network cisco ccna gns3 certification arteq

network cisco ccna gns3 certification arteq
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Sunday, October 7, 2012

eigrp phone home...

it is after all et's 30th birthday...

to do it's business, eigrp has 5 basic mechanisms...


EIGRP uses five packet types:
  • Hello—EIGRP uses hello packets in the discovery of neighbors. They are multicast to By default, EIGRP sends hello packets every 5 seconds (60 seconds on WAN links with 1544 Mbps speeds or less).
  • Acknowledgment—An acknowledgment packet acknowledges the reception of an update packet. It is a hello packet with no data. EIGRP sends acknowledgment packets to the unicast address of the sender of the update packet.
  • Update—Update packets contain routing information for destinations. EIGRP unicasts update packets to newly discovered neighbors; otherwise, it multicasts update packets to when a link or metric changes. Update packets are acknowledged to ensure reliable transmission.
  • Query—EIGRP sends query packets to find feasible successors to a destination. Query packets are always multicast.
  • Reply—EIGRP sends reply packets to respond to query packets. Reply packets provide a feasible successor to the sender of the query. Reply packets are unicast to the sender of the query packet.
hello, ack and update are fairly straightforward...

hello is discovery, ack is acknowledgement of updates, updates are ack'ed and contain destinations, but what about query and reply?

queries are sent to find feasible successors, and replies provide feasible successors to queries...

but according to doyle:

A router begins a diffusing computation by sending queries to all of its neighbors

that's an important distinction...

can it then be inferred that a successful reply ends the dual computation...

what if all queries have not been responded to?

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