Exam Professional Cloud Network Engineer All Questions

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Exam Professional Cloud Network Engineer topic 1 question 148 discussion

Actual exam question from Google's Professional Cloud Network Engineer

Question #: 148
Topic #: 1

[All Professional Cloud Network Engineer Questions]

You are designing a new application that has backends internally exposed on port 800. The application will be exposed externally using both IPv4 and IPv6 via TCP on port 700. You want to ensure high availability for this application. What should you do?

A. Create a network load balancer that used backend services containing one instance group with two instances.
B. Create a network load balancer that uses a target pool backend with two instances.
C. Create a TCP proxy that uses a zonal network endpoint group containing one instance.
D. Create a TCP proxy that uses backend services containing an instance group with two instances.

Show Suggested Answer

Suggested Answer: A 🗳️

by ccieman2016 at Dec. 4, 2022, 4:16 p.m.

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garytolson

Highly Voted 1 year, 11 months ago

D is the correct answer. The question has 3 criteria. High availability, IPv4 and IPv6 support, and translate the front end port to a different backend port. Answer A - Can not be correct because a Network load balancer is pass-through, the front end port and backend port will allways be the same. Answer B - same reason Answer C - Does not meet the HA requirement Answer D - Meets all 3 requirements, HA with 2 instance instance group, IPV4 and 6 support, and the port change requirement provided by the proxy component of the TCP LB. https://cloud.google.com/load-balancing/docs/tcp

upvoted 15 times

mity99

1 year, 9 months ago

One of the key features of the TCP Proxy Load Balancer is the ability to perform port forwarding, which allows you to change the incoming port number to a different port number when forwarding to a backend instance.

upvoted 1 times

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omermahgoub

1 year, 5 months ago

Internal TCP proxy load balancers do not support IPv6 https://cloud.google.com/load-balancing/docs/ipv6#limitations

upvoted 2 times

desertlotus1211

9 months, 3 weeks ago

It's external TCP proxy... not internal

upvoted 2 times

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pfilourenco

Highly Voted 2 years ago

Selected Answer: A

A is the correct, since with need to support IPV6: "Target pool-based network load balancers support only IPv4 traffic, and only support the TCP and UDP protocols." https://cloud.google.com/load-balancing/docs/network/networklb-target-pools

upvoted 12 times

nosense

2 years ago

yeap. A is right because needed IPv6.

upvoted 1 times

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pfilourenco

2 years ago

Looks like TCP proxy that uses backend services also support IPv6.

upvoted 1 times

pfilourenco

2 years ago

So maybe D is also correct...and is global.

upvoted 2 times

pfilourenco

2 years ago

Run dual stack. To serve both IPv6 and IPv4 clients, create two load balancer IP resources—one for IPv6 and the other for IPv4—and associate both with the same IPv4 application instances. IPv4 clients connect to the IPv4 address while IPv6 clients connect to the IPv6 address. So, A is the correct, since we are talking about only one load balancer.

upvoted 2 times

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pfilourenco

2 years ago

Only if we want IPv6 termination. If we need dual stack on backend the correct is A.

upvoted 1 times

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09bd94b

Most Recent 4 months, 1 week ago

Selected Answer: D

Must be D because of the port forwarding

upvoted 1 times

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rmx86

5 months, 2 weeks ago

Selected Answer: D

D because of the port mapping

upvoted 2 times

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thewalker

7 months, 3 weeks ago

Selected Answer: D

To ensure high availability for an application that is exposed externally using both IPv4 and IPv6 via TCP on port 700, you should use a TCP proxy with a backend service that contains an instance group with two instances. A network load balancer can only be used to expose applications that are exposed using HTTP or HTTPs. A target pool backend can only be used with a network load balancer. A zonal network endpoint group can only be used with a TCP proxy. Therefore, the best option is to create a TCP proxy that uses backend services containing an instance group with two instances. Here is an example of how to create a TCP proxy that uses backend services containing an instance group with two instances:

upvoted 2 times

thewalker

7 months, 3 weeks ago

gcloud compute target-tcp-proxies create my-tcp-proxy \ --project=my-project \ --backend-service=my-backend-service \ --port-name=port-700 gcloud compute backend-services create my-backend-service \ --project=my-project \ --protocol=TCP \ --port-name=port-800 \ --health-checks=my-health-check \ --instance-group=my-instance-group gcloud compute instance-groups managed create my-instance-group \ --project=my-project \ --zone=us-central1-a \ --template=my-instance-template \ --size=2 Once you have created the TCP proxy, backend service, and instance group, you can expose your application externally using both IPv4 and IPv6 via TCP on port 700.

upvoted 1 times

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desertlotus1211

9 months, 3 weeks ago

Answer is D: The questions mention High Availability. Although an External Network (passthrough LB) can do IPv4 and IPv6 and port forwarding - it's regional... External TCP Proxy is global...

upvoted 1 times

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gonlafer

10 months ago

Selected Answer: A

Tricky question. D & C do not mention LB, just TCP Proxy. To me it's A

upvoted 2 times

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Thornadoo

1 year, 3 months ago

This question is all over the place. Firstly options C & D all point to internal TCP Proxy LB which doesn't support IPv6. Same with Option B (Target Pool) which doesn't support IPv6. Now answer A supports IPv6, but passthroughs maintain the same port throughout whereas in this case the requirement is that 700 should change to 800. The right answer would be External TCP Proxy Load-Balancer.

upvoted 2 times

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didek1986

1 year, 4 months ago

Selected Answer: A

A is correct tcp proxy in eventually part but part of NLB https://cloud.google.com/load-balancing/docs/tcp

upvoted 2 times

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rglearn

1 year, 4 months ago

Selected Answer: D

you need to have proxy supported Load balancer in between to do port forwarding service. I checked on GCP console and could find option of mentioning ports for frontend and backend only in TCP proxy LB. on top of that it also supports IPv6. Hence Option D

upvoted 2 times

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Dan137

1 year, 6 months ago

Selected Answer: D

TCP proxy supports IPV6: https://cloud.google.com/load-balancing/docs/tcp#benefits

upvoted 2 times

Dan137

1 year, 6 months ago

Change my opinion, its A.

upvoted 1 times

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GeorgS

1 year, 8 months ago

Selected Answer: D

In my opinion D is correct. The network loadbalancer just supports pass-through. But in this case, we need to forward it to another port. That is not pass-through. https://cloud.google.com/load-balancing/docs/load-balancing-overview?hl=en#summary-of-google-cloud-load-balancers

upvoted 4 times

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mshry

2 years ago

Selected Answer: A

Totally assumed LB after the TCP Proxy. Tricky stuff. Answer should be A.

upvoted 3 times

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mshry

2 years ago

Selected Answer: D

Why not D. TCP Proxy is Global and supports IPv6 with a single port between 1-65535. https://cloud.google.com/load-balancing/docs/forwarding-rule-concepts#port_specifications

upvoted 3 times

nosense

2 years ago

I'm not sure, that TCP Proxy mean like load balancer. Probably "a server that acts as an intermediary between a client and another server" this reason why I choose A

upvoted 2 times

mshry

2 years ago

Oh wow, good catch. Totally assumed LB after the TCP Proxy. Tricky stuff. Answer should be A.

upvoted 1 times

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ccieman2016

2 years ago

Selected Answer: B

Exposed port 800 elimated C and D, that isn't support this port. A is wrong too, https://cloud.google.com/load-balancing/docs/backend-service#backends. B is correct.

upvoted 1 times

pfilourenco

2 years ago

Support for all ports. External TCP Proxy Load Balancing allows any valid port from 1-65535. https://cloud.google.com/load-balancing/docs/tcp#benefits

upvoted 1 times

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