4A0-100 Exam Dumps : Nokia IP Networksand Services Fundamentals

Tier 1 ISPs: Haveglobal reachabilityand exchange traffic via peering. Theydo not payfor transit.

Tier 2 ISPs: Purchasetransit services from Tier 1and provide transit to Tier 3 or other Tier 2 ISPs.

Tier 3 ISPs: Providelast-mileconnectivity to end users and donot provide transit services.

Option A is correct– Tier 1 and Tier 2provide transit services.

Link-State routing protocols(e.g.,OSPF,IS-IS) operate by:

Each routerflooding link-state advertisements (LSAs)throughout the network.

Every router constructs acomplete map of the network topology.

Then each router runs theSPF algorithmto compute optimal paths.

Option C is correct– routers know theentire network topology.

Option A isDistance Vector behavior(e.g., RIP).

Option B isnot efficient or accurate for Link-State.

Option D –hop-countis used inDistance Vector(e.g., RIP).

AMAC address(Media Access Control address) is a 48-bit identifier typically expressed in six groups of two hexadecimal digits (e.g., 00-20-60-CE-2B-28). It consists of two key parts:

OUI (Organizationally Unique Identifier)– The first24 bits(or first 3 octets, e.g., 00-20-60) are assigned by theIEEE to hardware manufacturers. This identifies the vendor or manufacturer.

Device Identifier (NIC Specific)– The remaining24 bits(e.g., CE-2B-28) are assigned uniquely by the vendor to each device/interface.

So in the address 00-20-60-CE-2B-28:

00-20-60 is theOUI

CE-2B-28 is thedevice-specific portion

Thus, the correct answer isD. 00-20-60.