<s>
Multiservice	B-Protocol
Switch	I-Protocol
(	O
MSS	O
)	O
is	O
originally	O
a	O
Nortel	O
line	O
of	O
routers	B-Protocol
,	O
historically	O
called	O
Passport	B-Protocol
,	O
designed	O
for	O
carrier	O
core	O
and	O
edge	O
routing	O
.	O
</s>
<s>
They	O
run	O
the	O
Passport	B-Protocol
Carrier	I-Protocol
Release	I-Protocol
operating	O
system	O
.	O
</s>
<s>
Some	O
core	O
features	O
of	O
the	O
Multiservice	B-Protocol
Switch	I-Protocol
series	O
are	O
:	O
</s>
<s>
The	O
Multiservice	B-Protocol
switches	I-Protocol
are	O
made	O
up	O
of	O
a	O
shelf	O
of	O
16	O
cards	O
.	O
</s>
<s>
The	O
MSS	O
has	O
historically	O
gone	O
through	O
two	O
generations	O
of	O
Fabric	O
Control	O
Processors	O
,	O
starting	O
with	O
the	O
i960	B-General_Concept
initially	O
,	O
and	O
later	O
moving	O
to	O
PowerPC	B-Architecture
.	O
</s>
<s>
MSS	O
software	O
development	O
started	O
in	O
1990	O
before	O
MSS	O
hardware	O
was	O
available	O
by	O
applying	O
paravirtualization	O
techniques	O
to	O
VxWorks	B-Operating_System
and	O
running	O
each	O
CP	O
or	O
FP	O
application	O
payload	O
on	O
Sun	O
SPARC	O
workstations	O
,	O
each	O
as	O
a	O
Unix	B-Application
user	O
process	O
.	O
</s>
<s>
The	O
Multiservice	B-Protocol
Switch	I-Protocol
line	O
is	O
divided	O
into	O
several	O
different	O
models	O
.	O
</s>
<s>
One	O
of	O
the	O
original	O
Passport	B-Protocol
switches	O
,	O
the	O
MSS	O
6400	O
has	O
a	O
significant	O
historical	O
installed	O
base	O
.	O
</s>
<s>
Initially	O
running	O
on	O
the	O
same	O
hardware	O
as	O
the	O
MSS	O
6400	O
,	O
the	O
MSS	O
7400	O
uses	O
Passport	B-Protocol
Carrier	I-Protocol
Release	I-Protocol
software	O
only	O
.	O
</s>
<s>
There	O
are	O
a	O
number	O
of	O
media	O
types	O
supported	O
by	O
the	O
Multiservice	B-Protocol
Switch	I-Protocol
,	O
both	O
modern	O
and	O
historical	O
.	O
</s>
<s>
For	O
example	O
,	O
Nortel	O
offers	O
line	O
cards	O
that	O
provide	O
Packet	B-Protocol
over	I-Protocol
SONET	I-Protocol
and	O
ATM	O
at	O
OC3	O
through	O
OC192	O
speeds	O
(	O
depending	O
on	O
the	O
fabric	O
capacity	O
)	O
.	O
</s>
<s>
As	O
well	O
,	O
Frame	B-Protocol
Relay	I-Protocol
and	O
other	O
historical	O
TDM	O
interfaces	O
can	O
be	O
purchased	O
.	O
</s>
<s>
More	O
recently	O
,	O
Ethernet	O
has	O
become	O
a	O
focus	O
for	O
these	O
switches	O
,	O
and	O
10/100/1000	B-Protocol
media	O
types	O
have	O
been	O
supported	O
(	O
again	O
depending	O
on	O
the	O
fabric	O
capacity	O
)	O
.	O
</s>
<s>
The	O
MSS	O
chassis	O
and	O
architecture	O
is	O
an	O
integral	O
part	O
of	O
Nortel	O
's	O
CDMA	B-Protocol
and	O
Alcatel-Lucent	O
'	O
s	O
(	O
through	O
acquisition	O
)	O
UMTS	B-Protocol
solutions	O
.	O
</s>
<s>
These	O
switches	O
run	O
enhanced	O
versions	O
of	O
Nortel	O
's	O
Passport	B-Protocol
Carrier	I-Protocol
Release	I-Protocol
software	O
,	O
but	O
effectively	O
are	O
Multiservice	B-Protocol
Switches	I-Protocol
.	O
</s>
