Week Two Agenda

1
Week Two Agenda

• Attendance
• Announcements
• Review week one information
• Current week information
• Discuss lab assignment
• Good example to review before starting project.
• Case Study Read ACMC Hospital Network Upgrade,
  page 121. Answers Appendix A.

2
Review Week One

• Internetworking Terminology
• Network segmentation is the breaking up of a
  large network into smaller networks. Routers,
  switches, and bridges are used to create network
  segmentation.
• Router is used to connect networks together and
  route packets of data from one network to
  another. By default, they break up broadcast
  domains.

3
Review Week One

• Internetworking Terminology
• 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.

4
Review Week One

• Internetworking Terminology
• 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. Provide example
• 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.
  Provide example

5
Review Week One

• Internetworking Terminology
• Flow control is implemented at the transport
  layer to prevent the receiving host buffers from
  being overflowed by the send host.
• 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.

6
Review Week One

• Internetworking Terminology
• 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.
• 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.

7
Review Week One

• Internetworking Terminology
• Protocol is a 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 (192.160.18.0). 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.
• Interface is the exit interface a packet will
  take when designated for a specific network.

8
Review Week One

• Internetworking Terminology
• 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.

9
Review Week One

• Internetworking Terminology
• ARP protocol requests what is my MAC address?
• RARP protocol requests what is my logical
  address (IP)?
• Broadcast storms are caused when there are
  redundant paths. Provide example.
• Spanning Tree Protocol (STP) looks for loops on
  the network.

10
Review Week One

• Internetworking Terminology
• 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.

11
Review Week One

• Layered Approach
• 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.

12
Review 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 doesnt hamper development.

13
Review 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.

14
Review Week One

• OSI Model
• Application - File, print, message, database,
  and application
• Presentation Data encryption, compression, and
  translation services
• Session Dialog control
• Transport End-to-end connection
  (connection-oriented)
• Network Routing
• Data Link - Framing
• Physical Physical topology

15
Review Week One

• ISO Model
• 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.

16
Review 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.

17
Review Week One

• OSI Model
• Connection-oriented communications three-way
  hand shake.
• Synchronize -gt
• Negotiate connection lt-gt
• Synchronize lt-
• Acknowledge -gt
• Connection established
• Data transfer (send segments) lt-gt

18
Review 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 user-interface specifications.

19
Review 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.

20
Review 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.

21
Review Week One

• Internetwork Devices
• A hub is really a multiple port repeater found
  at the Physical layer. A repeater receives a
  digital signal and re-amplifies 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.

22
Review 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 its readily scalable, meaning its
  comparatively easy to integrate new technologies,
  like Fast Ethernet and Gigabit Ethernet, into an
  existing network infrastructure.
• Ethernet networking uses Carrier Sense Multiple
  Access with Collision Detect (CSMA/CD).

23
Review Week One

• Ethernet Networking
• 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.

24
Review Week One

• 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 its like a freeway with
  multiple lanes instead of the single-lane road
  provided by half-duplex.

25
Review Week One

• Half- and Full-Duplex Ethernet
• Typical speeds are 10Mbps, 100Mbps, and 200Mbps
  for Fast Ethernet. 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.

26
Review 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.

27
Review 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, twisted-pair, and fiber physical media.
• The IEEE extended the 802.3 to two new
  committees known as 802.3U (Fast Ethernet) and
  802.3Z (Gigabit Ethernet).

28
Review Week One

• Ethernet Cabling
• Straight-Through Cable
• This type of Ethernet cable is used to connect
• Host to switch or hub (h/s lt--gt host)
• Router to switch or hub (h/s lt--gt router)
• Crossover Cable
• This type of Ethernet cable is used to connect
• Switch to switch (h/s lt--gt h/s)
• Hub to hub
• Host to host

29
Review 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 lt--gt Router/Switch)
• When preparing design drawings, you should
  specify the types of cables used between one
  device and another.

30
Review 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.

31
Review 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

32
Review Week One

• Serial Transmission
• Wide area network (WAN) services are typically
  dedicated leased lines using High-Level 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.

33
Review Week One

• Routing Protocols
• Administrative distance (AD) Used to rate the
  trustworthiness of routing information received
  on a router from a neighboring router
• Route Source Default AD
• Connected interface 0
• Static route 1
• EIGRP (Cisco) 90
• IGRP (Cisco) 100
• OSPF 110
• RIP 120
• External EIGRP 170

34
Review 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.
• Ciscos network design model represents the
  following three layers
• Core Layer
• Distribution Layer
• Access Layer

35
Review 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 networks 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.

36
Review 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 dont want to do.
• Dont anything to slow down traffic. This
  includes adding access lists, routing between
  virtual local networks (VLANs), and packet
  filtering.
• Dont support workgroup access at this level.
• Avoid expanding the core when the internetwork
  grows (i.e., adding routers).

37
Review 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.

38
Review 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.

39
Review 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.

40
Review Week One

• Cisco Three Layer Hierarchical Model
• Distribution Recommendations
• Implement tools such as access lists, of
  packet filtering, and of 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

41
Review 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.

42
Review Week One
43
Review Week One

• Network Addresses
• Class A 0 127
• Class B 128 191
• Class C 192 223
• Class D multicast
• Class E Research

44
Review Week One

• Sub netting
• 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

45
Review Week One

• Sub netting
• 10000000 128 /25
• 11000000 192 /26
• 11100000 224 /27
• 11110000 240 /28
• 11111000 248 /29
• 11111100 252 /30
• 11111110 254 /31

46
Review Week One

• Subnet 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?

47
Week Two

• Internetworking Terminology
• Packet-switched networks is one based on the
  transmission of data packets. Dividing a
  continuous stream of data into small units called
  packets, enables data from multiple devices on a
  network to share the same communications channel
  simultaneously, but
• requires precise routing information.
• Packet switch is a physical device that makes it
  possible for a communication channel to share
  several connections, its functions include
  finding the most efficient transmission path for
  packets.

48
Week Two

• Internetworking Terminology
• Leased lines are permanent connection between
  two points leased from the telephone company.
• Circuit-switched network is used with dial-up
  networks such as PPP and ISDN. Passes data, but
  needs to set up the connection first, similar to
  making a phone call.

49
Week Two

• Internetworking Terminology
• DSL is a high-bandwidth connection over the
  traditional copper telephone lines. DSL utilizes
  modems at either end of the wire. It is another
  technology that enables SPs to deliver a wide
  range of services to their customers.

50
Week Two

• Internetworking Terminology
• Convergence this is the process for all routers
  in an internetwork to update their routing tables
  and create a consistent view of the network,
  using the best possible path. No user data is
  passed during a convergence time.
• Latency is the time it takes a data packet to
  get from one location to another.
• Cable is a high-speed copper platform that
  supports analog and digital video services over
  coaxial cables.

51
Week Two

• Internetworking Terminology
• Internet Control Message Protocol (ICMP) is used
  by IP for many different services. ICMP is a
  management protocol and messaging service
  provider for IP. Its messages are carried as IP
  datagram's.
• If a router receives a packet destined for a
  network that the router doesnt know about, it
  will send an ICMP Destination Unreachable
  messages back to the sender station.

52
Week Two

• Internetworking Terminology
• If a routers memory buffer for receiving an
  incoming datagram is full, ICMP messages are sent
  out.
• Each IP datagram is allotted a certain number of
  routers, called hops, that it may go through.
• An ICMP message is sent to the sending station
  informing them that the packet was dropped.
• The ping command uses ICMP echo messages to
  check the physical connectivity of machines on an
  internetwork.

53
Week Two

• Internetworking Terminology
• Flood (Broadcast and multicast frames).
• Learning
• Provide example

54
Week Two

• Reasons Requiring Redesign
• If troubleshooting network problems becomes too
  frequent or even impossible to manage.

55
Week Two

• Cisco Vision of Intelligent Networks
• Network architecture exists today largely
  because there is an enormous variety of network
  application-level business solutions and a
  constant need to integrate applications into a
  new architecture. Ciscos vision and
  infrastructure enables customers to build a more
  intelligent network infrastructure. The Cisco
  Service Oriented Network Architecture (SONA)
  focuses on service and applications rather than a
  traffic transport-oriented view.

56
Week Two

• Cisco Vision of Intelligent Networks
• Integrating networked resources and information
  that have been largely separate entities.
• Sharing intelligence across multiple products
  and infrastructure layers.
• Full network component participation in the
  delivery of services and applications.

57
Week Two

• Evolving to an Intelligent Information Network
• Phase 1 Integrated transport is to consolidate
  all services (data, voice, and video) into an IP
  network for secure network convergence.
• Phase 2 Integrate Services When the network
  infrastructure is converged, IT resources can be
  pooled and shared, or virtualized, to flexibly
  address the organizations changing needs.

58
Week Two

• Evolving to an Intelligent Information Network
• Phase 3 Integrated application is where focus
  to the network application-aware so that it can
  optimize application performance and more
  efficiently deliver networked applications to
  users.

59
Week Two

• SONA Framework
• Networked Infrastructure layer This layer
  insures that all IT resources interconnect across
  a converged network foundation. The objective is
  to provide connectivity, anywhere and anytime.
• Interactive Services layer This layer includes
  both application networking services and
  infrastructure services. This will enable
  efficient allocation of resources to applications
  and business processes delivered through the
  network infrastructure.

60
Week Two

• SONA Framework
• Application layer Includes business
  applications and collaboration applications. The
  objective of this layer is to meet business
  requirements and achieve efficiencies by
  leveraging the Interactive Services layer.

61
Week Two
62
Week Two

• SONA Framework
• What are the benefits?
• Functionality Supports the organizational
  requirements.
• Scalability Supports growth and expansion of
  organizational tasks by separating functions and
  products into layers.
• Availability Provides the necessary services,
  reliability, anywhere, anytime.

63
Week Two

• SONA Framework
• Performance Provides the desired
  responsiveness, throughput, and utilization on a
  per application basis through the network
  infrastructure and services.
• Manageability Provides control, performance
  monitoring, fault detection.

64
Week Two

• SONA Framework
• Efficiency Provides the required network
  services and infrastructure with reasonable
  operational costs and appropriate capital
  investment on a migration path to a more
  intelligent network, through step-by-step network
  services growth.
• Security Provides for an effective balance
  between usability and security while protecting
  information assets and infrastructure from inside
  and outside users.

65
Week Two

• PPDIOO Network Lifecycle
• Prepare phase The network is built.
• Plan phase A network design specification is
  produced.
• Design phase Includes fault detection and
  correction and performance monitoring.
• Implement phase Network requirements are
  identified.
• Operate phase Business requirements and
  strategy related to the network are established.

66
Week Two

• PPDIOO Network Lifecycle
• Optimize phase Based on proactive management of
  the network.

67
Week Two

• Design Methodology
• Step 1 Identify your customer requirements.
• Step 2 Characterize the existing network and
  sites.
• Step 3 Design the network topology and
  solutions, which includes the following
• Possibly building a pilot or prototype
  network.
• Creating a detailed design document.

68
Week Two

• Design Mythology
• Planned application and network services.
• Organizational goals.
• Technical goals.
• Technical constraints.

69
Week Two

• Typical Organizational Design Constraints
• Budget
• Time frame for window of opportunity
• Availability of personnel
• Experienced
• Trainable
• Policies
• Schedule
• Timeline
• New applications

70
Week Two

• Typical Organizational Goals
• Increase revenue
• Shorter development cycles
• Improved customer support
• Open the organizations information
  infrastructure

71
Week Two

• Determining Factors Affecting the Scope of the
  Design Project
• Is the design for a new network or is a
  modification of an existing network?
• Is the design for an entire enterprise network, a
  subset of the network, or simply a single segment
  or module?
• Does the design address a single function or the
  entire networks functionality?
• What OSI protocol layers are involved.

72
Week Two

• New Application Schedule
• New network designs often are driven by the
  introduction of new network applications. The
  implementation time frame for new applications
  are often tightly connected and influence the
  availability time for network design.

73
Week Two

• Evaluate Capacities
• If parts of the network provide insufficient
  bandwidth and cannot be increased because of
  technical reasons, the situation must be resolved
  by implementing other means.
• Traffic analysis provides helpful information
  about applications and protocols used in the
  network and might reveal any shortcoming in the
  network.
• Audits can be useful in revealing marginal
  situations that might require temporary changes
  to the network.

74
Week Two

• Evaluate Capacities
• A saturated Ethernet segment occurs at 40
  percent network utilization.
• A WAN link saturates at about 70 percent network
  utilization.
• Network characterization can be a lengthy
  process. Factors to consider are the size of the
  network, and complexity, the experience of the
  network engineer, the quality of the
  documentation and communication, the efficiency
  of the tools.

75
Week Two

• Design Methodology
• Use a design document to list and identify the
  network. Categories are as follows
• Introduction
• Design requirements
• Existing network infrastructure
• Design
• Proof of Concept
• Implementation plan
• Appendixes

76
Week Two

• Implementation Process
• Step 1 Plan the implementation.
• Step 2 Implement and verify the design.
• Step 3 Monitor and optionally redesign.

77
Week Two

• Network Design Tools
• A pilot network Tests and verifies the design
  before the network is implemented to the real
  world. Could be a subset of the existing network.
• A prototype network Tests and verifies a
  redesign in an isolated network before it is
  applied to the existing network.

78
Week Two

• Network Design Tools
• Top-Down Approach can be used to design a
  network solution, after the organizational
  requirements and documenting the existing
  network. This approach allows the designer to
  view the picture before worrying about the
  details.
• Botton-up Approach has a limited usage. If the
  network is small or if the network is faced with
  a critical situation, should this approach be
  used.

79
Week Two

• Network Design Tools
• Decision tables or truth tables are used to make
  systematic decisions when there are multiple
  choices. Decision tables facilitate the
  selection of a certain choice from many choices
  and can provide helpful justification why a
  certain solution was chosen.
• Simulation and verification tools and services.

80
Week Two

• Design Verification
• The network designer should be involved in the
  implementation phase to assist in the design
  verification and take corrective action if
  necessary. He/she should be available after the
  implementation phase for a period of time to
  answer questions and provide training for those
  performing network support.
• Documentation should be in a central location
  and maintained with to provide reliable
  information for new personnel.

81
Week Two

• Site Contact Information
• Site location, name, address, and shipping
  address
• Site contacts name and all the possible ways to
  reach that person (phone, cell phone, pager, and
  e-mail address).
• Site owner
• Hours of operation
• Access procedures, including those for security,
  safety, and union labor.
• Specific location of equipment.