Course Content
Networking Today
0/7
Network Components
Network Representations and Topologies
Common Types of Networks
Internet Connections
Reliable Networks
Network Security Basic
Network Trends
Basic Switch and End Device Configuration
0/7
Cisco IOS Access
Cisco IOS Navigation
Cisco IOS Command Structure
Basic Cisco Device Configuration
Save Cisco IOS Configurations
Ports and Addresses
Configure IP Addressing
Protocols and Models
0/7
The Rules in Network Communications
Protocols
Protocol Suites
Standards Organizations
Reference Models
Data Encapsulation
Data Access
Physical Layer
0/6
Purpose of the Physical Layer
Physical Layer Characteristics
Copper Cabling
UTP Cabling
Fiber-Optic Cabling
Wireless Media
Data Link Layer
0/3
Purpose of the Data Link Layer
WAN and LAN topologies
Data Link Frame
Ethernet Switching
0/4
Ethernet Frames
Ethernet MAC Address
The MAC Address Table
Switch Speeds and Forwarding Methods
Network Layer
0/5
Network Layer Characteristics
IPv4 Packet
IPv6 Packet
How a Host Routes
Router Routing Tables
Number Systems
0/2
Binary Number System
Hexadecimal Number System
Address Resolution
Explain how ARP and ND enable communication on a network
0/3
MAC and IP
ARP
Neighbor Discovery
Basic Router Configuration
0/3
Configure Initial Router Settings
Configure Interfaces
Configure the Default Gateway
IPv4 Addressing
0/7
IPv4 Address Structure
IPv4 Unicast, Broadcast, and Multicast
Types of IPv4 Addresses
Network Segmentation
Subnet an IPv4 Network
VLSM
Structured Design
IPv6 Addressing
0/8
IPv4 Issues
IPv6 Address Representation
IPv6 Address Types
GUA and LLA Static Configuration
Dynamic Addressing for IPv6 GUAs
Dynamic Addressing for IPv6 LLAs
IPv6 Multicast Addresses
Subnet an IPv6 Network
ICMP
0/2
ICMP Messages
Ping and Traceroute Testing
Transport Layer
0/7
Transportation of Data
TCP Overview
UDP Overview
Port Numbers
TCP Communication Process
Reliability and Flow Control
UDP Communication
Application Layer
0/7
Application, Presentation, and Session
Peer-to-Peer
Web Protocols
Email Protocols
Dynamic Host Configuration Protocol (DHCP)
Domain Name Service
File Sharing Services
Network Security Fundamentals
0/4
Security Threats and Vulnerabilities
Network Attacks
Network Attack Mitigation
Device Security
Build a Small Network
0/7
Devices in a Small Network
Small Network Applications and Protocols
Scale to Larger Networks
Verify Connectivity
Host and IOS Commands
Troubleshooting Methodologies
Troubleshooting Scenarios
Basic Device Configuration
0/5
Configure a Switch with Initial Settings
Configure Switch Ports
Secure Remote Access
Basic Router Configuration
Verify Directly Connected Networks
CCNA: Switching, Routing, and Wireless Essentials
The second course in the CCNA curriculum focuses on switching technologies and router operations that support small-to-medium business networks and includes wireless local area networks (WLAN) and security concepts.
0/15
Switching Concepts
VLANs
Inter-VLAN Routing
STP
Etherchannel
DHCPv4
SLAAC and DHCPv6 Concepts
FHRP Concepts
LAN Security Concepts
Switch Security Configuration
WLAN Concepts
WLAN Configuration
Routing Concepts
IP Static Routing
Troubleshoot Static and Default Routes
CCNA: Enterprise Networking, Security, and Automation
The third CCNA course describes the architectures and considerations related to designing, securing, operating, and troubleshooting enterprise networks – including wide area network (WAN) technologies & quality of service (QoS) mechanisms for secure remote access, along with software-defined networking, virtualization, & automation concepts supporting network digitization.
0/14
Single-Area OSPFv2 Concepts
Single-Area OSPFv2 Configuration
Network Security Concepts
ACLs Concepts
ACLS for IPv4 Configuration
NAT for IPv4
WAN Concepts
VPN and IPsec Concepts
QoS Concepts
Network Management
Network Design
Network Troubleshooting
Network Virtualization
Network Automation
CCNA Course
About Lesson

How a Host Routes

Explain how network devices use routing tables to direct packets to a destination network.

Host Forwarding Decision

  • Packets are always created at the source.
  • Each host devices creates their own routing table.
  • A host can send packets to the following:

 

    • Itself – 127.0.0.1 (IPv4), ::1 (IPv6)
    • Local Hosts – destination is on the same LAN
    • Remote Hosts – devices are not on the same LAN

  • The Source device determines whether the destination is local or remote
  • Method of determination:
    • IPv4 – Source uses its own IP address and Subnet mask, along with the destination IP address
    • IPv6 – Source uses the network address and prefix advertised by the local router
  • Local traffic is dumped out the host interface to be handled by an intermediary device.
  • Remote traffic is forwarded directly to the default gateway on the LAN.

Default Gateway

  • A router or layer 3 switch can be a default-gateway.
  • Features of a default gateway (DGW):
    • It must have an IP address in the same range as the rest of the LAN.
    • It can accept data from the LAN and is capable of forwarding traffic off of the LAN.
    • It can route to other networks.
  • If a device has no default gateway or a bad default gateway, its traffic will not be able to leave the LAN.

A Host Routes to the Default Gateway

  • The host will know the default gateway (DGW) either statically or through DHCP in IPv4.
  • IPv6 sends the DGW through a router solicitation (RS) or can be configured manually.
  • A DGW is static route which will be a last resort route in the routing table.
  • All device on the LAN will need the DGW of the router if they intend to send traffic remotely.

 

Host Routing Tables

  • On Windows, route print or netstat -r to display the PC routing table
  • Three sections displayed by these two commands:
    • Interface List – all potential interfaces and MAC addressing
    • IPv4 Routing Table
    • IPv6 Routing Table

Other related topics

Topic Title Topic Objective
Network Layer Characteristics Explain how the network layer uses IP protocols for reliable communications.
IPv4 Packet Explain the role of the major header fields in the IPv4 packet.
IPv6 Packet Explain the role of the major header fields in the IPv6 packet.
How a Host Routes Explain how network devices use routing tables to direct packets to a destination network.
Router Routing Tables Explain the function of fields in the routing table of a router.

 

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