Free F5 Networks F5CAB2 Exam Dumps May 2026

In the F5 BIG-IP ecosystem, a trunk is a logical grouping of two or more physical interfaces that the system treats as a single data path. This configuration is based on the Link Aggregation Control Protocol (LACP) or static link aggregation.

Trunks provide two primary benefits to the data plane:

Increased Bandwidth: By aggregating multiple physical interfaces (e.g., combining two 10Gbps interfaces), the aggregate throughput of the logical connection is increased. This allows the BIG-IP to handle higher traffic volumes than a single interface could support.

Link Redundancy: Trunks provide high availability at the physical layer. If one physical interface within the trunk fails or the cable is disconnected, the BIG-IP system automatically redistributes traffic across the remaining active interfaces in the trunk. This prevents a single cable or port failure from causing a network outage.

Why the other options are incorrect:

Option C: While VLAN tags are often used on trunks, the ability to use tagged VLANs is a property of the VLAN configuration and 802.1Q tagging, not the trunk itself. A single interface can support tagged VLANs without being part of a trunk.

Option D: Trunks are agnostic to the type of application traffic (such as VoIP) passing through them. They operate at Layer 2 to provide a reliable pipe for any Layer 3+ traffic.

Although remote authentication (LDAP, RADIUS, TACACS+) is a control-plane / management-plane feature, it directly affects availability and resiliency of administrative access, which is a critical operational HA consideration.

How BIG-IP Remote Authentication Works:

BIG-IP can authenticate administrators against:

LDAP

RADIUS

TACACS+

When remote authentication is enabled, BIG-IP by default relies on the remote server for user authentication

If the remote authentication server becomes unreachable, administrators may be locked out unless fallback is configured

Why ''Fallback to Local'' Is Required:

The Fallback to Local option allows BIG-IP to:

Attempt authentication against the remote authentication server first

If the remote server is unreachable or unavailable, fall back to:

Local BIG-IP user accounts (admin, or other locally defined users)

This ensures:

Continuous administrative access

Safe recovery during:

Network outages

Authentication server failures

Maintenance windows

This behavior is explicitly recommended as a best practice in BIG-IP administration to avoid loss of management access.

Why the Other Options Are Incorrect:

A . Configure a second remote user directory

Provides redundancy only if both directories are reachable

Does not help if remote authentication as a whole is unavailable

B . Configure a remote role group

Maps remote users to BIG-IP roles

Does not affect authentication availability

D . Set partition access to ''All''

Controls authorization scope after login

Has no impact on authentication success

Key Availability Concept Reinforced:

To maintain administrative access resiliency, BIG-IP administrators should always enable Fallback to Local when using remote authentication. This prevents lockouts and ensures access even during authentication infrastructure failures.

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