EIGRP packet types

LinkedIn
Facebook
Facebook
Google+
https://netfixpro.com/eigrp-packet-types/
RSS
Follow by Email
This article summarizes all 5 different EIGRP packets. They are Hello, Acknowledgements, Updates, Queries and Replies, SIA-query and SIA-reply.
Hello
  • Hello packets are used by the neighbor discovery and recovery process.
  • are multicast and use unreliable delivery;
  • has an opcode of 5.
Acknowledgements
  • Acknowledgment packets are Hello packets with no data in them.
  • ACKs are always unicast and use unreliable delivery;
  • has an opcode of 5.
Updates
  • Update packet conveys the route information.
  • Unlike RIP and IGRP updates, these packets are transmitted only when necessary, contain only necessary information, and are sent only to routers that require the information.
  • When updates are required by a specific router, they are unicast.
  • When updates are required by multiple routers, such as upon a metric or topology change, they are multicast.
  • Updates always use reliable delivery; 
  • has an opcode of 1.
Queries and replies
  • Query is generated when the route becomes ACTIVE i.e link loss, neighbor loss, metric change. Query is sent for an exact match of lost route. i.e. 1.2.3.4/24…
  • Queries and Replies are used by the DUAL finite state machine to manage its diffusing computations.
  • Queries can be multicast or unicast, and replies are always unicast.
  • Both queries and replies use reliable delivery; 
  • has an opcode of 3.
SIA-Query and SIA-Reply
  • The SIA-Query packet is used to ask a particular neighbor to confirm that it is still working on the original Query packet. If the neighbor is reachable and the router is  still engaged in the diffusing computation for the destination specified in the SIA-Query, it will immediately respond with an SIA-Reply packet;
  • Both SIA-Query and SIA-Reply packets are unicast and reliably delivered.
  • SIA-Query uses an Opcode of 10, and SIA- Reply uses an Opcode of 11.

I hope you enjoyed this article. Please feel free to leave a comment or feedback.

LinkedIn
Facebook
Facebook
Google+
https://netfixpro.com/eigrp-packet-types/
RSS
Follow by Email

Ashutosh Patel

Ashutosh Patel is the Author and editor of netfixpro.com. He currently works as a Network Security Architect. Follow him on following social media to know more about him.

One thought on “EIGRP packet types

Leave a Reply

Your email address will not be published. Required fields are marked *

Show Buttons
Hide Buttons

Enjoy this article? Please spread the word :)