CS6250 CS 6250 Exam 2 Latest

CS6250 / CS 6250 Exam 2 (Latest Update 2025 / 2026) Computer Networks | Questions & Answers | 100% Correct | Grade A - Georgia Tech

Question:

What is P4 and why was it developed?

Answer:

P4 is a high level programming language

helps configure switches in conjunction with SDN control protocols

helps with programmability on DATA PLANE

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Question:

What plane does P4 help program?

Answer:

The data plane

Question:

Why does openflow include multiple stages of rule table, and an increasing number of header fields?

Answer:

Helps to expose the functionalities of the switch to the controller

Question:

How does openflow address the increasing number of header fields?

Answer:

flexible approach to match headers P4 allows configuring switch programmatically controller can define how switches operate

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Question:

What are the 3 primary goals of P4?

Answer:

• reconfigurability - parsing and processing should be modifiable by

controller

• protocol independence - switches should be INDEPENDENT of any

particular protocol (how the switches are programmed)

• target independence - packet processing programs should be programmed

INDEPENDENT of underlying devices (how applications are programmed)

Question:

How do switches using P4 forward packets?

Answer:

• use a programmable parser

• use set of match + action tables to forward packets

• match + action tables can be accessed in PARALLEL

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Question:

How does p4 improve openflow with forwarding packets and accessing tables?

Answer:

• openflow supports only fixed parsers based on PREDETERMINED header

fields

• openflow supports only a series combo of match+action tables

Question:

How does generalization of packet processing work with p4?

Answer:

• design of common language to write packet processing programs

INDEPENDENT of underlying devices

• compiler maps programs to different devices

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