IP Networking: Part 2 ‐ Routing and SwitchingA webinar to help you prepare for the CBNE™ Certification 

Wayne M. Pecena, CPBE, CBNE

Texas A&M University

Office of Information Technology

Educational Broadcast Services

"IP Networking: Part 2 ‐ Routing and Switching"

Advertised Presentation Scope:

IP Networking Fundamentals for Broadcast Engineers is an intensive instructor-lead webinar series focused on major IP networking topics. The goal is to equip the broadcast engineer with the knowledge and understanding of IP networking fundamentals and the ability to apply conceptual theory in a practical mannerfundamentals and the ability to apply conceptual theory in a practical manner.

Today’s webinar will focus on IP Routing & Switching.

l l bl f h fMy Goals & Deliverables for This Afternoon:

‐ Provide an Understanding of IP Routing & Switching Fundamentals‐ Know When to Switch & When to Route‐ Understand Multicast‐ Understand QoS Basics  ‐ Provide a Foundation for SBE CBNT & CBNE Certification Exams

P id R f M t i l & R t Obt i F th K l d‐ Provide Reference Material & Resources  to Obtain Further Knowledge

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"IP Networking: Part 2 ‐ Routing and Switching“dAgenda

• Remembering the OSI Reference Modelg

• Switching Fundamentals

• Routing Fundamentals

• When Do I Switch ‐When Do I Route?

• Unicast  vs Multicast

( )• QoS Basics (broadcast oriented)

• Questions

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POLL QUESTIONPOLL QUESTION

A f ili ith th OSI R fAre you familiar with the OSI Reference Model, Ethernet Frame Structure, & IP Packet Structure?

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OSI Model RefresherOSI Model Refresher

The OSI Reference Model is important to understanding networkingterminology!

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Ethernet Frame – Layer 2Ethernet Frame  Layer 2

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IP Packet – Layer 3RFC 791

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Switching vs RoutingWhen to Switch? ‐‐When to Route?

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Switching FundamentalsSwitching Fundamentals

• Switches Allow Segmentation of Network– Allows Dedicated Bandwidth and Creates Point‐Point Communication

– Increased Throughput Due to Zero or Minimal Collisions

– Provides Full‐Duplex Operation

– Increased Security Capability

S i h S l i l d di id l “ ” f i i• Switches Selectively Forward Individual “Frames” from a Receiving Port to a Destination Port

– Builds Internal Table of Destination Address on each Port

Forwards Ethernet Frame if in Table– Forwards Ethernet Frame if in Table

– Floods Ports if Broadcast Frame

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MAC AddressesMAC Addresses

• Layer 2 Media Access Control “MAC” Address

• Unique Hardware Encoded Address– Burned In Address

– Physical Address

“ f d”– But Can Be “Spoofed”

• Hexadecimal Format: 12:3A:4D:66:3A:1C or FF‐FF‐FF‐FF‐FF‐FF

• Switches “Learn” a Table of MAC Addresses

– MAC Table – Maps Destination MAC Addresses to a Port

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A Simple MAC Table ExampleA Simple MAC Table Example

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Switching Types“Forwarding Method”

• Store – and – Forward

– Receives the Entire Frame Then Makes Decision

– Drops Any Errored Frame Based Upon CRC

– SLOW! (but insures no frame errors)SLOW! (but insures no frame errors)

• Cut – Through

Look Only @ Destination Address in Header of the Frame– Look Only @ Destination Address in Header of the Frame

– FAST! (but no error checking)

F F ( difi d C Th h)• Fragment Free (modified Cut‐Through)

– Known as “Runt Free” Switching

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VLANSIEEE 802.1Q 

• Virtual Local Area Network – VLAN– Logical Network of a Physical Network

• Allows Separation of Networks Across a Common Physical Media– Creates Subset of Larger Network

– Control Broadcast Domains – Each VLAN is a Broadcast Domain

– Architecture Flexibility

– Security

S i d ( )• Static Port Based VLAN(s)– Most Popular

– Manual Configuration

D i P t B d• Dynamic Port Based– MAC‐Based VLAN(s)

• Assignment Based Upon MAC Address

– Protocol‐Based VLAN(s)( )• Assignment Based Upon Protocol

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VLAN TrunkingVLAN Trunking

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VLAN IdentificationIEEE 802.1Q 

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VLAN ExampleVLAN Example

Switch Port Type Configuration:

Access Link – Member of One VLAN Only Connects to a Host

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yTrunk Link – Carries Traffic From Multiple VLANS Between Switches

Spanning Tree Protocol “STP”IEEE 802 1DIEEE 802.1D

Creates a Self‐Healing Network While Preventing a “Broadcast Storm”

STP Operation:1 - Determine Root Bridge2 - Select Root Port3 Select Designated Ports3 - Select Designated Ports4 - Block Ports with Loops

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Another Look at Spanning TreeAnother Look at Spanning TreeElected ROOT

1. Root Bridge Elected:- First Powered On- Priority Configuration

DesignatedPorts Designated

Port

Root Port

y g- Lowest MAC Address

2. Root Ports Identified Based Upon Path Cost R t P tBased Upon Path Cost

3. Designated Ports IdentifiedLowest Path Cost to Root

Root Port

4. Port BlockedDesignated Port with Highest Cost

In The End:

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In The End:1 Root per Network / 1 Designated Port per Segment / 1 Root Port per Non-Root Switch

POLL QUESTIONPOLL QUESTIONCan I hookup up a PCwith Ethernet monitoringsoftware running to a vacantSwitch port in order to monitorIP packets between Host 1 andHost 2?

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Port MirroringAnalyze “Sniff” Data Flow Between Two Hosts

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Managed vs Un‐Managed Ethernet SwitchesManaged vs Un Managed Ethernet Switches

• Managed Switch– User Configurable

• Un‐Managed Switch– Fixed Configuration

– Provides Ability to Control & Monitor Host Communications

– Port Configuration , Security, & i i

– “Plug & Play”

– Provides Basic Host Communications

Monitoring

– VLAN Implementation

– Redundancy  Supported (STP)

( )

Communications

– Cheaper

– QoS (Prioritization) Implementation

– Port Mirroring

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Routing

• Routing is Simply the Moving of Data Between Networks 

• OSI Model Layer 3 Process

• Routing Involves Two Processes:

– Determining the Best PathDetermining the Best Path

– Actually Sending of the Data

• Routing Types:

S i i– Static Routing

– Dynamic Routing

• Routing Protocols:

– Interior Gateway Protocol (IGP)

– Exterior Gateway Protocols (EGP)

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Routing

“Routing Decisions are Based Upon Routing Protocols”

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Routing Types

• Static Routing– Appropriate for Small Networks– Appropriate for Stable Networks– Use in “Stub” Networks– Human Intervention Required– Less Skill Needed– Predictable Routing Topology– Secure– Minimal Hardware

• Dynamic Routing• Dynamic Routing– Appropriate for Changing Topology Environments– Desirable When Multiple Paths Exist– Applicable to Complex Environments

Ad T l Wi h H I i– Adapts to Topology Without Human Intervention– More Scalable– Less Configuration Error Prone– Higher Skill & Knowledge Required

I d H d R i d– Increased Hardware Required

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Routing Fundamentals• Routing is Simply Moving Data From One Network to Another Network

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Dynamic RoutingDetermine the Best Path

• The “Best” Path Between Networks is Determined By Routing y gAlgorithm Metrics Maintained in a Routing Table.– Administrative Distance (AD) – Trustworthiness of the Routing 

InformationInformation

Route Source: Administrative Distance (default)

Direct 0

Highest Reliability

Direct 0

Static 1

EIGRP 90

OSPF 110

RIP 120

Unknown 255

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Routing Protocols:Routing Protocols:• Routing Protocols:

I i G P l (IGP)– Interior Gateway Protocols (IGP)Used With Routers Under the Same Organizational Control

• Distance‐Vector

• Link‐State

– Exterior Gateway Protocol (EGP)Th R ti P t l f th I t t (b t ISP’ )The Routing Protocol of the Internet (between ISP’s)

Interior Gateway Protocol Sample:RIP v1 & RIP v2IGRPEIGRPOSPF

Exterior Gateway Protocol Sample:IS-ISBGP v4 (BGP4)

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( )

Routing Metric FactorsRouting Metric Factors

• Hop Count The Number of Routers in a Path

• Bandwidth Throughput (bps)

• Load Traffic Flowing Through a Router

• Delay Network Latency (distance or congestion)Delay Network Latency (distance or congestion)

• Reliability Amount of Downtime of a Network Path

• Cost Administrator Assigned

Smaller Metrics = Best Route

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Distance‐Vector Routing Protocols

• “Routing by Rumor” – The Overall Network is Unknown, Only Directly Connected Neighbors Are Known by Each Router

R ti D i i B d U “Di t ” M t i d “Di ti ” V t t D ib• Routing Decision Based Upon a “Distance” or Metric and “Direction” or Vector to Describe the “Next‐Hop”

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Simplified Distance Vector Routing Example:

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Link‐State Routing ProtocolsLink State Routing Protocols

• Network Topology Information is Flooded Throughout the Network

• Each Router Determines its Own “Best Path”

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Link – State AlgorithmsLink  State Algorithms

• More Efficient for Large NetworksMore Efficient for Large Networks

• Maintains Topology of the Entire Network

• Only Forwards Updates When Changes OccurOnly Forwards Updates When Changes Occur(OSPF “Paranoia” Updates Every 30 Minutes)

• Classless IP Addressing SupportedClassless IP Addressing Supported

• Metrics More Complex – Thus More CPU Overhead

• Fast ConvergenceFast Convergence

• No Hop Count Limits

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Routing Protocols:Which One is Best?

“It Depends”

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Routing Protocol ChoicesRouting Protocol Choices

Interior Distance Vector

Interior Link State Exterior Path Vector

Cl f l RIP IGRP EGPClassful RIP                   IGRP EGP

Classless RIP v2            EIGRP OSPF v2             IS‐IS BGP v4

IPv6 RIPng EIGRP v6 OSPF v3        IS‐IS v6 BGP v4

Our Focus

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Routing Protocols:Which One is Best?

“It Depends”ISP BGP RIP

It Depends

OSPF

EIGRP

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RoutinggProtocolSelection Static DynamicSelection Routing

yRouting

EGP IGP

BGP

DistanceVector

Protocol:

Link State Protocol:

RIP IGRP OSPF IS-ISRIP IGRP OSPF IS IS

Hybrid

Standards Based

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Protocol:

EIGRP

Proprietary

Practical Routing Protocol Choices“Common” IGP Protocols – VLSM Support

RIP v2 EIGRP (Cisco) OSPF v2

Type: Distance Vector Hybird Link‐State

Metric: Hop Count Bandwidth/Delay Cost

Administrative 120 90 110Administrative Distance:

120 90 110

Hop Count Limit: 15 224 None

Convergence: Slow Fast FastConvergence: Slow Fast Fast

Updates: Full Table Every 30 Seconds

Send Only Changes When Change Occurs

Send Only When Change Occurs, But RefreshedChange Occurs But Refreshed Every 30m

RFC Reference: RFC 1388 N/A RFC 2328

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RIP v2Routing Information ProtocolRouting Information Protocol

RFC 1388 

• Advantages:– Simple – Easy to Configure

– Low Maintenance

– General Understanding Of

• Disadvantages:• Disadvantages:– Higher Router CPU Utilization

– High Bandwidth Use for Routing Updatesg g p

– No Knowledge of Link Bandwidth

– Slow Convergence

Limited Network Size (hop count = 15)– Limited Network Size (hop count = 15)

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OSPF v2Open Shortest Path FirstOpen Shortest Path First

RFC 2328

• Advantages:– Fast Convergence

– Routing Updates Are Small

– Scales to Varying Network Sizes

– Considers Link Bandwidth Into Metric Calculation– Considers Link Bandwidth Into Metric Calculation

• Disadvantages:– More Knowledge Required – A lot of OptionsMore Knowledge Required  A lot of Options

– Complex to Configure

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When to Switch? ‐‐When to Route?

When to ROUTE?To Create a Broadcast Domain

Create Separate Networks

SiSiSiSiSiSi

When to SWITCH?“Eliminate a Collision Domain”

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POLL QUESTIONPOLL QUESTIONIn order to minimize Broadcast IP packetsFrom propagating between inter-connected networks, a Broadcast Domain can be created.A Broadcast Domain is created by what OSI ModelA Broadcast Domain is created by what OSI Modellayer?

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What Is A “Layer 3” Switch?

• “Marketing Terminology” Applied to a One Box Solution:Marketing Terminology  Applied to a One Box Solution:

– Layer 2 Switching or Forwarding

• Traditionally Performed in Hardware

La er 3 Ro ting or For arding– Layer 3 Routing or Forwarding

• Traditionally Performed in Software

• Layer 3 Switch Performs Both

• Not for All Environments

– Typically Found in Workgroup Environment

– Limited to Ethernet

– Limited to OSPF and RIP Protocols

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Layer 3 “Routing Switch”Layer 3  Routing Switch

• Performs Layer 2 & Layer 3 Functions:

– Layer 2 Forwarding Performed:

• Destination MAC Address is different from the switch MAC• Destination MAC Address is different from the switch MAC Address

– Layer 3 Forwarding Performed:

D ti ti MAC Add i th th it h MAC Add• Destination MAC Address is the same as the switch MAC Address

• No WAN Ports (Ethernet Only)

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Layer 3 Routing Switch OperationLayer 3 Routing Switch Operation

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Multi‐Layer Switch Terminology dSummarized

• Layer 1 Switch = Really Does Not Exist Often a Simple “Hub”• Layer 1 Switch = Really Does Not Exist  ‐ Often a Simple  Hub

• Layer 2 Switch = Traditional Data‐Link Layer Switching

• Layer 3 Switch = Performs Layer 3 Forwarding Decisions

• Layer 4 Switch = Implements Transport‐Layer Flow Decisions– Firewall

– VPN Concentrator

• Layer 7 Switch = Provides Applications Level Functionality– Often Based Upon a Uniform Resource Locator (URL):

• Load Balancing

• Content Management

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UNICAST vs MULTICASTUNICAST vs MULTICAST

• Unicast– 1 to 1 Model 

– Traditional IP Communications Mode

l ll– Does Not Scale Very Well

• Multicast– 1 to Many Model or 1 to a Specific Group1 to Many Model or 1 to a Specific Group

– Traditional Broadcast Communications Mode

– Utilizes Routers to “Replicate” Packets

B d• Broadcast– 1 to All

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Multicast Terminology Key PointsMulticast Terminology Key Points

• A Multicast IP Packet is Sent from a Server to a Group of Hosts

• A Host MUST Request Joining a Multicast Group

• Class D Address Space Allocated for Multicast– 224.0.0.0 to 239.255.255.255224.0.0.0 to 239.255.255.255

– Ranges further allocated for specific purposes

• Routers Must Run a “Multicast Routing Protocol”

• IGMP Internet Group Management Protocol• IGMP – Internet Group Management Protocol– Allows Hosts to Request Joining a Multicast Group

• PIM – Protocol Independent MulticastR i P l Th Di ib M l i P k– Routing Protocol That Distributes Multicast Packets

– Creates a Multicast “Tree” and Dynamically “Prunes” the Tree

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IMPORTANT NOTE – Multicast Is Not Available Across the “Internet”Use is Limited to Local Network Segments in Most Cases

Unicast EnvironmentUnicast Environment

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Multicast EnvironmentMulticast Tree Multicast Environment

Multicast Clients Are “Pruned” as Multicast Streams AreNo Longer Required

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No Longer Required

Multicast in a Broadcast EnvironmentMulticast in a Broadcast Environment

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Diagram Courtesy of:

Quality of Service – “QoS”IEEE 802.1P/Q

• Why QoS?• Why QoS?– All IP Packets Are Created Equal, But The Application Data Contained 

Within an  IP Packet May Not Be.

– Q0S Allows Network Traffic to Be Prioritized Based Upon the Application to Insure Packet Delivery:

• Streaming Media (Audio over IP – Video Over IP)

• IP Telephony (Voice over IP)

• Real‐Time Control (automation control)

• Mission Critical ApplicationsMission Critical Applications

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Why is QoS Important?

• Why is QoS Important for Broadcasters?

– Broadcasters Handle “Real Time Media”Broadcasters Handle  Real Time MediaCreate It, Manipulate It, Distribute It

– Network Factors Impacting Quality of Experience (QoE):• ThroughputThroughput

• Errors

• Dropped Packets

• Latency

• Jitter

• Packet Delivery Out‐of‐Order

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Implementing QoS

Implementation ArchitecturePacket Type Identification & MarkingPacket Type Identification & MarkingNetwork Element ProvisioningEnd-End Policy Management

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Priority MarkingIEEE 802.1Q 

Preamble TypeSourceAddress

DestinationAddress Data FCS

8100h Priority VLAN ID

3 bits

Priority Marking

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QoS continued…..QoS continued…..

• Implementing QoSBEST EFFORT

– VLAN Implementation

– Bandwidth Over Provisioning

– Traffic ShapingGUARANTEED

DIFFERENTIATED

BEST EFFORTGeneral IP Traffic

Prioritized Traffic

Guaranteed Applications

Traffic Shaping

– DiffServ Implementation• Mark Packets According to Type of Service

• Assigned to Multiple Queues

The Network

Assigned to Multiple Queues

– Queue Scheduling Algorithms:

• Techniques Raise or Lower Queue PriorityWFQ Weighted Fair Queuing– WFQ ‐Weighted Fair Queuing

– Class Based Weighted Fair Queuing

– WRR – Weighted Round Robin

– HFSC – Hierarchical Fair Service Curve

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Web Reference Sources:

IETF RFC Documents:www.rfc-editor.org

Learn More About the OSI Model:http://www.9tut.com/osi-model-tutorial

Learn More About Switching:http://www technick net/public/code/cp dpage php?aiocp dp=guide networking switchinghttp://www.technick.net/public/code/cp_dpage.php?aiocp_dp=guide_networking_switching

Learn More About Routing:http://www.inetdaemon.com/tutorials/internet/ip/routing/index.shtml

Learn More About Layer 3 Switching:y ghttp://happyrouter.com/layer-3-switches-explained

Learn More About QoS:http://docwiki.cisco.com/wiki/Quality_of_Service_Networking

Learn More About Multicast:http://www.cisco.com/en/US/docs/ios/solutions_docs/ip_multicast/White_papers/mcst_ovr.pdf

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CBNE Recommended Study:

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My Favorites:My Favorites:

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? Questions ?? Questions ?

Thank You for Attending!

Wayne M. PecenaWayne M. PecenaTexas A&M Universityw‐pecena@tamu.eduN1WP@t dN1WP@tamu.edu

979.845.5662

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