Perle Systems IOLINK-520 Bridging and the IOLINK-PRO & 520 Routers, RIP/X Requests, RIP/X Metrics

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Introduction

RIP/X Requests

A Client may also request a route to a given network or server. To do so, the Client generates a Route Request broadcast that the routers hear, and routers that know of the route requested will respond to the originating station. In this way a new Client may find routes without waiting for the routers’ broadcast, that could be up to 30 seconds away (if it just missed one). A new router on a network will also broadcast a general Route Request to fill its route tables quickly. Again, without this mechanism the router would have to wait for about 30 seconds until it heard from all other routers via their standard RIP/X broadcasts.

RIP/X Metrics

The RIP/X routing protocol measures routes based on two metrics, the hop count and the ticks delay. These metrics are used to compare different routes to the same network, with the goal of selecting the best (shortest) route.

The ticks delay is the primary metric used to determine the optimal route. The tick count is an indicator of how long a packet will take to get to the destination. Novell has defined 1 tick to be the length of time it takes a 512-byte frame to be transmitted on a 10-Mbps (Ethernet) LAN. This works out to about 18 ms. The real value of the tick delay is when evaluating routes across WAN connections. In these cases, the tick count is dependent on the link speed of the WAN connection(s), where a slower link will have a higher tick count.

The hop count is the secondary measure of the length of a route; it is exactly the same as the IP hop count. If a route goes through 1 router (the shortest route), it will have a hop count of 1. If a route goes through 6 routers, the hop count for that route will be 6. The maximum number of hops RIP/X supports is 15, but this is a very large number, considering the size of most internetworks. When two or more routes to the same network have the same tick count, the router will use the route with the smallest hop count.

Bridging and the IOLINK-PRO & 520 Routers

The bridge portion of the IOLINK-PRO & 520 router is an Ethernet Media Access Control (MAC) level bridge providing an efficient means of interconnecting IEEE 802.3 Local Area Networks supporting a choice of standard Ethernet (10Base5), Thin Ethernet (10Base2) and Twisted Pair (10BaseT) interfaces. With the support of these industry-standard LAN interface technologies, the IOLINK-PRO & 520 routers will resolve the media conflicts that might have otherwise prevented the consolidation of these resources.

The IOLINK-PRO & 520 routers will also fit right into those environments that may require more than one bridge by using the IEEE 802.1D Spanning Tree Protocol. With this protocol, the IOLINK-PRO & 520 routers will perform automatic network reconfiguration in the event of a link failure to one of the LAN segments. This provides maximum availability of the attached LAN services.

Immediately following are several short descriptions of LAN bridging operations specific to the IOLINK-PRO & 520 routers. These descriptions will help you understand the concepts of bridging and how the IOLINK-PRO & 520 routers performs these functions.

The remaining sections of this document describe how these functions are performed and configured. You are urged to spend the small amount of time necessary to familiarize yourself with the IOLINK-PRO & 520 router and the advanced functions it may perform for you.

1.12IOLINK-PRO & 520 Reference Manual

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Contents Reference Manual IP Routing and the IOLINK-PRO & 520 Routers IOLINK-PRO & 520 RoutersProxy ARP ARP-Address Resolution ProtocolComplete IP Connection IOLINK-PRO & 520 Reference Manua Protocol IP Header DetailsTime to live Header ChecksumOptions Icmp MessagesUnreachable RedirectTime and Mask server PingRIP-Routing Information Protocol Update MechanismRoute Tables IPX Addressing IPX Routing and The IOLINK-PRO & 520 RoutersNetwork Layer Addressing vs. MAC Addressing IPX Address FormatIPX Header Other IPX Header InformationEstablishing an IPX Connection Service Advertisement ProtocolSAP Broadcasts Routing Information Protocol Server TypesSAP Requests RIP/X OperationRIP/X Requests Bridging and the IOLINK-PRO & 520 RoutersRIP/X Metrics Station Address Learning Initial Bridging ProcessAddress Purging Aging TimerAging Exception Filled Address TableTelnet Iolink Router Feature DefinitionsLink Compression Introduction Bandwidth On Demand WAN TopologiesPoint-to-Point MultipointTime of Day Connect Application Operating Software Upgrades Disaster Recovery Backup LinkIsdn Single Active Link & Dual Active Link Wide Area Network Topologies Supported Iolink PRO & 520 Isdn Connection ManagementCall Establishment Methods Auto-Call Time-of-Day Connections Isdn Connection ManagementManual Call Address ConnectCombination Connection ProcessProtocol Awareness Idle TimerSuspension Process Interesting TrafficTermination Process Session Keepalive MessagesIP Address Connect IP SpecificsSuspension of TCP/IP Sessions RIP-Routing Information ProtocolRIP/IPX and SAP/IPX IPX SpecificsSuspension of IPX Sessions IPX Serialization FramesModule Identification Pinout InformationLink Clocking Information Link Interfaces Reference ATL CSU/DSU Link Module InformationConsole Pinouts T1/E1 Module CSU/DSU ModuleRS232 Link Pinouts 24 & RS232C Link PinoutsDB15 Female DTE Direction Contact Circuits From Number 11 & X.21 Link PinoutsDB25 Female DTE Direction Contact Circuit From Number Name RS442 & RS530 Link PinoutsDB25 Link PinoutsNumber Name 11 RS232 Null-Modem Cable RS232 Null-Modem Cable Configuration12 V.35 Null-Modem Cable Null-Modem Cable Configuration13 RS530 Null-Modem Cable RS530 Null-Modem Cable Configuration14 RS530 to RS449 Conversion Cable RS530 To RS449 Conversion Cable15 V.11/X.21 Null-Modem Cable 11/X.21 Null-Modem Cable ConfigurationWAN Link Control-Signal Operation Event logs Appendix a Event LogsEvent Logs IOLINK-PRO & 520 Reference Manual A.3 Event Logs IOLINK-PRO & 520 Reference Manual A.5 Event Logs IOLINK-PRO & 520 Reference Manual A.7 Event Logs Alarm Logs Event Logs IOLINK-PRO & 520 Reference Manual A.11 Event Logs IOLINK-PRO & 520 Reference Manual A.13 Event Logs IOLINK-PRO & 520 Reference Manual A.15 Event Logs IOLINK-PRO & 520 Reference Manual A.17 Event Logs IOLINK-PRO & 520 Reference Manual A.19 PPP Security Logs Security MAC Address FilteringSecurity-Filter if Destination Programmable FilteringSecurity-Filter if Source Security-Forward if Destination Security-Forward if Source Programmable Filtering Bridge Pattern Filtering Pattern Filter OperatorsProtocol Discrimination Internet Protocol IP Protocol Type FieldFilter all IP Packets IP, and no moreFilter only TCP/IP Transport Control Protocol / Internet Protocol TCP/IPFilter all IP without TCP traffic Filter all except TCP/IPFilter all DEC Bandwidth ConservationEthernet Broadcasting Ethernet MulticastingInternet Addresses General RestrictionsEthernet Station Addresses Mask would be 6-010203040506&12-0800&23-06 Example Mask CombinationsIPX Router Pattern Filtering IP Router Pattern FilteringPage Appendix C Frame Formats Octet Locations on an IP Routed TCP/IP Frame IOLINK-PRO & 520 Reference Manual C.3