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	<199812250119.KAA09343@robo1.mech.eng.osaka-u.ac.jp>
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 $BKY@n$G$9!#(B

 "Internetworking With TCP/IP", Volume I, Principles, protocols, and
architecture, second edition, Douglas E. Comer, 1991. $B$H$$$&K\$G$O!"(B

4.5 Network And Broadcast Addresses
   We have already cited the major advantage of encoding network
information in internet addresses: it makes efficient routing
possible.  Another advantage is that internet address can refer to
networks as well as hosts.  By convention, hostid 0 is never assigned
to an individual host.  Instead, an IP address with hostid zero is
used to refer to the network itself.  In summary:

	Internet addresses can be used to refer to networks as well as
	individual hosts.  By convention, the network address has
	hostid with all bits 0.
[snip]


16.9 Subnet Mask Representation
[snip]
   The literature also contains examples of subnet addresses and
subnet masks represented in braces as a 3-tuple:

	{<network number>, <subnet number>, <host number>}

In this representation, the value -1 means ``all ones.''
[snip]
To see why values are sometimes more important than bit fields,
consider the 3-tuple

	{128.10, -1, 0}

which denotes an address with a network number 128.10, all ones in
the subnet field, and all zeros in the host field.
[snip]

$B$H!"(B
 o network address: hostid $B$,(B all 0 (192.168.0.0 $B$J$I(B)$B!#(B
 o network number: network $BIt(B (192.168 $B$J$I(B)$B!#(B
$B$N$h$&$K;H$C$F$$$^$9!#(B

 $B$b$C$H?7$7$$HG$r$*;}$A$NJ}!"(Bnetwork number, network address $B$K4X$9$k(B
$B5-=R$,JQ99$5$l$F$$$^$7$?$i!"%U%)%m!<4j$$$^$9!#(B


> > $B$H$$$&>u67$G$7$?!#$3$3$G$I$A$i$b4^$`(B ifconfig.8 $B$r8+$F$_$k$H!"(B
 	:
> > $B!V(BIP $B%"%I%l%9$N%M%C%H%o!<%/It!W$H$$$&0UL#$G$O$J$/!"!V%M%C%H%o!<%/%$%s(B
> > $B%?%U%'!<%9$N%"%I%l%9!W$b$7$/$O!V%M%C%H%o!<%/4XO"$N%"%I%l%9!W$H$$$&0UL#(B
> > $B$G(B network address $B$H8F$s$G$$$k$h$&$KFI$a$^$9!#(B
 	:
> > $B$3$3$b!V%M%C%H%o!<%/%$%s%?%U%'!<%9$N%"%I%l%9!W$^$?$O!V%M%C%H%o!<%/4XO"(B
> > $B$N%"%I%l%9!W$H$$$&0UL#$@$H;W$$$^$9!#(B
> > 
> >  $B$H$$$&$o$1$G!"(Bnetowrk address != network number $B$H$$$&%^%K%e%"%k$b$"(B
> > $B$k$N$G!"!V(Bnetwork address$B!W!V(Bnetwork number$B!W$H$b!V%M%C%H%o!<%/%"%I%l(B
> > $B%9!W$HLu$9$N$O4m81$@$H;W$$$^$9!#(B
> $B$3$N$3$H$+$i$o$+$k$N$O!"(Bnetwork address, network number$B$H$b$K!"(BIP$B%"%I(B
> $B%l%9$N%M%C%H%o!<%/It$r;X$9>l9g$H!"%[%9%HIt$^$G4^$a$?>l9g$,$"$k$H$$$&$3(B
> $B$H$G$O$J$$$G$7$g$&$+!#(B
 $B99$J$kD4::$r$7$?J}$,3N<B$@$H$O;W$$$^$9$,!"(Bnetworks.7 tcpdump.1
ifconfig.8 $B$r8+$?8B$j$G$O!"(Bnetwork number $B$H=q$$$F$"$C$?$H$-$K$O!"%[%9(B
$B%HIt$r4^$`$3$H$O$J$$$H;W$$$^$9!#(B

> $B1Q8l$G$OF1$88l$r7+$jJV$9$N$,3f9%$,0-$$$H$$$&$N$,(B
> $B$"$j$^$;$s$G$7$?$C$1!#(B
 $B$=$&$$$&$3$H$bJ9$$$?$3$H$,$"$j$^$9$,!"!V5;=QJ8=q!W$G$OF1$8$b$N$r;X$7(B
$B$F0c$C$?I=8=$r$9$k$3$H$ONI$/$J$$$HJ9$/$3$H$NJ}$,B?$$$G$9!#(B
# $B>/$J$/$H$b8D?ME*$K$O(B

 $B$H$O$$$(!"<B:]LdBj$H$7$F!"(B
 o $B86Cx<T$,8@$$49$($r9T$&$3$H$,$"$k!#(B
 o $B86Cx<T$,=Q8l$r8mMQ$9$k!#(B
$B$H$$$&$3$H$O$"$k$H;W$$$^$9!#(B

> $B$@$+$i5!3#E*$K$3$N8l$,Mh$?$i$3$l$HLu$9$N$G$O$J$/!"(B
> $B=@Fp$KLu$9I,MW$,$"$k$H$$$&$3$H$@$H;W$$$^$9!#(B
 $BKY@n$N9M$($O(B ($B$^$H$^$C$F$^$;$s$,(B)$B!"(B
 o $B$+$J$jFq$7$$$3$H$@$H;W$&$N$G!"=PMh$kHO0O$G$d$j$?$$!#$^$?!"!V=@Fp$K(B
   $BLu!W$7$?>l9g$O!"8e$G%A%'%C%/$9$k?M$,:.Mp$7$J$$$h$&$K!"(Broff $B$N%3%a%s(B
   $B%H$r;D$7$FM_$7$$!#(B
 o $B86Cx<T$,=Q8l$r8mMQ$7$F$$$k>l9g$K$O!"$^$:86J8$rD>$9$Y$-$@$H;W$&!#(B

> $B$=$l$H$OJL$K!"(Bjpman$B%W%m%8%'%/%H$H$7$F!"(BIP$B%"%I%l%9$N%M%C%H%o!<%/It$r;X(B
> $B$9F|K\8l$r!"!V%M%C%H%o!<%/%"%I%l%9!W$H$9$k$N$+!V%M%C%H%o!<%/HV9f!W$H$9(B
> $B$k$N$+E}0l$9$kOC$O$"$C$F$$$$$H;W$$$^$9!#(B
 Comer $BK\$K=>$$!"(B

	network number = $B%M%C%H%o!<%/HV9f(B = 192.168 $B$J$I$N$3$H(B

$B$H$$$&2r<a$K$D$$$F9g0U$G$-$k$N$G$O$H;W$$$^$9$,!"K]Lu:Q$NA4%^%K%e%"%k$N(B 
network address, network number $B$N0UL#$rA4It%A%'%C%/$7$F!D$C$F$N$O7k9=(B
$BBgJQ$+$b$7$l$^$;$s!#(Bnetwork and hogehoge address $B$d(B network and
hogehoge number $B$J$s$F$N$b$"$j$^$9$N$G!#(B
--
$BKY@nOBM:(B
