Free Access Huawei.H12-831_V1.0.v2026-05-29.q126 Practice Test (Page 3)

Question 6

In the hub-spoke networking shown in the figure, which of the following commands must be configured on the Hub-PE to ensure correct route transmission?

A.[Hub-PE-bgp-VPN_out] peer x.x.x.x allow-as-loop

B.[Hub-PE-bgp-VPN_in] peer x.x.x.x allow-as-loop

C.[Hub-PE-bgp-VPN_in] peer x.x.x.x soo 200:1

D.[Hub-PE-bgp-VPN_out] peer x.x.x.x soo 200:1

Correct Answer: C

Comprehensive and Detailed In-Depth Explanation:
1. Understanding the Hub-Spoke Network Model in MPLS VPN
* Hub-Spoke (or Route Reflector) topology is used in MPLS Layer 3 VPNs where multiple spoke sites communicate through a central hub.
* The Hub-PE acts as an intermediate BGP speaker and redistributes routes between spokes.
* The challenge is preventing routing loops when exchanging routes between spokes.
2. Understanding the Role of Site of Origin (SoO) in BGP/MPLS VPNs
* BGP Site of Origin (SoO) is a route attribute used to prevent routing loops in scenarios where a hub redistributes routes between spokes.
* If a route originating from a spoke is advertised back to the same site, SoO prevents it from being re-learned.
* The SoO value (e.g., 200:1) ensures that a site does not accept its own previously advertised prefixes.
3. Analyzing the Answer Choices
# A. [Hub-PE-bgp-VPN_out] peer x.x.x.x allow-as-loop (Incorrect)
* The allow-as-loop command allows BGP to accept routes with its own AS number in the AS path.
* This is NOT needed in a Hub-Spoke VPN because BGP routes are not being looped through the same AS.
# This is unnecessary for preventing loops in a Hub-Spoke VPN.
# B. [Hub-PE-bgp-VPN_in] peer x.x.x.x allow-as-loop (Incorrect)
* Again, allow-as-loop is used when a router needs to accept its own AS number in the BGP AS path.
* This is NOT the mechanism used for preventing loops in Hub-Spoke VPNs; SoO is used instead.
# This is not required in this scenario.
# C. [Hub-PE-bgp-VPN_in] peer x.x.x.x soo 200:1 (Correct Answer)
* The correct way to prevent spoke routes from looping through the hub is to apply the Site of Origin (SoO) attribute.
* This command ensures that if a route with SoO 200:1 is received, it is not advertised back to the same spoke.
# This is the correct answer.
# D. [Hub-PE-bgp-VPN_out] peer x.x.x.x soo 200:1 (Incorrect)
* Applying SoO on outgoing routes is NOT effective because the hub should mark received routes and prevent loops when re-advertising them.
* SoO should be applied on the inbound (received) routes at the Hub-PE, not outbound.
# This is not the correct implementation of SoO.
Final Conclusion:
# Correct answer: C. [Hub-PE-bgp-VPN_in] peer x.x.x.x soo 200:1# A. allow-as-loop is unnecessary in a Hub-Spoke MPLS VPN.# B. allow-as-loop is not relevant here.# D. SoO should be applied inbound, not outbound.
Thus, the correct answer is: C. [Hub-PE-bgp-VPN_in] peer x.x.x.x soo 200:1.

Question 7

In the network shown in the figure, adjacent routers use directly connected interfaces to establish EBGP neighbor relationships. The Router ID of each device is 10.0.XX, and the AS number is
6500X, where X is the router number. R1 and R4 both have static routes to 192.168.1.0/24, which are introduced into BGP through import.

Which of the following statements are correct by default? (Multiple choice)

A.The traffic path from R5 to 192.168.1.0/24 is R5-R4

B.The traffic path from R2 to 192.168.1.0/24 is R2-R1

C.The traffic path from R6 to 192.168.1.0/24 is R6-R5-R4

D.The traffic path from R3 to 192.168.1.0/24 is R3-R2-R1

Question 8

On an MPLS network, an LSR ID uniquely identifies an LSR. An LSR ID defaults to the IP address of a physical interface on a device and can be manually set to a loopback interface address.
Options:

A.TRUE

B.FALSE

Question 9

When a large number of MAC addresses drift in the network in a short period of time, it is generally because there is a loop in the network. The Layer 2 loop can be eliminated through the STP spanning tree protocol.

A.False

B.True