Advanced IP Networking Series: “Routing The Network of Networks“

Wayne M. Pecena, CPBE, CBNE

Texas A&M University

Office of Information Technology

Educational Broadcast Services

Advanced IP Networking Series: “Routing The Network of Networks “

• The Quick IP Networking Fundamentals Review

• The Routing Protocol

• Which Routing Protocol?

• Implementing Routing

• Access Control Lists

• The Layer 3 Switch

• Summary – Q&A

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Advertised Webinar Scope: Part 2 of Advanced IP Networking builds on the previous Network of Networks webinar by incorporating IP Layer 3 routing and selective access features utilizing Access Control Lists (ACL) to a VLAN-based layer 2 multiple network based infrastructure. Theoretical concepts of routing protocol choices and ACL implementation will be reinforced with real-world equipment configuration examples.

Prerequisite Knowledge: Attendees should have knowledge of IP networking concepts that includes OSI Layers 1-3, Ethernet switching, IP routing,

and VLAN principals.

WEBINAR OUTLINE:

The Quick IP Networking Fundamentals Review

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5 Things Required To Build a Network

• Send Host

• Receive Host

• Message or Data to Send Between Hosts

• Media to Interconnect Hosts

• Protocol to Define How Data is Transferred

Reference Models

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Application

Session

Presentation

Transport

Physical

Data Link

Network

7

5

6

4

1

2

3

Transport

Internetwork

Network AccessProvides Media

Interface, Topology

Provides Data Sequencing, Flow Control, Integrity

Provides Logical Addressing, Fragmentation,

End-End Delivery

Provides Physical Addressing, Error

Correction

Service Provided to Applications

Provides Conversation Control

Provides Data Formatting

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1

2

LLC

MAC

The OSI Model TCP/IP Model Encapsulation

Application4

IP

Network Interface

TCP UDP

Application Data

Segments

Bits

Frames

Packets

DoD Model

Another Look at the “OSI Model”

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EMAIL RS-xxx

PPPIPv4TCP

25POPSMTP

Net Mgmt

File Transfer

WEB

Directory

SNMP

FTP

HTTP

DNS

161 / 162

20 / 21

80

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UDPIPv6

802.2 SNAP

Ethernet II

ISDN

ADSL

Fiber

Coax

CAT 5

Application7

Presentation6

Session5

Transport4

Network 3

Data Link2

Physical1

Application Layers

Network Layers

Layer 2 Standards:

• Project 802 Ethernet Standards:

– 802.1 Bridging

– 802.3 Ethernet

– 802.11 Wireless

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http://standards.ieee.org/about/get/

Layer 3 Standards:

• Request for Comments – RFC’s – The “Standards Bible” of the Internet

– Explains All Aspects of IP Networking

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www.rfc-editor.org/rfc.html

Layer 2 & Layer 3 Addressing

• Each Host on an Ethernet Based IP Network Has:

• An Unique MAC Address – Layer 2 Physical Address (local network segment)

• An Unique IP Address – Layer 3 Logical Address (global routed)

172.15.1.1 172.15.2.2 DATA Trailer00:12:3F:8D:4D:A7FF:FF:FF:FF:FF:FF

DestinationMAC

SourceMAC

DestinationIP

SourceIP

IP Packet

Ethernet Frame

Simplified Representation

Common Port Numbers

• RESERVED PORTS

“System Port Numbers” • Port 20 / 21 – FTP “File Transfer Protocol”

• Port 23 – TELNET

• Port 53 – DNS “Domain Name Service”

• Port 80 – HTTP

• Port 110 – POP3 “Post Office Protocol”

• Port 123 – NTP “Network Time Protocol”

• Port 161 – SNMP “Simple Network Management Protocol” (UDP)

• Port 443 - HTTPS

• REGISTERED PORTS

“User Port Numbers” • Port 1720 – H.323 Video Call Setup

• Port 1812 – RADIUS Authentication

• Port 2000 – CISCO “Skinny”

• Port 3074 – “X-Box” Live

• Port 4664 – Google Desktop

• Port 5004 – RTP “Real Time Transport Protocol”

• Port 5060 – SIP “Session Initiation Protocol

• Port 5631 – PC Anywhere

• Port 8080 – Alternate HTTP

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http://www.iana.org/assignments/port-numbers

Broadcast Domain – Collision Domain

Layer 3 Routing Fundamentals

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Key Terminology

• The “Routed” Protocol

• The “Routing” Protocol

• The “Routing” Table Contains: – The Destination Network

– The “Next-Hop” Information

– Routing Metric & Administrative Distance

• The Router Looks at the “Destination” Address – Determines Appropriate Interface

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Routing

• Routing is Simply the Moving of Information Between Networks (Subnets or Broadcast Domains)

• OSI Model Layer 3 Process

• Routing Types:

– Static Routing

– Dynamic Routing

• Routing Protocol Classes:

– Interior Gateway Protocol (IGP)

– Exterior Gateway Protocols (EGP)

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Routing Types • Static Routing

– Appropriate for Small & Simple Networks – Minimal Router CPU/Memory – No Routing Update Overhead – Appropriate for Stable Networks – Often Used in “Stub” Networks – Human Intervention / Administration Required Yy

• Dynamic Routing – Appropriate for Changing Topology Environments

– Automatically Adapts to Changes

– Desirable When Multiple Paths Exist

– More Scalable

– Hardware More Complex

– Less Configuration Error Prone

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Dynamic Routing Categories

• Distance Vector Routing Protocol – Periodic Routing Table Updates

– “Distance” Used as a Metric

– Neighbors “Trust” Neighbors

– Slow Convergence

• Link State Routing Protocol – Maintains Neighbor, Topology, & Shortest-Path Tables

– Each Router Updates From All Others

– “Cost” Used as a Metric

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Routing Metrics & Administrative Distance Determines The Best Path to Target Host

• Cost Metrics: – Hop Count The Number of Routers in a Path

– Bandwidth Throughput (bps)

– Load Traffic Flowing Through a Router

– Delay Network Latency (distance or congestion)

– Reliability Amount of Downtime of a Network Path

• Administrative Distance – Indicates Believability of the Route

– Often Used When Multiple Protocols Are Used

– Often Used to Prefer A Certain Path When Multiple Paths Exist

– Routing Protocols Have Default Administrative Distances

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Smaller Metrics = Best Route Lower Administrative Distance = More Believed

The “Administrative” Distance

• The Administrative Distance Determines Which Route to Trust

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Route Source: Administrative Distance (default)

Direct 0

Static 1

EIGRP 90

OSPF 110

RIP 120

Unknown 255

Used When Multiple Routes Exist

Hop Count May Not Be The Best Metric!

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The Routing Protocol

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The Routing Protocol

• Learn the route to each subnet in the internetwork (build routing table)

• Determine the “best’ route (one route)

• Remove routes that are no longer valid

• Update routing table to reflect changes

• Perform updates quickly

• Prevent routing loops

Routing Fundamentals

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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

• Routing Decision Based Upon a “Distance” or Metric and “Direction” or Vector to Describe the “Next-Hop”

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Link-State Routing Protocols

• Network Topology Information is Flooded Throughout the Network

• Each Router Determines its Own “Best Path”

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Which Routing Protocol?

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IGP and EGP Protocols

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ExteriorGatewayProtocol

InteriorGatewayProtocol

InteriorGatewayProtocol

IS-IS BGP

RIP IGRP

EIGRP OSPF

RIP IGRP

EIGRP OSPF

Routing Protocol Choices “Most Popular”

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Interior Distance Vector

Interior Link State Exterior Path Vector

Classful 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

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 Distance:

120 90 110

Hop Count Limit: 15 224 None

Convergence: Slow Fast Fast

Updates:

Full Table Every 30 Seconds

Send Only Changes When Change Occurs

Send Only When Change Occurs, But Refreshed Every 30m

RFC Reference: RFC 1388 N/A RFC 2328

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RIP v2 Routing Information Protocol

RFC 1388

• Advantages: – Simple – Easy to Configure

– Low Maintenance

– General Understanding Of

• Disadvantages: – Higher Router CPU Utilization

– High Bandwidth Use for Routing Updates

– No Knowledge of Link Bandwidth

– Slow Convergence

– Limited Network Size (hop count = 15)

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OSPF v2 Open Shortest Path First

RFC 2328

• Advantages: – Fast Convergence

– Routing Updates Are Small

– Scales to Varying Network Sizes

– Considers Link Bandwidth Into Metric Calculation

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

– Complex to Configure

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EIGRP v4 Enhanced Interior Gateway Routing Protocol

CISCO Proprietary

• Advantages: – Fast Convergence

– No OSPF Area Assignments = Less Complex

– Complex Cost Metric: • Bandwidth

• Delay

• Reliability

• Utilization

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

– Need “Cisco” Environment

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Implementing Routing

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VLAN Example from Part 1

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Switch Port Type Configuration:

Access Link – Member of One VLAN Only Connects to a Host Trunk Link – Carries Traffic From Multiple VLANS Between Switches

Switch Interface Configuration

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No Connectivity Exists Between Broadcast Domain, Networks, or Subnets!

Add Connectivity Between Broadcast Domains

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Add Router

Router Configuration:

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Configuration Disclaimer: Exact configuration commands may vary based upon specific equipment models and software version. Generic “Cisco” commands utilized for illustration purposes.

Blue Network: 192.168.100.0 /24 Green Network: 192.168.200.0 /24 Red Network: 192.168.300.0 /24

Assign Network to an Interface: interface ge0 ip address 192.168.100.1 255.255.255.0 no shutdown interface ge1 ip address 192.168.200.1 255.255.255.0 no shutdown interface ge2 ip address 192.168.300.1 255.255.255.0 no shutdown

Enable RIP Routing: router rip network 192.168.100.0 network 192.168.200.0 network 192.168.300.0

Add Connectivity Between Broadcast Domains

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Sub-Interface Created on Router GE1 Interface

Access Control Lists The “ACL”

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The “ACL” Rules:

• Simply a “Set of Rules” That Provides a “Permit” or “Deny” Based Upon: – Layer 3 IP Address

– Layer 4 Port Number

• An ACL is: – A Table (with explicit DENY)

– Applied to a Specific Router Interface

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The “ACL” Rules continued…..

• ACL’s can be Numbered or Named

• Numbered ACL’s Structure: – 1-99 IP Standard Access List

– 100-199 IP Extended Access List

– 200-299 Protocol Access List

– 1300-1999 IP Standard Access List-Expanded

– 2000-2999 IP Extended Access List-Expanded

• Named ACL Structure: – Standard Named

– Extended Named

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The “ACL” Rules continued…..

• Standard Access List – Can Only Permit or Deny The Source Host IP Address

– Placed Closest to Destination Host

• Extended Access List – Can Permit or Deny Based Upon:

• Source IP Address

• Destination IP Address

• TCP Port #

• UDP Port #

• TCP/IP Protocol

– Placed Closest to Source Network

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The “ACL” Rules continued…..

• One “ACL” per Interface per Direction – Ingress

– Egress

• An ACL Only Acts of IP Traffic Passing Through Router

• Organize Structure of ACL: – More specific statements placed first

– Process Sequentially

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ACL Example(s): access-list 110 deny ip any host 192.168.100.110 access-list 123 deny ip any host 192.168.100.110 eq 23

ACL Structure

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Create an Access-List:

access-list [number] [deny | permit] [host] [source ip] [wildcard]

Apply Access-List to Interface:

ip access-group [number] [in | out]

Logical Operators Can Be Used:

lt Less Than gt Greater Than eq Equal To neq Not Equal To range port number range

Wild Card Mask

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Inverse of the “Subnet” Mask

The Subnet Mask:

192.168.100.100 / 24 or

192.168.100.100 mask 255.255.255.0

The Inverse Mask:

0.0.0.255

Network Host

Match Don’t Care

Standard IP List Example #1: Prevent Host 192.168.30.30 from Accessing Host 192.168.10.10

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Create Access List on Router 1: access list 101 192.168.30.30 0.0.0.0 access-list 101 permit any Apply Access List to Interface: interface E1 ip access-group 101 in

Configuration Disclaimer: Exact configuration commands may vary based upon specific equipment models and software version. Generic “Cisco” commands utilized for illustration purposes.

Extended IP List Example: Allow Only http Access to Host 192.168.10.10 from 192.168.30.0 /24

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Create Access List on Router 2: Access-list 101 permit tcp 192.168.30.0 0.0.0.255 host 192.168.10.10 eq 80 access-list 101 permit ip any any Apply Access List to Interface: interface E0 ip access-group 101 in

Configuration Disclaimer: Exact configuration commands may vary based upon specific equipment models and software version. Generic “Cisco” commands utilized for illustration purposes.

A “Practical” ACL Example Block External Users From “Pinging” Inside Hosts

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Create Access List on Router 1: access list 101 deny icmp any any access-list 101 permit ip any any Apply Access List to Interface: interface E1 ip access-group 101 in

Configuration Disclaimer: Exact configuration commands may vary based upon specific equipment models and software version. Generic “Cisco” commands utilized for illustration purposes.

The Layer 3 Switch

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What Is A “Layer 3” Switch? • “Marketing Terminology” Applied to a One Box Solution:

– Layer 2 Switching

– Layer 3 Routing

• Layer 3 Switch Performs Both!

• Multilayer Switch Port Types:

– Switchport: Layer 2 Port – MAC Addresses Learned

– Layer-3 Port: Routing Port

– Switched Virtual Interface: VLAN Virtual Interface

• Not for All Environments:

– Typically Found in Workgroup Environment

– Limited to Ethernet Ports/Interfaces

– Limited to OSPF and RIP Protocols

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Summary Q & A

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Takeaway Points • Routers Create “Broadcast Domains”

• Routing is Moving an IP Packet from One Network to Another Network

• Static & Dynamic Routing Each Have Advantages & Disadvantages

• The Routing Protocol Determines the Best Path to a Destination Host

• ACL’s Can Be Used to Control IP Traffic

• A Layer 3 Switch Combines Layer 2 Switching & Layer 3 Routing in One Box

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Further Study:

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SBE Networking Certifications CBNT Certified Broadcast Networking Technician

• This certification is designed for persons who wish to demonstrate a basic familiarity with networking hardware as utilized in business and audio/video applications in broadcast facilities.

• Exam Focus: – Network topologies and layouts – Common network protocols – Wiring standards and

practices – Maintenance, troubleshooting and

connectivity issues – Challenges unique to broadcast-

based networks

CBNE Certified Broadcast Networking Engineer

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• This certification is an “Advanced” level that reflects the skill and knowledge that will be required in today's world of converged IT and broadcast engineering.

• Exam Focus: – Audio/Video over IP

– Digital Content Management

– Video Systems in an IT World

– Data Transmission Systems

– General IT Hardware

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Thank You for Attending! Wayne M. Pecena Texas A&M University w-pecena@tamu.edu N1WP@tamu.edu 979.845.5662

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? Questions ?