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CIS 271

Implementing Cisco IP Switched Network (SWITCH)

CCNP-SWITCH 300-115

Chapter 1:

ingProgram

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Fundamentals Review

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Fundamentals Review

Switching Introduction The term LAN switching is becoming legacy (popular term 1990s-mid-2000s)

In todays networks, LANs have been segmented into distinct functional areas: data

centers and campus networks

Campus Networks

ingProgram

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The focus of this course

Take a generally more conservative approach to architectures

Use Cisco Catalyst switches

Leverage traditional Layer 2 and Layer 3 hierarchical designs

Data Centers

In a state of evolution

Focus on applications, dev/ops, and software programmability

Use bleeding-edge technologies such as FabricPath, Dynamic Fabric Allocation

(DFA), Application Centric Infrastructure (ACI), etc.

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Hubs and Switches

Hubs are archaic terminology should be

avoided

Even the simplest mulitport home Ethernet

devices (usually termed as wireless routers) are

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n ac sw c es

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Hubs

Hubs died off as a product because they are

shared-bandwidth devices

Allowed multiple devices to be connected to the

same network segment

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Devices on a segment shared bandwidth with

each other

A hub is a Layer 1 (physical layer device)

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Switches

Introduced dedicated bandwidth

Bandwidth between a switch and a end-use

device is reserved for communication to and

from that device alone

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Greatly increase available bandwidth on

networks and lead to improved network

performance

Support additional capabilities (such as PoE)

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Bridges and Switches

A basic switch is a Layer 2 device

Assembles electrical signals into a frame (layer 2)

and decides what to do with it

Switches determine what to do with a frame by

ingProgram

Kevin McLaughlin Spring 2006

borrowing the algorithm from another legacy

networking device: a transparent bridge

Act like a transparent bridge would, but handle

frames much faster than a bridge could (due tospecial hardware and architecture)

Switches decide where frames should be sent

and passes the frames out the appropriate port(s)

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Todays Switches

Have evolved beyond switching frames

Most modern switches can also route (Router)

traffic

Switches can also:

ingProgram

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- Prioritize traffic

- Support no downtime through redundancy

- Provide convergence services (IP Telephony andWireless networks)

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Cisco Catalyst Switches

Application Intelligence secure and prioritize

Unified Network Services 10-Gig (Te) and PoE (Power

over Ethernet) technology supporting new application and

devices

Nonsto communications redundant hardware, nonsto

ingProgram

Kevin McLaughlin Spring 2006

forwarding, stateful switchover providing reliability

Integrated security first line of defense against internal

network attacks and preventing unauthorized intrusion

Operational manageability remote access, monitoring

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CCNA Review

Broadcast Domains

A broadcast domain is a set of network devices

that receive broadcast frames originating from any

device within the group

ingProgram

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MAC Addresses

Standardized data link layer addresses that are

required for every port or device that connects to

a LAN

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IEEE Basic Ethernet Frame Format

ingProgram

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The IEEE 802.3 standard defines a basic frame format that is required for

all MAC implementations, plus several additional optional formats that are

used to extend the protocols basic capability

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Basic Switching Function

Switches must decide what to do with frames it

receives. Should the switch:

Ignore the frame?

Pass it out a single port?

ingProgram

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Pass it out multiple ports?

Switches learn the locations of all devices on the segment

through the CAM, or content addressable memory, table.

The CAM table shows device MAC addresses and the port

the MAC is reachable at

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CAM table decisions

Forwarding - if the destination MAC address is

found in the CAM table, the switch sends the frame

out the associated port that the address is

connected to

ingProgram

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er ng e assoc a e por s e same por a

the frame originated from, the frame is ignored, as

forwarding is not needed

Flooding if the destination MAC address is notfound in the CAM table (unknown unicast), or is the

broadcast address of a segment, the switch sends

the frame out all other ports that are in the same

VLAN (but not out the receiving port)

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Other Refreshers

VLANs

Special grouping of ports to further segment traffic

Spanning Tree Protocol

Used to identify and temporarily block the loops in

ingProgram

Kevin McLaughlin Spring 2006

a network segment or VLAN

Trunking

Allows multiple VLANs to function independentlyacross multiple switches

Port Channels

Grouping ports together to work as one unit

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Multilayer Switching

Ability of a switch to forward frames based on

information in the Layer 3 and sometimes Layer 4

header.

Almost all Cisco Catalyst switches model 3500 or

ingProgram

Kevin McLaughlin Spring 2006

a er suppor

Becoming a legacy term due to wide support

Switches can route or switch frames at wire-rate

speeds using specialized hardware