Hierarchical Network Design – a Review

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Internetworking Campus Networks Issues - nonhierarchical network multilayer switches in nonhierarchical network Enterprise Composite module (ECNM)

◦ benefits of the ECNM Campus Infrastructure module of the ECNM

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Typical Enterprise Network

Internetworking is the communication between two or more networks◦ Requires many protocols and features to

permit scalability manageability without constant manual

intervention Large internetworks can consist of the

three distinct components:1. Campus networks, which consist of

locally connected users in a building or group of buildings

2. Wide-area networks (WANs), which connect campuses together

3. Remote connections, which link branch offices and single users (mobile users and/or telecommuters) to a local campus or the Internet

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Campus Network

A campus is a building or group of buildings all connected into one enterprise network that consists ofmany local area networks (LANs).◦ A large campus with groups of

buildings can also use WAN technology to connect the buildings

Campus network generally optimized for the fastest functional architecture that runs on existing physical wire.

Scalable to requirements of emerging applications

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Trends: Past and Present Trends in campus design

Past: Limited hardware

options◦ routers or hubs when purchasing a technology for their campus networks

Recent: deploying LAN switches

to replace shared concentrator hubs and give higher bandwidth connections to the end user

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Disadvantages Flat Network

Large collision domain

Large broadcast domain

High latency

Difficult to troubleshoot

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Issues

No traffic between VLANs

Unbounded broadcast domain

Servers not centrally located

Features and Issues Switched Network

Features

Hardware-based bridging

Wire-speed performance

Collision domain per port

Traffic containment based on MAC address

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Features and Issues Routed Network

Single broadcast domain per interface

ACLs can be applied between segments

Issues

High per-port cost

Layer 3 processing required

High latency over Layer 2 switching

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Combined functionalityLayer 2 switching

Layer 3 switching

Layer 4 switching

Low latency

High-speed scalability

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Single point of failure for Layers 2 and Layers 3

Underutilization of hardware

Spanning tree complexity

Servers not centrally located

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Multilayer switches combine both Layer 2 and Layer 3 functionality to support the modern campus network topology.

Multilayer switches can be used in nonhierarchical networks; however, they will not perform at the optimal level.

The enterprise composite model identifies the key components and logical design for a modern topology.

Implementation of an ECNM provides a secure, robust network with high availability.

The Campus infrastructure, as part of an ECNM, provides additional security and high availability at all levels of the campus.

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Cisco Service-Oriented Network Architecture◦ http://cisco.com/en/US/partner/netsol/ns629/netw

orking_solutions_market_segment_solutions_home.html

Cisco Intelligent Information Network◦ http://cisco.com/en/US/partner/netsol/ns650/netw

orking_solutions_market_segment_solution.html

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Designing LANs◦ Routed Network

Compatibility, conformance, and Interoperability

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