Exam Professional Cloud Network Engineer topic 1 question 9 discussion

The correct answer is B HTTP/S port 80/443 TFTP port 69 Session affinity, (sticky sessions), overrides the load-balancing algorithm by directing all requests in a session to a specific application server. So, we need a Session affinity by Client IP. Session affinity https://cloud.google.com/load-balancing/docs/backend-service#session_affinity Session affinity options https://cloud.google.com/load-balancing/docs/internal#session_affinity The answer A&D produces the same (Client IP, protocol, and port) by the way.

The correct answer is B. Client IP. This option ensures that all traffic from the same client IP is consistently directed to the same backend instance, providing session stickiness based solely on the client’s IP address. Since the question does not specify the need to differentiate between HTTP or TFTP services, Client IP affinity is sufficient to meet the requirement for sticky sessions. Therefore, B offers the simplest and most efficient solution for your use case.

D, Client IP only is a good starting point but insufficient when dealing with multiple services on different ports which is why its crucial to include both port and protocol

B. Client IP In the context of session affinity, selecting "Client IP" means that the load balancer uses the client's IP address to determine which backend instance should receive the traffic. Each unique client IP is consistently directed to the same backend instance. If you are looking for stickiness based on the client's IP address only, and you don't need to consider the specific protocol (HTTP or TFTP), then option B is appropriate. So, if the requirement is solely to maintain stickiness based on the client IP and the protocol (HTTP or TFTP) doesn't need to be considered, then option B is indeed the correct choice. I appreciate your clarification, and I hope this provides a clear explanation.

If you include more parameters than ClientIP then you will split workloads across servers between the 2 application endpoints.

this part of the question "but need to ensure that clients are sticky to a particular instance across both services." has to be client IP.. (B)

D is the correct

Has to be D, cos no stated reason why http and tftp will always need to be served from the same machine as each other. Also you can serve either from any port, not just the defaults. So you need client, port and protocol tuple

B is correct answer for me

Answer is B

Answer is B: https://medium.com/google-cloud/google-cloud-load-balancer-setup-tweaking-and-observations-c12d704e6d52' ffinity Typically the LB is going to route new requests to any instance and traffic from one connection is going to route to the same instance. Say you want to set stickiness to make sure all connections from one client go to the same instance. Configure session affinity to client IP. You can also set by cookie. The GCLB sends a cookie on the first client request and future incoming requests with that cookie will be sent to the same instance.

Is the answers showing the syntax to use?

ANS is B. HTTP traffic uses TCP, TFTP uses UDP. Session Affinity does not work in UDP traffic, thus, using protocol and port is useless. Ref:https://cloud.google.com/load-balancing/docs/internal "Session affinity works on a best-effort basis for TCP traffic. Because the UDP protocol doesn't support sessions, session affinity doesn't affect UDP traffic."

Question mentions about HTTPS i.e. TCP and TFTP i.e. UDP protocols in an internal load balancer so it's definitely provides Client IP, Protocol and IP as options. So answer D is correct. https://cloud.google.com/load-balancing/docs/backend-service#session_affinity

B is the one

Why not D, TFTP is UDP protocol

why not D? The same client could be accessing both HTTP and FTP, so the session stickiness based on Client IP only is not enough.