4.0 CONFIGURATION
The Model 2701/I features configuration capability via hardware
DIP switches. This section describes all possible DIP switch configura-
tions of the Model 2701/I.
4.1 DIP SWITCH CONFIGURATION
The Model 2701/I has two sets of internal DIP switches that allow
configuration for a wide range of applications. The sets of switches are
accessed from the underside. Figure 3 (below) shows the location of
the DIP switches on the bottom of the printed circuit board.
The Model 2701/I DIP switches (Switch Sets 1-2) can be config-
ured as either “ON” or “OFF”. Figure 4 (below) shows the orientation
of the DIP switches with respect to ON/OFF positions.
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Figure 3. Underside of Model 2701/I, Showing Location of DIP Switches
Front
Rear
ON
S1
S2
OFF
Figure 4. Close up of configuration switches
OFF
ON
ON
For example, the customer site is assigned the addresses
192.168.1.0/24 through 192.168.1.1/24. The address
192.168.1.1/24 is also the default gateway for the remote net-
work. The above settings remove any routing/forwarding intel-
ligence from the CPE. The associated Cisco configuration will
set serial interface (s0) to accommodate half bridging for the
above example.
Authentication is optional under PPP. In a point-to-point
leased-line link, incoming customer facilities are usually fixed
in nature, therefore authentication is generally not required. If
the foreign device requires authentication via PAP or CHAP,
the PPP software will respond with default Peer-ID consisting
of the units Ethernet MAC address and a password which
consists of the unit’s Ethernet MAC address.
Some networking systems do not define network numbers
in packets sent out over a network. If a packet does not have
a specific destination network number, a router will assume
that the packet is set up for the local segment and will not for-
ward it to any other sub-network. However, in cases where
two devices need to communicate over the wide-area, bridg-
ing can be used to transport non-routable protocols.
Figure 2 illustrates transparent bridging between two
routers over a serial interface (s0). Bridging will occur
between the two Ethernet Interfaces on Router A (e0 and e1)
and the two Ethernet Interfaces on Router B (e0 and e1).
Patton
2701/I
Bridge
Ethernet LAN
PEC Device w/ Serial I/F
Router
Figure 1. Cisco router with serial interface, configured as PPP Half Bridge.
!
no ip routing
!
interface Ethernet0
ip address 1.1.1.1 255.255.255.0
bridge-group 1
!
interface Serial0
ip address 1.1.1.1 255.255.255.0
encapsulation PPP
bridge-group 1
!
interface Serial1
ip address 2.2.2.2 255.255.255.0
bridge-group 1
!
bridge 1 protocol ieee
!
Router A
Router B
e0
e0
S1
e1
S1
S0
S0
LAN
LAN
LAN
LAN
LAN
Serial Interface
Serial Interface
Using Bridge-Groups, multi-
ple remote LANs can be
bridged over the wide-area.
5
2701/I
2701/I
E1/FE1 Link
E1/FE1 Link
Figure 2. Transparent bridging between two routers over a serial interface.
