Advantages and Disadvantages of Mikrotik Extreme Protocols in Wireless Networks - Assignment Example

PROBLEM SOLVING REPORT 2 Name Course Tutor University City and State Date Question 1 a) Polling is a method used to check the readiness of a terminal device. In a network, a central controlling device sends a poll message to a specific device connected to that network, all terminals receive the message but only the intended recipient device replies to it. If that recipient device has data that needs to be transmitted, it will reply to the poll message by making that transmission. This polling method therefore creates an orderly transmission basis that avoids the issue of packets filling the buffer. Advantages I. No packets are dropped due to buffer overflow II. Polling method is not limited by distance of the controlling device and the recipient terminals (Ghorbani 2015). Disadvantages I. Polling causes overhead that may reduce the data transmission time (Ghorbani 2015) . II. Polling method can cause latency on the network which slows down the network response time. b) A token bus has the features of a token ring network and a bus topology. This network type has its stations organized to resemble a ring. It uses a token, which is a small data frame that goes round the ring communicating to all attached devices. If a device wants to send data through the network, it has to wait and possess the token. Once the token is captured, the device only has a limited time to conduct transmission before the token is released back to the network. This method employs an orderly transmission that avoids collisions. As transmission speed increases, the performance of the token bus increases as well. c) 1) Collisions occur when more than one device on a network wants to transmit data at the same time. In a bus topology, all devices communicate in one single line. Due to that singular path of communication, a collision is very costly and adversely reduces the throughput of that network. 2) Broadcasts are messages that are sent through the network and are received by all connected devices. If there are many devices connected on the bus topology, the broadcast message will not be received properly by the devices that are far from the source due to increase of attenuation (Faria n.d). Also, due to only one path being used for the broadcast, the throughput will be greatly reduced. 3) Repeaters are used to amplify a wireless network signal. This amplification ensures that broadcast messages are received properly by all connected devices. However, they negatively influence collisions since a wider network range means more devices are exposed to it and hence more likelihood of collisions to occur. A hub works as a central device that connects many terminals on the network. It broadcasts all the packets it receives to all terminals hence ideal for broadcasts. Hubs can be used to send a jam signal to connected devices if they detect a collision has occurred. 4) Bridges connect two networks in a way that packets can be forwarded between them. Connecting two networks increases the chances of collisions but fortunately bridges are equipped with collision detection systems. When two networks are connected, broadcasts become exposed to more recipient devices. Switches are used to connected devices to a network. Switches reduce possibility of collisions by dividing a network into many VLANs. Broadcasts are easily done with switches since all devices connected to the switch are forwarded a copy of the message. Question 2 a) Only the header is used since that’s the place where the 16 –bits required for calculation of the checksum are located. Cyclic Redundancy Check tries to fix any errors it might find with the data (Koopman 2002). However, IPv4 error checking is still necessary to ensure that all issues were resolved. b) Since subnet mask = 255.255.192.0 then 255- 192= 63 My chosen IP address 111.123.133.143 So the range is 111.123.133.0 111.123.133.63 111.123.133.126 111.123.133.189 The chosen IP belongs in the 111.123.133.126 range c) Fragmentation is dividing a datagram into fragments. This division is done so to enable the datagrams to pass through a link which has a small maximum transmission unit (MTU). Routers in IPv4 conduct this fragmentation (Houston 2016). The host destination device, on the other hand, is responsible for reassembling the fragments. If a fragment gets lost during transmission, the TCP protocol must resend the fragments. This retransmission can easily cause congestion. d) i) The protocol Source information is stored on datagram header. Checksum information is imprinted on datagram header Datagram is transmitted along the network Router or destination host checks for data corruption in the checksum information If corruption occurs, source host information is read from the header. A discard message is sent to it. Datagram is then discarded Source host resends message for a limited number of trials. If no error occurs, source information is read from the header. A successful delivery message is sent to from the source host. ii) source & checksum on header data is not corrupted data is corrupt Successful delivery message Sequence Diagram above is for the successful and the unsuccessful delivery of datagrams. iii) Advantages The source host is notified in case of any data corruption. The datagram is resent to make sure information eventually reaches its intended destination host. Disadvantages Each datagram needs additional header information which might slightly impact on transmission efficiency. Resending the datagram severally wastes the network resources. Question 3 a) 1) Routing Information Protocol version 2 (RIPv2) contains information which includes a command that differentiates if a packet was a request or a response, version information that indicates which routing protocol version was used, AFI indicates the type of addresse family that was used, route tag information differentiates between internal routes and external routes, the IP address of the destination, the subnet mask of the destination, the next IP address hops, and finally the number of hops to the destination (Bruno & Kim 2003). 2) RIPv2 gets its information from its neighboring routers. 3) Since the protocol has no way of calculating its own routes, it can only depend on the information it gathers from its neighbors; hence it’s of the second hand variant. 4) Open Shortest Path First version 2(OSPFv2) contains information that includes usable interfaces, the closest neighbors, the destination of the next hop, the outgoing interface and also all the destinations the router has learnt. 5) This information is collected from neighboring routers 6) OSPFv2 authenticates every exchange to make sure that the router that gave the information is credible. This authentication process makes the information to be considered legitimate and hence first hand. b) A to B= - no cost A to C= 1 Cost of 2 A to D = A + F+D= 1+2= 3 cost of 3 A to E= 4, but shortest path is A to C then to E = 1+2=3 cost of 3 A to F= 1 cost of 1 c) i) IPv4 HLEN s=indicates the length of the header while the total length illustrates the length of the packet. On IPv6, payload length indicates how much information a packet contains. Both fields are related in that they indicate the length of the data portion of the packet being transmitted. The change was made in IPv6 to save the host the trouble of checking if a packet was big enough in its initial phase. This change increased efficiency of packets transmission. ii) Protocol field in IPv4 indicates the transport protocol being utilized. On the other hand, next header field in IPv6 indicates what protocol is to be expected after the header. Both fields conduct the same job of revealing the protocol in use. IPv6 was changes to prepare the network about protocol status in advance before receiving the packet. iii) TTL (time to live) in IPv4 indicates the number of hoops that a packet may be subjected to. In IPv6, hop limit field shows the number of hops a packet is limited to. These two measures are related in that they both ensure that there are no rooting loops of the same packet. In IPv6, when the hop limit is reached, the packet is discarded to avoid wasteful looping. This enhances the utilization of network resource. References Bruno, A and Kim, J 2003,CCDA self –Study: RIP, IGRP and EIGRP Characteristics and Design, Cisco Press. Available from: < http://www.ciscopress.com/articles/article.asp?p=102174&seqNum=4>[27th August 2016]. Faria, D n.d, Modelling Signal Attenuation in IEEE802.11 Wireless LAN, Stanford Univeristy. Available from: < http://www-cs-students.stanford.edu/~dbfaria/files/faria >[27th August 2016]. Ghorbani, N 2015, Review: Advantages and disadvantages of mikrotik nstreme protocols an wireless networks, International Journal of Computer Networks and Communications Security, vol. 3, no. 6, pp. 244-247.Available from:[27th August 2016]. Houston, G 2016, Evaluating IPv4 and IPv6 Packet Fragmentation, APNIC. Available from: < http://blog.apnic.net/2016/01/28/evaluating-ipv4-and-ipv6-packet-frangmentation/>[27th August 2016]. Koopman, P 2002, 32-Bit Cyclic Redundancy Codes For Internet Application, Carnegie Mellon University. Available from: < https://users.ece.cmu.edu/~koopman/networks/dsn02/dsn02_koopman.pdf >[27th August 2016]. Read More