Module 1- Scalable Networks pdf

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BSCI Module 1 Lesson 2 - Scalable Networks
Scalable Network
Design
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Objectives
 Cisco PPDIOO
 Describe scalable network design
 Five Characteristics of a Scalable Network
 Making the Network Reliable and Available
 Making the Network Responsive
 Making the Network Efficient
 Making the Network Adaptable
 Making the Network Accessible But Secure
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Cisco PPDIOO
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Using the Design Methodology under PPDIOO
 Three steps in the design methodology:
1. Identify the customer requirements.
2. Characterize the existing network and sites.

3. Design the topology and network solutions.
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Identifying Customer Requirements
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Characterizing the Existing Network and Sites
 Gathering as much information about the network as possible.
 Auditing and analyzing the network to add detail.
 Developing a summary report describing the health of the network.
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Designing the Topology and Network
Solutions
 Use top-down design to for smaller, more manageable steps.
 Define the scope of a network design
 Develop the design by module
 Document the design, including implementation and migration
plans
 Verify the design.
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Scalable Network Design
 The ECNM breaks the complex problem of network design into
smaller, more manageable problems. Each level, or tier in the
hierarchy, addresses a different set of problems. This helps the
designer optimize network hardware and software to perform
specific roles. For example, devices at the lowest tier are optimized
to accept traffic into a network and pass that traffic to the higher
layers.
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Scalable Network Design
 Layered models are useful because they facilitate modularity.
Devices at each layer have similar and well-defined functions. This
allows administrators to easily add, replace, and remove individual
pieces of the network.
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Five Characteristics of a Scalable Network
 Although every large internetwork has unique features,
all scalable networks have essential attributes in
common. A scalable network has five key
characteristics:
–Reliable and available
–Responsive
–Efficient
–Adaptable

–Accessible but secure
 The Cisco IOS offers a rich set of features that support
network scalability.
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Making the Network Reliable and Available
 Support for scalable routing protocols: OSPF,
EIGRP, ISIS
 Support for alternate paths: Core links should always
be redundant. EIGRP actually maintains a database of
all alternate paths if the primary route is lost.
 Support for load balancing: Routers can distribute the
traffic load across multiple links to the same
destination.
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Making the Network Responsive
 Users expect network resources to respond quickly, as
if network applications were running from a local hard
drive.
 Networks must be configured to meet the needs of all
applications, especially time delay-sensitive
applications, such as voice and video.
 Cisco IOS addresses priority and responsiveness
issues through queuing.
–FIFO queuing, Priority queuing (PQ), Custom queuing (CQ),

Weighted fair queuing (WFQ) and distributed WFQ (DWFQ),
Class-based WFQ (CBWFQ) and Distributed CBWFQ
(DCBWFQ), Low Latency Queuing (LLQ)
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Making the Network Efficient
 An efficient network should not waste bandwidth, especially over costly
WAN links. To be efficient, routers should prevent unnecessary traffic from
traversing the WAN and minimize the size and frequency of routing
updates with
–Access lists
–Route maps
–Compression over WANs
–Route summarization
–Incremental updates
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Making the Network Adaptable
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Making the Network Accessible But Secure
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Self Check
1. Name 5 characteristics os A Scalable Networks
2. Name 3 characteristics that Available and Reliable
Network Support
3. What is the main technique to meet Network
Responsive?
4. How to make an efficient network?
5. What is Network Adaptable?
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Summary
 Reliable and available
 Responsive
 Efficient
 Adaptable
 Accessible but secure
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Q and A
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