5
Chapter
86
Routing
Principles of routing
IP
routing
is
one
of
the
most
fundamental
functions
of
the
SEG.
Any
IP
packet
flowing
through
an
SEG
will
be
subjected
to
at
least
one
routing
decision
at
some
point,
so
properly
setting
up
routing
is
crucial
for
the
system
to
function
as
expected.
Routers
IP
routing
is
the
mechanism
used
in
TCP/IP
based
networks
for
delivering
IP
packets
from
their
source
to
their
ultimate
destination
through
a
number
of
intermediary
network
devices.
These
devices
are
most
often
referred
to
as
routers
since
they
perform
the
task
of
routing
packets
to
their
destination.
Routing tables
In
each
router,
one
or
more
routing
tables
contain
a
list
of
routes,
which
are
used
to
find
out
through
which
interface
to
send
a
packet
so
it
can
reach
its
intended
destination.
In
the
SEG,
there
can
be
one
or
more
routing
tables.
At
minimum,
there
is
a
single,
default
routing
table
called
main
.
The
interfaces
of
routes
in
these
tables
may
be
a
physical
Ethernet
interface
or
it
might
be
a
configuration
object
that
behaves
like
an
interface
such
as
a
VPN
tunnel.
Example: Listing the routing table main contents
This
example
shows
how
to
list
the
contents
of
the
default
routing
table
main
.
First,
change
the
current
context
to
be
the
main
routing
table:
Device:/>
cc
RoutingTable
main
Now,
list
the
contents
of
the
table:
Device:/RoutingTable/main>
show
#
Interface
Network
Gateway
Local
IP
‐ ‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐‐
1
sfp2
10.6.0.0/16
<empty>
10.6.58.100
This
shows
that
the
main
table
contains
a
single
route,
which
says
that
the
network
10.6.0.0/16
can
be
found
on
the
interface
sfp2
.
The
components
of
a
single
route
in
an
SEG
routing
table
are
discussed
next.
