TCP flow Abdullah Al Masud, Hossain Md. Shamim, Amina Akhter

More information

CREW - FP7 - GA No. 258301. Cognitive Radio Experimentation World. Project Deliverable D7.5.4 Showcase of experiment ready (Demonstrator)

CREW - FP7 - GA No. 258301. Cognitive Radio Experimentation World. Project Deliverable D7.5.4 Showcase of experiment ready (Demonstrator) Cognitive Radio Experimentation World!"#$% Project Deliverable Showcase of experiment ready (Demonstrator) Contractual date of delivery: 31-03-14 Actual date of delivery: 18-04-14 Beneficiaries: Lead beneficiary:

More information

DIN 2012 Tutorial. physical links between primary and secondary stations: Synchronous Connection Oriented (SCO); Asynchronous Connection Link (ACL).

DIN 2012 Tutorial. physical links between primary and secondary stations: Synchronous Connection Oriented (SCO); Asynchronous Connection Link (ACL). DIN 2012 Tutorial (Q1a) In the IEEE 802.15 standard (Bluetooth), describe the following two types of : physical links between primary and secondary stations: (i) (ii) Synchronous Connection Oriented (SCO);

More information

Infrastructure Components: Hub & Repeater. Network Infrastructure. Switch: Realization. Infrastructure Components: Switch

Infrastructure Components: Hub & Repeater. Network Infrastructure. Switch: Realization. Infrastructure Components: Switch Network Infrastructure or building computer networks more complex than e.g. a short bus, some additional components are needed. They can be arranged hierarchically regarding their functionality: Repeater

More information

ProSafe Plus Switch Utility

ProSafe Plus Switch Utility ProSafe Plus Switch Utility User Guide 350 East Plumeria Drive San Jose, CA 95134 USA September 2010 202-10524-03 v1.0 ProSafe Plus Switch Utility User Guide 2010 NETGEAR, Inc. All rights reserved. No

More information

3. MONITORING AND TESTING THE ETHERNET NETWORK

3. MONITORING AND TESTING THE ETHERNET NETWORK 3. MONITORING AND TESTING THE ETHERNET NETWORK 3.1 Introduction The following parameters are covered by the Ethernet performance metrics: Latency (delay) the amount of time required for a frame to travel

More information

EXTENDING NETWORK KNOWLEDGE: MAKING OLSR A QUALITY OF SERVICE CONDUCIVE PROTOCOL

EXTENDING NETWORK KNOWLEDGE: MAKING OLSR A QUALITY OF SERVICE CONDUCIVE PROTOCOL EXTENDING NETWORK KNOWLEDGE: MAKING OLSR A QUALITY OF SERVICE CONDUCIVE PROTOCOL by Pedro Eduardo Villanueva-Pena, Thomas Kunz Carleton University January, 2006 This report examines mechanisms to gradually

More information

Life of a Packet CS 640, 2015-01-22

Life of a Packet CS 640, 2015-01-22 Life of a Packet CS 640, 2015-01-22 Outline Recap: building blocks Application to application communication Process to process communication Host to host communication Announcements Syllabus Should have

More information

other. A B AP wired network

other. A B AP wired network 1 Routing and Channel Assignment in Multi-Channel Multi-Hop Wireless Networks with Single-NIC Devices Jungmin So + Nitin H. Vaidya Department of Computer Science +, Department of Electrical and Computer

More information

Module 6. Internetworking. Version 2 CSE IIT, Kharagpur

Module 6. Internetworking. Version 2 CSE IIT, Kharagpur Module 6 Internetworking Lesson 1 Internetworking Devices Specific Instructional Objectives At the end of this lesson, the students will be able to: Specify the need for internetworking State various issues

More information

Accelerating Service Discovery in Ad-hoc Zero Configuration Networking

Accelerating Service Discovery in Ad-hoc Zero Configuration Networking Accelerating Service Discovery in Ad-hoc Zero Configuration Networking Se Gi Hong, Suman Srinivasan and Henning Schulzrinne Columbia University, New York, NY {segihong, sumans, hgs}@cs.columbia.edu Abstract

More information

A Wireless Mesh Network NS-3 Simulation Model: Implementation and Performance Comparison With a Real Test-Bed

A Wireless Mesh Network NS-3 Simulation Model: Implementation and Performance Comparison With a Real Test-Bed A Wireless Mesh Network NS-3 Simulation Model: Implementation and Performance Comparison With a Real Test-Bed Dmitrii Dugaev, Eduard Siemens Anhalt University of Applied Sciences - Faculty of Electrical,

More information

4. MAC protocols and LANs

4. MAC protocols and LANs 4. MAC protocols and LANs 1 Outline MAC protocols and sublayers, LANs: Ethernet, Token ring and Token bus Logic Link Control (LLC) sublayer protocol Bridges: transparent (spanning tree), source routing

More information

A UBIQUITOUS PROTOCOL FOR ADDRESS DYNAMICALLY AUTO CONFIGURATION FOR MOBILE AD HOC NETWORKS

A UBIQUITOUS PROTOCOL FOR ADDRESS DYNAMICALLY AUTO CONFIGURATION FOR MOBILE AD HOC NETWORKS A UBIQUITOUS PROTOCOL FOR ADDRESS DYNAMICALLY AUTO CONFIGURATION FOR MOBILE AD HOC NETWORKS Chandanpreet Kaur Global Institute of Management and Emerging Technologies, Amritsar, Punjab, India, lpu_chandan@yahoo.co.in

More information

A Quality of Experience based Approach for Wireless Mesh Networks*

A Quality of Experience based Approach for Wireless Mesh Networks* A Quality of Experience based Approach for Wireless Mesh Networks* Anderson Morais, and Ana Cavalli Télécom SudParis, France {anderson.morais, ana.cavalli}@it-sudparis.eu Abstract. Wireless Mesh Network

More information

Switches and Bridges. COS 461: Computer Networks Spring 2009 (MW 1:30-2:50 in COS 105) Guest Lecture Jennifer Rexford 1

Switches and Bridges. COS 461: Computer Networks Spring 2009 (MW 1:30-2:50 in COS 105) Guest Lecture Jennifer Rexford 1 Switches and Bridges COS 461: Computer Networks Spring 2009 (MW 1:30-2:50 in COS 105) Guest Lecture Jennifer Rexford 1 Goals of Todayʼs Lecture Devices that shuttle data at different layers Repeaters and

More information

Connectivity Fault Management. Norman Finn

Connectivity Fault Management. Norman Finn Connectivity Fault Management Norman Finn 1 DISCLAIMER IEEE P802.1ag is a work in progress. Some of the information in this slide deck reflects consensus among IEEE 802.1 and ITU-T Q.3/13 participants.

More information

UIP1868P User Interface Guide

UIP1868P User Interface Guide UIP1868P User Interface Guide (Firmware version 0.13.4 and later) V1.1 Monday, July 8, 2005 Table of Contents Opening the UIP1868P's Configuration Utility... 3 Connecting to Your Broadband Modem... 4 Setting

More information

CHAPTER 6. VOICE COMMUNICATION OVER HYBRID MANETs

CHAPTER 6. VOICE COMMUNICATION OVER HYBRID MANETs CHAPTER 6 VOICE COMMUNICATION OVER HYBRID MANETs Multimedia real-time session services such as voice and videoconferencing with Quality of Service support is challenging task on Mobile Ad hoc Network (MANETs).

More information

Building Secure Network Infrastructure For LANs

Building Secure Network Infrastructure For LANs Building Secure Network Infrastructure For LANs Yeung, K., Hau; and Leung, T., Chuen Abstract This paper discusses the building of secure network infrastructure for local area networks. It first gives

More information

Introduction to Local Area Networks

Introduction to Local Area Networks For Summer Training on Computer Networking visit Introduction to Local Area Networks Prepared by : Swapan Purkait Director Nettech Private Limited swapan@nettech.in + 91 93315 90003 Introduction A local

More information

4m. MONITORING OF ETHERNET/IP NETWORK TRAFFIC.

4m. MONITORING OF ETHERNET/IP NETWORK TRAFFIC. 4m. MONITORING OF ETHERNET/IP NETWORK TRAFFIC. Wireshark (see Section 6) is a network packet analyser. It is used to: troubleshoot network problems, examine security problems, debug protocol implementations,

More information

HARTING Ha-VIS Management Software

HARTING Ha-VIS Management Software HARTING Ha-VIS Management Software People Power Partnership HARTING Management Software Network Management Automation IT - with mcon Switches from HARTING With the Ha-VIS mcon families, HARTING has expanded

More information

Zarząd (7 osób) F inanse (13 osób) M arketing (7 osób) S przedaż (16 osób) K adry (15 osób)

Zarząd (7 osób) F inanse (13 osób) M arketing (7 osób) S przedaż (16 osób) K adry (15 osób) QUESTION NO: 8 David, your TestKing trainee, asks you about basic characteristics of switches and hubs for network connectivity. What should you tell him? A. Switches take less time to process frames than

More information

Lab Exercise Ethernet

Lab Exercise Ethernet Lab Exercise Ethernet Objective To explore the details of Ethernet frames. Ethernet is a popular link layer protocol. Modern computers connect to Ethernet switches rather than use classic Ethernet. The

More information

Virtual PortChannels: Building Networks without Spanning Tree Protocol

Virtual PortChannels: Building Networks without Spanning Tree Protocol . White Paper Virtual PortChannels: Building Networks without Spanning Tree Protocol What You Will Learn This document provides an in-depth look at Cisco's virtual PortChannel (vpc) technology, as developed

More information

Datagram-based network layer: forwarding; routing. Additional function of VCbased network layer: call setup.

Datagram-based network layer: forwarding; routing. Additional function of VCbased network layer: call setup. CEN 007C Computer Networks Fundamentals Instructor: Prof. A. Helmy Homework : Network Layer Assigned: Nov. 28 th, 2011. Due Date: Dec 8 th, 2011 (to the TA) 1. ( points) What are the 2 most important network-layer

More information