Chapter 06 - Advanced EIGRP

What type of routing problem can occur with EIGRP stub routers?

C. Incomplete routing tables leading to unreachable destinations

What does the EIGRP stub site feature prevent?

A. Prevents the advertisement of certain routes

What is the role of the backup VPN tunnel in EIGRP configurations?

B. To ensure redundancy and reliability

In which configuration mode is the EIGRP stub site function available?

Router configuration mode

How can the administrator resolve the issue of a device being stuck in the Active state?

Verify the configuration of the Active Timer

What role do SIA queries play in the context of route deletion?

SIA queries help identify stale routes for deletion

What effect does metric manipulation have on route selection?

It affects the chosen route for data transfer

How can filtering techniques improve data flow in the network?

By minimizing excess traffic and improving efficiency

What is the primary function of EIGRP hello packets?

To establish and maintain neighbor relationships

Explain the process of how EIGRP detects the absence of a neighbor.

• Sends hello packets at regular intervals

• Waits for a response

• After a specified hold time, considers the neighbor down

• Updates its routing table accordingly

Which algorithm does EIGRP use for fast convergence?

DUAL (Diffusing Update Algorithm)

Describe the steps involved in calculating a new route in EIGRP after a link failure.

1. Detect link failure

2. Remove failed route from the routing table

3. Trigger EIGRP to send updates

4. Calculate new routes using DUAL algorithm

5. Select the best route

6. Update the routing table with the new route

What are the implications of using unequal-cost load balancing in EIGRP?

• Better utilization of available bandwidth

• Increased redundancy and reliability

• Improved overall network performance
  However, it may lead to:

• Potentially uneven traffic distribution

• Increased complexity in configuration and troubleshooting.

What type of routing protocol is EIGRP classified as?

Hybrid routing protocol

What are the benefits of configuring an EIGRP stub router?

• Reduced routing table size

• Decreased CPU and memory usage

• Improved network stability

• Faster convergence

• Limited routing updates, enhancing security

• Simplified network management

What are the implications of forgetting that EIGRP stub routers do not advertise learned routes from peers?

• Misconfigured routing tables

• Suboptimal path selection

• Increased network latency

• Potential routing loops

• Inefficient use of bandwidth

How does EIGRP ensure that only necessary routes are advertised in a network?

• Route summarization: Combines multiple routes into a single advertisement

• Split horizon: Prevents sending route updates back out the same interface

• Querying: Only requests specific routes when needed
  These methods reduce unnecessary routing information.

How does the EIGRP stub site feature affect the overall topology of a network?

It reduces routing table size and minimizes unnecessary traffic, enhancing efficiency. Stub sites only send specific routes, preventing them from receiving full routing information from other routers.

How does the EIGRP stub site feature enhance network efficiency in a multi-router environment?

It reduces unnecessary routing updates and minimizes bandwidth usage, allowing stub routers to only send and receive essential routing information,

What is the role of discard routes in EIGRP?

Discard routes indicate invalid routes.

What considerations should be made when implementing redundant circuits in an EIGRP setup?

• Load balancing across links

• Proper route summarization

• Configuration of EIGRP metrics

• Ensuring fast convergence

• Monitoring link status

• Avoiding routing loops

• Implementing backup paths for reliability

What are the two main types of EIGRP query packets?

A. EIGRP Query and EIGRP Reply

Explain how EIGRP stub routers handle route advertisements.

EIGRP stub routers only send and receive specific route advertisements. They typically advertise their own networks and a default route but do not share routes learned from other routers.

How do EIGRP neighbors on WAN links behave when a route becomes active for a stub site?

EIGRP neighbors will not be informed until the route stabilizes.

What is the default value of the active timer in EIGRP?

180 seconds

What advantages does EIGRP offer over traditional distance vector protocols that could address the slow convergence issue experienced by the network?

EIGRP provides rapid convergence through the use of DUAL (Diffusing Update Algorithm), which allows for faster route recalculation and minimizes routing loops compared to traditional distance vector protocols.

How does EIGRP enhance network convergence compared to traditional distance vector protocols?

By using DUAL for rapid route recalculation

What feature of EIGRP allows it to maintain a loop-free environment?

Feasible Successor concept

What does the term "transit site" refer to in the context of EIGRP stub sites?

A location where traffic can pass through

What action should the router take if it does not receive a Hello packet from a neighbor within the hold timer?

The router should consider the neighbor as down and start a route recalculation process using the DUAL algorithm.

How do Hello packets contribute to the stability of a network topology?

Hello packets help maintain neighbor relationships by allowing routers to detect failures quickly, ensuring timely updates to routing tables and minimizing downtime in the network

What approach should the logistics company prioritize to ensure scalability in their route summarization system?

The company should prioritize a hierarchical design approach,

What configuration would best prevent routing loops in the company's WAN setup while optimizing bandwidth utilization?

Implementing split horizon to avoid sending route updates back out the same interface they were received on, thus preventing potential routing loops.

What factors should be considered when implementing EIGRP in a WAN environment?

• Bandwidth utilization

• Split horizon rules

• Next-hop self configuration

• Redundancy (additional routers and circuits)

• VPN tunnels for backup

• Network topology and interface types

How does configuring a router as an EIGRP stub benefit the branch office?

It reduces unnecessary route advertisements.

What technique could help prevent routing loops in the WAN?

Split Horizon

How do hello packets contribute to failure detection in routing protocols?

Hello packets help identify active neighbors.

What impact does a short hold timer have on network stability?

A short hold timer can lead to frequent route flaps.

How does the EIGRP split horizon rule interact with stub routers?

The EIGRP split horizon rule prevents routers from advertising routes back out the interface they were learned on

What filtering technique can the administrator use to reduce congestion on specific routes without affecting overall network performance?

The administrator can implement access control lists (ACLs) to filter out non-essential traffic, allowing only high-priority packets to traverse the congested routes.

How might altering the metric values of certain routes impact the routing decisions made by the network's routers?

By lowering the metric values for critical routes, the routers will prefer these paths over others, effectively directing more traffic through less congested routes and improving overall efficiency.

How can hierarchical design improve route summarization in large networks?

By decreasing the number of routes shared across network levels

What is a key benefit of interface-specific summarization?

It allows for tailored summaries based on specific interface needs

What are the potential challenges of managing EIGRP configurations across different modes (classic vs. named)?

• Different command syntax for classic vs. named mode

• Potential for misconfiguration due to varied settings

• Complexity in troubleshooting and documentation

• Need for understanding both modes for effective management

How does EIGRP manage the scalability of large networks through route summarization?

• Reducing the size of routing tables

• Creating query boundaries to limit the scope of route queries

• Summarizing routes at different network layers (access, distribution, core)

• Using interface-specific summarization to advertise summary routes only when needed

What is the difference between automatic summarization and manual summarization in EIGRP?

Automatic Summarization:

• Happens automatically at classful boundaries

• Simplifies routing by advertising summary routes

Manual Summarization:

• Configured by the administrator

• Allows for more control and specific route aggregation

• Enhances scalability and reduces routing table size

How do EIGRP metrics affect route selection and path determination?

EIGRP metrics affect route selection by determining the best path based on factors like bandwidth, delay, reliability, and load. The route with the lowest metric is preferred

What is the significance of the EIGRP stub site identifier?

The identifier facilitates efficient routing by indicating stub networks

What is the purpose of route summarization in EIGRP?

To reduce the size of the routing table