Getting the Netopia 3342 working with the Copper Mountain IP netmodel

Getting the Netopia 3342 working with the Copper Mountain IP netmodel

Summary: The Netopia 3342 ADSL pocket modem (PDF data sheet) provides an ADSL modem and broadband router in an extremely compact form factor. USB powered, it does not require an external AC adaptor. The 3342 is thus well suited for use in a single-computer household. It is also ideal for use with a battery-powered notebook computer as a outside-plant test equipment for installation and testing of G.Lite circuits.

Copper Mountain makes a popular line of DSLAMs (DSL access multiplexers) that can use a G.Lite ADSL 24-port card. The Copper Mountain operating system offers several "netmodels" each defining the manner in which a port on the DSLAM is connected. One of the netmodels is called "IP".

This note explains how to configure the Netopia 3342 to work with the Copper Mountain IP netmodel.

Applicability of this note: This note applies to the Copper Mountain CopperEdge CE-150 and CE-200 DSLAMs, using the Copper Mountain 24-port G.Lite line card. This card, as shown in the figure, is identified in the CopperView configuration software as "brdGliteModule-24". This note assumes that the driver installed in the DSLAM for this card is the "LC6.BIN" driver with a file date of June 19, 2001. This note assumes that the G.Lite card has a hardware version of R 1.2.

This note assumes that the Netopia 3342 has a firmware version of 7.3.1r0.

Conceptual model. In the so-called IP netmodel, the Copper Mountain DSLAM is acting as a layer-3 router. Each port has an IP address and a netmask and the DSLAM routes packets according to routes defined in a routing table in the DSLAM. (Most of the routes are generated automatically based upon the port configurations, and usually the only route that needs to be configured manually by the user is the default route. Note that in the Copper Mountain DSLAMs the default route cannot be configured by means of the CopperView software but must be configured manually by means of the command-line interface on the craft port.) With this netmodel, a typical system is as follows: The DSLAM has a default route to the Internet. A particular end user will have an ADSL modem (e.g. Alcatel Speed Touch Home), a broadband router, and one or more personal computers. The end-user's broadband router is typically a NAT router providing NAT IP addresses to PCs at the end-user's location. The NAT router preferably also provides a DHCP server, so that the end-user's PCs can obtain IP addresses automatically.

The ADSL modem is connected to a particular port on the DSLAM and that DSLAM port is configured with an IP address and a netmask. The end user's broadband router has a WAN port connected to the modem, and the WAN port is configured with a (static) IP address and netmask. The typical netmask is 255.255.255.252, defining a subnet of four IP addresses. In this subnet the highest and lowest IP addresses are reserved for broadcast; the middle two IP addresses are allocated to the DSLAM port and to the WAN port of the broadband router.

The link from the LAN port of the end-user's broadband router and the end-user's PC is typically ethernet. The link from the WAN port of the end-user's broadband router and the ADSL modem is ethernet. The link from the ADSL modem to the DSLAM is a telephone line. This telephone line may be a dedicated copper pair or it may be the high-frequency portion of a copper pair that is shared with an analog POTS (plain old telephone service) line. The link from the DSLAM to the Internet may be any desired link (e.g. T1, ethernet), and the type of link actually used is not important to this note.

In this system, the only link that uses ATM is the link between the DSLAM and the ADSL modem. This link uses RFC 1483 encapsulation. In other words, so far as the end-user's CPE is concerned, the only device that knows anything about ATM, encapsulation, or virtual circuits is the modem.

In this system, the end-user's broadband router is purely a layer-3 device (passing IP packets), and knows nothing about encapsulation or ATM or virtual circuits. Indeed in this system the end-user's broadband router could be eliminated altogether, with the end-user's PC connected directly to the ADSL modem. In such a case the end-user's PC would be configured with the IP and netmask that would have been programmed into the WAN port of the end-user's broadband router.

The goal of this note is to permit replacing the ADSL modem and the broadband router with the Netopia 3342.

Configuring the DSLAM. The most convenient way to configure Copper Mountain DSLAMs is by means of the CopperView software which provides a graphical user interface (GUI) as shown in the figure. It is, however, quite possible to perform all configuration steps using an SNMP-like command-line interface (CLI) through a terminal emulator connected to the "craft" port. Most configuration steps (other than setting the initial IP address of the DSLAM) can also be performed using the CLI through a telnet connection.

The figure shows configuration of a CE-150 DSLAM which has a maximum of two line cards and thus 48 ports. This note, however, applies equally well to the CE-200 DSLAM which can have up to eight line cards and thus 192 ports.

In the CopperView GUI, you can click on a card to bring up the card information screen shown above (showing the hardware version and other information). You can also click on a particular port to bring up a configuration screen for the particular port. The screen initially displays the "interface" tab, as shown in this figure. First, note the "NetModel" setting which in this case is "ip". This note is specific to the IP netmodel and does not apply to other netmodels such as VWAN. When an interface in a Copper Mountain DSLAM is configured in with the IP netmodel, the subscriber is essentially furnished with a high-speed connect-point to the public network. The CPE (customer provided equipment) behaves as an ordinary router and communication is based on a layer-3 model using IP addresses and subnet masks of the originating and destination stations.

Second, note the "EncapsulationType" which in this case is set to "rfc1483". This note assumes that the encapsulation type being used in the port is RFC 1483 and does not apply to other encapsulation types.

Third, note the "ATM Circuits" tab. Clicking on this tab brings up a screen that is used to display the ATM virtual circuits for the port, as shown in the figure. This port has been set up, as may be seen, with a single virtual circuit with a VPI of 0 and a VCI of 35. (Most ISPs choose either 0 and 35 or 8 and 35 as the VPI/VCI settings.) In Copper Mountain DSLAMs each interface is identified using a "permanent interface identifier" or PII which in this case is 1.5.9.528. The first part of the PII is always "1". The second part is the slot number, in this case 5. The third part is the port number, in this case 9. The fourth part is a virtual circuit number, in this case 528. In Copper Mountain DSLAMs where RFC 1483 encapsulation is being used, the virtual circuit number must be 528.

If no ATM circuit has been set up for the port, it must be set up. Click on "insert" to add an ATM circuit, bringing up the screen shown in the figure. This screen expects the user to select the fourth part of the PII and it must be 528 as mentioned above. The user must also select a VPI and a VCI. The administrative status should be "up". Click "insert".

Configuring the 3342. The most convenient way to configure the 3342 is by means of the web-based GUI. (It is also possible to configure the 3342 by means of a telnet CLI.) It is important to keep in mind that the 3342 is both an ADSL modem and a router, and that each must be configured.

The modem portion of the 3342 must be configured with an ATM circuit to match that of the DSLAM. A typical ATM circuit configuration is shown in the figure. The VPI and VCI in the 3342 must match the VPI and VCI set in the DSLAM for the DSLAM port to which the 3342 is connected. The encapsulation must be "RFC-1483 Bridged Ethernet" and the multiplexing must be "LLC/SNAP".

The router portion of the 3342 needs to have its WAN interface configured. In the WAN interface, a default gateway must be configured as shown in the figure. In this case the default gateway is configured to match the IP address of the DSLAM port to which the 3342 is connected. The remaining needed WAN setting is the WAN IP address and netmask, as shown in the figure. Here the WAN netmask needs to match the netmask of the DSLAM port, e.g. 255.255.255.252. The WAN IP address is selected to be in the same subnet as the IP address of the DSLAM port. The interface must be enabled if a DSL connection is to be made.

Testing the connection. The 3342 provides a very convenient diagnostic function testing layer-2 and layer-3 functions. Unfortunately the Copper Mountain DSLAM does not respond to ATM OAM Segment pings nor does it respond to ATM OAM End-To-End pings. Thus, as shown in this diagnostic report, you will always get (at a minimum) two warnings, namely the ATM OAM segment ping through warning and the ATM OAM end-to-end ping through warning.

One oddity in this 3342 firmware is that it always passes the "DNS query for netopia.com." Thus this test will have a result of "pass" even if there is no DSL connection at all.

If all has been configured and connected correctly, the remaining tests will all pass. IP connectivity is confirmed by the successful ping of the gateway and the primary DNS.

==== Checking LAN Interfaces
Check USB LAN connect                                  : PASS
==== Checking DSL (WAN) Interfaces
Check DSL Synchronization                              : PASS
 Check ATM Cell-Delineation                            : PASS
  ATM OAM Segment Ping through  (vcc1)                 : WARNING
    *** Don't worry, your service provider may not support this test
  ATM OAM End-To-End Ping through  (vcc1)              : WARNING
    *** Don't worry, your service provider may not support this test
  Check Ethernet connect to AAL5  (vcc1)               : PASS
   Check IP connect to Ethernet  (vcc1)                : PASS
    Pinging Gateway                                    : PASS
==== Checking Miscellaneous
Check DNS- Query for netopia.com                       : PASS
Ping DNS Server Primary IP Address                     : PASS
TEST DONE
author:  Carl Oppedahl, Ruby Ranch Internet Coop
revised August 1, 2004
this page is http://www.rric.net/3342