H12-811_V1.0 Exam Dumps - HCIA-Datacom V1.0 Exam

Comprehensive Explanation: In STP (Spanning Tree Protocol), the root bridge is elected based on the lowest Bridge ID. The Bridge ID consists of two parts: the bridge priority and the MAC address of the switch. The switch with the lowest Bridge ID is elected as the root bridge. If two switches have the same priority, the switch with the lowest MAC address becomes the root. Other parameters such as Port ID and Root path cost are used in subsequent decisions to determine the best paths to the root bridge, but they are not used in the root bridge election itself.

Detailed Explanation:In a Spanning Tree Protocol (STP) environment, the root bridge is selected based on the bridge ID. Here, SWA has the lowest bridge ID (4096:0001-0203-04AA), making it the root bridge. For each network segment, STP elects one designated port to forward traffic, and all other ports in that segment will be blocked to prevent loops.

Following the STP rules:

SWA is the root bridge, so all of its ports (G0/0/2 and G0/0/3) will be designated ports.

Each non-root switch (SWB and SWC) selects one root port, which is the port with the lowest path cost to the root bridge (SWA).

SWB's G0/0/3 will have a higher path cost when compared with G0/0/1 (if assuming equal link costs), thus making G0/0/1 the root port on SWB.

SWB will then block its G0/0/3 port to prevent a loop, as SWA's G0/0/3 is already the designated port for that link.

Hence, G0/0/3 of SWB will be in the blocking state to maintain a loop-free topology

Impact of Loops in Layer 2 Networks:Loops in a Layer 2 network cause packets to be repeatedly forwarded, leading to broadcast storms, high CPU utilization, and network disruption​​.

Correct Answer:TRUE. Loops can cause broadcast storms on Layer 2 networks.

Detailed Explanation:The default preference of static routes on Huawei routers is 0. This means that if a static route is present, it will always take precedence over routes with higher preferences, such as dynamically learned routes, unless a lower preference is manually assigned​​.

ICMP and NAPT:ICMP packets do not have port numbers, but NAPT (Network Address and Port Translation) can still manage ICMP traffic by matching identifiers in the ICMP header. This allows NAPT to handle ICMP messages properly​​.

Correct Answer:FALSE. ICMP packets can be handled by NAPT.

The command defines a static route to the network 10.0.12.0 with a 255.255.255.0 subnet mask, using 192.168.1.1 as the next-hop address. Static routes are manually set routes with fixed paths, and by default, they have higher priority than dynamic routes, but the specific preference value depends on configuration. This setup enables targeted routing for traffic towards the specified destination​.