mediumMultiple Choice
300-410 Practice Question: In MPLS, what is the default behavior of a Cisco…
In MPLS, what is the default behavior of a Cisco IOS-XE router regarding the 'auto-summary' command for BGP routes?
⚠ Common exam trap
300-410 often tests the contrast between classful protocol defaults (RIP/EIGRP auto-summary on) and BGP's classless default (auto-summary off), catching candidates who assume all routing protocols behave the same way.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Auto-summary is disabled by default for BGP.
In Cisco IOS and IOS-XE, BGP auto-summary is disabled by default. Unlike older Interior Gateway Protocols such as RIP or EIGRP (where auto-summary was historically enabled by default), BGP does not automatically summarize routes to their classful network boundaries unless explicitly configured with the 'auto-summary' command under the BGP router configuration. This default behavior ensures that BGP advertises the exact prefixes it learns, which is essential for precise routing in modern classless networks.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Auto-summary is disabled by default for BGP.
Why this is correct
Cisco IOS-XE disables BGP auto-summary by default, so no configuration is needed to advertise subnet routes rather than classful summaries. This default satisfies the stem's requirement to identify out-of-the-box behaviour, unlike RIP or EIGRP, where auto-summary is enabled by default.
- ✗
Auto-summary is enabled by default for BGP.
Why it's wrong here
BGP auto-summary is disabled by default on Cisco IOS-XE; enabling it requires the explicit 'auto-summary' command under the router bgp process. The option inverts this default. Auto-summary would matter only when redistributing classful networks into BGP and wanting them summarised to classful boundaries.
- ✗
Auto-summary is enabled by default only for directly connected routes.
Why it's wrong here
Auto-summary is not scoped to directly connected routes; it is a BGP (and RIP) process-level command affecting redistributed classful networks, and it is disabled by default. The option misattributes the mechanism. It would be relevant only when injecting classful routes into BGP and wanting them summarised.
- ✗
Auto-summary is disabled by default for BGP but enabled for OSPF.
Why it's wrong here
BGP auto-summary defaults to disabled, but OSPF has no auto-summary command at all — it summarises only via 'area range' or 'summary-address'. The option invents an OSPF behaviour. Auto-summary applies solely to BGP and RIP, where it would summarise redistributed classful routes.
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
Related to this question
Learn chapter
ACL-Based Traffic Filtering and Policy-Based Routing
Key term
LDP Protocol
LDP, or Label Distribution Protocol, is a protocol that routers use to automatically exchange labels that enable MPLS (Multiprotocol Label Switching) to create fast, efficient paths for data packets across a network.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.