Download TND-Aggregation-Redundancy and more High school final essays Computer science in PDF only on Docsity!
- WAN networks and protocols: Analyse features and requirements of enterprise networks.
- Analyse WAN enterprise architecture, uptime, bandwidth, ISPs, traffic flows, prioritisation, queuing, latency, QoS, teleworking.
- WAN Technologies
- Examine WAN operations and services, analyse and compare private and public WAN technologies, select the appropriate WAN protocol and service for a specific network requirement.
- Tutor-led/facilitated group discussions and tutorials on redundant network design.
- Individual work: Examine redundant network designs.
- Discuss and evaluate redundancy needs at router level.
- Individual work: Explore, investigate and compare router redundancy protocols. Objectives Transport Network Design Learning Outcomes and Assessment Criteria Pass Merit Distinction LO1 Explore LAN design principles and their application in the network design process LO1 & 2 D1 Evaluate different implementations of link aggregation using EtherChannel to solve bandwidth and load issues. P1 Examine the network design models and features of scalable networks based on a given set of business needs. P2 Discuss LAN redundancy, bandwidth and load related issues and possible solutions with reference to Layer 2 and Layer 3 of the OSI Model. M1 Analyse the switch and router redundancy protocols and their effectiveness in supporting scalable networks. LO2 Implement a network using LAN design principles based on a predefined set of requirements P3 Select LAN devices based on features and requirements, and apply basic configuration commands for network connectivity. P4 Implement a LAN design with Layer 2 and Layer 3 redundancy using switch and router redundancy protocols. M2 Analyse different switch redundancy protocols and their effectiveness in solving redundancy issues. M3 Analyse Layer 3 redundancy implementations for IPv4 and IPv6. Transport Network Design 3
Learning Outcomes and Assessment Criteria Pass Merit Distinction LO3 Produce an appropriate WAN solution to a set of organisational requirements LO3 & 4 D2 Evaluate troubleshooting methods and their effectiveness in solving enterprise-wide networking issues. P5 Examine WAN technologies and select the appropriate one for a set of enterprise requirements. P6 Configure WAN protocols as part of an enterprise network solution M4 Analyse the benefits and drawbacks of private and public WAN technologies. M5 Evaluate features and benefits of different VPN types based on organisational needs. LO4 Solve a range of network related problems using appropriate troubleshooting techniques and methods P7 Deploy network monitoring tools and troubleshooting methods to establish network baselines and produce network documentation. P8 Troubleshoot LAN and WAN connectivity issues at different networking layers. M6 Develop effective documentation of troubleshooting methods and steps based on a given scenario. Transport Network Design 4 WAN Technology Concepts
WAN and the OSI Model:
In relation to the OSI reference model, WAN operations focus on Layer 1 and Layer 2. Standards describe how to provide…
WAN and the OSI Model:
In relation to the OSI reference model, WAN operations focus on Layer 1 and Layer 2. Standards describe how data is encapsulated for transmission to a remote location.
- Another Data Link layer protocol is the Multiprotocol Label Switching (MPLS) protocol.
- MPLS is increasingly being deployed by service providers to provide an economical solution to carry circuit-switched as well as packet-switched network traffic.
- It can operate over any existing infrastructure, such as IP, Frame Relay, ATM, or Ethernet.
- It sits between Layer 2 and Layer 3 and is sometimes referred to as a Layer 2.5 protocol. Data Link layer protocols define how the data is encapsulated as well as how it is transported between sites.
A number of technologies for the transport of data exist.
While the encapsulation will vary with the technology, most use the ISO HDLC standard or a modification of it.
Data Link layer protocols: How the data is encapsulated.
The choice of encapsulation protocols depends on the WAN technology and the
equipment.
Most framing is based on the HDLC standard. The data is encapsulated with some form of header information and an FCS field. The entire frame is then encapsulated with Flag fields to indicate the beginning and end of the frame. FLAG HEADER DATA FCS FLAG It is important to note that most vendors (Cisco included) use their own proprietary version of HDLC on HDLC links between their own products.
Examining the Frame:
The control field is protocol dependent. It usually indicates whether the content of the data is control information or Network layer data (1 Byte).
Examining the Frame:
The address and control fields form the header information in the standard HDLC frame. Both PPP and Cisco HDLC add the Protocol field to the header to identify the Layer 3 protocol of the encapsulated data. Cisco HDLC only communicates with Cisco HDLC…..
WAN switched networks fall into two categories: Circuit switched.
POTS, ISDN
Packet switched.
Frame Relay, ATM, X.
When a subscriber makes a telephone call, the dialed number is used to set
switches in the exchanges along the route of the call so that there is a continuous
circuit from the originating caller to that of the called party.
Because of the switching operation used to establish the circuit, the telephone
system is called a circuit-switched network.
Circuit Switching and TDM:
Each device to be multiplexed is assigned a specific “time slot” in the frame. At each time slot, 8 bits is read from each device and a fixed length frame is built using that data. If there is nothing to send for that time slot, 8 null bits are placed in the frame for that device.
An alternative is
to allocate the
capacity to the
traffic only when
it is needed and
share capacity
among many
users.
If the circuit is to be shared, there must be some mechanism to label the bits so
that the system knows where to deliver them.
The bits are gathered into groups called cells, frames, or packets.
Each packet
must contain the
network
information
in order to be
delivered to the
correct
destination.
The packet passes from exchange to exchange for delivery through the provider
network.
Packet Switched describes the type of network in which relatively small units of data called packets are routed through a network based on the destination address contained within each packet.
The circuits only
exist while data
travels through
them.
They are termed
virtual circuits
and are
categorised as
switched or permanent.
Switched Virtual Circuit (SVC): Is constructed at the time of the connection
and disappears when the user is done.
Permanent Virtual Circuit (PVC): Is a pre-configured pathway through the
provider’s network. This path is always available to the user for data transmission.
Dedicated or leased- line networks are the simplest of the implementations. A dedicated point-to- point link is provided by the vendor. Bandwidth is guaranteed between the end points. Leased lines are also used to connect the subscriber to the vendor to make use of other technologies. Once that connection is made, the other options come into play.
Switched
communication links can be either circuit switched or packet switched.
Circuit Switched:
PSTN ISDN
Packet Switched:
Frame Relay X. ATM
- Public: Public connections use the global Internet infrastructure.
Until the development
of VPN technology,
the Internet was not
a viable connection
option. Security
issues prevented its use.
The Internet is now an inexpensive and secure option for connecting to
teleworkers and remote offices where performance guarantees are not critical.
DSL, Cable Broadband Wireless
- A point-to-point link is used to provide a pre-established WAN communications path from the customer premises through the provider network to a remote destination.
- Point-to-point links are usually more expensive than shared services such as Frame Relay. Dedicated or Leased Line Connection
- Enables the local loop to carry end-to-end digital signals.
- Higher capacity connections.
- ISDN changes the internal connections of the PSTN from carrying analog signals to time-division multiplexed (TDM) digital signals. Integrated Services Digital Network (ISDN)
- Basic Rate Interface (BRI):
- Two 64 kb/s B (bearer) and a 16 kb/s D (delta) channel.
- Bearer channels (B) for carry voice or data.
- Delta channel (D) for call setup and signaling.
- Home, small business, leased line backup. Integrated Services Digital Network (ISDN)
- Primary Rate Interface (PRI):
- 23 - 64 kb/s B (bearer) and 1 - 64 kb/s D (delta) channel.
- Bearer channels (B) for carry voice or data.
- Delta channel (D) for call setup and signaling.
- Large enterprise, dial-in access Integrated Services Digital Network (ISDN)
X.25 :
- Legacy network layer protocol.
- Typical applications are point-of-sale card readers.
- Speeds vary from 2400 b/s up to 2 Mb/s. However, public networks are usually low capacity and rarely exceeding 64 kb/s.
- Now in dramatic decline.
- They are still in use in many portions of the developing world. X.
