11 September 2015 RE Meyers, Ms.Ed. CCENT ICND1 Exam Topics Review Describe the Operation of Data Networks: Network Diagrams and Data Paths

11 September 2015 Disclaimer  This review is for the exclusive non-profit use by Cisco Academy instructors and students only!  Contents of this review were derived from the following sources under the doctrine of US copyright “Fair Use” section 107: Cisco Networking Academy Curricula: Discovery Networking for Home and Small Businesses version 4.x Interactive Course Guide, Cisco Learning Institute CCENT/CCNA ICND 1 Official Exam Certification Guide, 2 nd ed. by Wendell Odom, Cisco Press, 2008; ISBN Cisco Learning Network Other references footnoted in individual slide notes area.

11 September 2015 Error Reporting  Please report any errors in this presentation to:   Don’t rant! Let me know where I made a mistake so it can be fixed.  Feel free to modify this presentation to suit your needs. Please remove the WVU master and my name from your edited presentation to protect WVU’s logo acceptable use policy.

11 September 2015 CCENT Exam Topics  Describe the operation of data networks  Describe the impact of applications (Voice over IP and Video over IP) on a network

11 September 2015 TCP and UDP Protocols  Both work at the transport layer of the network models

11 September 2015 TCP: Transport Control Protocol  A transport layer protocol used by applications that require guaranteed delivery.  Establishes a full duplex virtual connection between two endpoints.  The byte stream is transferred in segments  Window size determines the number of bytes of data that can be sent before an acknowledgement from the receiver is necessary  A “sliding window” provides handling for both timeouts and retransmissions.

11 September 2015 TCP Action  TCP protocol operations is divided into 3 phases  Connection Establishment  Data Transfer  Connection Termination

11 September 2015 TCP: Connection Establishment  TCP Connection uses a three- way handshake 1.Client sends a SYN to the server  Segment sequence number set to a random value 2.Server replies with a SYN-ACK  Acknowledgment is set to one more than the received sequence number 3.Client sends an ACK back to the server  Sequence number is set to the received acknowledgement value  Acknowledgement number is set to one more than the received sequence number

11 September 2015 TCP: Data Transfer  Ordered data transfer  Destination host rearranges according to sequence number  Retransmssion of lost packets  Discards duplicate packets  Error-free data transfer  Flow control limits the rate a sender transfers data to guarantee reliable delivery.  Congestion control - sliding window

11 September 2015 TCP: Connection Terminated  A typical tear-down requires a pair of FIN and ACK segments from each endpoint  When an endpoint wishes to stop its half of the connection, it transmits a FIN packet  The other end acknowledges with an ACK.

11 September 2015 UDP  User Datagram Protocol  Unreliable data transfer service  Datagrams may arrive out of order, duplicated, or go missing without notice.  It assumes that error checking and correction is either not necessary or performed by the application

11 September 2015 TCP vs. UDP

11 September 2015 TCP vs. UDP

11 September 2015 Video On Demand  Streaming video servers can be found on LANs and WANs  Bandwidth use is intensive  Very sensitive to data congestion, latency, and jitter

11 September 2015 Voice Over IP  A family of transmission technologies for delivery of voice communications over IP networks such as the Internet or other packet-switched networks  Bandwidth use is intensive  Very sensitive to data congestion, latency, and jitter

11 September 2015 VoIP and VoD Delivery  VoD and VoIP UDP use UDP  Acknowledgments would slow down delivery  Retransmissions are undesirable.  If a few packets are missed, the user might hear a slight break in the sound or a short glitch in the video.

11 September 2015 Quality of Service  QoS provides different priority to applications, users, or data  VoIP traffic can be tagged to get priority over TCP data traffic to increase speed of delivery with minimal latency

11 September 2015