Free CCNA | First Hop Redundancy Protocols | Day 29 | CCNA 200-301 Complete Course

Welcome to Jeremy’s IT Lab

In this section, Jeremy introduces his IT Lab and the purpose of the CCNA course. He also mentions the first hop redundancy protocols (FHRPs) that will be covered in the video.

Introduction to First Hop Redundancy Protocols (FHRPs)

• FHRPs are a type of protocol used for first hop redundancy.

• There are three FHRPs: HSRP (Hot Standby Router Protocol), VRRP (Virtual Router Redundancy Protocol), and GLBP (Gateway Load Balancing Protocol).

• The purpose of FHRPs is described in topic 3.5 of the CCNA exam.

Basic Configurations for FHRPs

• Configuration of FHRPs is not required for the CCNA exam.

• However, basic configurations for HSRP will be shown in this video for hands-on practice.

• Understanding these configurations can help in understanding how FHRPs work.

Three Different FHRPs

• HSRP: Hot Standby Router Protocol

• VRRP: Virtual Router Redundancy Protocol

• GLBP: Gateway Load Balancing Protocol

Importance of Redundancy in Networks

This section discusses the importance of redundancy in networks and introduces a scenario where redundant connections are necessary.

Importance of Redundancy

• Redundant connections are crucial for modern businesses to avoid network failures.

• Losing Internet access can be a big problem for businesses.

Scenario with Redundant Connections

• A diagram is used to demonstrate a network with redundant connections to the Internet.

• If one connection fails, an alternate path can be used as a backup until the main connection is recovered.

Default Gateway and First-Hop Redundancy Protocols

This section explains the concept of a default gateway and the role of first-hop redundancy protocols (FHRPs) in ensuring seamless network connectivity.

Default Gateway Configuration

• PCs in a network are configured with a default gateway, which is typically the IP address of the router.

• In the example network, R1's IP address (172.16.0.254) is set as the default gateway for all PCs.

Problem with Default Gateway

• If the default gateway router (R1) goes down, there is no automatic failover to another router.

• The PCs continue to send traffic to R1 even if it is not functioning.

Role of First-Hop Redundancy Protocols (FHRPs)

• FHRPs ensure automatic failover to a backup router when the active router fails.

• FHRPs use virtual IP addresses shared between routers and negotiate roles such as active and standby.

How First-Hop Redundancy Protocols Work

This section provides an explanation of how first-hop redundancy protocols (FHRPs) work in ensuring seamless network connectivity.

Negotiation of Roles

• Routers using FHRPs send multicast "Hello" messages to each other to negotiate their roles.

• One router becomes the active router, while the other becomes the standby router.

Active and Standby Router Roles

• The active router acts as the default gateway for network traffic.

• The standby router remains idle unless the active router fails.

• If the active router fails, the standby router automatically takes over as the new default gateway.

Conclusion

In this video, Jeremy introduces his IT Lab and discusses first hop redundancy protocols (FHRPs). He explains why redundancy is important in networks and demonstrates a scenario where redundant connections are necessary. He also explains how FHRPs work by negotiating roles between routers and ensuring automatic failover. Although FHRP configurations are not required for the CCNA exam, understanding their basic configurations can provide hands-on practice and a better understanding of network redundancy.

ARP and FHRP Overview

In this section, the instructor discusses Address Resolution Protocol (ARP) and First Hop Redundancy Protocols (FHRPs). ARP is used to learn the MAC address of an IP address. FHRPs provide redundancy for default gateways in a network.

ARP Request and Reply

• When PC1 needs to encapsulate a packet for the default gateway, it sends an ARP request to learn the MAC address of the default gateway.

• The ARP request message is broadcasted over the network, reaching all hosts.

• Both R1 and R2 receive the ARP request since they share the same virtual IP address mentioned in the request.

• R1, being the active router, sends a unicast ARP reply to PC1 with its virtual MAC address.

Virtual MAC Address

• The virtual IP address used by FHRP is associated with a virtual MAC address.

• Each FHRP uses a different virtual MAC address.

Traffic Flow

• When PC1 needs to send traffic to another destination (e.g., Google server), it uses its own source IP and MAC addresses.

• The destination IP remains unchanged as per the desired destination (e.g., 8.8.8.8).

• However, instead of using the actual default gateway's MAC address, PC1 uses the virtual MAC address associated with FHRP.

• The frame is sent to R1, which then forwards the packet over the Internet.

Failover Scenario

• If R1 goes down, after a few seconds, R2 becomes active by assuming that it hasn't received any "Hello" messages from R1 recently.

• End hosts (PCs) don't need to change their ARP tables as they already have mappings for virtual IP addresses and corresponding virtual MAC addresses.

• To ensure traffic starts going through R2, R2 sends gratuitous ARP replies with the virtual MAC address as the source MAC address.

• These gratuitous ARP replies are broadcasted to update the switches' MAC address tables.

FHRP Behavior and Preemption

In this section, the instructor explains the behavior of First Hop Redundancy Protocols (FHRPs) and discusses preemption.

Active and Standby Router

• FHRPs elect an active router and a standby router.

• The active router handles traffic while the standby router remains ready to take over if needed.

Non-preemptive Behavior

• By default, FHRPs are non-preemptive, meaning that the active router will not automatically give up its role when the former active router returns.

• If R1 comes online again after being down, it becomes the standby router while R2 remains active.

• However, it is possible to configure preemption to allow R1 to automatically take back its active role from R2.

Summary

This section provides a summary of Address Resolution Protocol (ARP) and First Hop Redundancy Protocols (FHRPs).

Key Points

• Virtual IP addresses and virtual MAC addresses are used in FHRPs for redundancy purposes.

• Different FHRPs use different formats for virtual MAC addresses.

• FHRPs elect an active router and a standby router.

• By default, FHRPs are non-preemptive but can be configured for preemption.

FHRP Overview

This section provides an overview of FHRPs (First Hop Redundancy Protocols) and their basic functionality.

Default Gateway Failover

• FHRPs function as the default gateway for a network.

• If the active router fails, the standby router becomes the next active router.

• The new active router sends gratuitous ARP messages to update MAC address tables on switches.

• By default, if the old active router comes back online, it won't take back its role as the active router.

Preemption in FHRPs

• In FHRPs, such as HSRP (Hot Standby Router Protocol), you can configure "preemption" to allow the old active router to take back its role if it comes back online.

Introduction to Specific FHRPs

This section gives a brief overview of three major FHRPs - HSRP, VRRP, and GLBP.

HSRP (Hot Standby Router Protocol)

• HSRP is Cisco proprietary and only runs on Cisco devices.

• It elects an active and standby router.

• There are two versions of HSRP - version 1 and version 2.

• Version 2 adds IPv6 support and allows more configured groups for different subnets/VLANs.

• Virtual IP addresses are configured for each subnet using separate HSRP groups.

Addressing in HSRP

This section covers addressing details related to HSRP.

Multicast Hello Messages

• Routers communicate with each other by sending multicast hello messages.

• For HSRP version 1, the multicast address used is 224.0.0.2.

• For HSRP version 2, the multicast address used is 224.0.0.102.

Virtual MAC Address Formats

• In HSRP version 1, the virtual MAC address format is 0000 0c07 ac followed by the group number.

• In HSRP version 2, the virtual MAC address format is 0000 0c9F Fxxx, where xxx is the group number.

Load Balancing in HSRP

This section explains how load balancing can be achieved using multiple HSRP groups.

Active Router Configuration for Load Balancing

• In situations with multiple subnets/VLANs, you can configure a different active router in each subnet to achieve load balancing.

• Similar to configuring different root bridges in each VLAN for spanning-tree protocol load balancing.

Example Scenario with Multiple Subnets/VLANs

This section provides an example scenario demonstrating load balancing with multiple subnets and VLANs using HSRP.

VLAN1 and VLAN2 Configuration

• R1 is configured as the active router in VLAN1 and standby in VLAN2.

• R2 is configured as the standby router in VLAN1 and active in VLAN2.

• Each subnet has its own default gateway provided by separate virtual IP addresses.

VRRP (Virtual Router Redundancy Protocol)

This section introduces VRRP as an alternative FHRP to HSRP.

VRRP Overview

• VRRP is an open standard that can be run on devices from any maker.

• It functions similarly to HSRP but uses different terminology - master and backup routers instead of active and standby routers.

• The IPv4 multicast address used in VRRP is 224.0.0.18.

Virtual MAC Address Format

• The virtual MAC address format for VRRP is different from HSRP.

These are the main sections covered in the transcript, providing an overview of FHRPs, focusing on HSRP and VRRP, their functionality, addressing details, load balancing capabilities, and a brief comparison between them.

Understanding VRRP and Load Balancing

In this section, the instructor explains how VRRP (Virtual Router Redundancy Protocol) can perform load balancing between different subnets by configuring a different master router in each subnet.

VRRP Load Balancing

• VRRP can load balance between different subnets by configuring a different master router in each subnet.

• The diagram shows the load balancing between two subnets.

• Instead of using "active" and "standby," VRRP uses "master" and "backup" terminologies.

Subnets and VLANs

This section highlights the relationship between subnets and VLANs, explaining that subnets divide the network at Layer 3 while VLANs divide the network at Layer 2. They work together, with each subnet being its own VLAN.

Subnets and VLANs

• Subnets divide the network at Layer 3, while VLANs divide the network at Layer 2.

• Each subnet is its own VLAN.

• All hosts in a particular VLAN are in the same subnet.

• The course emphasizes that throughout the CCNA exam topics, it's important to understand how subnets and VLANs are used together.

Comparison of HSRP and VRRP

This section provides a comparison chart highlighting the similarities and differences between HSRP (Hot Standby Router Protocol) and VRRP.

Comparison of HSRP and VRRP

• Functionally, HSRP and VRRP are nearly identical.

• Differences include terminology, multicast IP addresses, and virtual MAC addresses.

• HSRP is Cisco proprietary, while VRRP is an open standard that can run on any network device supporting it.

Introduction to GLBP

This section introduces GLBP (Gateway Load Balancing Protocol), which is different from HSRP and VRRP. GLBP allows multiple active routers to load balance traffic within a single subnet.

Gateway Load Balancing Protocol (GLBP)

• GLBP is Cisco proprietary and only runs on Cisco devices.

• Unlike HSRP and VRRP, GLBP load balances among multiple routers within a single subnet.

• Each host in the subnet can use a different router as its default gateway for load balancing purposes.

• A single Active Virtual Gateway (AVG) is elected for the subnet, which assigns up to four Active Virtual Forwarders (AVFs) responsible for load balancing within the subnet.

Understanding GLBP Functionality

This section explains the functions of GLBP in more detail, including multicast IP addresses and virtual MAC address formats.

Functions of GLBP

• GLBP allows multiple active routers to load balance traffic within a single subnet.

• The multicast IPv4 address used by GLBP is 224.0.0.102, similar to HSRP version 2.

• The virtual MAC address format for AVFs in GLBP is 0007 b400 followed by the group number and AVF number.

Importance of Remembering IP and MAC Addresses

This section emphasizes the importance of remembering IP and MAC addresses related to FHRPs (First Hop Redundancy Protocols) like HSRP, VRRP, and GLBP.

Importance of Remembering IP and MAC Addresses

• It's crucial to remember the IP addresses and virtual MAC address formats associated with FHRPs like HSRP, VRRP, and GLBP.

• Memorizing this information will be helpful for answering questions about FHRPs on the CCNA exam.

Basic Configuration of HSRP

This section provides a brief overview of configuring HSRP and demonstrates basic configurations for HSRP.

Basic Configuration of HSRP

• The instructor simplifies the network to focus on configuring R1 and R2 to use HSRP as a redundant default gateway address.

• HSRP is configured directly on the interface, G0/0 in this case.

• The instructor demonstrates how to change the HSRP version from 1 to 2.

• The virtual IP address is configured using the STANDBY command followed by the desired IP address.

• Priority is set using the PRIORITY command, determining which router becomes the active router based on priority levels.

The remaining sections will be summarized in subsequent chapters.

HSRP Configuration

In this section, the speaker discusses the configuration of HSRP (Hot Standby Router Protocol) and explains the concept of preemption.

Configuring Preemption

• Enabling 'preemption' allows a router to take on the role of active router, even if another router already has that role.

• The preempting router must have a higher priority or IP address than the current active router.

• Preemption ensures that when a failed router recovers, it can regain its role as the active router.

Configuring HSRP on R2

• HSRP version 2 is enabled on R2's G0/0 interface to ensure compatibility with R1.

• The same virtual IP address (172.16.0.254) is configured on R2 as on R1.

• Setting priority and enabling preemption are unnecessary in this case since R1 already has a higher priority and preemption doesn't need to be enabled on the standby router.

Output of SHOW STANDBY Command

• The output displays information about HSRP configuration for both R1 and R2 routers.

• It shows the HSRP group number (1), version used (version 2), virtual IP address, virtual MAC address, timers, preemption status, active and standby routers, and priority value.

Review and Quiz

This section provides a review of the topics covered in the video and concludes with a quiz related to HSRP.

Review

• FHRPs (First Hop Redundancy Protocols) provide redundant default gateways for subnets.

• Three common FHRPs are HSRP, VRRP, and GLBP.

• Basic HSRP configurations include setting version, virtual IP address, priority, and preemption.

• Memorize the multicast IP addresses and virtual MAC addresses associated with each FHRP.

Quiz Questions

1. HSRP version 1 virtual MAC address: D (0000 0c07 acab)

2. VRRP virtual MAC address: A (0000 5e00 010a)

3. Valid VRRP router roles: B (backup) and D (master)

The remaining quiz questions are not included in the transcript.

Conclusion

The transcript covers the configuration of HSRP, including enabling preemption and configuring HSRP on multiple routers. It also provides a review of FHRPs and concludes with a quiz to test understanding.

HSRP and Boson ExSim Practice Questions

In this section, the speaker discusses HSRP (Hot Standby Router Protocol) and provides explanations for some practice questions from Boson ExSim for CCNA.

HSRP Hello Messages and Gratuitous ARP

• Routers using HSRP always send Hello messages. When the standby router becomes the new active router, it continues sending HSRP hello messages.

• Option A is not entirely incorrect because of this behavior, but option B is a better answer as it states that gratuitous ARP messages are only sent when the router becomes the new active router.

• Option D, ARP reply, is also not entirely incorrect as gratuitous ARP messages are a type of ARP reply. However, option B is more specific and should be selected as the best answer.

Accurate Description of HSRP

• Question 5 asks for an accurate description of HSRP.

• Option A: Configuring a different default gateway address on each end host - Incorrect.

• Option B: Multiple routers load-balancing traffic for hosts in a subnet - Incorrect.

• Option C: Providing a redundant default gateway address for hosts in a subnet - Correct answer.

• Option D: Each router selecting a unique virtual IP and MAC address - Incorrect.

• Load balancing can be achieved by configuring different active routers in each subnet, but not within a single subnet.

Boson ExSim Practice Question on HSRP

• The speaker presents another practice question from Boson ExSim regarding true statements about HSRP.

• Options A and B are incorrect. Only one virtual MAC address is used in an HSRP group, not multiple virtual MAC addresses or backup state routers.

• Options C and D are correct. One router is elected as the active router while another becomes the standby router. Only one virtual IP and MAC address are used in an HSRP group.

• Option E is incorrect. All routers in an HSRP group cannot participate by forwarding traffic; this feature is specific to GLBP (Gateway Load Balancing Protocol).

Conclusion and Recommendations

• Boson ExSim is recommended as a valuable resource for CCNA practice exams.

• Supplementary materials, such as flashcards and packet tracer lab files, are available for the course.

• The speaker expresses gratitude to JCNP-level channel members for their support.

Conclusion and Call to Action

In this section, the speaker concludes the video and encourages viewers to subscribe, like, comment, and share the video. They also mention supplementary materials available for the course.

Appreciation for Support

• The speaker thanks JCNP-level channel members for their support.

• A list of JCNP-level members at the time of recording is shown.

• Viewers who recently signed up will be acknowledged in future videos.

Call to Action

• Viewers are encouraged to subscribe to the channel, like the video, leave a comment, and share it with others.

Supplementary Materials

• Flashcard decks for Anki software are available as supplementary materials.

• A packet tracer practice lab will be provided in the next video.

• Viewers can sign up for the mailing list via the link in the description to receive all flashcards and packet tracer lab files for the course.