<s>
A	O
JID	B-Protocol
or	O
Jabber	B-Protocol
Identity	O
(	O
also	O
called	O
a	O
Jabber	B-Protocol
ID	I-Protocol
)	O
is	O
the	O
username	O
or	O
account	O
name	O
used	O
to	O
access	O
a	O
Jabber	B-Protocol
account	O
.	O
</s>
<s>
The	O
resource	O
component	O
is	O
not	O
necessary	O
in	O
order	O
to	O
contact	O
a	O
Jabber	B-Protocol
user	O
.	O
</s>
<s>
Transports	O
,	O
agents	O
,	O
and	O
other	O
automated	O
parts	O
of	O
the	O
Jabber	B-Protocol
network	O
may	O
not	O
have	O
a	O
user	O
part	O
to	O
the	O
JID	B-Protocol
.	O
</s>
<s>
A	O
common	O
example	O
would	O
be	O
the	O
AIM	B-Protocol
transport	O
,	O
where	O
the	O
transport	O
itself	O
has	O
a	O
JID	B-Protocol
along	O
the	O
lines	O
of	O
,	O
and	O
contacts	O
on	O
AIM	B-Protocol
would	O
appear	O
as	O
.	O
</s>
<s>
In	O
a	O
similar	O
way	O
to	O
Sendmail	B-Application
,	O
accessing	O
other	O
protocols	O
is	O
possible	O
with	O
Jabber	B-Protocol
transports	O
.	O
</s>
<s>
Users	O
can	O
then	O
contact	O
from	O
a	O
client	O
such	O
as	O
MSN	B-Protocol
Messenger	I-Protocol
using	O
the	O
JID	B-Protocol
form	O
.	O
</s>
<s>
Jabber	B-Protocol
usernames	O
are	O
limited	O
to	O
1023	O
characters	O
and	O
the	O
following	O
characters	O
are	O
not	O
allowed	O
:	O
</s>
