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This chapter provides an overview of the OfficeConnect Remote 840. It contains the following sections:
The OfficeConnect Remote 840 is a stand-alone BRouter with data interfaces to a Local Area Network (LAN) and a Wide Area Network (WAN). The Symmetric Digital Subscriber Line (SDSL) port composes the WAN interface, which can support Point-to-Point protocol (PPP), RFC 1483, or RFC 1490 connections. The LAN port is a twisted-pair Ethernet 10Base-T interface. Additionally, the OfficeConnect Remote 840 has a standard serial interface console port.
The OfficeConnect Remote 840 allows one or more networked workstations to connect to other computers on a remote LAN. Once connected, local users (a local branch office) can communicate with remote computers (the main office) as if they were connected locally (see the figure below). The OfficeConnect Remote 840 moves data back and forth quickly, and accesses any program or file you would ordinarily use on the network.
Figure 1¯1 Connection to Remote Networks
The OfficeConnect Remote 840 can provide high-speed access to the Internet.
The OfficeConnect Remote 840 provides static and dynamic routing of the Internet Protocol (IP) and Internetwork Packet Exchange (IPX) protocols as well as bridging, with support for learning bridge and 802.1d spanning tree functionality to eliminate loops. Other important features include: Routing Information Protocol (RIP), Simple Network Management Protocol (SNMP), address translation, telnet, and packet filtering. The web browser-based OfficeConnect Remote 840 Manager and the IP Wizard provide a user-friendly configuration interface.
To simplify the installation process, the OfficeConnect Remote 840 can be initialized with pre-configured parameters using DIP switches located on the back of the unit. There are three operational modes: DHCP Smart Mode, Default Bridge Mode, and Unconfigured Mode.
An SDSL modem is a device that transmits and receives data through regular telephone lines at speeds that far exceed traditional analog modem technology.
It allows your workstation to connect to a remote site using a network protocol such as IP or IPX. The OfficeConnect Remote 840 contains one SDSL modem port which is the WAN interface.
Asynchronous Transfer Mode (ATM) is a modern networking technology that provides support for a wide variety of services and applications. The OfficeConnect Remote 840 provides support for ATM over SDSL.
ATM is based on the transfer of fixed-length cells containing a header and an information field. The header is used to route the cells through the ATM network backbone.
ATM defines connections by two main parameters, which are explained later in this Guide:
Frame Relay is a framed-based technology that runs over HDLC (High Level Data Link Control). Virtual Circuits are defined which connect the OfficeConnect Remote 840 to up to 16 remote sites within a Frame Relay Network. Each Virtual Circuit is identified by a Data Link Connection Identifier (DLCI), which is included in the frame header.
A BRouter is an interface between two networks, functioning as a router and/or a bridge. A router finds the best route between networks and provides network management capabilities. The OfficeConnect Remote 840 is a protocol independent router that does not rely on the workstations on a LAN for routing information, such as the destination location and best route.
Routers forward packets based on network-level addresses. Bridges forward packets based on hardware-level, or media access control (MAC) addresses. In other words, when a router receives a packet from one port, it looks at the destination network level address (for example, the IP address) to determine which port to forward the packet to. When a bridge receives a packet from one port, it looks at the destination MAC address to determine which port to forward the packet to.
In each case, the unit maintains either a forwarding table (bridges) or a routing table (routers) that contains information about which port to use to reach the destination address. These tables are for the most part maintained automatically by the unit so the administrator does not have to add or delete entries as the network topology changes.
An example illustrating the difference between bridges and routers would be the case where both a bridge and a router have tables with 256 entries. Because the bridge forwards based on MAC address, it can know about the location of 256 MAC addresses (physical machines such as workstations, servers, etc.). The router can know about the location of 256 networks, where each network can contain many physical machines.
Bridges make forwarding decisions based on destination addresses, while routers makes forwarding decisions based on networks to which destination addresses belong. Therefore, routers are more efficient and capable of handling more traffic.
The OfficeConnect Remote 840 provides a Bridge Firewall function which allows flexible configuration of simultaneous bridging and routing. For more information on the Bridge Firewall, see Appendix A, "Bridging and Routing".
MAC-Encapsulated Routing enables the OfficeConnect Remote 840 to function as a router but to work in a bridged environment. When enabled, the network level addresses are used for forwarding, but the MAC layer addresses are pre-pended in the ethernet header over the Wide Area Connections. Address Resolution procedures (ARP), are used to dynamically learn the MAC address of the remote router.
The OfficeConnect Remote 840 can be configured to route IP or IPX, and/or bridge other protocols between workstations on the Local Area Network (LAN) and up to 16 remote locations over an ATM or Frame Relay Wide Area Network (WAN). This is illustrated in the diagram below, showing the local LAN simultaneously connected to a remote office and the Internet.
Figure 1¯2 Connection to a Remote Internet Network
Data is transmitted to and from remote sites through ATM or Frame Relay. With ATM, each VC has a configured Quality of Service (QOS) and is identified by a Virtual Path Identifier (VPI) and a Virtual Channel Identifier (VCI). With Frame Relay, each Virtual Circuit is identified by a DLCI. Obtain these parameters from your Service Provider.
The data is framed in either PPP, RFC 1483 or RFC 1490 encapsulation, which also is specified by your Service Provider.
The IP, IPX, and bridge protocols transmit over the ATM VCs. When a remote site is configured to route IP, there will be a corresponding remote network IP subnet address and (optionally) a local WAN interface address within the same subnet. When the local side of the WAN interface has an assigned address, it is referred to as being "numbered." Otherwise, it is referred to as "unnumbered."
For a more in-depth description of "numbered" versus "unnumbered" interfaces, see Appendix B, "IP Addressing".
When PPP is used, both the local and remote WAN addresses can by dynamically learned. Otherwise, they must be specified. The diagram below shows a OfficeConnect Remote 840 with 3 VCs and the corresponding IP addresses.
When PPP is used, both the local and remote WAN addresses can by dynamically learned. Otherwise, they must be specified. The diagram below shows an OfficeConnect Remote 840 with 3 VCs and the corresponding IP addresses.
Figure 1¯3 Connection with Three Virtual Circuits (VCs)
RFC 1483 is a protocol standard that describes two encapsulations methods for carrying network interconnect (Bridging and Routing) traffic over ATM AAL5.
RFC 1483 is a single-link interface between two packet-switching devices, such as a bridge or router. An RFC 1483 link may be created between the OfficeConnect Remote 840 and a remote router after they establish a connection. RFC 1483 is a conduit for multiple protocols such as IP and IPX, which are encapsulated and passed across the communications datalink.
The OfficeConnect Remote 840 supports RFC 1483 and can establish a RFC 1483 connection to other devices supporting RFC 1483.
RFC 1483 offers interoperability of multi-vendor equipment and identification and aggregation of multiple protocol packets into one data stream.
It is a protocol standard that describes an encapsulation method for carrying network interconnect traffic over a Frame Relay backbone. It covers aspects of both Bridging and Routing.
The OfficeConnect Remote 840 supports RFC 1490 and can establish a RFC 1490 connection to other devices supporting RFC 1490.
The Point-to-Point Protocol (PPP) is a WAN protocol. It is a single or multi-link interface between two packet switching devices, such as a bridge or router. A PPP link may be created between the OfficeConnect Remote 840 and a remote router after they connect. PPP is an efficient conduit for multiple protocols such as IP and IPX, which are encapsulated across the communications datalink.
PPP provides built-in negotiation for addresses and connection parameters, and it can route multiple protocols over a single link.
The OfficeConnect Remote 840 supports PPP and can establish a PPP connection to other devices supporting PPP.
PPP offers interoperability of multi-vendor equipment, and support for dynamic configuration between the connecting devices.
Dynamic Host Configuration Protocol (DHCP) is designed to provide a centralized approach to configuring IP addresses and parameters.
When a workstation is configured for automatic assignment of IP addresses, it broadcasts a request on the LAN. The DHCP Server responds with an IP address for the workstation and the IP addresses of the default router and Domain Name Server.
The OfficeConnect Remote 840 can be configured to be a DHCP Server, with a pool of up to 40 IP addresses.
A Domain Name Server (DNS) provides an IP address to a host computer for a given domain name. A DNS Proxy receives requests and attempts to find an entry in its local tables, and if one is not found, forwards the request to a remote DNS Server. The remote DNS Server can be learned dynamically through PPP or can be statically assigned.
The OfficeConnect Remote 840 can be configured as a DNS proxy. A static local host entry of ocrdsl-3com.com is configured for the OfficeConnect Remote 840 by default. Therefore, the OfficeConnect Remote 840 can be easily accessed with a web browser, by typing in ocrdsl-3com.com in the location or address field in the browser.
In unconfigured mode, ocrdsl-3com.com is not configured by default. In this mode, you will have to configure a static host entry.
Address Translation allows private network addresses to be mapped into public addresses. The OfficeConnect Remote 840 provides two methods for mapping private, non-registered LAN IP addresses to the public Internet address(es) used for a wide-area connection. The two methods are:
NAT and PAT can be configured for each remote site.
To simplify the installation process, the OfficeConnect Remote 840 can be initialized with a set of pre-configured parameters. This operational mode is referred to as DHCP Smart Mode. In DHCP Smart Mode, the unit will automatically be assigned an IP address and will provide a pool of IP addresses to be assigned to each workstation attached to the LAN. When you choose this boot option, you will set up your workstation(s) for automatic IP address assignment.
The second operational mode is Default Bridge Mode. This mode preconfigures the unit to bridge all packets. The unit can be automatically set up so that you will not be required to fill out any forms, use Setup Wizard, or install any software from the CD unless you want to change the configuration.
Unconfigured Mode allows you to set all configuration parameters yourself. You can configure it using Command Line Interface (CLI) (see the OfficeConnect Remote 840 CLI User's Guide), or the Web-based OfficeConnect Remote 840 Manager.
The features described above can be utilized to make configuring the OfficeConnect Remote 840 very easy.
Use these features together and all you will need to do is enter authentication and ATM information for your remote site IP connection. Or:
All LED and status information can be found on the front panel of the unit, while the power jack and ports are located on the back of the unit.
Below is a representation of the front panel of your unit:
Figure 1¯4 OfficeConnect Remote 840 Front Panel
Table 1¯1 LED definitions
A table of LED operation is provided in Chapter 3 of the OfficeConnect Remote 840 SDSL Router Installation Guide in the section "Installing The OfficeConnect Remote 840."
Below is a representation of the back panel of your SDSL router: 
Figure 1¯5 OfficeConnect Remote 840 Back Panel
Table 1¯2 DIP Switch Modes
The OfficeConnect Remote 840 configuration is divided into three areas: Local Site (LAN), Remote Site (WAN), and Global configuration. The following shows the areas of configuration for each.
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Local Site |
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Remote Site |
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Global |
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IP |
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Network Service |
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DHCP |
To successfully configure the OfficeConnect Remote 840 to route or bridge a network, you should perform the following steps.
The following steps provide an outline to follow when configuring the OfficeConnect Remote 840 to route or bridge. For detailed instructions on first time installation and basic configuration, see the OfficeConnect Remote 840 SDSL Router Install Guide.
Perform the following steps to configure the OfficeConnect Remote 840 to route or bridge a network:
1 . Complete the appropriate Configuration Planning Form. A form is provided in the box when you purchase your OfficeConnect Remote 840. Copies of the forms are provided in the OfficeConnect Remote 840 SDSL Router Install Guide for your convenience.
2 . Install the OfficeConnect Remote 840 utilities from your OfficeConnect Remote 840 CD. If necessary, install a web browser on your workstation (Microsoft Internet Explorer 4 is included on the CD).
3 . Connect to the OfficeConnect Remote 840 through either the web browser or the CLI.
4 . Configure the OfficeConnect Remote 840.
You can manage the OfficeConnect Remote 840 either through the Command Line Interface (CLI) or through a web browser. If you choose to manage the unit through CLI, see the OfficeConnect Remote 840 SDSL Router CLI User's Guide, included on the CD shipped with your unit.
If you choose to use a web browser, you will use the web browser-based OfficeConnect Remote 840 Manager. This user-friendly system is the preferred method of management. The OfficeConnect Remote 840 Manager uses the HTTP protocol via a web browser (such as Netscape Navigator or Microsoft Internet Explorer) to allow you to easily setup and manage the OfficeConnect Remote 840. In order for the OfficeConnect Remote 840 Manager to function correctly, you will need to use at least Netscape Navigator 4.0 or Internet Explorer 3.02. Internet Explorer 4 is provided on the OfficeConnect Remote 840 Installation CD.
You do not need to be connected to the Internet to use this method.
The main features of the OfficeConnect Remote 840 Manager are:
The OfficeConnect Remote 840 must have an IP address and an administrative login profile (username and password) in order to connect to it with a browser. The IP address and administrative login profile are automatically created when the unit is initially configured using the IP Wizard or in DHCP Smart Mode or Default Bridge Mode, or the IP address and administrative login profile can be created using the CLI.
See the OfficeConnect Remote 840 SDSL Router Installation Guide for information about assigning an IP address and creating an administrative login profile.
To access the OfficeConnect Remote 840 Manager, either enter the unit's LAN IP address or DNS host name into the Location or Address field of your web browser. When entering the IP address or DNS host name you do not have to enter http:// (i.e., you can enter http://192.168.200.254 or simply 192.168.200.254).
If you initially configured your unit with DHCP Smart Mode, your unit will have an IP address of 192.168.200.254 and a DNS host name of ocrdsl-3com.com.
When prompted to login to the unit, enter the administrative login name and password. After successful authentication, you will access the OfficeConnect Remote 840 Manager "home page."
The OfficeConnect Remote 840 Manager is a hierarchical menu-based interface. The highest level page in the hierarchy is the OfficeConnect Remote 840 Manager home page. The home page displays a list of five menu choices:
Each of the 5 main menus contain sub-menus with more choices.
All OfficeConnect Remote 840 Manager screens have three basic areas:
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Header | |
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To access a particular OfficeConnect Remote 840 Manager page follow the links through the menu hierarchy in the Main area. You can use the Quick Link area to quickly get back to the top of the menu hierarchy or to one of the five menu options selections.
You can configure your web browser's link display options to customize the colors of the Quick Links.
References to specific OfficeConnect Remote 840 Manager pages in this document will use a specific notation to describe the location of a page relative to the OfficeConnect Remote 840 Manager home page. The notation uses the ">" character to indicate that a sub-menu on a page must be accessed.
For example, to monitor the IP ARP Table you would (starting from the home page) access the Monitor menu. From the Monitor menu you would access the Networks sub-menu. From the Networks sub-menu you would access the IP sub-menu. Finally, from the IP sub-menu, you would access the ARP Table page. This is specified as Monitor > Networks > IP > ARP Table.
The OfficeConnect Remote 840 Manager provides two methods of obtaining help.
The Online User's Guide and HTML help screens are not part of the OfficeConnect Remote 840 operational software. They must be installed on each workstation where you will run your OfficeConnect Remote 840 Manager browser. That is, if you have two workstations from which you will run the OfficeConnect Remote 840 Manager, and if you want access to the Online Guide and screen HTML help screens, you must run the CD installation at both workstations.
See the referenced chapters of this Guide to help you perform the following tasks:
