JIR - Chapter 3: Load Balancing and Filter-Based Forwarding

Question 1

What is per-packet load balancing?

V1-3-5

Answer 1

It forwards packets in a round-robin fashion, out the egress interfaces, which connect to the equal cost paths that lead to the destination.

Question 2

What is a disadvantage to using per-packet load balancing?

V1-3-5

Answer 2

Packets may arrive out of order which can cause the receiving router to reorder the packets or the source device to retransmit the packets, thus causing a reduction in performance.

Question 3

What is per-flow load balancing?

V1-3-6

Answer 3

Per-flow load balancing maintains individual traffic flows between end stations. Thus, the end station does not have to reorder packets and applications experience less delay.

Question 4

By default, what does JunOS consider a single flow?

V1-3-6

Answer 4

By default, the JunOS considers all traffic that enters the same ingress interface with the same source address, destination address and the same protocol a single flow.

Question 5

True or False: All traffic belonging to the same flow is forwarded by the system out different egress interfaces.
(V1-3-6)

Answer 5

False; the traffic is forwarded out the same egress interface.

Question 6

What is the default IGP load balancing behavior?

V1-3-7

Answer 6

Junos chooses one of the equal cost paths over which traffic for the received destination prefixes will be sent.

Question 7

What is the default BGP load balancing known as?

V1-3-7

Answer 7

Per-prefix load balancing

Question 8

REVIEW (V1-3-7) to better understand this page

Answer 8

Reference this video: https://www.youtube.com/watch?v=9MSPRgVS_xE&ab_channel=SunsetLearningInstitute

Question 9

What is the command to load balance traffic for all routes in the routing table?
(V1-3-11)

Answer 9

set policy-option policy-statement then load-balance per-packet

-note that no “from” was used which causes all routes to match.

Question 10

What is the command to load balance traffic for the following prefixes:

172. 24.0.0/24
173. 24.1.0/24

(V1-3-11)

Answer 10

set policy-options policy-statement from route-filter 172.24.0.0/24 exact;

Question 11

To perform load balancing where must you apply the policy?

V1-3-11

Answer 11

You must apply the “export” policy under [edit routing-options]