Chapter 3 IPv6 Addressing 51 With IPv4,decimal is used to make the IPv4 addresses more palatable for humans and a 32-bit address becomes 4 decimal numbers separated by the period (.)character.With IPv6, dotted-decimal representation would result in 16 decimal numbers separated by the period (.)character.IPv6 addresses are so large that there is no attempt to make them palatable to most humans.Configuration of typical end systems is automated,and end users will almost always use names rather than IPv6 addresses.Therefore,the addresses are expressed in a way to make them more palatable to computers and IPv6 network administrators who understand the semantics and relationship of hexadecimal and binary numbers. Table 3-1 lists the conversion between binary,hexadecimal,and decimal numbers. Table 3-1 Converting Between Binary,Hexadecimal,and Decimal Numbers Binary Hexadecimal Decimal 0000 0 0 0001 1 1 0010 2 2 0011 3 3 0100 4 4 0101 5 5 0110 6 6 0111 1 7 1000 8 8 1001 9 9 1010 A 10 1011 B 11 1100 ( 12 1101 13 1110 E 14 1111 F 15 Compressing Zeros Some types of IPv6 addresses contain long sequences of zeros.To further simplify the representation of IPv6 addresses,a single contiguous sequence of 16-bit blocks set to 0 in the colon hexadecimal format can be compressed to :known as a double colon.For example. the link-local address of FE80:0:0:0:2AA:FF:FE9A:4CA2 can be compressed to FE80::2AA:FF: FE9A:4CA2.The multicast address FF02:0:0:0:0:0:0:2 can be compressed to FF02::2. Note You cannot use zero compression to include part of a 16-bit block.For example,you cannot express FF02:30:0:0:0:0:0:5 as FF02:3::5,but FF02:30::5 is correct.￾     !"#$%&% '"#(  #) %% %"') *#$##+$ ,')&"#-%#-# ./0+#) %%+ !'" % !"#$-&"+ )%% *#)# +1 * )'234!#)#! )35 ' 0 !"#$) *) % -#'-6'&$) %&$-75 !"#$-&"+ )%% *#)# +1 * )' 234!#)#! )35#) %% %#) %'$#)8 # ) %-'# "*'"#(  "*#$##+$ ' "'%&"#-%39'-,8&)#'-',1*!#$ -%1% "%%#&'"# #- -&% )%6$$#$"'% #$6#1%&% -#" %)# )#-5#) %% %3: ) ,')  #) %% %#)  ;*) %% -# 6#1'"#(  ""') *#$##+$ '!'"*& )%#-5- 6')(#"-%)#')%6' &- )%#- % "#-!%#-) $#'-%*', ;# !"#$#-+-#)1-&"+ )%3 :#+$ .07$%% !'- )%'-+ 6 -+-#)1 ;# !"#$#- !"#$-&"+ )%3 ￾<=>< ?'" 1* %',5#) %% %!'-#-$'-8% @& -! %',A )'%3:',&) )%"*$,1  ) *) % -#'-',5#) %% %#%-8$ !'-8&'&%% @& -! ',750++$'!(%% 'B-  !'$'- ;# !"#$,')"#!#-+ !'"*) %% 'CC(-'6-#%#DEFGHIJEHEK3L') ;#"*$   $-(0$'!#$#) %%',LMNBCBCBCBC/OOCLLCLMPOC9O/!#-+ !'"*) %% 'LMNBCC/OOCLLC LMPOC9O/3: "&$!#%#) %%LLB/CBCBCBCBCBCBC/!#-+ !'"*) %% 'LLB/CC/3 Q< RSTUVWWSXTYZ[Z\SUS]^\ZYY_SWXS_WU`TaZ^V\XSbVcdef_Xf`SUghiS\ZjV]^`ZklST UVWWSXZj^\ZYYiimnopmomomomomomoqVYiimnopooqkfTXiimnopmooq_YUS\\ZUXh rst uv ￾<wxwyz{|}=tz~}=tQ=s wy {|}=t ~}=t €€€€€ €   €‚ ‚ ƒ ƒ €€„ „ … … €† † ‡ ‡ €€€ˆ ˆ ‰ ‰ €Š € ‹  €€Œ ‚  ƒ €Ž „  …