Variable-width subnetworks | Cabletron Systems DMS-100 manual

160Appendix E: Understanding IP and IP addressing

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Variable-width subnetworks

When subnetworks were ﬁrst invented, they were intended to be used in a star topology, with the major router at the port of entry connected to all subnetworks. All subnetworks were supposed to have address ranges of the same size. Later IP implementations have retained the expectation that the width of the subnet mask is uniform throughout all the subranges of the top level (class A or B) network number.

With the current increased emphasis on conservation of IP addresses, it is often desirable to allocate subnet ranges of “just the right size”. To allocate ranges consistently, all protocol exchanges that communicate a network address range must include the associated subnet mask. OSPF performs this, and future releases of other route information protocols (for example, RIP Version 2) allow this too. On the other hand, some protocols do not carry this information, since knowledge of subnet structure is contained within a routing domain, and is invisible outside of a routing domain.

It is important to realize that support for variable-width subnetworks does not allow for subnetworking subnetworks. For example, an IP port can have the class B address 129.191.14.1 with subnet mask 255.255.255.0. IP address 129.191.0.0 is the network, and IP address 129.191.14.0 is the subnet. You cannot further subnet the 129.191.14.0 subnet—for example, 129.191.14.128 with mask 255.255.255.128. However, a new subnet can be created with a longer mask, such as 129.191.15.128 with mask 255.255.255.128.

Protocols related to Internet Protocol

This section provides brief descriptions on the constituent protocols of TCP/IP.

Internet Protocol

IP is a connectionless datagram service that provides the following beneﬁts:

•best-effort delivery

•internetwork-wide addressing

•fragmentation and reassembly

•time-to-live control of datagrams

•checksum veriﬁcation of header contents

IP is deﬁned in RFC791.

297-8991-910 Standard 03.01 August 1999

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Cabletron Systems DMS-100 manual Variable-width subnetworks, Protocols related to Internet Protocol

Contents

Ethernet Interface Unit Page Ethernet Interface Unit Standard 03.01 August Publication history AugustMay March Vi Publication history Standard 03.01 August Contents EIU messaging protocols Chapter EIU datafill EIU maintenance 103 Appendix C Using FTP 117Appendix D Using telnet 141 Volume listing Appendix I Obtaining a MAC address 185 Appendix H ASU background information 177List of terms 189 List of figures Xii List of tables Xiii Xiv When to use this document How to check the version and issue of this documentAbout this document References in this document Internet request for comment documents Xvi Possible loss of service What precautionary messages meanXvii How commands, parameters, and responses are represented Risk of personal injuryRisk of electrocution Input prompt Variables Commands and ﬁxed parametersResponses Standard 03.01 August Introduction to the EIU Possible loss of network security Overview of the EIU System architecture DMS-bus interface and expansion SLMIOC SOS Unix EIU Inter-message switch links required with LPP Data communications interface architecture Ethernet interface data ﬂow LAN Introduction to the EIU AUI PB Hardware descriptionUTP PB Slot EIU Rear paddle boardsFront cards DMS SuperNode switch LPP with an EIU SSLPP, with 2-slot EIU locations Top view of Sslpp shelf Ethernet interface card NT9X84 DMS SuperNode Flis with an EIU Ethernet physical interfaces Attachment unit interface-NT9X85AALPP NTEX22 CPU/IPF MAU Unshielded twisted-pair NT9X85BA Capabilities, limitations, and restrictionsGrounding requirements EIU hardware capabilities and limitations Introduction to the EIU Limitations associated with maintenance System-wide limitations Limitations associated with protocols Routing information protocol Feature packaging DMS-Core feature packages Package Title DescriptionInternet Protocol and Internet Control Message Protocol NTXF05AA DMS-bus inter-MS provisioning EIU provisioning requirementsSheet 2 Example of DMS-bus intermessage switch conﬁguration DMS-bus external MS provisioning EIU sparing and redundancy EIU provisioningNT9X17AA NT9X23BA User interface characteristics Service ordersBilling Logs, alarms, and OMs AlarmsPossible loss of information Log reports Introduction to the EIU Standard 03.01 August EIU messaging protocols Shows the structure of the DMS-100 switch EIU protocol stack Software architecture TCP UDP Icmp ARP FTP Telnet Snmp Bootp RIPFTS Ethernet TCP/UDP FTS DMS-busEthernet LAN Workstation TCP Boot protocol Supported protocols File transfer protocol Wsls Internet Protocol Telnet Address resolution protocol Transmission control protocolUser datagram protocol Internet control message protocol MAC addresses AddressingInternet addresses EIU messaging protocols How to get IP addresses for SuperNode What is the SuperNode network topology? Routing EIU messaging protocols APUX10 LIU7 APX LMSAPUX20 LIU7 Routing tables Protocol engineering IP ScreeningIP throttling TCP connection management UDP connection limits by SuperNode subsystem EIU APUSubsystem Maximum UDP connections FTP session control Protocol buffer engineering Receive 1518 Icbm common pool 1024 128 Transmit TCP own IP throttling IP throttling for LPP IP throttling for Sslpp Application Sheet 2 EIU dataﬁll Interdependency and auto-conﬁguration Table Liuinv Dataﬁll sequence and implications Table Liuinv dataﬁllLink interface unit name Link interface unit type Message switch card Message switch portLink interface unit number Location Link interface slot Software load nameProcessor information Processor product engineering code EIU MAC addresses Sheet 4 IP addresses Table IpnetwrkSample dataﬁll for table Liuinv Dataﬁll for table Ipnetwrk Ipnetwrk Computing module Internet Protocol Internet Protocol network subnet rangeEthernet interface unit. Enter EIU Ethernet interface unit range. Enter Parm Scrnflag EiuinterfaceDfltgtwyip Addr Sample dataﬁll for table Ipnetwrk GtwyipaddrIomnum Packlet Table Iprouter Supplementary information Dataﬁll Ethernet address resolution protocol Ethernet proxy address resolutionTable Iphost Sample dataﬁll for table Iprouter Index IndexNodeidx Node index Node name Node File processor index Internet porotocol address SuperNodeTransmission control Protocol Connections Application processor Unix index Support Operating SwitchInternet protocol host identification for Cmindex Computing module index Eiuindex Ethernet interface unit indexInternet protocol address for node Lanaddr Eliuindex Second IP address for Eliu host Nodename = MS Apux Message switch index Table IpthronSample dataﬁll for table Iphost Msindex EIU datafill Transmit capacity Local message switch nodeReceive capacity Option SuperNode nodeSynchronized and matched node index Application processor unit index Table Ipproto Sample dataﬁll for table IpthronField descriptions for table Ipthron for EIU datafill Field Subfield or Entry Explanation and action Refinement Iprsmtmo Sample dataﬁll for table IpprotoArprftmo Table Ensites Table EntypesSample dataﬁll for table Ensites Alphanumeric Table Exndinv Sample dataﬁll for table EntypesEntype External node type Pmloads External node key External node peripheral module typeExternal node number External node name DMS boot protocol Internet Protocol addressMachine address External node load file name Floor number RowBay position External node information External node no-link alarm External node one-link alarmExternal node alarm scan points Critical alarm scan point Major alarm scan point Minor alarm scan pointSample dataﬁll for table Exndinv Sheet 5 EIU maintenance 103 EIU diagnostics In-service stateOut-of-service diagnostics EIU MAP level In-service diagnostics In-service leaky bucket audit EIU overload control EIU sparing requirements Automated system maintenance EIU Eliu Manual system maintenance Logs relevant to EIU OA&M OMs relevant to EIU OA&M Appendix a EIU installation checklist 111 Software NTXF05AA EIUConsult the DMS-100 PM Software Release Document Datafill Appendix B EIU troubleshooting 113 EIU troubleshooting checklist Problem Probable cause Troubleshooting checklistTools Sheet 2 Appendix B EIU troubleshooting Standard 03.01 August Appendix C Using FTP 117 Automatic Record Length Detection What is FTP?Where DMS Volume listing FTP on the DMS-100 switchFTP cookbook File name conventions DMS FTP client commands FTP commands on the DMS-100 switch Command Description Obtaining the IP address of the SuperNode host Procedure 1 Establishing an FTP session Step Action Where Userid Is a valid userID for that hostTutorial basic FTP operations Ftp ‘nnn.nnn.nnn.nnn ’Page Ftp dir Ftp cd pathnameFtp cd ‘/team/bin’ Ftp lcd pathname Tutorial moving ﬁles Where Pathname Is a valid directory path ExampleIf the file If the filename Ftp lcd ‘/S00DTEMP’Ftp lrecl Ftp get ‘ﬁle1.txt54 ’ Ftp get ‘ﬁle1.dmo ’Ftp put ‘RECORDFILE’ ‘jan18.log’ Ftp cd ‘ /team/bin’ Ftp get ‘ﬁle1.bin’ Tutorial advanced operations Procedure 7 Showing the status of server sessionsFtp get ‘ﬁle1.bin1020’ Ftp svreserve Procedure 9 Remove a server userID and unreserve a sessionFtpadduserinfo ‘johnh’ ‘johnh’ ‘/S00DTEMP’ y Procedure 10 Adding a userID with limited set of commands Where Userid Is the userID ExampleFtpdeluserinfo ‘johnh’ Ftp commandmask mkdir set Procedure 11 Adding a userID with a new command timeout Ftpcommandmask FtpcommandtimeoutFTP operations reference WS ftp IPaddress WS pwdWS cd /pathname WS lcd /directory WS ascii WS get filenameWS site Lrecl WS put filename Newfilename WSput filename.image Filename WS put filename.sosimage FilenameuniplCM Ftpopen ‘IPaddress’ CM FTP ‘IPaddress’ CM cd ‘pathname’ CM lcd ‘/PATHNAME’CM lcd CM ls CM put filename CM binaryCM get ‘filename.load68k’ CM get ‘filename.bin1020’ Appendix D Using telnet 141 Telnet access to a switch Table Ipnetwrk Appendix D Using telnet Standard 03.01 August Appendix E Understanding IP and IP addressing What is internetworking?145 What is routing? Routing and routed protocols Planning overview Mapping the network Simple network map Detailed network diagram Choosing IP addresses IP address structure Class Range Description Class Range Description IP addressing class a Subnet mask class a Class a subnet masks IP addressing class B Subnet mask class B Class B subnet masks IP addressing class C Address masks IP addressing class D Network numbering example Address mask example Network node Firewalls and network security Simple network numbering Variable-width subnetworks Protocols related to Internet Protocol Internet control message protocol Bootstrap Protocol Reverse ARPProxy ARP Inverse ARP Open shortest path ﬁrst Page Appendix F EIU supported conﬁgurations 165 Host conﬁguration Router conﬁgurations Host and router conﬁguration Interface conﬁguration part Subnet ClassA .networkidB .subnetX .hostZ 47.105.150.3 Appendix G IP network number requests OverviewConsiderations for obtaining IP addresses 171 NIC IP address request form NIC IP network number request formYour Application Must be Typed Sheet 2 Sheet 3 Sheet 4 Appendix G IP network number requests Standard 03.01 August Application-speciﬁc units and supported services Appendix H ASU background informationLink interface unit Ethernet interface unit Frame relay interface unit 25/X.75 link interface unit Voice processor unit and Adas Network interface unitASUs and Cellular digital packet data External routers PlatformsLink peripheral processor LPP architecture ASU Single-shelf link peripheral processor On page 183 provides an overview of the Sslpp conﬁguration SuperNode SE link interface shelf Sslpp architecture SNSE-LIS architecture Shelf MAC address format Appendix I Obtaining a MAC address185 EIU MAC address format How to get the MAC address for an EIU Appendix I Obtaining a MAC address Standard 03.01 August List of terms 189 List of terms LIS MTP List of terms UDP Page Ethernet Interface Unit