EIGRP Flashcards
What is DUAL?
Diffusing Update Algorithm; computational algorithm of EIGRP
What are two functions of DUAL?
- Guarantee loop-free backup routes.
2. Store all available routes to achieve rapid convergence
What multicast addresses are used by EIGRP RTP?
224.0.0.10, FF02::A
Describe the EIGRP Hello packet in terms of:
- Function
- Reliable or Unreliable transmission
- Sent unicast or multicast
- Neighbor discovery
- sent unreliably
- multicast
Describe the EIGRP Acknowledgment packet in terms of:
- Function
- Reliable or Unreliable transmission
- Sent unicast or multicast
- Acknowledge Receipt of Query, Reply, and Update Packets.
- sent unreliably
- unicast
Hello packets are sent unreliably in an effort to discover and maintain neighbor adjancencies. To which addresses are hello packets sent to?
IPv4: 224.0.0.10
IPv6: FF02::A
The default EIGRP hello interval and hold timer are dependent on interface bandwidth. What are the default hello and hold values for links faster than 1.544 Mb/s?
5s Hello 15s Hold (3x hello)
The default EIGRP hello interval and hold timer are dependent on interface bandwidth. What are the default hello and hold values for links slower than 1.544 Mb/s?
60s Hello 180s Hold (3x hello)
EIGRP update packets are always sent (reliably/unreliably). Are they sent as unicast or multicast?
Reliably, and can be sent as either unicast or multicast
EIGRP Query packets are always sent (reliably/unreliably). Are they sent as unicast or multicast?
Reliably, and can be sent as either unicast or multicast
EIGRP Reply packets are response to queries regarding other available routes. Are they sent unicast or multicast? Are they sent reliably?
Unicast, reliably
EIGRP Acknowledgement packets are “dataless” packets acknowledging receipt of an update, query, or reply. It is actually a “Hello” packet with a non-zero value in the Acknowledgment field. Are EIGRP ACKs sent unicast or multicast?
Unicast
What does “reliable delivery” imply about an EIGRP message?
Implies that an acknowledgment is expected in return?
In an encapsulated EIGRP message, what IPv4 address is likely to be found in the IP packet header?
Destination address 224.0.0.10
In an encapsulated EIGRP message, what will be the value of the protocol field in the IP packet header?
88
What two pieces of critical information are found in the EIGRP packet header?
Opcode and Autonomous System Number
What is the purpose of the opcode field in the EIGRP packet header?
The opcode field specifies the EIGRP message packet type.
An EIGRP packet header arrives with an opcode field value of 1. What does this imply about the EIGRP packet?
This is an EIGRP update packet