Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Exhibit
interface Tunnel0 ip address 10.10.10.1 255.255.255.252 tunnel source GigabitEthernet0/0 tunnel destination 198.51.100.2
Based on the exhibit, what is the main purpose of the configured tunnel?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
It creates a logical tunnel across another network.
This is correct because the tunnel source and destination define a virtual tunnel path.
B
Distractor review
It enables PPP authentication on a serial interface.
This is wrong because the exhibit is not PPP on a serial link.
C
Distractor review
It configures WPA3 security for a wireless bridge.
This is wrong because the exhibit is a Layer 3 tunnel, not wireless security.
D
Distractor review
It enables BGP between autonomous systems automatically.
This is wrong because a tunnel does not itself establish BGP automatically.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is confusing GRE tunnels with encryption or automatic routing protocol establishment. Candidates often assume that because GRE creates a tunnel, it also encrypts traffic or automatically enables protocols like BGP. However, GRE only encapsulates packets and does not provide confidentiality or integrity. Encryption requires pairing GRE with IPsec. Additionally, routing protocols must be explicitly configured over the tunnel interface; the tunnel itself does not initiate or enable them. Misreading the tunnel configuration as PPP authentication or wireless security is another common pitfall, as GRE operates at Layer 3 and is unrelated to those technologies.
Technical deep dive
How to think about this question
Generic Routing Encapsulation (GRE) is a tunneling protocol that encapsulates packets of one protocol inside packets of another protocol, enabling the creation of a virtual point-to-point link over an IP network. GRE tunnels allow the transport of packets between two endpoints as if they were directly connected, regardless of the underlying network topology. This encapsulation supports routing protocols, multicast traffic, and non-IP protocols, making GRE versatile for various network designs. In Cisco devices, configuring a GRE tunnel involves specifying a tunnel source and a tunnel destination IP address, which define the logical endpoints of the tunnel. The tunnel interface acts as a virtual interface that routes traffic through the encapsulated path. The main purpose of this configuration is to create a logical tunnel across an existing IP network, effectively extending Layer 3 connectivity over an intermediate network that may not support the tunneled protocols natively. A common exam trap is assuming that GRE tunnels provide encryption or automatic routing protocol establishment. GRE itself does not encrypt traffic; it only encapsulates it. Encryption requires additional protocols like IPsec. Also, GRE tunnels do not automatically enable routing protocols such as BGP; these must be configured separately. Understanding these distinctions is critical to correctly interpreting tunnel configurations and their purposes in Cisco networking scenarios.
KKey Concepts to Remember
- GRE tunnels encapsulate packets to create a logical point-to-point link over an IP network, enabling traffic to traverse intermediate networks transparently.
- Cisco GRE tunnel configuration requires defining tunnel source and destination IP addresses to establish the virtual tunnel endpoints.
- GRE tunnels support the transport of multicast and non-IP protocols, allowing routing protocols to operate over the tunnel interface.
- GRE tunnels do not provide encryption by themselves; additional protocols like IPsec are necessary for securing tunneled traffic.
- Routing protocols such as BGP or OSPF must be manually configured over GRE tunnels; the tunnel does not automatically establish these protocols.
- The tunnel interface behaves like a virtual Layer 3 interface, forwarding encapsulated traffic as if it were a direct physical link.
- GRE tunnels enable network extension and segmentation by logically connecting remote sites over an IP backbone without requiring physical connectivity.
- Misinterpreting GRE tunnels as wireless security or PPP authentication mechanisms is a common exam mistake and should be avoided.
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
GRE tunnels encapsulate packets to create a logical point-to-point link over an IP network, enabling traffic to traverse intermediate networks transparently.
What is the correct answer to this question?
The correct answer is: It creates a logical tunnel across another network. — GRE is a tunneling mechanism used to carry one type of traffic over another network path by encapsulating packets. In practical terms, the configuration creates a logical tunnel between endpoints so traffic can cross an underlying IP network as if a virtual path existed between them. The key point is that GRE is about tunneling, not encryption by itself. This distinction matters because people often assume tunnels automatically imply encryption. GRE by itself does not provide that.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
Discussion
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