The answer is a straight-through Ethernet cable. This is the correct choice because, in a standard network topology, a switch and a router are considered unlike devices, and straight-through cabling is designed to connect unlike devices by aligning the transmit pins on one end with the receive pins on the other. However, with modern interfaces supporting Auto-MDIX, the cable type switch router auto-mdix scenario becomes more flexible, as Auto-MDIX automatically detects and corrects the signal pairings, making either cable type functional in practice. On the CCNA 200-301 v2 exam, this question tests your understanding of legacy cabling rules versus modern hardware capabilities, often appearing as a trick where the correct answer remains the straight-through cable despite Auto-MDIX’s existence. A common trap is assuming Auto-MDIX eliminates the need to know the traditional rule, but the exam expects you to recognize the standard answer. Memory tip: think “switch-to-router, straight-through” — like a straight line between two different device types.
CCNA Network Infrastructure and Connectivity Practice Question
This 200-301 practice question tests your understanding of network infrastructure and connectivity. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: a straight-through Ethernet cable connects devices with different interface types, such as a switch and a router, by matching transmit pins to receive pins.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which cable type is commonly used to connect a switch to a router when using standard Ethernet interfaces on modern devices with auto-MDIX support?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Straight-through Ethernet cable
A straight-through Ethernet cable is the common expected answer for switch-to-router Ethernet connections. On modern interfaces, auto-MDIX often makes crossover requirements less important in practice.
Key principle: A straight-through Ethernet cable connects devices with different interface types, such as a switch and a router, by matching transmit pins to receive pins.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Rollover cable
Why it's wrong here
Rollover cables are typically used for console access, not data-plane Ethernet forwarding.
When this WOULD be correct
If the exam question asked about connecting a console port of a router to a computer for configuration purposes, then a rollover cable would be the correct answer. This scenario focuses on terminal access rather than standard Ethernet connections.
✓
Straight-through Ethernet cable
Why this is correct
Correct. Straight-through is the standard answer for this connection type.
Related concept
A straight-through Ethernet cable connects devices with different interface types, such as a switch and a router, by matching transmit pins to receive pins.
✗
Serial DCE cable
Why it's wrong here
Serial DCE cables are used for serial WAN links, not Ethernet switch-to-router links.
When this WOULD be correct
If the exam question asked about connecting a router to a console port of a switch for configuration purposes, specifically mentioning serial communication, then a serial DCE cable would be the correct answer.
✗
Fiber patch cable only
Why it's wrong here
Fiber may be used in some environments, but not only fiber and not as the default answer here.
When this WOULD be correct
In a question that asks about connecting devices over a fiber optic network, specifically mentioning the use of fiber optic interfaces or when discussing long-distance connections between network devices, a fiber patch cable would be the correct answer.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Straight-through Ethernet cableCorrect answer▾
Why this is correct
Correct. Straight-through is the standard answer for this connection type.
✗Rollover cableWrong answer — click to see why▾
Why this is wrong here
A rollover cable is used to connect a console port of a router or switch to a computer terminal, not for connecting switches to routers over Ethernet interfaces. In modern networking setups with auto-MDIX, a straight-through cable is the standard choice.
★ When this WOULD be the correct answer
If the exam question asked about connecting a console port of a router to a computer for configuration purposes, then a rollover cable would be the correct answer. This scenario focuses on terminal access rather than standard Ethernet connections.
Why candidates choose this
Candidates may confuse the rollover cable with other types of cables due to its use in networking, leading them to mistakenly think it could be applicable in various connection scenarios, especially if they have limited hands-on experience.
✗Serial DCE cableWrong answer — click to see why▾
Why this is wrong here
A serial DCE cable is used for connecting devices in a serial communication setup, typically for console access or point-to-point connections, not for standard Ethernet interfaces between a switch and a router.
★ When this WOULD be the correct answer
If the exam question asked about connecting a router to a console port of a switch for configuration purposes, specifically mentioning serial communication, then a serial DCE cable would be the correct answer.
Why candidates choose this
Candidates may choose this option due to familiarity with various cable types and their uses in networking, leading them to mistakenly associate serial cables with device connections in a broader context.
✗Fiber patch cable onlyWrong answer — click to see why▾
Why this is wrong here
A fiber patch cable is not used to connect a switch to a router over standard Ethernet interfaces, as it requires compatible fiber optic ports and transceivers. Ethernet interfaces typically use copper cabling, such as straight-through cables, for such connections.
★ When this WOULD be the correct answer
In a question that asks about connecting devices over a fiber optic network, specifically mentioning the use of fiber optic interfaces or when discussing long-distance connections between network devices, a fiber patch cable would be the correct answer.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of network connections, thinking that fiber optics are superior for all types of connections, or because they recall fiber cables being used in networking scenarios without considering the specific context of Ethernet interfaces.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Remember that auto-MDIX allows for the use of straight-through cables in situations where crossover cables were once required.
Detailed technical explanation
How to think about this question
Ethernet cabling is fundamental to establishing physical connectivity in Cisco networks. A straight-through Ethernet cable has identical wiring on both ends, connecting pins 1 to 1 and 2 to 2, which aligns transmit pins on one device to receive pins on the other. This wiring scheme is ideal for connecting devices with different roles, such as a switch and a router, where one device transmits on pins 1 and 2 and the other receives on those pins. This ensures proper data flow without signal collisions or miswiring.
The decision to use a straight-through cable for switch-to-router connections is based on the complementary nature of their Ethernet interfaces. Switch ports are typically configured as MDI (Medium Dependent Interface), while router ports are MDI-X (Medium Dependent Interface Crossover). This difference means a straight-through cable correctly aligns transmit and receive pairs. However, modern Cisco devices support auto-MDIX, which automatically detects cable type and adjusts the interface accordingly, allowing either straight-through or crossover cables to work without manual intervention.
A common exam trap is assuming that a crossover cable is required for switch-to-router connections, which was true before auto-MDIX became widespread. Candidates may also confuse rollover cables, which are used for console access, or serial DCE cables, which apply only to serial WAN links. Understanding the physical layer roles and the evolution of auto-MDIX technology helps avoid these mistakes. In practical networking, using straight-through cables simplifies inventory and deployment, while auto-MDIX enhances flexibility and reduces cabling errors.
KKey Concepts to Remember
A straight-through Ethernet cable connects devices with different interface types, such as a switch and a router, by matching transmit pins to receive pins.
Auto-MDIX technology automatically detects and corrects for crossover or straight-through cable wiring, allowing modern devices to use straight-through cables regardless of device type.
Rollover cables are designed for console port connections and do not support standard Ethernet data transmission between switches and routers.
Serial DCE cables are used for serial WAN interfaces and are not applicable for Ethernet connections between switches and routers.
Fiber patch cables provide physical layer connectivity for fiber optic interfaces but are not the default or most common cable type for standard Ethernet switch-to-router connections.
Switch-to-router Ethernet connections typically use straight-through cables because the switch port and router port have complementary pinouts, which is the expected standard in CCNA scenarios.
Auto-MDIX reduces the need for crossover cables by automatically adjusting the interface pinouts, simplifying network cabling requirements in modern Cisco devices.
Understanding cable types and their appropriate use cases is essential for configuring physical connectivity in Cisco networks and avoiding common cabling mistakes.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
A straight-through Ethernet cable connects devices with different interface types, such as a switch and a router, by matching transmit pins to receive pins.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review a straight-through Ethernet cable connects devices with different interface types, such as a switch and a router, by matching transmit pins to receive pins., then practise related 200-301 questions on the same topic to reinforce the concept.
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — A straight-through Ethernet cable connects devices with different interface types, such as a switch and a router, by matching transmit pins to receive pins..
What is the correct answer to this question?
The correct answer is: Straight-through Ethernet cable — A straight-through Ethernet cable is the common expected answer for switch-to-router Ethernet connections. On modern interfaces, auto-MDIX often makes crossover requirements less important in practice.
What should I do if I get this 200-301 question wrong?
Review a straight-through Ethernet cable connects devices with different interface types, such as a switch and a router, by matching transmit pins to receive pins., then practise related 200-301 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
A straight-through Ethernet cable connects devices with different interface types, such as a switch and a router, by matching transmit pins to receive pins.
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