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Advance EIGRP Configuration

jk865
Level 1
Level 1

Hi 

I am learning about advanced EIGRP and have made the following notes for advanced features that can be implemented , would somebody kindly pass comment on if I have missed anything or if theres any other advanced features I can configure as part of best practise. 

Thanks in advance 

To implement EIGRP (Enhanced Interior Gateway Routing Protocol) advanced features for optimum performance, you can follow these best practices:

  1. Metric Optimization
  • K Values: Ensure that the K values used for EIGRP are set appropriately. The default K values are usually sufficient, but you can modify them for specific network requirements.
  • Bandwidth and Delay: Adjust the interface bandwidth and delay settings to ensure that EIGRP calculates the best path accurately. Use the bandwidth command on interfaces to reflect actual available bandwidth.
  1. EIGRP Authentication
  • Configure Authentication: Use MD5 authentication to secure EIGRP messages. This prevents unauthorized devices from forming EIGRP neighbor relationships.

bash

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interface GigabitEthernet0/1

  ip authentication mode eigrp [AS number] md5

  ip authentication key-chain eigrp [AS number] [key-chain-name]

  1. EIGRP Route Summarization
  • Summarization at Boundaries: Configure summarization at EIGRP boundary routers to reduce routing table size and improve convergence time.

bash

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interface GigabitEthernet0/0

  ip summary-address eigrp [AS number] [summary-address] [subnet-mask]

  1. Load Balancing
  • Equal-Cost Multi-Path (ECMP): Enable ECMP to use multiple paths to a destination. By default, EIGRP supports up to 4 equal-cost paths; you can increase this limit using the maximum-paths command.

bash

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router eigrp [AS number]

  maximum-paths [number]

  1. EIGRP Timers
  • Adjust Hello and Hold Timers: Optimize the EIGRP hello and hold timers based on network conditions. For stable links, you might increase the hold time, while for unstable links, you might decrease it.

bash

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router eigrp [AS number]

  timer hello [seconds]

  timer hold [seconds]

  1. Diverse Path Selection
  • Use of Feasible Successor (FS): Ensure that feasible successors are configured properly. This will help in faster convergence since the feasible successor can be used as a backup route.
  • EIGRP Topology Table: Regularly check the topology table to ensure that backup routes are available.
  1. EIGRP Route Filtering
  • Distribute Lists: Use distribute lists to control which routes are advertised or received by EIGRP neighbors.

bash

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router eigrp [AS number]

  distribute-list [access-list] in|out

  1. EIGRP Stub Routing
  • Stub Routers: Configure stub routing on remote routers to reduce unnecessary EIGRP traffic and improve performance. This is particularly useful for branch offices.

bash

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router eigrp [AS number]

  eigrp stub

  1. Monitoring and Troubleshooting
  • Use EIGRP Commands: Utilize commands like show ip eigrp neighbors, show ip eigrp topology, and debug eigrp packets to monitor the EIGRP operation and troubleshoot issues.
  • Regularly Update and Review: Keep your network documentation and EIGRP configurations updated as the network changes.
  1. Documentation and Change Management
  • Document Changes: Always document any changes made to the EIGRP configuration for future reference and compliance with best practices.
  • Review Configuration Regularly: Schedule periodic reviews of the EIGRP configurations and performance metrics to ensure ongoing optimization.

By implementing these advanced features and best practices, you can significantly enhance the performance and reliability of your EIGRP deployment.

 

4 Replies 4

Gopinath_Pigili
Spotlight
Spotlight

Hello jk865,

Eigrp also supports Unequal path load-balancing (4 Unequal paths default) using Variance command

Eigrp supports 100 hops by default, you can increase up to 255 using metric maximum-hops command

Lastly, main imprtant this Eigrp named configuration ( router eigrp <name>),  what commands you mentioned that's for eigrp classic configuration. Named mode configuration is more advanced.

Best regards
******* If This Helps, Please Rate *******

Many thanks

Cristian Matei
VIP Alumni
VIP Alumni

Hi,

    There's some important differences between what you can do I theory and what you'll end up doing in production networks:

  1. 99.9% of the time you'll not change fault K values
  2. you'll only change BW to reflect actual line BW for logical interfaces/overlays (e.g tunnels), but never play with BW to influence EIGRP best-path as BW is also used by QoS; to influence EIGRP best-path you'll always play around with delay
  3. use SHA for EIGRP authentication, for security reasons, it requires EIGRP named mode configuration though
  4. route summarization, long story short, do it ONLY if you have memory issues and need less routes in RIB, otherwise there are many collateral consequences that you might not want to deal with
  5. hello/hold timers you usually leave it to defaults, if you want fast convergence you end up using BFD as opposed to lowering these timers

Best,

Cristian.

Hello,

You have some great starting notes and are well on your way to understanding EIGRP. Among other tips I'd like to add a few of my own.

Under your timers you may have the syntax reversed. I believe you would want the stable links to have lower timers and unstable links to have higher timers. However most organizations leave the timers as is since its fine for general operations.

STUB routing - In your notes you put that EIGRP stub routing is configured to reduce unnecessary EIGRP traffic and improve performance. I would make sure you understand how it does this. What is the default setting when its enabled and what are some other options you can configure?

Route manipulation - you can also use offset lists for adding metric to a link although not sure how much this is used in production.

EIGRP named mode - named mode has many other features you can use. One such improvement is the authentication. You can still use MD5 but you can also configure HMAC-SHA authentication.


Hope this helps with your studies and understanding and good luck.

-David

 

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