Black Box MDU9705A-10BT User Manual

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Compact mDSL Modem

464 Basingstoke Road, Reading, Berkshire RG2 0QN

© Copyright 2000. Black Box Catalogue, Ltd.

MDU9705A-10BT
August 2000

Table of Contents

Section Page

Radio and TV Interference.....................................................2

CE Notice...............................................................................2

General Information...............................................................3

Features

Description

PPP Operational Background..............................................4

Configuration.......................................................................6

Plug-and-Play

Configuring the Hardware DIP Switches

Configuration DIP Switch Set “S2”
Configuration DIP Switch Set “S3”

Installation...........................................................................12

Connecting DSL Interface

Connecting 10BaseT Ethernet Port to PC (DTE)

Connecting 10BaseT Ethernet Port to Hub (DCE)

Power Connection

Operation.............................................................................15

Power-Up

LED Status Monitors

LED Descriptions Table

Test Modes

Appendix A - Specifications........................................................21

Appendix B - Transmission Distance Chart................................22

Black Box Contact Information....................................................23

Radio and TV Interference

The Compact mDSL Modem generates and uses radio frequency
energy, and if not installed and used properly—that is, in strict accor­dance with the manufacturer's instructions—may cause interference to
radio and television reception. The Compact mDSL Modem has been
tested and found to comply with the limits for a Class A computing
device in accordance with the specifications in Subpart J of Part 15 of
FCC rules, which are designed to provide reasonable protection from
such interference in a commercial installation. However, there is no
guarantee that interference will not occur in a particular installation. If
the Compact mDSL Modem does cause interference to radio or televi­sion reception, which can be determined by disconnecting the unit, the
user is encouraged to try to correct the interference by one or more of
the following measures: moving the computing equipment away from
the receiver, re-orienting the receiving antenna and/or plugging the
receiving equipment into a different AC outlet (such that the computing
equipment and receiver are on different branches).

CE Notice

The CE symbol on your Black Box equipment indicates that it is in
compliance with the Electromagnetic Compatibility (EMC) directive and
the Low Voltage Directive (LVD) of the European Union (EU). A
Certificate of Compliance is available by contacting Technical Support.

1

Compact mDSL Modem

2

Compact mDSL Modem

3

Compact mDSL Modem

PPP Operational Background

PPP is a protocol used for multi-plexed transport over a
point-to-point link. PPP operates on all full duplex media, and is
a symmetric peer-to-peer protocol, which can be broken into
three main components: 1. A standard method to encapsulate
datagrams over serial links; 2. A Link Control Protocol (LCP) to
establish, configure, and test the data-link connection; 3. A family
of Network Control Protocols (NCPs) to establish and configure
different network layer protocols.

In order to establish communications over a point-to-point
link, each end of the PPP link must first announce its capabilities
and agree on the parameters of the link’s operation. This
exchange is facilitated through LCP Configure-Request packets.

Once the link has been established and optional facilities
have been negotiated, PPP will attempt to establish a network
protocol. PPP will use Network Control Protocol (NCP) to
choose and configure one or more network layer protocols.
Once each of the network layer protocols have been configured,
datagrams from the established network layer protocol can be
sent over the link. The link will remain configured for these com­munications until explicit LCP or NCP packets close the link
down, or until some external event occurs.

The PPP Bridging Control Protocol (BCP), defined in RFC
1638, configures and enables/disables the bridge protocol on
both ends of the point-to-point link. BCP uses the same
packet exchange mechanism as the Link Control Protocol
(LCP). BCP is a Network Control Protocol of PPP, bridge
packets may not be exchanged until PPP has reached the
network layer protocol phase.

Applications

In situations where a routed network requires connectivity
to a remote Ethernet network, the interface on a router can
be configured as a PPP IP Half Bridge. The serial line to the
remote bridge functions as a Virtual Ethernet interface, effec­tively extending the routers serial port connection to the
remote network. The bridge device sends bridge packets
(BPDU's) to the router's serial interface. The router will
receive the layer three address information and will forward
these packets based on its IP address.

Figure 1 shows a typical Cisco router with a serial interface
configured as a PPP Half Bridge. The router serial interface uses
a remote device that supports PPP bridging to function as a node
on the remote Ethernet network. The serial interface on the
Cisco will have an IP address on the same Ethernet subnet as
the bridge.

Compact mDSL Modem

4

General Information

Thank you for your purchase of this Black Box product. This product has
been thoroughly inspected and tested and is warranted for One Year parts and
labor.

Features

• Provides MAC Level Data Link (Layer 2) connection between two peered
10BaseT Ethernet LANs

• Operates transparently to higher level protocols such as TCP/IP, DECnet,
NETBIOS and IPX

• PPP (Point to Point Protocol, RFC 1661) with Bridge Control Protocol
(RFC 1638)

•Automatically learns, loads and removes MACaddresses

•Point-to-Point Connectivity over 2-Wire mDSL up to 10km

• Plug-and-Play Slave

• HTTP/SNMP Manageable as CP (Customer Premises) Unit with mDSL
CO (Central Office) Rack Card

• Internal or receive recovered clocking between units

• LEDindicators for 10BaseT Link, DSL Link, Status, No Signal, Error and
Test Mode

Description

The Compact10BaseT mDSL Modemis a Multi-Rate DSL Modem that

provides seamless MAC Layer connectivity between 2 peered 10BaseT LANs.
Now, Enterprise users no longer need to hassle with a bridge anda CSU/DSU
or recurring leased line costs. The Compact mDSL Modem allows users to
add additional nodes to a LAN that has reached its maximum distance limits or
separate high traffic areas of a LAN. The Compact mDSL Modem connects
peered LANs and automatically forwards and receives LAN broadcasts, multi­casts and frames across a 2-Wire DSL span. The Compact mDSL Modemsup­ports PPP (RFC 1661) and BCP (RFC 1638).

The Compact10BaseT mDSL Modem features include loopback diag-

nostics, inband SNMP/HTTP remote management capabilities using Plug-and­Play and externally accessible configuration switches. As a symmetric DSL
modem, the CompactmDSL Modemoffers the same data rates in both direc-
tions over a single pair of regular telephone lines using Carrierless Amplitude
and Phase (CAP) modulation. The Compact mDSL Modem connects to the
DSL line via an RJ-45 jack. Standard power options include 115VAC, 230VAC,
Universal (115/230VAC) and any DC input between 36-60VDC.

Compact mDSL Modem

Configuration

There are two modes of operation for the Compact mDSL Modem:
Plug-n-Play and self configuration. Both are described below.

Plug-n-Play

The Plug-and-Play feature allows ISPs, carriers and PTTs to
quickly upgrade the link speed for a customer without requiring a truck
roll to configure the Customer Premise (CP) Compact mDSL Modem.
This feature also allows service providers to set up all of the configura­tions at the Central Office (on the rack cards) before installing the
stand alone units, saving time spent configuring or re-configuring DIP
switches.

The Plug-n-Play feature allows the user to configure the DTE rate
(bandwidth allocation, see Switches S3-1 through S3-6) of the CP unit
from the rack card at the Central Office (CO). The stand alone unit at
the Customer Premise (CP) site will automatically configure itself to the
DTE rate (Bandwidth Allocation) of the rack card. Other configuration
parameters remain in the default setting.

Follow the instructions below to activate Plug-n-Play between CO
(mDSL Rack Card) and CP (Compact mDSL Modem) units:

1. Set the mDSL Rack Card (CO) to either Internal or External
clocking mode as defined by the application.

2. Set the Compact mDSL Modem (CP) to “Plug-and-Play CP”
by setting all S2 and S3 DIP switches in the OFF position as
described in Figure 3, below.

When the CO and CP units connect over DSL, the CP will enter a
predefined default configuration (Receive Recovered Clocking). During
the negotiation process between the units, the CO unit will configure
the DTE rate/line rate on the CP unit as defined by the settings of the
CO unit. When additional bandwidth is required, only the configuration

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 net­work. The above settings remove any routing/forwarding intel­ligence 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 for­ward it to any other sub-network. However, in cases where
two devices need to communicate over the wide-area, bridg­ing 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).

Black Box

MDU9705A-10BT

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

e0S1e1

S1

S0

S0

LAN

LAN

LAN

LAN

LAN

Serial Interface

Using Bridge-Groups, multi­ple remote LANs can be
bridged over the wide-area.

MDU9705A-10BT

MDU9705A-10BT

mDSL

Figure 2. Transparent bridging between two routers over a serial interface.

Compact mDSL Modem

5

6

NOTE: Plug-and-Play is only available when using a rack-

mounted mDSL Rack Card as the CO unit.

Compact

mDSL Modem

(CP)

DIP Switches all in OFFposition

DIP Switches or NMS configured

according to specific application

requirements

Figure 3. Typical Plug-and-Play Application

DSL Span

mDSL

Rack Card

(CO)