mediumMultiple Select
350-401 Practice Question: Which three statements about BGP peering are…
Which three statements about BGP peering are true? (Choose three.)
⚠ Common exam trap
It's easy for candidates to confuse the default TTL for eBGP (which is 1) with the maximum TTL (255), and mistakenly thinking the BGP router ID is used by OSPF.
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
✓
eBGP peers are typically directly connected, but can be multi-hop with the ebgp-multihop command.
Option A is correct because eBGP peering normally requires directly connected neighbors, but the Cisco IOS command neighbor x.x.x.x ebgp-multihop <ttl> allows an eBGP session to be established across multiple hops. Option B is correct because iBGP peers do not have to be directly connected; they commonly peer using loopback interfaces, relying on an IGP or static routes for reachability. Option D is correct because iBGP has a split-horizon-like rule preventing routes learned from one iBGP peer from being advertised to another, so full mesh peering is required unless route reflectors or confederations are used. Option C is not correct because the default TTL for eBGP packets is 1, not 255; 255 is the maximum TTL value. Option E is not correct because the BGP router ID is a 32-bit value used by BGP to identify the router, not an OSPF-only concept.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
eBGP peers are typically directly connected, but can be multi-hop with the ebgp-multihop command.
Why this is correct
eBGP peers conventionally establish sessions across directly connected interfaces, since TTL defaults to one. The ebgp-multihop command raises that TTL, permitting sessions between non-adjacent routers separated by intermediate hops. This satisfies the stem's requirement that eBGP peering is typically direct but can be extended across multiple hops when needed.
- ✓
iBGP peers can be non-directly connected and often use loopback interfaces for reachability.
Why this is correct
Internal BGP sessions rely on IP reachability rather than link adjacency, so peers may sit several hops apart. Peering via loopback interfaces keeps the session stable when any single physical path fails, satisfying the stem's requirement that iBGP neighbours need not be directly connected.
- ✗
The default TTL for eBGP packets is 255.
Why it's wrong here
eBGP peers are typically directly connected, so the default IP TTL is 1, not 255; 255 applies to iBGP sessions between non-adjacent peers. It is tempting because 255 is the maximum TTL value and is the default for iBGP.
- ✓
In iBGP, all routers within the same AS must be fully meshed unless route reflectors or confederations are used.
Why this is correct
iBGP requires a full mesh because routes learned from one iBGP peer are not re-advertised to other iBGP peers, preventing loops within the autonomous system. Route reflectors and confederations relax this scaling constraint by providing controlled route propagation, satisfying the stem's requirement for a true BGP peering statement.
- ✗
The BGP router ID is used only for OSPF, not for BGP.
Why it's wrong here
The BGP router ID is a 32-bit identifier elected per BGP speaker and used in OPEN messages and path selection; it is unrelated to OSPF, which has its own router ID. It is tempting because both protocols do have a router ID concept, so the terms look interchangeable.
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.
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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 350-401 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 350-401 exam.