Question 1mediummatching
Full question →Match each WAN or edge concept to its most accurate description.
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mediummatchingObjective-mapped
Match each WAN or edge concept to its most accurate description.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is confusing PPP and PPPoE as the same protocol or interchangeable encapsulations. PPP is designed for serial point-to-point links, while PPPoE encapsulates PPP frames inside Ethernet frames to support broadband access. Another trap is assuming GRE provides encryption; GRE only encapsulates packets and requires additional protocols like IPsec for security. Candidates also often mistake eBGP as an internal routing protocol, but eBGP strictly operates between different autonomous systems. Misunderstanding these distinctions leads to incorrect matching of WAN or edge concepts to their descriptions.
Technical deep dive
How to think about this question
Point-to-Point Protocol (PPP) is a WAN encapsulation protocol designed to establish direct connections between two nodes over serial links. It supports features such as authentication (PAP/CHAP), link quality monitoring, and multilink capabilities. PPP is fundamental in legacy WAN environments and remains relevant for point-to-point serial connections in Cisco networks. PPPoE (PPP over Ethernet) adapts PPP to Ethernet networks, allowing broadband providers to manage subscriber sessions with PPP features while using Ethernet as the physical and data link layer. This is common in DSL and fiber access networks. Generic Routing Encapsulation (GRE) is a tunneling protocol that encapsulates packets inside IP headers, enabling the transport of various Layer 3 protocols across IP networks. GRE tunnels create virtual point-to-point links that can carry routing protocols or non-IP traffic transparently. In Cisco environments, GRE is often used to build VPN overlays or connect remote sites. eBGP (external Border Gateway Protocol) is the routing protocol used between different autonomous systems (ASes). It exchanges routing information across the internet or between large enterprise networks, using path vector mechanisms and policy controls to select optimal inter-AS routes. A common exam trap is confusing PPP and PPPoE as interchangeable or misunderstanding GRE as a WAN encapsulation rather than a tunneling protocol. PPP is strictly for point-to-point serial links, while PPPoE operates over Ethernet. GRE tunnels do not provide encryption by default, which can mislead candidates into thinking GRE alone secures traffic. Additionally, mixing eBGP with iBGP or assuming eBGP operates within a single AS can cause errors. Understanding the distinct roles of these protocols at the WAN edge and in routing is critical for CCNA success.
KKey Concepts to Remember
- PPP encapsulates point-to-point WAN links by providing authentication, encryption, and compression features suitable for serial connections.
- PPPoE extends PPP functionality over Ethernet networks, enabling ISPs to manage subscriber sessions using PPP mechanisms on Ethernet access links.
- GRE creates virtual point-to-point tunnels by encapsulating packets within IP headers, allowing routing of non-IP protocols or secure VPNs.
- eBGP operates between different autonomous systems to exchange routing information, enabling inter-domain routing across the internet.
- WAN edge devices use PPP and PPPoE to establish and manage subscriber links, while GRE tunnels facilitate overlay networks and eBGP exchanges routing information between ASes.
- PPP and PPPoE differ primarily in their link layer encapsulation, with PPP designed for serial links and PPPoE designed for Ethernet-based broadband connections.
- GRE tunnels encapsulate packets without encryption by default, making them useful for routing protocol transport but requiring additional security for confidentiality.
- eBGP uses path vector routing to select best paths between autonomous systems, relying on attributes like AS path length and policy rules.
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?
PPP encapsulates point-to-point WAN links by providing authentication, encryption, and compression features suitable for serial connections.
What exam trap should I watch out for?
Common exam trap: answer the scenario, not the keyword: A frequent exam trap is confusing PPP and PPPoE as the same protocol or interchangeable encapsulations. PPP is designed for serial point-to-point links, while PPPoE encapsulates PPP frames inside Ethernet frames to support broadband access. Another trap is assuming GRE provides encryption; GRE only encapsulates packets and requires additional protocols like IPsec for security. Candidates also often mistake eBGP as an internal routing protocol, but eBGP strictly operates between different autonomous systems. Misunderstanding these distinctions leads to incorrect matching of WAN or edge concepts to their descriptions.
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.
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