UGC NET Questions (Paper – 1)

IPv6 was introduced to provide a vastly larger address space than IPv4, and it does this by using 128 bit addresses. These are typically written as eight groups of hexadecimal numbers separated by colons. The large number of possible addresses supports future growth of the internet and new types of devices. Hence, the blank should be filled with 128 bits.

Option A:
Option A, 32, repeats the IPv4 length and would not solve the problem of limited address space, which is the key motivation for IPv6.

Option B:
Option B is correct because formal specifications state that IPv6 addresses are 128 bits long, enabling an enormous number of unique identifiers.

Option C:
Option C, 64, would increase the address space but is not the standard length defined for IPv6.

Option D:
Option D, 256, is larger than necessary and does not match the protocol definition used in practice.

IPv4 stands for Internet Protocol version 4 and uses a 32 bit addressing scheme. These bits are often represented as four decimal octets separated by dots, such as 192.168.0.1. The 32 bit structure limits the total number of unique addresses that can be assigned. Therefore, the blank in the stem should be filled with 32 bits.

Option A:
Option A is correct because standard networking texts describe IPv4 addresses as 32 bit numbers, which is the basis for the dotted decimal notation commonly seen. This length explains the eventual exhaustion of IPv4 address space.

Option B:
Option B, 64, corresponds to some internal addressing schemes but not to the globally defined size of IPv4 addresses.

Option C:
Option C, 128, is associated with IPv6, the newer version of the protocol that expands the address space, not IPv4.

Option D:
Option D, 16, would allow far too few addresses to support modern networking and has never been the standard size for IP addressing.

An IP address uniquely identifies a device on an IP-based network and allows data packets to be routed correctly. It contains information that helps determine the network and host portions of the address. Both IPv4 and IPv6 formats serve this purpose. Hence the numeric label described in the stem is an IP address.

Option A:
Option A, access server, refers to a machine that provides connectivity or services to clients but is not a numeric label. It can possess an IP address but is a physical or virtual device rather than the address itself.

Option B:
Option B is correct because IP addresses are defined in networking standards precisely as numerical identifiers for interfaces or hosts. Without them, communication using the Internet Protocol cannot be properly directed.

Option C:
Option C, domain alias, relates to human-readable names managed by DNS and may map to IP addresses, but the alias itself is not the numeric label assigned by the protocol.

Option D:
Option D, internet service, is a broad term for facilities provided by an ISP or application and does not denote an addressing scheme.