Perle Systems manual IP Routing and the P840 Router, ARP-Address Resolution Protocol, Proxy ARP

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Introduction

IP Routing and the P840 Router

The P840 router may be used to route between subnets within the same network or between different networks.

Network broadcasts sent within a subnet-routed environment will not be forwarded to the other subnets in the network.

The procedure for establishing an IP connection through an IP router is explained on the next few pages.

ARP—Address Resolution Protocol

A protocol called ARP (Address Resolution Protocol) is used to determine the MAC address of a particular IP address. The MAC (Medium Access Control) address is unique predefined number for each device on the LAN. The manufacturer of the device assigns MAC addresses. The IP address for each device is assigned by the network administrator according to the network structure.

If the originating station does not know the MAC address of the destination station, a MAC broadcast will be transmitted onto the LAN asking “Who has IP address 170.22.10.4?” This MAC broadcast is called an ARP request. Because the ARP request is a MAC broadcast, every device on the LAN will see the frame. The device that has the IP address 170.22.10.4 will respond with a frame to the originating station. The ARP reply frame will include the MAC address of the destination device.

Now when the two devices wish to send data across the LAN to each other, they will both use the MAC and IP address of the other device.

Each device on the LAN maintains a table for MAC addresses and IP addresses called the ARP cache. The ARP cache contains a list of IP addresses and their corresponding MAC addresses.

Proxy ARP

Each time an originating station does not know the MAC address of a destination station, the originating station sends out an ARP request. If the destination station is on a different network, the router connected to the originating network will see the frame and look at the IP address being requested. The router will look in its routing table to see if it has an entry for that IP network address. If the router has an entry, the router will generate an ARP reply to send back to the originating station. The ARP reply will specify the MAC address of the router as the MAC address to send frames to for the IP address of the destination station.

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Contents Perle P840 P840 Router IntroductionARP-Address Resolution Protocol IP Routing and the P840 RouterProxy ARP Complete IP Connection IP Header Details Quench Icmp MessagesUnreachable RedirectTime and Mask server Update MechanismRIP-Routing Information Protocol PingBridging and the P840 Router Initial Bridging ProcessStation Address Learning Aging Timer Filled Address Table Address PurgingAging Exception P840 Router Feature Definitions TelnetLink Compression Typical Compression Ratios by File Type Multipoint WAN TopologiesBandwidth On Demand MultilinkTime of Day Connect Application Operating Software UpgradesP840 Isdn Connection Management Wide Area Network Topologies SupportedCall Establishment Methods Auto-Call Time-of-Day Connections Isdn Connection ManagementManual Call Address ConnectCombination Connection ProcessInteresting Traffic Idle TimerProtocol Awareness Suspension ProcessSuspended Server P840 Session Participation SpoofingSuspension of TCP/IP Sessions IP SpecificsTermination Process IP Address ConnectPinout Information Console ConnectorEvent logs Event LogsEvent Logs Event Logs Event Logs Event Logs Event Logs Alarm logs Event Logs Event Logs Event Logs Code Description Code Event Logs Event Logs Event Logs Event Logs Event Logs PPP Security logs Security MAC Address FilteringSecurity-Filter if Destination FilteringSecurity-Filter if Source Security-Forward if Destination Security-Forward if Source FilteringFiltering Pattern Filter Operators Bridge Pattern FilteringProtocol Discrimination IP, and no more Protocol Type FieldInternet Protocol IP Filter all IP PacketsFiltering Filter all except TCP/IP Transport Control Protocol / Internet Protocol TCP/IPFilter only TCP/IP Filter all IP without TCP trafficEthernet Multicasting Bandwidth ConservationFilter all DEC Ethernet BroadcastingGeneral Restrictions Internet AddressesEthernet Station Addresses Mask would be 6-010203040506&12-0800&23-06 Example Mask CombinationsIP Router Pattern Filtering Frame Formats Ethernet Type Codes Octet Locations on an IP Routed TCP/IP Frame Octet Locations on a Bridged XNS Frame

P840 specifications

Perle Systems is renowned for its high-performance networking hardware, and the Perle P840 model exemplifies this reputation with its advanced features and technologies. Designed for small to medium-sized enterprises, the P840 serves as a versatile and reliable solution for connectivity needs.

One of the main features of the Perle P840 is its robust network performance, supporting both Ethernet and serial connectivity. With support for RS-232, RS-422, and RS-485 interfaces, the P840 enables seamless integration of legacy devices into modern network architectures, allowing businesses to leverage existing infrastructure without the need for extensive upgrades.

The P840 also boasts advanced security features to protect sensitive data during transmission. It supports SSL encryption and VPN capabilities, ensuring that data travels securely across the network. Additionally, it implements strong authentication protocols, providing organizations with peace of mind knowing that their communications are safeguarded against potential threats.

Another standout characteristic of the P840 is its flexibility in configuration. It offers multiple port configurations, allowing for customization based on specific user needs. With options for both managed and unmanaged modes, the device can easily adapt to various network environments. This flexibility makes it suitable for diverse applications, including industrial automation, process control, and telecommunications.

The Perle P840 is designed for durability and reliability, featuring a rugged enclosure that can withstand demanding environments. Its solid-state components reduce the risk of failure, contributing to increased uptime and lower maintenance costs. Furthermore, the compact design allows for easy installation in tight spaces, making it a practical choice for various deployment scenarios.

In terms of management and monitoring, the P840 includes an intuitive web-based interface, enabling administrators to configure settings and monitor network performance effortlessly. SNMP support further enhances management capabilities, allowing for integration into larger network management systems.

Overall, the Perle P840 stands out as a powerful solution for enterprises seeking seamless connectivity, robust security, and flexibility in configuration. Its combination of advanced features and durable design makes it an ideal choice for industries requiring reliable serial and network connectivity in challenging environments. With the P840, businesses can build a resilient networking infrastructure that supports their growing demands while safeguarding their critical data.
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