Computer Networks — Test 12

Correct Answer: A. A. To identify which VLAN they belong to
Explanation: Generally, no host knows to which VLAN it belongs to and it is the switch who takes the responsibility of tagging VLAN identifiers to frames. Before placing a packet on the trunk link, the packet should have VLAN identifier to be identified uniquely.

Correct Answer: B. B. Security, cost reduction, efficiency and application management
Explanation: Main purpose of VLANs is providing security. Along with security it reduces the cost by reducing usage of many devices, improves efficiency and it makes application easy to maintain.

Correct Answer: D. D. VLAN hooping
Explanation: In VLAN hooping an attacker can access all the VLANs. The attacker gets the access by penetrating other VLANs with traffic. There are two ways to do this hooping, they are switch spoofing and double tagging.

Correct Answer: A. A. VLAN 2-1001
Explanation: VLAN 2-1001 is a normal range where we can create the VLANs. These VLANs are editable means we can create, delete and update. Actually 1-4094 is the complete valid range to create the VLANs.

Correct Answer: D. D. Native VLAN
Explanation: When a switch encounters a frame without a VALN tag, then it routes the frame to the native VLAN. Basically, a native VLAN is VLAN1. But it is not advisable to let the VLAN1 be a native VLAN.

Correct Answer: C. C. Automatic, manual and semi-automatic
Explanation: VLAN configuration uses VLAN software and in that software, if we type all the addresses then it is manual. If a particular criterion is used to create the VLAN then it is automatic. In semi-automatic, we use manual configuration only for initializing.

Correct Answer: B. B. 12 bits
Explanation: VLAN identifier occupies 12 bits in a frame tag to be distinguished from other VLANs. A tag field is present in between a source MAC address and ethernet type in the ethernet frame. This tag contains VLAN identifier.

Correct Answer: B. B. Stub, transit and multi-homed
Explanation: Transit is the only AS that allows data traffic to go through it. Stub and multi-homed will have connections with single and multiple AS respectively and do not allow themselves to be a service provider to allow traffic across them.

Correct Answer: C. C. To interchange the routing information
Explanation: Usually BGP uses TCP services while establishing the sessions between BGP routers. A session is more like a connecting link to exchange only the information of routing and these BGP sessions are persistent.

Correct Answer: B. B. E-bgp session
Explanation: E-BGP stands for external border gateway protocol and internal BGP sessions are used only within the AS. Unlike I-BGP, external BGP sessions are used to share and retrieve the routing information of the routers which belongs to different AS.