Transcript Week One Agenda - Computing Sciences

Week One Agenda
Announcements
Course objective
Review current week information
Review terms
Week One
Announcements
ITEC275 Instructor for Network Design:
Professor Bob D’Andrea
Home phone number: 614.898.0457
Cell phone number: 614.519.5853
[email protected]
Program Chair of Information and Technology:
Mr. Todd Whittaker
Phone # 614.947.6110
[email protected]
Week One
Announcements
• Submit all assignments in drop box. In addition, send
an email notification to me that your assignment is
ready to be graded.
• The mid-term will be administered by the Student
Learning Center, June 13 through 18. The exam is
electronic.
• April 16, 2011 vacation
• Memorial Day April 30 (No School)
Lab Assignment
• Individually
• Class
Week One
Announcements
Email a notification when an assignment is completed
and ready to be graded. The “Subject” line of your
email notification should be one of the following
formats:
1. Email format for completed lab assignments:
<User name> <Section Number/ND> <Assign 1-3>
Example: dandrear V1FF/ND Assign. 1-3
2. Email format for questions:
<User name> <Section Number/ND> <Question>
Example: dandrear V1FF/ND Question
Week One
Announcements
Instructor commitment
• Respond daily to student emails.
• Post exam grades and lab assignments as quickly
as possible in the official electronic grade book.
• Post student mid-term and final exam status on the
Announcement page as soon after each exam has
been received from the Student Learning Center
(SLC).
Week One
Announcements
Weekly Recorded Power Point Presentations
http://cs.franklin.edu/~dandrear/itec275/Summer_2011_Network_Design_Presentations
Power Point file naming convention and format:
Example: Week_One_Net_Design.pptx
Week_One_Net_Design_ppt.ppt
Weekly Power Point files will be available on Monday
mornings the day of class for printing.
Week One
Course Objective
• This course was developed to parallel the Certified
Design Professional (CCDP) certification.
• Build upon the base level of the CCNA knowledge
and experience.
• Design simple routed LAN, routed WAN, and
switched LAN and ATM networks.
• Use Network-layer lists.
• Filter with access lists.
• Use and propagate VLAN.
• Evaluate existing network components.
Week One
History of Cisco
Len and Sandy Bosack, 1980s
Worked in different departments at Stanford
University. They were having trouble getting their
individual systems to communicate.
They built a gateway server that made it easier for
their disparate computers to communicate using the
IP protocol.
Week One
Internetworking Basics
Networks and networking have grown exponentially
over the last 30 years. This technology has evolved at
light speed just to keep up with the huge increases in
basic mission-critical user needs. Currently, there is a
basic need to use VoIP, increase transmission speeds,
and combine voice, data, and video for medium and
enterprise sized networks. This will involve the
design of new and/or the re-design of existing
networks.
Week One
Internetworking Basics
What is a network?
It is where data is sent and received via cables (e.g.,
telephone lines or fiber optics ) or wireless relay
systems. Networks contain a variety of hardware
devices and software implementations to accomplish
transmitting data.
A network makes it possible for people or devices to
communicate with each other near and far from each
other.
Week One
Internetworking Basics
Internetwork is a collection of individual networks
connected by networking devices that function as a
single large network
Protocol is a set of rules computers follow in order to
communicate with each other.
Frame is a set of data that includes addressing and
control information and is transmitted and received
between network devices.
Week One
Internetworking Basics
Best-effort delivery means that the protocol will not
check to see whether the data was delivered intact.
Multiplexing allows many applications to use the
same physical connection.
Encapsulation is the technique used by layered
protocols in which a layer adds header information to
the Protocol Data Unit (PDU) from the layer above.
Week One
Internetworking Basics
Network segmentation is the breaking up of a large
network into smaller networks. Routers, switches,
and bridges are used to create network segmentation.
Routers are used to connect networks together and
route packets of data from one network to another. By
default, routers break up broadcast domains.
Week One
Internetworking Basics
Switch is a device responsible for multiple functions
such as filtering, flooding, and sending frames. It
works using the destination address of individual
frames. By default, switches break up collision
domains.
Bridge is a device for connecting two segments of a
network and transmitting packets between them. Both
segments must use identical protocols to
communicate. Their purpose is to filter, send, or flood
any incoming frame, based on the MAC address of
that particular frame.
Week One
Internetworking Basics
Broadcast domain is a group of devices receiving
broadcast frames initiating from any device within the
group. Because they do not forward broadcast frames,
broadcast domains are generally surrounded by
routers.
Collision domain is the network area in Ethernet over
which frames that have collided will spread.
Collisions are propagated by hubs and repeaters, but
not by LAN switches, routers, or bridges.
Week One
Internetworking Basics
What is a collision?
The effect of two nodes sending transmissions
simultaneously in Ethernet. When they meet on
the physical media, the frames from each node
colide and are damaged.
Week One
Internetworking Models
Open Systems Interconnection (OSI) reference
model was introduced in the late 1970s. Created
by the International Organization for
Standardization (IOS).
Why was standardization needed?
This standard was created to allow computing
installations to incorporate multiple vendor
hardware and software products within their
operation. Prior to this standardization, computers
could only communicate with computers from the
same manufacturer.
Week One
Layered Approach
A reference model is a conceptual blueprint of
how communications should take place. It
addresses all the processes required for
effective communication and divides these
processes into logical groupings called layers.
Designs such as the OSI Model, are known as
layered architecture.
Example: Start up company. Identify the tasks
involved. Group similar tasks into
departments. These departments are a
metaphor for the layers in this scenario.
Week One
Layered Approach
Similarly, software developers can use a
reference model to understand computer
communication processes and see what types
of functions need to be accomplished on any
one layer. If they are developing a protocol for
a certain layer, they only want to focus
themselves with this specific layers functions,
not those of any other layer. Another layer and
protocol will handle the other functions.
Week One
Layered Approach
Advantages of using the OSI layered model
are:
Allows multiple-vendor development through
standardization of network components.
Allows various types of network hardware and
software to communicate.
Allows changes in one layer from affecting
other layers, so it doesn’t hamper
development.
Week One
OSI Model
The top three layers define how the applications within
the end stations will communicate with each other and
with users. The bottom four layers define how data is
transmitted end-to-end.
Application provides a user interface
Presentation presents data and handles encryption
Session keeps different applications data separate.
Transport provides reliable or unreliable delivery.
Network provides logical addressing
Data Link provides access to media using MAC address
Physical moves bits between devices, specifies voltage,
wire speed, and pin-out of cables.
Week One
OSI Model
Application – File transfer, print, database, and
application
Presentation – Data encryption, compression,
and translation services
Session – Dialog control
Transport – End-to-end connection
Network – Routing of packets
Data Link - Movement of frames
Physical – Physical topology
Week One
OSI Model
Network devices that operate at all seven
layers of the OSI model include:
Network management stations
Web servers
Gateways
Network hosts
Week One
OSI Model
Flow control is implemented at the transport layer to prevent
the receiving host buffers from being overflowed by the
sending host. This is an event that can result in data loss.
Reliable data transport employs a connection-oriented
communications session between systems, and the protocols
involved ensure that the following is achieved:
The segment delivered are acknowledged back to the sender
upon their reception.
Any segments not acknowledged are retransmitted.
Segments are sequenced back into proper order upon arrival at
their destination.
A manageable data flow is maintained in order to avoid
congestion overloading, and data loss.
Week One
OSI Model
Connection-Oriented communications is a
transport operation. One device first
establishes a connection-oriented session with
its peer system. This is called three-way
handshake. Data is then transferred, and when
finished, a call termination takes place to tear
down the virtual circuit.
Week One
OSI Model
Connection-oriented communications threeway hand shake.
Synchronize ->
Negotiate connection <->
Synchronize <Acknowledge ->
Connection established
Data transfer (send segments) <->
Week One
OSI Model
Buffer is used when a machine receives a flood
of datagram's to quickly for a process to
handle. Buffering can only solve the problem
temporarily if the burst is small. If the flood of
datagram's is too intense and the capacity is
exhausted, it will discard any additional
datagram's that arrive.
Week One
OSI Model
Windowing is a flow control (Transport layer)
method used with TCP at the Transport layer.
Windows are used to control the amount in
outstanding, unacknowledged data segments.
The data and route update packets are used at
the Network layer. The data packet to transport
user data through the internetwork. Route
update packets are used to update neighboring
routers about the networks connected to all
routers within the internetwork.
Week One
OSI Model
Protocols that send route update packets are
called routing protocols; examples of some
common ones are RIP, EIGRP, and OSPF.
Network addresses are protocol specific
network addresses. A router must maintain a
routing table for individual routing protocols
because each routing protocol keeps track of a
network with a different addressing scheme.
Week One
OSI Model
Interface is the exit interface a packet will take
when designated for a specific network.
Week One
OSI Model
Metric is the distance to the remote network.
Different routing protocols use different ways
of computing this distance.
Hop count is the number of routers a packet
passes through en-route to a remote network.
Week One
OSI Model
The Media Access Control (MAC) defines how packets
are placed on the media. Contention media access is
“first come/first served” access where everyone
shares the same bandwidth. MAC is a Data Link layer
function.
Logical Link Control (LLC) is a sub-layer
responsible for identifying Network layer protocols
and then encapsulating them. An LLC header tells the
Data Link layer what to do with a packet once the
frame is received.
Week One
TCP/IP Model
The TCP/IP model is basically a condensed
version of the OSI model. It is composed of
four layers.
Process/Application is the integration of the
first three layers of the OSI Model. The
Presentation/Application layer defines
protocols for node-to-node application
communication and also controls userinterface specifications.
Week One
TCP/IP Model
Host-to-Host parallels the Transport layer ,
defining protocols for setting up the level of
transmission service for applications. Issues
are addressed like reliable end-to-end
communication and ensuring the error-free
delivery of data. It handles packet sequencing
and maintains data integrity. In summary, this
layer shields the upper three layers from the
Internet layer.
Week One
TCP/IP Model
Internet layer exists for routing, and providing
a single network interface to the upper layers.
Network Access bottom layer that handles
similar functions as the Data Link and Physical
layers. It provides media access.
Week One
Internetwork Devices
Hubs are really multiple port repeater found at
the Physical layer. A repeater receives a digital
signal and preamplifiers or regenerates that
signal, and then forwards the digital signal out
all active ports without looking at any data.
Physical layer function
The switches and bridges work at the Data
Link layer and filter the network using
hardware (MAC) addresses.
Week One
Ethernet Networking
Ethernet is a contention media access method
that allows all hosts on a network to share the
same bandwidth of a link. Ethernet is popular
because it’s readily scalable, meaning it’s
comparatively easy to integrate new
technologies, like FastEthernet and Gigabit
Ethernet, into an existing network
infrastructure.
Ethernet networking uses Carrier Sense
Multiple Access with Collision Detect
(CSMA/CD).
Week One
Ethernet Networking
CSMA/CD is a protocol that helps devices
share the bandwidth evenly without having
two devices transmit at the same time on the
network medium. This protocol was created to
overcome the problem of those collisions that
occur when packets are transmitted
simultaneously from different nodes.
Week One
Ethernet Networking
A good collision management protocol is
needed like CSMA/CD because when a node
transmits in a network, all other nodes on the
network receive and examine that
transmission. Only bridges and routers can
effectively prevent a transmission from
propagating throughout the entire network.
Week One Review
Half- and Full-Duplex Ethernet
Half duplex uses only one wire pair with a
signal running in both directions on the wire.
Half duplex Ethernet typically 10BaseT.
Full-duplex uses two pairs of wires. It uses a
point-to-point connection between the
transmitter of the transmitting device and the
receive of the receiving device. There are no
collisions to worry about because now it’s like
a freeway with multiple lanes instead of the
single-lane road provided by half-duplex.
Week One
Half- and Full-Duplex Ethernet
Typical speeds are 10Mbps, 100Mbps, and
200Mbps for FastEthernet. Full-duplex
Ethernet can be used in three situations:
With a connection from a switch to a host.
With a connection from a switch to a switch.
With a connection from a host to a host using a
crossover cable.
Week One
Ethernet at the Data Link Layer
Ethernet at the Data Link layer is responsible for
Ethernet addressing, framing packets received
from the Network layer and preparing them for
transmission on the local network through the
Ethernet contention media access method.
Week One
Ethernet at the Data Link Layer
There are four different types of Ethernet frames
available:
Ethernet_II
IEEE 802.3
IEEE 802.2
SNAP
Week One
Ethernet at the Data Link Layer
Ethernet addressing uses the Media Access
Control (MAC) burned into each and every
Ethernet Network Interface Card (NIC). The
MAC, or hardware address, is a 48 bit address
written in a hexadecimal format.
Week One
Ethernet at the Physical Layer
Ethernet was first implemented by a group
called DIX (Digital, Intel, and Xerox). They
created and implemented the first Ethernet
LAN specification, which the IEEE used to
create the IEEE 802.3 Committee. This was a
10Mbps network that ran on coax, twistedpair, and fiber physical media.
The IEEE extended the 802.3 to two new
committees known as 802-3U (FastEthernet)
and 802.3Z (Gigabit Ethernet).
Week One
Ethernet Cabling
Straight-Through Cable
This type of Ethernet cable is used to connect:
Host to switch or hub (h/s <--> host)
Router to switch or hub (h/s <--> router)
Crossover Cable
This type of Ethernet cable is used to connect:
Switch to switch (h/s <--> h/s)
Hub to hub
Host to host
Week One
Ethernet Cabling
Rolled Cable
A rolled Ethernet cable can be used to connect
a host to a router console serial communication
(com) port.
(host <--> Router/Switch)
Week One
Data Encapsulation
Encapsulation is a technique used by layered
protocols in which a layer adds header
information to the Protocol Data Unit (PDU)
from the layer above.
Week One
Data Encapsulation
Application
Presentation
Session
Transport – PDU (Segment) TCP header/Data
Network – PDU (Packet) IP header/Data
Data Link – PDU (Frame)
LLC header/Data/FCS
MAC header/Data/FCS
Physical – PDU (Bits) 0101110101010101
Week One
Serial Transmission
Wide area network (WAN) services are
typically dedicated leased lines using HighLevel Data Link Control , Point-to-Point
(PPP), Integrated Services Digital Network
(ISDN), and Frame Relay. Typical speeds run
at 2400bps to 1.544 Mbps (T-1).
WAN serial connectors use serial transmission,
which is one bit at a time, over a single
channel. Parallel transmission sends at least 8
bits at a time.
Week One
Parallel Transmission
Parallel transmission sends at least 8 bits at a
time.
Week One
Data Terminal Equipment and Data
Communication Equipment
What is a DTE and DCE?
DTE – router interface and they connect into
DCE. A channel service unit/data service unit
(CSU/DSU). The CSU/DSU then plugs into a
demarcation location (demarc) and is the
service provider’s last responsibility. The
demarc is usually an RJ-45 female connector
located near your equipment.
Week One
Data Terminal Equipment and Data
Communication Equipment
A DCE supplies the physical connection to the
network, forwards traffic, and provides a
clocking signal to synchronize data
transmission between DTE and DCE devices.
Week One
Routing Protocols
Administrative distance (AD) is used to rate
the trustworthiness of routing information
received on a router from a neighboring router.
AD values range from 0 to 255, where 0 is the
most trusted and 255 means no traffic will pass
via this route.
Week One
Routing Protocols
Route Source
Connected interface
Static route
EIGRP (Cisco)
IGRP (Cisco)
OSPF
RIP
External EIGRP
Default AD
0
1
90
100
110
120
170
Week One
Cisco Three Layer Hierarchical Model
A hierarchy helps us to understand where
things belong, how things fit together, and
what functions go where. It brings order and
understandability to otherwise complex
situations.
Cisco’s network design model represents the
following three layers:
Core Layer
Distribution Layer
Access Layer
Week One
Cisco Three Layer Hierarchical Model
The core layer is responsible for transporting
large amounts of traffic both reliably and
quickly. The main purpose of the network’s
core layer is the switch traffic as fast as
possible. The traffic transported across the core
is common for a majority of users.
If there is a failure at the core layer, every user
can be affected. Fault tolerance at this layer is
a critical issue.
Week One
Cisco Three Layer Hierarchical Model
The core layer must be concerned about high levels of
traffic, and the speed and latency of the traffic.
Things you don’t want to do.
Do anything to slow down traffic. This includes
adding access hosts, routing between virtual local
networks (VLANs), and packet filtering.
Don’t support workgroup access at this level.
Avoid expanding the core when the internetwork
grows (i.e., adding routers).
Week One
Cisco Three Layer Hierarchical Model
The core layer must perform at peak level of
efficiency and speed. If performance becomes
an issue in the core, give preference to
upgrades over expansion.
Week One
Core Layer Design Recommendations
Design the core for high reliability.
Design for speed as a major consideration.
Select routing protocols with low
convergence times.
Week One
Cisco Three Layer Hierarchical Model
The distribution layer is sometimes referred to
as the workgroup layer and is the
communication point between the access layer
and the core. The primary function of the
distribution layer are to provide routing,
filtering, and WAN access and to determine
how packets can access the core.
Week One
Cisco Three Layer Hierarchical Model
Distribution Recommendations:
Implement tools such as access lists,
packet filtering, and queuing.
Implementation of security and network
policies, including address translation and
firewalls.
Redistribution between routing protocols,
including static routing.
Routing between VLANs and other
workgroup support functions
Week One
Cisco Three Layer Hierarchical Model
Distribution Recommendations:
Definitions of broadcast and multicast
domains.
Week One
Cisco Three Layer Hierarchical Model
The access layer controls user and workgroup
access to internetwork resources. The access
layer is sometimes referred to as the desktop
layer. The network resources most users will
be available locally.
Ethernet switching and static routing are
frequently seen in the access layer.
Week One
Network Terms
Logical address: IP address
Physical address: MAC address
Hub: Layer one (physical). No real intelligence.
Switch: Layer two.
Router: Layer three.
Unicast transmission: One source to one
destination.
Broadcast transmission: Distribute to all devices.
Multicast transmission: Group of devices.
Week One
Network Terms
ARP protocol: What is my MAC address?
RARP protocol: What is my logical address?
Broadcast storms: Caused when there are
redundant paths.
Spanning Tree Protocol (STP): Looks for loops
on the network.
Week One
Network Addresses
Class A: 0 – 127
Class B: 128 – 191
Class C: 192 – 223
Class D: multicast
Class E: Research
Week One
Subnetting
Network address: 192.168.10.0
Dotted decimal notation: xxx.xxx.xxx.xxx
Default subnet: 255.255.255.0
nnnnnnnn.nnnnnnnn.nnnnnnnn.hhhhhhhh
Subnet mask: 255.255.255.192 or /26
nnnnnnnn.nnnnnnnn.nnnnnnnn.nnhhhhhh
Binary representation (192.168.10.0):
11000000.10101000.00001010.00000000
Binary representation (255.255.255.192):
11111111.11111111.11111111.11000000
Least significant byte (192): .11000000
Week One
Subnetting
10000000 128
11000000 192
11100000 224
11110000 240
11111000 248
11111100 252 /30
11111110 254
/25
/26
/27
/28
/29
/31
Week One
Questions
How many subnets?
How many hosts per subnet?
What are the valid subnets?
What is the broadcast address for each subnet?
What are the valid hosts?