Transcript CCENT 640-822 ICND1 Exam Topics Review

CCENT 640-822 ICND1 Exam Topics Review
Describe the Operation of Data Networks:
Network Diagrams and Data Paths
5 April 2016
RE Meyers, Ms.Ed.
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, 2nd ed.
by Wendell Odom, Cisco Press, 2008; ISBN1-58720-182-2
• Cisco Learning Network
https://learningnetwork.cisco.com/docs/DOC-4987
• Other references footnoted in individual slide notes area.
5 April 2016
Error Reporting
Please report any errors in this presentation to:
[email protected]
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.
5 April 2016
CCENT Exam Topics
 Describe the operation of data networks
Describe the impact of applications (Voice over IP and
Video over IP) on a network
https://learningnetwork.cisco.com/docs/DOC-4987
5 April 2016
TCP and UDP Protocols
Both work at the transport layer of the network
models
5 April 2016
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.
5 April 2016
TCP Action
TCP protocol operations is divided into 3 phases
Connection Establishment
Data Transfer
Connection Termination
5 April 2016
TCP: Connection Establishment

TCP Connection uses a threeway 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
5 April 2016
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
5 April 2016
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.
5 April 2016
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
5 April 2016
TCP vs. UDP
5 April 2016
TCP vs. UDP
5 April 2016
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
5 April 2016
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
5 April 2016
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.
5 April 2016
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
5 April 2016
5 April 2016