Module 5: Configuring Routing and Advanced Switching

Module Objectives

  • Compare and contrast routing concepts.
  • Compare and contrast dynamic routing concepts.
  • Install and troubleshoot routers.
  • Explain tiered switching architecture.
  • Explain Virtual LANs (VLANs).

Lesson 5.1: Routing Technologies

Network+ N10-009 Certification Exam Objectives:

  • 1.2 Compare and contrast networking appliances, applications, and functions.
  • 2.1 Explain characteristics of routing technologies.
  • 5.5 Given a scenario, use the appropriate tool or protocol to solve networking issues.
Routing Technologies
  • Routing Tables and Path Selection
  • Static and Default Routes
  • Routing Table Example
  • Packet Forwarding
  • Fragmentation
  • Router Configuration
  • Routing Table Tools
  • tracert and traceroute
Routing Tables and Path Selection
  • Definition and Components of Routing Table:
      - Protocol: Indicates the protocol used to get the route.
      - Destination: The network address to which a route leads.
      - Interface: Refers to the network interface through which the packet is routed.
      - Gateway/Next Hop: The next stop on the route to the destination.
Static and Default Routes
  • Directly connected routes: Routes that are directly connected to the router.
  • Remote routes: Routes that lead to networks that are reachable but not directly connected.
  • Host routes: Routes that specify a single host.
  • Default route: A route used if no specific route to a destination is known.
Routing Table Example

  • Router A Routing Table:
      - Network: 10.0.1.0/24 - Interface Source: GO - Connected
      - Network: 10.0.2.0/24 - Interface Source: 61 - Connected
      - Network: 10.0.3.0/24 - Interface Source: G1 - Static
      - Network: 10.0.4.0/24 - Interface Source: 61 - Static

  • Router B Routing Table:
      - Network: 10.0.1.0/24 - Interface Source: GO - Static
      - Network: 10.0.2.0/24 - Interface Source: GO - Connected
      - Network: 10.0.3.0/24 - Interface Source: G1 - Connected
      - Network: 10.0.4.0/24 - Interface Source: G1 - Static

  • Router C Routing Table:
      - Network: 10.0.4.0/24 - Interface Source: G1 - Connected

Packet Forwarding
  • Key Metrics:
      - Hop count: The number of nodes a packet meets on its way to its destination.
      - Time to live (TTL): A field in a packet that determines how long it can exist in a network before being discarded.
Fragmentation
  • IPv4 fragmentation: Process of breaking down packets that are too large to transmit over a network segment.
  • IPv6 fragmentation: Fragmentation is handled differently, as it is done by the sender, not routers along the path.
  • Avoiding fragmentation: Ensuring packets are within the Maximum Transmission Unit (MTU) size of the network path.
Router Configuration
  • Edge Router: Connects to an external network, such as the internet.
  • Internal Router: Manages traffic between internal networks.
Routing Table Tools
  • show route: Command used to display the routing table in a router.
  • show arp: Command used to display the ARP table.
  • route and ip route: Commands used to view and modify the routing table.
tracert and traceroute
  • Purpose:
      - traceroute: Displays the path packets take to a network destination.
      - tracert: A Windows version of the traceroute command.
  • Common usage: Network troubleshooting and path verification.

Lesson 5.2: Dynamic Routing Technologies

Network+ N10-009 Certification Exam Objective:

  • 2.1 Explain characteristics of routing technologies.
Dynamic Routing Technologies
  • Dynamic Routing Protocols: Protocols that enable routers to automatically adjust and share routing information.
  • Types of Dynamic Routing Protocols:
      - Routing Information Protocol (RIP): One of the oldest distance-vector protocols.
      - Enhanced Interior Gateway Routing Protocol (EIGRP): A hybrid protocol that employs both distance vector and link-state features.
      - Open Shortest Path First (OSPF): A link-state routing protocol that uses a different method than RIP.
      - Border Gateway Protocol (BGP): A path vector protocol used to exchange routing information for the internet.
  • Route Selection: Mechanisms that determine the best route for data packets.
Dynamic Routing Protocol Characteristics
  • Topology and metrics: The layout of the network and criteria for route selection.
  • Convergence: The time it takes for all routers in a network to have consistent information after a change in topology.
  • Autonomous Systems:
      - Interior Gateway Protocol (IGP): Used within a single autonomous system.
      - Exterior Gateway Protocol (EGP): Used to exchange routing information between autonomous systems.
Routing Information Protocol (RIP)

  • Example:
      - Router B Routing Table:
        - Network: 10.0.1.0/24 - Metric: 1 - Source: RIP
        - Network: 10.0.2.0/24 - Metric: 0 - Source: Connected
        - Network: 10.0.3.0/24 - Metric: 0 - Source: Connected
        - Network: 10.0.4.0/24 - Metric: 1 - Source: RIP

  • Router A and C: Follow a similar structure showing RIP metrics.

Enhanced Interior Gateway Routing Protocol (EIGRP)

  • Distance vector protocol: Utilizes both distance and vector metrics such as bandwidth and delay to calculate router performance.
  • Encapsulation and protocol specifics: EIGRP’s operational mechanisms for relaying messages.

Open Shortest Path First (OSPF)

  • Typical OSPF topology: Demonstrates multiple areas and their interconnections in a hierarchical model.
      - Backbone Router: Connects different areas.
      - Area Border Router: Connects the backbone to other areas.

Border Gateway Protocol (BGP)

  • Autonomous Systems (AS): BGP is primarily for exchanging routing information between different AS.
  • Network Layer Reachability Information (NLRI): Provides information for finding reachable networks.

Route Selection

  • Source:
      - AD Local interface/Directly connected: 0
      - Static route: 1
      - BGP: 20
      - EIGRP: 90
      - OSPF: 110
      - RIP: 120
      - Unknown: 255

Lesson 5.3: Network Address Translation (NAT)

Network+ N10-009 Certification Exam Objective:

  • 2.1 Explain characteristics of routing technologies.
Network Address Translation
  • Functions as an intermediary for translating private IP addresses to a public IP address for the internet.
  • Edge Routers: Integrated services router providing functionality like DSL, Ethernet, Wi-Fi, and VoIP in one device.
  • Types of NAT:
      - Source Address Translation: Maps the source IP address of outgoing packets.
      - Destination Address Translation: Maps the destination IP address of incoming packets.
Port Address Translation (PAT)
  • Allows multiple devices on a local network to be mapped to a single public IP address but using different port numbers for tracking.
  • Example:
      - Inside Local: 10.0.0.1
      - Inside Global: 217.45.253.5
      - Outside Global: 77.72.206.10

Lesson 5.4: Firewalls

Network+ N10-009 Certification Exam Objective:

  • 1.2 Compare and contrast networking appliances, applications, and functions.
Firewalls
  • Uses and Types of Firewalls:
      - Packet Filtering Firewalls: Filter packets based on predefined rules for IP, protocol type, and port number.
      - Stateful Inspection Firewalls: Track the state of active connections and determine which packets to allow through.
Firewall Selection and Placement
  • Types of firewalls to consider:
      - Network firewalls: Protect the entire network.
      - Host firewalls: Protect individual hosts.
      - Appliance firewalls: Dedicated hardware appliances for specific functions.
      - Router firewalls: Firewalls integrated into routers.

Lesson 5.5: Enterprise Network Topologies

Network+ N10-009 Certification Exam Objective:

  • 1.6 Compare and contrast network topologies, architectures, and types.
Enterprise Network Topologies
  • Hybrid Topology: Involves multiple kinds of topologies, ie., star, bus, or ring in a single network.
      - Hierarchical Topology: Establishes parent/child relationships where networks operate in layers, enhancing the efficiency of network management.
Three-Tiered Network Hierarchy
  • Components include:
      - Access/Edge Layer: The first point of access for devices to connect to the network.
      - Distribution/Aggregation Layer: Acts as a mediator directing network traffic between access and core layers.
      - Core Layer: The backbone of the network handling large amounts of data across long distances.
      - Collapsed Core: Consolidation of the core and distribution functions into a single layer for simplicity.

Lesson 5.6: Virtual LANs (VLANs)

Network+ N10-009 Certification Exam Objectives:

  • 2.1 Explain characteristics of routing technologies.
  • 2.2 Given a scenario, configure switching technologies and features.
  • 5.5 Given a scenario, use the appropriate tool or protocol to solve network issues.
Virtual LANs
  • Definition: Logical segmenting of networks into different broadcast domains regardless of their physical location.
  • Subnets: VLANs and subnets facilitate improved organization and management of network segments.
VLAN IDs and Membership
  • VLAN Configuration: Involves selecting VLAN IDs, managing VLAN ranges, and updating the VLAN database.
Trunking and IEEE 802.1Q
  • IEEE 802.1Q: A networking standard that allows for VLAN tagging on Ethernet frames.
  • VLAN Trunk Link: A link that carries traffic for multiple VLANs.
Tagged and Untagged Ports
  • Untagged Ports (Access Ports): Facilitate communication with a single VLAN and lack VLAN tags on frames.
  • Tagged Ports (Trunk Ports): Support multiple VLANs, carrying frames with VLAN tagging information.
Voice VLANs
  • Functionality: Allowing voice traffic to be prioritized or segregated from other types of data traffic on the same physical line.
  • Example Setup: Configuring VoIP and PC to share the same port while ensuring traffic management through different VLANs.
Default VLAN and Native VLAN
  • VLAN ID 1: Default VLAN characteristics and best practices for usage.
  • Native VLAN: Handles untagged traffic, utilized for accommodating devices not capable of VLAN tagging.
VLAN Routing
  • Involves Subinterfaces to manage different VLANs and their respective routing.
  • Example Setup: Routing with sub-interfaces arranged for each VLAN/subnet.

Lesson 5.7: Routing and VLAN Troubleshooting

Network+ N10-009 Certification Exam Objective:

  • 5.3 Given a scenario, troubleshoot common issues with network services.
Routing and VLAN Troubleshooting
  • Routing Table Issues:
      - Identifying potential issues with routing configurations.
      - Investigating routing topologies for consistency.
      - Checking for missing routes and factors affecting route selection.
      - Addressing overlapping routes that may cause conflicts.
Default Route and Routing Loop Issues
  • Routing Loops: Occur when routers continue to send packets in a circular path without reaching the destination.
  • Preventive Measures: Implementing techniques such as split horizon can help eliminate routing loops.
VLAN Assignment Issues
  • Issues can block traffic or misroute communications due to incorrect configurations in VLAN assignments.
  • Troubleshooting Steps: Include connectivity tests such as ping to ensure physical and logical connections are correctly established.

Module Summary

  • Routers use routing tables to make data packet routing decisions.
  • Dynamic routing concepts utilize protocols for efficient data delivery.
  • NAT manages communications between public/private address schemes.
  • Firewalls enforce security controls for accessing private networks from public ones.
  • Ethernet, switching, and IP routing considerations are critical for cabled local networks.
  • Hosts and routers implement route selection logic while VLANs enhance performance and security by segmenting networks.