Week Four Agenda
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Attendance
Announcements
Review Week Three
Current Week Information
Upcoming Assignments
Review Week Three
The SONA Model segregates the different applications
and services into a highly integrated network system.
The SONA framework is built on three layer model.
Application Layer
Interactive Services Layer
Networked Infrastructure Layer
Benefits of using the SONA model are as follows:
Functionality, Scalability, Availability,
Performance, and Manageability
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PPDIOO
Prepare Phase
Plan Phase
Design Phase
Implement Phase
Operate Phase
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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.
Top-Down Approach should 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.
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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
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Cisco Enterprise Architecture
Enterprise Campus
Enterprise Edge
Service Provider
Remote Enterprise
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Designing an Enterprise Campus
The Enterprise Campus is the foundation for delivering
the applications, services, and user requirements.
Network application characteristics (requirements)
Organizational requirements
Services
Applications
Environment characteristics (requirements)
Geography
Transmission media
Infrastructure device characteristics (requirements)
High availability
High throughput
Network Application Characteristics
Peer-Peer Applications
The peer-peer applications are designed with the
majority of users in mind. It is likely to be
most heavily traffic path from one network
edge device to another through the
organizational network.
Instant messaging
IP phone calls (strict network requirements
for QoS)
File sharing
Videoconferencing systems (requirements
similar to IP phone QoS)
Network Application Characteristics
Quality of Service (QoS)
A set of metrics used to measure the quality of
transmission and service availability of any
given transmission system.
Network Application Characteristics
Client-Local Server Applications
80/20 Workgroup Rule
Because the traffic on corporate networks has
typically increased, it has resulted in more
isolated segments. These isolated segments
resemble departments within a corporate
structure, where segments have their own local
servers, users, and applications. This design
configuration usually has the local servers and
users in the same VLAN. The traffic leaving the
network segment will connect to the campus
backbone to connect to other VLANs or
destinations.
Network Application Characteristics
Client-Server Farm Applications
Large organizations require their users to have
fast, and reliable access to critical applications.
Today, banks, state, and other governmental
organizations needed this access in order to verify
and maintain the integrity of individuals.
Because of this high accountability requirement,
high-performance multilayer switches are
implemented, increased network bandwidth, and
locating the servers in a central location rather
than a workgroup has been achievable due to
scale of economies. These configurations require
high-end LAN switches connected to the fastest
LAN technologies, such as Gigabit Ethernet.
Network Application Characteristics
Client-Server Farm Applications
20/80 Rule
Server farms include the following:
Organizational mail servers (Microsoft
Exchange)
File servers (Microsoft and Sun)
Database servers (Oracle)
Network Application Characteristics
Client-Enterprise Edge Application
The Enterprise Edge application is used to
transmit data between the organization and its
public servers. Data transmission exchange can
come from web based technologies, external
mail, and DNS servers.
Communications with these servers is crucial,
because two-way replication of data. In order to
sustain this high accountability, redundancy and
security are the most important requirements for
these applications.
Network Application Characteristics
Client-Enterprise Edge Application
Connectivity has increased the use of LAN
switching at Layer 2. LAN switching has resulted
in increased performance and more bandwidth for
specific applications requirements of new
organizational applications.
Throughput is the average rate of successful
message delivery over a communication channel.
This data may be delivered over a physical link,
and/or pass through a certain network node. The
throughput is usually measured in bits per second
(bit/s or bps), and sometimes in data packets per
second or data packets per time slot. Throughput
varies between user workgroups and high capacity
links to servers, and/or server farms.
Network Application Characteristics
Client-Enterprise Edge Application
High Availability is a function of the application
and the entire network between the client
workstation and server(s) located in the network.
Summary
Project costs are driven by it’s size and
applications used. If your implementing a peerpeer environment, normally the cost will be low.
If your designing a network with redundancy and
with high end application(s), your costs will be
significantly higher. The types of applications
used will also raise the cost
Environment Characteristics
Environmental characteristics play a significant role
in determining the location of the Enterprise Campus,
the distance between buildings, the size and shapes of
the buildings, and which technology to use to
maximize the organizations investment.
Normally, the distance between nodes and their
locations within an Enterprise Campus drive the type
of technology utilized. In addition to the node (s)
proximity, organizational requirements also influence
the type of technology to be used. Users can’t just be
connected to a network and be expected to tolerate
data loss, access failures, poor performance, and
intermittent connectivity problems.
Environment Characteristics
Structural considerations within the network geography
Intrabuilding campus network structure provides
connectivity for all terminating nodes located in
the same building and provides external access to
network resources. The Building Access and
Building Distribution layers are located in the
same building.
User workstations are usually connected to the
Building Access switches in the floor wiring
closet with twisted-pair copper cable. Wireless
technology can also be used to provide
connectivity within the building and/or between
buildings without the use of UTP and cables.
Environment Characteristics
Structural considerations within the network geography
The access layer switches connect to the Building
Distribution switches over optical fiber.
This building configurations lend themselves
to having a compressed hierarchical network
where the Building Distribution switches and
Campus Core switches are combined.
Environment Characteristics
Structural considerations within the network geography
Interbuilding characterics is where there are two
or more individual buildings connected to each
other. These buildings could have the same
configuration (compressed hierarchical network)
or contain only the Building Access layer. The
distance between buildings is within close
proximity, typically within a few hundred meters
to a few kilometers apart. The medium used to
interconnect campus buildings is normally
customer owned, high-speed optical fiber.
Environment Characteristics
Structural considerations within the network geography
A distant remote building is when the buildings
exceed more than a few kilometers, but are in the
same metropolitan area. For this situation, the
physical media is the most important factor. The
speed and cost are directly related to the media
selection.
Some companies own their own media, like
copper lines , or fiber. However, if they do not
have the connectivity to their remote locations,
the Enterprise Campus must connect through the
Enterprise edge using connectivity options from
public service providers, such as WAN links or
Metro Ethernet.
Environment Characteristics
Structural considerations within the network geography
The service level agreement (SLA) and the risk of
downtime must be addressed if inexpensive and
unreliable links are used. Mission critical application(s)
demand fast-speed links and high-reliability connections.
Enterprise Camps Device Connectivity
An Enterprise Campus can use a variety of different
physical media to connect to their devices. The type of
media used will normally set the precedence for the
next 10 years. The cost of the media should be inline
with the companies budget, and the technical
requirements that would influence signal attenuation
and electromagnetic interference.
Transmission Media
Copper: Twisted-pair cable of four pairs of
isolated wires that are wrapped together in
plastic cable.
Category 5, and 5e for greater for speeds of
100 megabits (Mbps) or higher
Category 6 is recommended for Gigabit
Ethernet.
Because of the possibility of signal attenuation
in wires, the maximum cable length is usually
100 meters.
Transmission Media
Signal attenuation affects the propagation of
waves and signals in electrical circuits, in
optical fibers, as well as in air (radio waves). It
is a damping affect on the original signal
strength.
Distances greater than 100 meters may require
Long-Reach Ethernet (LRE). LRE is a Cisco
proprietary technology that runs on voice
grade copper wire, and it accommodates the
greater distance to access the technologies in
WANs.
Transmission Media
Different types of fiber
Multimode (MM) fiber carries multiple
light waves or modes concurrently, each at
a slightly different reflective angle within
the optical fiber core. Because modes tends
to spread out over longer lengths,
multimode fiber id used for shorter
distances. The diameter of multimode
fiber is 50 to 62.5 micrometers.
Transmission Media
Different types of fiber
Single-mode (SM) fiber carries a single wave
(laser) of light. The diameter of a single-mode
fiber is 2 to 10 micrometers. Single-mode fiber
preserves the dispersion and loss of light, and
therefore is used for distant transmissions. SM is
an excellent solution for future high-speed
connectivity.
In summary, optical fiber is used where the
transmission distance exceeds 100 meters and
immunity to electromagnetic interference is
required.
Transmission Media
Wireless is also referred to as a radio receiver. The
term refers to without cables or cords, chiefly using
radio frequencies and inferred rays.
WLAN are useful when it comes to extending
an existing network or replacing a traditional
cabled network.
Inside buildings, the WLAN equipment includes
an access point (AP), which acts similar to a
wired hub, and PC client adapter.
Transmission Media
IEEE Standards
802.11g allow speeds up to 54 Mbps in the 2.4 GHz
band over a range of 100 feet.
802.11b supports speeds up to 11 Mbps in the 2.4
GHz band.
802.11a supports speeds up to 54Mbps in the 5 GHz
band.
See chart on page 233 in your Designing for Cisco
Internetwork Solutions (DESIGN) text.
Infrastructure Device Characteristics
Today, most network end users are connected using
switched technology and not shared media segment.
The benefits of switched technology are dedicated
network bandwidth for each device on the network.
Switched networks also support infrastructure
services, like QoS, security, and network
management.
LAN switches in the recent past were for Layer 2
devices. Now, Layer 2 switching supports multiple
simultaneous frame flows. Multilayer switching
performs packet switching and several functions at
Layer 3 and higher up in the OSI layers. The
technology is moving in the direction of replacing
routers in the LAN switched environment.
Infrastructure Device Characteristics
Differences between Layer 2 and Multilayer
Switching
Multilayer switching provides different
information inside the frame to determine the
correct output interface.
Multilayer switching forwards frames based on
network layer information rather than MAC
address.
Multilayer switching is a hardware based
switching and routing integrated into a single
platform.
Infrastructure Device Characteristics
Convergence time is the time it takes to update
switching tables to reflect the actual network
configuration. A loop prevention mechanism
at Layer 2 topology called Spanning Tree
Protocol (STP) took approximately 30 to 50
seconds to converge. Now the Campus Core
links that were connecting to core switches
should be routed links, and not VLAN trunks.
Multilayer switching reduces convergence time to
seconds, because all the devices detect their
connected link failure immediately and act
accordingly.
Infrastructure Device Characteristics
Multilayer switching in a structured design
reduces the scope of spanning-tree domains.
In a mixture of Layer 2 and Layer 3
environment, the convergence time depends on
both layers, and the convergence of STP.
Switching can also include Layer 4.
Multilayer switching allows switching to take
place at different protocol layers.
Infrastructure Device Characteristics
IP Multicast
IP multicast technology is a way to sending
one data stream to multiple end users and
maintain required bandwidth. The data stream
is sent from one source, and replicated for the
registered users at the destination.
Class D IP address ranges from 224.0.0.0 to
239.255.255.255.
Cisco Protocols for Routers and Hosts
Internet Group Management Protocol (IGMP)
The IGMP protocol is used between the router
and the registered hosts intended to receive
multicast data. The hosts notify the router to
join or leave a specific multicast group.
Cisco Group Management Protocol (CGMP)
The CGMP protocol is used by switches and
routers. The router informs the switches
directly connected to them about the IGMP
registration(s) from it’s hosts to receive
multicast data stream.
Cisco Protocols for Routers and Hosts
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.
QoS Considerations
Classification and marking
Packet classification – partitioning traffic into
multiple priority levels, or class of service
Marking – changing the frame priority or class of
service
Congestion management
Queuing – separating traffic into different queues.
The marking inside the frame or packet is used to
determine which queue
Scheduling – is used to determine the order in
which the queues are serviced
QoS Considerations
Policing and shaping is a process of identifying
violations of threshold levels and reduces a
stream of data to a predetermined rate or level.
Traffic shaping buffers the frames for a short period
of time. Policing drops or lowers the priority of the
frame in violation.
Upcoming Assignments
Assignment 4-1-1, Simulator Tutorial and Basic
IOS Command Exploration is due May 24, 2010
Assignment 5-1, Concept Question 4 is due May 31,
2010
Assignment 4-1-2, Basic Routing and LAN Switching
Configuration is due June 28, 2010
Assignment 4-1-3, Basic Network Troubleshooting is
due July 26, 2010