Features

Flexible Network Design

The Access Node meets the connectivity needs of remote offices while providing an extra level of availability. Additionally, the AN supports SNA/SDLC integration. Six network design options are available (see Figure 1):

  1. Integrated Router-Hub Connectivity Integrated Ethernet hub configurations allow the AN to manage and connect 8 or 12 10BASE-T remote workgroup resources directly to a central site via leased line and/or packet switched services.

  2. Dial Back-up Dial Back-up maintains remote office connectivity if the primary remote-to-central site link (leased line or packet switched service) fails. The AN initiates, monitors, and terminates dial backup connections to maximize network availability, while minimizing dial-up charges.

  3. Bandwidth-on-Demand Bandwidth-on-Demand provides a supplemental dial connection if the primary link becomes congested, maintaining user-required performance levels.

  4. Alternate Paths This option provides routing paths to the backbone through two different sites. If one path fails, the AN routes traffic through the alternate path. The remote office continues to communicate, unaffected by the failure.

  5. Dial-on-Demand Because of the limited amount of internetwork traffic generated by small remote offices, maintaining dedicated links to such sites is not always cost effective. Dial-on-Demand cost-effectively extends internetwork connectivity to remote offices on an as-needed basis.

  6. SDLC Transport SDLC transport enables the AN to transmit SNA/SDLC traffic across a multiprotocol backbone via standards-based DLSw for SDLC or Transparent Sync Pass-Thru features. These features reduce the cost of wide area networks by consolidating parallel lines, allowing SDLC traffic to be sent across the multiprotocol backbone to a remote IBM host.

    Figure 1: Network Design Options

    LAN and Serial Interfaces

    The Wellfleet AN supports one Ethernet and/or one Token Ring, and either two Synchronous interfaces or one Synchronous and one ISDN BRI (see Figure 2) to meet a wide variety of LAN connectivity requirements.

    Ethernet/802.3 All Ethernet/802.3 interfaces support IEEE 802.3 and Version 1.0/2.0 Ethernet frame formats. Ethernet/802.3 models (single Ethernet only, and single Ethernet and single Token Ring) are available in configurations that provide one 10BASE-T (RJ45) connector and one AUI connector for a choice of connectivity. The 8-port ANH also provides one AUI connector in addition to its eight repeater ports. A cable from the interface's 15-pin AUI connector provides optional connectors to a variety of media, including broadband, baseband, Starlan, fiber, and shielded twisted-pair. This flexibility accommodates the media that best suits distance, cost, and reliability criteria.

    Ethernet Hub The AN single Ethernet/802.3 models are also available in an 8- or 12-port hub configuration. These Access Node Hub (ANH) configurations simplify remote site equipment requirements and management by integrating Ethernet connectivity with routing services in the AN. The ANH provides 8 or 12 managed 10BASE-T (RJ45) repeater ports for shielded or unshielded twisted-pair cable attachment. Each connector is configured as a Medium-Dependent Interface with internal crossover (MDI-X) to connect directly to any 10BASE-T network interface card (NIC). ANH models can also be configured as a Medium-Dependent Interface (MDI) to allow the AN to be connected to other 10BASE-T hubs, accommodating additional devices. Router/hub rear panel LEDs report per-port link integrity status and port partitioning status, as well as the MDI/MDI-X port 12 switch setting (see Tables 3 and 4).

    Token Ring/802.5 The Token Ring interface can operate at either 4- or 16-Mbps ring speeds (software configurable), providing the flexibility to migrate to higher speeds as performance requirements dictate. A 9-pin D-subminiature connector is provided on the Token Ring AN models for Token Ring cable attachment.

    The Token Ring interface also supports the IEEE 802.5 Media Access Control (MAC) token passing protocol, the 802.2 Type 1 (connectionless) protocol, the 802.2 Type 2 (connection-oriented) protocol, and the 16-Mbps Early Token Release (ETR) protocol.

    Synchronous The Synchronous interfaces support V.35, RS232, RS449/422 balanced, and X.21. Each Synchronous interface operates from 1200 bps to 2.048 Mbps, full-duplex, allowing use of lines up to T1 and E1 rates. Internal and external clocking, as well as all major area networking protocols, are supported by the Synchronous interfaces.

    Alternatively, the Synchronous interfaces can be configured to integrate IBM SDLC traffic across the internetwork by connecting local or remote IBM equipment directly to the Synchronous interface and using either integrated DLSw for SDLC or Transparent Sync Pass-Thru. PU Types 2.0 and 2.1 devices are supported to provide a highly flexible interconnection solution. The Synchronous interfaces support connection to these devices using a V.24 (RS232), V.35, or X.21 physical interface. Additionally the Synchronous interfaces ensure optimum SDLC performance by supporting numerous SDLC parameters (see Table 1).


    Table 1: SDLC Parameters

    Parameter               Function
    
    NRZ/NRZI                Specifies line support: Non-Return to
                            Zero or Non-Return to Zero Inverted
    
    Half-/Full-Duplex       Specifies how server communicates with
                            downstream PU 
    
    Constant/Switched       Specifies how server controls
    Carrier                 Request To Send signal to a modem 
    
    Transmit Clocking       Specifies transmit clocking type:
                            Internal or External
    

    ISDN Basic Rate Interface (BRI) The AN's ISDN BRI option provides two 64-Kbps B-channels for data and one 16-Kbps D-channel for signaling. The ISDN BRI feature supports many signaling specifications (see Table 2). This feature is supported on the single Ethernet, single Token Ring, and Ethernet/Token Ring AN router; and the 12-port ANH router/hub models.


    Table 2: ISDN Signaling Specifications

    Region /      
    Country         ISDN Standard           Certification
    
    Australia       AUSTEL TS013            Q2, 1995
    
    Europe          Euro ISDN (NET3)        Q1, 1995
    
    France          VN-3                    Q1, 1995
            
    Japan           INS-64                  Q1, 1995
    
    North America   National ISDN-1         Q2, 1995
                    AT&T 5E6 ISDN           Q2, 1995
                    Northern Telecom DMS    Q2, 1995         
    
    Figure 2: AN Enet and Token Ring Design Logic

    High-Performance Processor

    The AN, incorporating Motorola's 68360 microprocessor, maintains high forwarding and filtering rates across its network interfaces. Additionally, management inquiries are processed without affecting performance. The AN supports 4, 8, or 16 megabytes of DRAM, which is configurable to support customized partitioning between local and global memory. Router software resides in local memory, while global memory is dedicated to packet buffers. Through these reserved buffers, the AN prevents traffic overflow - and resulting network delays - caused by large bursts of traffic (file transfer operations, for example). Additionally, the AN supports 2 or 4 megabytes of Flash memory for software and configuration file storage (see Figure 2). To provide redundancy, the 4-MB Flash can be logically divided into two partitions of equal size. Each partition is a uniquely addressable and fully functional Flash file system volume. Copies of boot images and configuration files can be stored on each partition.

    Multiprotocol Routing and Bridging

    The AN maximizes remote office connectivity in multivendor, multiprotocol environments by supporting all major LAN and WAN protocols. Industry-standard IBM transport is also supported via the Wellfleet router's Data Link Switching (DLSw) support (RFC 1434). To maintain remote office availability, ANs also support dial-up services. This allows ANs to provide fully featured router functionality to meet a wide range of remote office requirements.

    Software Options Three software suites are available for the AN - IP Access, Remote Office, and Corporate (see Table 5). This allows the AN to be configured with software that fits a site's requirements.

    Traffic Management

    Comprehensive traffic management capabilities are provided through Multiline Circuits, Uniform Traffic Filters, Traffic Prioritization, and Data Compression.

    Multiline Circuits Multiline Circuits allows a single circuit to be composed of up to 16 individual serial network data paths, guaranteeing circuit availability in the event of a single data path failure. Multiline Circuits also increases bandwidth between two sites without the circuit management complexities associated with multiple circuits. Following initial configuration, the use of multiple data paths to form a single circuit is completely transparent.

    Multiline Circuits provides two methods for transmitting traffic over its data paths - address-based selection and random selection. Address-based selection determines the path a packet takes based on its source and destination addresses. Once a path has been established for a given address pair, subsequent packets will follow the same path. This ensures the sequentiality of packets and is a valuable feature for protocols that cannot tolerate packets received out of order. Random selection determines the path each packet takes based on a randomly assigned number that corresponds to a particular data path in the circuit. This provides for even distribution across the circuit to avoid congestion and is intended for use with protocols that can accept packets received out of sequence. The ability to select the method of transmitting data across the circuit enables Multiline Circuits to maximize the performance of a wide range of applications.

    Uniform Traffic Filters Uniform Traffic Filters enables inbound and outbound traffic filters to be easily established for all supported network protocol traffic. Uniform Traffic Filters provides an efficient method for developing an effective and comprehensive network security strategy. In addition, Uniform Traffic Filters preserves WAN bandwidth and can increase performance by reducing network congestion.

    Inbound traffic filters can be configured to accept or drop incoming packets from any Wellfleet local area or serial network interface. Outbound traffic filters can be configured to drop outgoing packets destined for any Wellfleet serial interface. Additionally, Uniform Traffic Filters can be configured to execute a log action when a datagram's fields match the values defined in the filter.

    Filters can be created using predefined protocol-specific fields or user-defined fields. Up to 31 inbound filters and 31 outbound filters (including Traffic Prioritization filters) can be defined for each protocol on every network interface. Filter precedence can be defined for multiple filters configured on an interface, reducing definition complexity. All filters are configured via Site Manager, the node management application for Wellfleet routers.

    Traffic Prioritization Traffic Prioritization filters can assign a high priority to time-sensitive and/or mission-critical traffic, thereby reducing the occurrence of session timeouts and improving application response times. Priority filters can be configured to place packets into one of three priority queues - high, normal, or low - for transmission through a Wellfleet router's outbound serial interface. Priority filters can be applied to the complete family of network and bridging protocols supported by Wellfleet routers.

    Priorities can be assigned to packets based on their protocol, source network, destination network, packet type, and other protocol-specific fields, as well as other fields that are identifiable by an offset in a packet.

    The number of priority filters defined for a protocol on an interface depends on the number of outbound Uniform Traffic Filters assigned to the protocol on the interface. For example, if there are no other outbound filters defined for a protocol, then 31 priority filters can be assigned. However, if 16 outbound nonpriority filters are defined for a protocol, then only 15 priority filters can be assigned.

    Traffic Prioritization can be configured to use either a strict dequeuing algorithm or a bandwidth allocation dequeuing algorithm to transmit packets across a serial line. Bay Networks strict dequeuing algorithm transmits all packets from the high-priority queue before transmitting packets from the normal and low-priority queues. The bandwidth allocation dequeuing algorithm allows packets from the normal and low-priority queues to be transmitted when the high-priority queue still contains packets, based on user-assigned bandwidth allocation percentages for each queue. This ensures that packets assigned lower priorities are transmitted in environments with large amounts of high-priority traffic. Each serial line attached to a Wellfleet router can use the strict or bandwidth allocation dequeuing algorithm, and can be reconfigured at any time in response to changes in configuration and/or performance requirements.

    Data Compression The software-based Data Compression feature maximizes internetwork performance by reducing the amount of bandwidth required to transport LAN protocols over WAN links. Based on the Lempel-Ziv algorithm, the Wellfleet payload compression mechanism provides a compression ratio of 2:1 and is optimized for Fractional T1/E1 links. Payload compression compresses only the data portion of network protocol packets, leaving packet headers intact. Because packet headers are not compressed, packet switched services, such as X.25 and Frame Relay, can still be used.

    Remote Installation and Management

    EZ-Install and EZ-Update, and Directed Netboot simplify AN installation and make router reconfiguration and software updates from a central site quick and easy.

    EZ-Install EZ-Install eliminates the time and expense of sending a technical resource to install and configure an AN. All that is required at the remote site is connecting the AN's LAN and serial interfaces, and turning on the power. With EZ-Install, the AN obtains its software image from Flash memory and its configuration file through the network. Using EZ-Install, an AN automatically obtains its IP address from a central-site Wellfleet router and its configuration file from a central-site server using the BOOTP protocol (see Figure 3). After verifying that an AN's configuration file has been successfully downloaded to DRAM via EZ-Install, the unit's configuration file can be saved to Flash memory for nonvolatile local storage.

    Figure 3: EZ-Install

    EZ-Update EZ-Update facilitates the automatic downloading of software updates and configuration files, minimizing the time and expense associated with remote site software maintenance. The existing AN configuration file and software image is stored in the AN's nonvolatile Flash memory for use as backup in case problems are encountered while downloading new software. To use EZ-Update, the AN is dynamically configured to boot its configuration file and software image from the central site. The AN can then be rebooted or power-cycled, and a new configuration file and/or software image will be downloaded to the AN's DRAM from a central site server. Once it has been determined that the new configuration file or software update is acceptable, it can be saved to the AN's Flash memory, replacing the previous configuration file and/or software image.

    SNMP-based Node Management

    Bay Networks provides comprehensive node configuration, monitoring, and control by combining a management support foundation with SNMP-based tools - Optivity/Internetwork and the Technician Interface (TI). The EZ-Configure, Online Dynamic Reconfiguration, and Dynamic Software Builder and Loader features reduce memory requirements and enable remote sites to be configured quickly and easily without disrupting network operation.

    Security is ensured with a two-level password mechanism (read vs. read/write). The AN supports a TFTP client/server agent and an SNMP agent that enables configuration, monitoring, and control of each of the AN's network interfaces. The SNMP agent can respond to Get/Set requests independently. All MIB variables (MIB II and the Wellfleet router's extensive, enterprise-specific MIB) are also provided. The ANH also supports RFC 1516 - the Standard IETF Definitions of Managed Objects for IEEE 802.3 Repeater Devices, allowing a remote management station to monitor statistics and operational status of each hub port.

    Optivity/Internetwork Optivity/Internetwork integrates Site Manager, Bay Networks node management application for Wellfleet routers with RouterMan, an intuitive router monitoring application, and PathMan, a graphical network diagnostic tool to simplify and improve management of complex router internetworks.

    RouterMan offers real-time router performance and status reporting. The application's intuitive graphical user interface provides at-a-glance overall router status. Fault and performance statistics, history and analysis are provided for the overall router, by protocol or by interface. A simple color-coded interface and fault history log provides proactive detection and indication of potential router problems.

    PathMan dynamically determines the complete data path between any two network end stations, assisting network managers in troubleshooting large complex networks. All network components on the selected path appear automatically in a system-generated display of the route, showing exactly how devices are connected within the network. Color-coded icons display each device's status, enabling rapid problem identification.

    Site Manager is a platform-independent, SNMP-based application developed expressly for simplifying the configuration and management of Wellfleet routers. It provides an intuitive point-and-click user interface that streamlines the configuration process and eliminates cryptic commands. Site Manager offers central configuration management that simplifies network setup and expansion, real-time operations and monitoring, and real-time event and fault monitoring for efficient problem identification and isolation. Site Manager is available for MS Windows, Sun SPARC, HP/9000 and IBM RS/6000 platforms.

    Optivity/Internetwork operates independently or with the leading SNMP Platforms - HP OpenView, IBM NetView for AIX, and SunNet Manager for additional capabilities.

    Technician Interface (TI) This terminal-based (TTY-compatible) tool enables basic configuration and maintenance locally or through Telnet. The Technician Interface is based on a simple command line interpreter that supports SNMP-based access to the MIB, displays the event log, and supports file system management and other administrative commands. The TI also supports out-of-band access to the AN through a modem connection.

    EZ-Configure Site Manager's EZ-Configure feature enables configuration file templates to be copied or modified for use at sites with similar configurations. This saves the time associated with building a configuration file from scratch when a new remote site is brought online. EZ-Configure is useful for networks with many ANs that have similar configuration requirements, such as branch banks.

    Online Dynamic Reconfiguration Dynamic reconfiguration eliminates the need to schedule network downtime to reconfigure any AN. Configuration parameters can be changed by issuing SNMP Set commands while the switch is operational. Any changes made with SNMP Set are volatile and are lost when the AN reboots. To preserve changes, the AN's active configuration must be saved permanently to a file in nonvolatile memory. This file defines the AN's new baseline configuration and ensures that it is properly configured to meet the current network requirements.

    Dynamic Software Builder and Loader Site Manager's Software Builder works with the AN's Dynamic Loader to preserve the AN's Flash memory and DRAM space. The Software Builder allows AN software images to be customized. Only required software functionality is maintained in the remote AN's software image. For example, if a remote site requires only IP and IPX support, other network protocols can be deleted from the software image to preserve Flash memory space. The AN's Dynamic Loader feature preserves DRAM space by loading to DRAM only the routing functionality that is required by a particular AN configuration. Using the previous example, if a particular branch office does not require IPX support, then Dynamic Loader will load only IP to DRAM rather than the AN's complete software image.

    Managed Hub Support Complying with RFC 1516, the ANH supports SNMP GET and SET management for the monitoring and configuration of individual hub port statistics and operational status information. In addition, the ANH provides automatic port partitioning to prevent a faulty hub port from affecting the rest of the network. When excessive collisions on an individual hub port are detected, this feature "detaches" the problematic end station. This allows packets to be transmitted to the end station but does not permit the hub port to accept packets sent from the end station. Once packet collisions are no longer sensed, the hub port is automatically returned to normal operation.

    Figure 4: ANH Connector Panel

    Compact Packaging

    The AN routers and the ANH router/hubs require minimal space and are quiet and compact. Both can operate in either a wiring closet or desktop environment and are rack- or wall-mountable. LEDs indicate module status for easy trouble-shooting (see Figure 4 and Tables 3 and 4).



    Table 3: AN LEDs

    LED       Status Indicator
    
    RLS       Receive line signal detect (Synchronous)
    TX        Transmitting data to Ethernet LAN
    RX        Receiving data from Ethernet LAN
    CL        Collision (Ethernet)
    Link      End station transmitting data to hub 
              connector
    Part      End station has been logically detached 
              from the hub connector
    MDI       Indicates configuration of hubUs twelfth port 
    WFAIL     Detection of a wire fault in either the
              receive or transmit line (Token Ring)
    NSRT      Port is inserted into the Token Ring LAN
    RCVR      Receiving data from the Token Ring LAN 
    


    Table 4: ANH LEDs

    LED       Status Indicator
    
    DCM       Remote Monitor (RMON) option (8-port ANH)
    AUI Part  AUI port is logically detached from the repeater
              (8-port ANH)
    DCD1      First Synchronous port active (8-port ANH)
    DCD2      Second Synchronous port active (8-port ANH)
    <LAN>     Data present in repeater (8-port ANH)
    CL        Collision in AUI repeater (8-port ANH)
    RLSD      Receive line signal detect (Synchronous)
              (12-port ANH)
    MDI       Indicates configuration of hub's twelfth port
              (12-port ANH)
    Link      End station transmitting data to hub connector
    Part      End station has been logically detached from
              the hub connector
    

    Specifications

    Architecture
    Single-board module based on Motorola 68360 microprocessor

    Connectivity
    Ethernet interface (15-pin AUI connector, RJ45)
    Token Ring Interface (9-pin MAU connector)
    Synchronous interface (RS449/422, RS232,V.28, V.35, X.21)
    ISDN BRI (RJ45)
    10BASE-T hub port connectors (RJ45)

    Packaging
    AN/8-port ANH/12-port ANH Type Tabletop/Wall-Mount/Rack-Mount AC Voltage 100 - 240 Vac at 1.0A max. Wall Receptacle NEMA 5-15R (100 - 240 Vac) (for use in North America) AN and 12-port ANH Height 3.30 in. (8.45 cm) Width 17.50 in. (44.45 cm) Depth 9.15 in. (23.24 cm) Weight 11.41 lb (5.17 kg) 8-port ANH Height 1.75 in. (4.5 cm) Width 17.25 in. (43.80 cm) Depth 11.25 in. (28.60 cm) Weight 7.5 lb (3.2 kg)

    Environmental and Regulatory
    Altitude 0 - 8000 ft (0 - 2400 m) Humidity 20% - 80% (noncondensing) Temperature 32 - 104 F (0 - 40 C) Safety UL 1950, TUV EN60 950, CSA 22.2 950 RFI/EMI FCC Part 15, VDE 0878 Limit B, CISPR 22B


    Table 5: AN Software Functionality and Availability

                                      IP Access   Remote Office   Corporate
    Feature                             Suite         Suite         Suite
    
    Network Protocols IP x x x OSI x DECnet Phase IV x Novell IPX x x Banyan VINES x AppleTalk Phase 2 x x Xerox XNS x
    IBM Integration Source Route Bridge x x x LAN Network Manager Agent x x Data Link Switching for Ethernet and Token Ring x x Data Link Switching for SDLC x Transparent Sync Pass-Thru x x x
    Bridging Transparent (Ethernet) x x x Translation Bridge Ethernet-Token Ring x x x Native Mode LAN (NML) x x x
    Wide Area Networking Wellfleet HDLC Encapsulation x x x Point-to-Point Protocol (PPP) x x x Frame Relay x x x SMDS x x x X.25 x x x ATM DXI x x x Dial Back-up x x x Bandwidth-on-Demand Q2,1995 Q2,1995 Q2,1995 Dial-on-Demand x x x
    Traffic Management Multiline Circuits x x x Uniform Traffic Filters x x x Traffic Prioritization x x x Data Compression x x x
    Node Management EZ-Install / EZ-Update x x x Dynamic Loader x x x