H12-821_V1.0 Practice Questions

Router LSAs (Type 1) and Network LSAs (Type 2) are advertised only within a single OSPF area, as they describe the topology within the area. In contrast, Summary LSAs (Type 3) and AS External LSAs (Type 5) are used for inter-area and external routing, respectively ​.

Explanation of VLAN Pool Assignment Algorithms:

In WLANs, VLAN pools help reduce broadcast domains and improve network performance by distributing users across multiple VLANs. Two algorithms are used for VLAN assignment:

Even Assignment Algorithm:

The number of users in each VLAN is even.

This algorithm assigns users evenly across VLANs, ensuring a balanced distribution of users in each VLAN.

When STAs go offline and online again, their VLANs and IP addresses may easily change.

Since the assignment is based on maintaining even distribution, a device (STA) may not be assigned the same VLAN when it reconnects, leading to potential IP address changes.

Hash Assignment Algorithm:

The number of users in each VLAN is uneven.

The hash algorithm assigns users to VLANs based on a hash value (e.g., derived from the MAC address). This may result in an uneven distribution of users across VLANs.

VLANs and IP addresses remain unchanged for STAs that go offline and online again.

The hash algorithm ensures that a device reconnects to the same VLAN, preserving its IP address.

A screenshot of a computer Description automatically generated

The LS age field in OSPF LSAs (Link State Advertisements) is measured in seconds and increments over time in the Link State Database (LSDB). If the LS age reaches the LSRefreshTime (30 minutes), the router that originated the LSA must regenerate it to keep the LSA valid in the network. Options C and B are incorrect since LS age does not decrease, and only the originator regenerates LSAs ​.

By default, Huawei firewalls create security zones named untrust , dmz , trust , and local . These zones facilitate security policies for inbound, outbound, and inter-zone traffic control ​.

Access Control Lists (ACLs) can be classified into several types, including Basic ACL (filters based on source IP), Advanced ACL (filters based on multiple parameters like source and destination IP, protocol, and ports), and Layer 2 ACL (filters based on MAC addresses). User-defined ACLs are not a standard classification ​.

In a route-policy, attributes such as MED (Multi-Exit Discriminator) and Local-Preference can be used in apply clauses to influence BGP route selection. Attributes like AS_Path and Tag are typically matched or filtered but not directly applied in the apply clause ​.