An address fulfills the functions of identifying the host and locating it on the network in destination routing. The most common network addressing architecture is Internet Protocol version 4 (IPv4), but its successor, IPv6, has been increasingly deployed since approximately 2006. An IPv4 address consists of 32 bits. An IPv6 address consists of 128 bits. In both architectures, an IP address is divided into two logical parts, the network prefix and the host identifier. All hosts on a subnet have the same network prefix. This prefix occupies the most-significant bits of the address. The number of bits allocated within a network to the prefix may vary between subnets, depending on the network architecture. The host identifier is a unique local identification and is either a host number on the local network or an interface identifier.
aN addreSs fULfills the FunctIons Of IdEntifying the host And locating it On tHe nETwORk iN dEstinatIon RoutinG. thE mosT ComMon network aDDRESsinG aRcHitecture is iNternet ProTocOl verSioN 4 (ipV4), bUt ItS succEsSor, ipv6, has been InCreAsingLy dEPlOyed sInce ApProXimatEly 2006. an ipv4 addResS COnsiSTS oF 32 biTs. an IpV6 addrESs consISTS OF 128 bITs. in bOTh aRchitecturEs, aN ip ADDress is Divided intO TwO loGicAl pARTs, The neTWork prefiX AND The Host iDentifieR. AlL hosts On a subnet HAVE The saMe NeTwOrK pRefiX. this prefiX oCcupiEs the MOst-SiGNIFicAnt BIts oF thE addresS. tHe numbeR of bitS aLlocateD wIthIn A Network To The prefiX mAy VaRY betwEEn subNeTs, depending ON the NeTwoRK arCHiteCTure. the Host identIFier is a uniQue lOcaL iDentIficaTiON anD Is either a host nuMBEr On thE locAL nETwOrK OR an InTeRFaCe IDentifIER.