NN46205-102_02.01_Terminology

Nortel Ethernet Routing Switch 8600

TerminologyRelease: 5.1Document Revision: 02.01

www.nortel.com

NN46205-102.

Nortel Ethernet Routing Switch 8600Release: 5.1Publication: NN46205-102Document release date: 16 March 2009

Copyright © 2009 Nortel NetworksAll Rights Reserved.

LEGAL NOTICEWhile the information in this document is believed to be accurate and reliable, except as otherwise expresslyagreed to in writing NORTEL PROVIDES THIS DOCUMENT "AS IS" WITHOUT WARRANTY OR CONDITION OFANY KIND, EITHER EXPRESS OR IMPLIED. The information and/or products described in this document aresubject to change without notice.

THE SOFTWARE DESCRIBED IN THIS DOCUMENT IS FURNISHED UNDER A LICENSE AGREEMENT ANDMAY BE USED ONLY IN ACCORDANCE WITH THE TERMS OF THAT LICENSE.

Nortel, the Nortel logo, and the Globemark are trademarks of Nortel Networks.

SANS is a trademark of The SANS Institute.

All other trademarks are the property of their respective owners.

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ContentsNew in this release 5Features 5

Introduction 7

A 9

B 13

C 17

D 21

E 27

F 29

G 31

H 33

I 35

J 39

L 41

M 45

N 51

O 55

P 57

Q 63

R 65

S 71

T 77

Nortel Ethernet Routing Switch 8600Terminology

NN46205-102 02.0116 March 2009

Copyright © 2009 Nortel Networks

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U 81

V 83

W 85

Customer service 87Updated versions of documentation 87Getting help 87Express Routing Codes 87Additional information 88


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New in this releaseThe following section details what’s new in Nortel Ethernet Routing Switch8600 Terminology (NN46205-102) for Release 5.1:

• “Features” (page 5)

FeaturesFollowing are the new feature definitions for the Release 5.1:

• "Bidirectional Forwarding Detection (BFD)" (page 14)

• "Minimum Link (MinLink)" (page 46)

• "Multicast Source Discovery Protocol (MSDP)" (page 47)

• "Terminal Access Controller Access-Control System Plus (TACACS+)"(page 77)


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6 New in this release


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IntroductionThis document provides information about the terms and acronyms used inthe Nortel Ethernet Routing Switch 8600 documentation.

Navigation• “A” (page 9)

• “B” (page 13)

• “C” (page 17)

• “D” (page 21)

• “E” (page 27)

• “F” (page 29)

• “G” (page 31)

• “H” (page 33)

• “I” (page 35)

• “J” (page 39)

• “L” (page 41)

• “M” (page 45)

• “N” (page 51)

• “O” (page 55)

• “P” (page 57)

• “Q” (page 63)

• “R” (page 65)

• “S” (page 71)

• “T” (page 77)

• “U” (page 81)


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8 Introduction

• “V” (page 83)

• “W” (page 85)


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A

Authentication, Authorization, Accounting (AAA)Authentication—is the action of determining whoa user (or entity) is, before allowing the user toaccess the network and network services.

Authorization—is the action of determining whatan authenticated user is allowed to do.

Accounting—is the action of recording what auser is doing or has done.

access control entry (ACE)One of the filter rules that comprise an accesscontrol list (ACL). A filter rule statement definesa pattern (in a packet) and the desired behaviorfor packets that carry the pattern. When thepackets match an ACE rule, the specified actionexecutes.

access control list (ACL)An ordered list of filter rules referred to asaccess control entries. The ACEs providespecific actions, such as dropping packets withina specified IP range, or a specific TransmissionControl Protocol (TCP) or User DatagramProtocol (UDP) port or port range. When aningress or egress packet meets the matchcriteria specified in one or more ACEs within anACL, the corresponding action executes.

access control template (ACT)Defines the selection of match fields for a givenACL. Before you add an ACE to an ACL, youmust first associate the ACL with an existingACT.


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10 A

add/drop multiplexer (ADM)A network element in which facilities areadded, dropped, or passed directly through fortransmission to other network elements.

Address Resolution Protocol (ARP)Maps an IP address to a physical machineaddress, for example, maps an IP address to anEthernet media across control (MAC) address.

address resolution unit (ARU)An application specific integrated circuit (ASIC)that makes forwarding decisions that do notrequire CPU activity and, therefore; does notadversely affect forwarding speed.

Advanced Encryption Standard (AES)A privacy protocol. AES is the current encryptionstandard (FIPS-197) intended for use by U.S.government organizations to protect sensitiveinformation.

aggregateA prefix length that is formed by combiningseveral specific prefixes. The resulting prefix isused to combine blocks of address space into asingle routing announcement.

American Standard Code for Information Interchange(ASCII)

A code for representing characters in computers.ASCII uses uppercase and lowercase alphabeticletters, numeric digits, and special symbols.

application-specific integrated circuit (ASIC)A application-specific integrated circuitdeveloped to perform more quickly and efficientlythan a generic processor.

area border router (ABR)A router attached to two or more areas inside anOpen Shortest Path First (OSPF) network. ABRsplay an important role in OSPF networks bycondensing the amount of disseminated OSPFinformation.


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asymmetric digital subscriber line (ADSL)A standard that allows digital broadband (over 6Mbit/s) signals and plain old telephone service totransmit up to 12 000 feet over a twisted copperpair.

Asynchronous Transfer Mode (ATM)A transfer mode that organizes information intocells and the recurrence of cells depends on therequired or instantaneous bit rate.

attenuationThe decrease in signal strength in an optical fibercaused by absorption and scattering.

attributeA unit of data that is used by BGP to describeany of the following prefixes: AS-PATH,LOCAL-PREF, NEXT-HOP, and so on.

automatic protection switching (APS)A Synchronous Optical Network (SONET)feature that protects against line failure.

AS (autonomous system)A set of routers under a single technicaladministration, using a single IGP and commonmetrics to route packets within the AS, and usingan EGP to route packets to other ASs.

AS confederationA single logical AS that comprises multiplesub-ASs to ensure scalability.

autonomous system border router (ASBR)A router attached at the edge of an OSPFnetwork. An ASBR uses one or more interfacesthat run an interdomain routing protocol suchas BGP. In addition, a router distributing staticroutes or Routing Information Protocol (RIP)routes into OSPF is considered an ASBR.

ASN (autonomous system number)A two-byte number that is used to identify aspecific AS.


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12 A

AV pairsstrings of text in the form "attribute=value" sentbetween a NAS and a TACACS+ daemon aspart of the TACACS+ protocol.


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B

backplane forwarding module (BFM)Connects the switching module on the WebSwitching Module (WSM) and SSL AccelerationModule (SAM) to the Nortel Ethernet RoutingSwitch 8600 backplane.

backup designated router (BDR)Assumes the designated router (DR) role for theOpen Shortest Path First (OSPF) protocol if theDR fails.

bandwidthA measure of transmission capacity for aparticular pathway, expressed in megabits persecond (Mbit/s).

BAP memory controller (BMC)A Field Programmable Gate Array (FPGA)device on the R module.

basic rate interface (BRI)A type of Integrated Services Digital Network(ISDN) access provided by a set of time divisionmultiplexed digital channels that include twoB-channels at 64 kbit/s (for digitized voice anddata), one D-channel at 16 kbit/s (for signalinginformation), and one or more maintenancechannels.

Baysecure Access Control (BSAC)A Nortel Remote Authentication Dial-In UserService (RADIUS) server.


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bit error rate (BER)The ratio of the number of bit errors to thetotal number of bits transmitted in a given timeinterval.

Bidirectional Forwarding Detection (BFD)A simple Hello protocol used between twopeers to periodically transmit BFD packetsto each other. BFD provides low-overhead,short-duration detection of failures in the pathbetween adjacent forwarding engines.

Border Gateway Protocol (BGP)An inter-domain routing protocol that providesloop-free inter-domain routing betweenautonomous systems (ASs) or within an AS.

BGP neighborBGP routers that have interfaces to a commonnetwork.

BGP peerA relationship that is formed between any tworouters that open a TCP connection to eachother for the purpose of exchanging routinginformations.

BGP sessionAn active connection between two routersrunning BGP.

BGP speakerAn entity within a BGP router that is used tocommunicate with other BGP speakers byestablishing a peer-to-peer session.

bit interleaved parity (BIP)A simple parity check mechanism.

bladeA synonym for a line card.


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Bootstrap Protocol (BootP)A User Datagram Protocol (UDP)/InternetProtocol (IP)-based protocol that a booting hostuses to configure itself dynamically and withoutuser supervision.

bootstrap router (BSR)A dynamically elected Protocol IndependentMulticast (PIM) router that collects informationabout potential Rendezvous Point routers anddistributes the information to all PIM routers inthe domain.

Border Gateway Protocol (BGP)An exterior gateway protocol that routers use indifferent autonomous systems (AS) to exchangerouting information.

boundary portA bridge port that attaches a Multiple SpanningTree (MST) bridge to a LAN in another region.

Breaker Interface Panel (BIP)A central rack location that connects redundantinput DC-power feeds and routes to one or two8010co chassis. The BIP provides an alarmmodule and display panel that monitors systemcomponents, generates alarms, and controlsLED status indicators.

Bridge Protocol Data Unit (BPDU)A data frame used to exchange informationamong the bridges in local or wide area networksfor network topology maintenance.

burst tolerance (BT)For ATM traffic, the maximum burst size (MBS)minus 1 multiplied by the difference betweenthe peak cell rate (PCR) and sustained cell rate(SCR) intervals.


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C

cable assemblyAn optical-fiber cable with connectors installedon one or both ends. The cable assemblyinterconnects the cabling system withopto-electronic equipment at either end of thesystem. Cable assemblies with connectors onlyon one end are called pigtails. Cable assemblieswith connectors on both ends are called jumpersor patch cords.

cable plantAll the optical elements, such as fiber connectorsand splices, between a transmitter and areceiver.

candidate bootstrap router (C-BSR)Provides backup protection in case the primaryrendezvous point (RP) or boostrap router (BSR)fails. Protocol Independent Multicast (PIM) usesthe BSR and C-BSR.

Central Office (CO)A major equipment center that serves thecommunication traffic of a specific geographicalarea.

central processor unit (CPU)The main system processor that resides on theCSU.

Challenge Handshake Protocol (CHAP)An access protocol that exchanges a randomvalue between the server and the client and isencrypted with a challenge password.


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Circuitless IPA virtual interface that does not map to anyphysical interface. This interface is often calleda loopback.

class of service (CoS)A method used to manage traffic congestionbased on the CoS level assigned to the packet.

classless interdomain routing (CIDR)The protocol defined in RFCs 1517 and 1518 forusing subnetwork masks, other than the defaultsfor IP address classes.

clusterOne or more route reflectors and their associatedclients that form a relationship where thedesignated route reflectors provide routereflection for their clients, as well as nonclientpeers.

coarse wavelength division multiplexing (CWDM)A technology that uses multiple optical signalswith different wavelengths to simultaneouslytransmit in the same direction over one fiber, andthen separates by wavelength at the distant end.

command line interface (CLI)A nongraphical user interface. When you usea CLI, you respond to a prompt by typing acommand. After you enter the command, youreceive a system response.

common and internal spanning tree (CIST)The single spanning tree calculated by theSpanning Tree Protocol (STP) and RapidSpanning Tree Protocol (RSTP), and MultipleSpanning Tree Protocol (MSTP) to ensure thatall LANs in a bridged Local Area Network (LAN)are simply and fully connected.

common spanning tree (CST)The single spanning tree calculated by STP,RSTP, and MSTP to connect multiple spanningtree (MST) regions.


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communityA BGP attribute that contains a list of 32-bitvalues used to identify a route as belongingto a category of routes. All of the routes in thecategory are treated equally by routing policies.

constant bit rate (CBR)A data service that conveys bits regularly intime and at a constant rate, between source(transmitter) and sink (receiver), for example,follows a timing source or clock.

Custom AutoNegotiation Advertisement (CANA)An enhancement of the IEEE 802.3autonegotiation process on the 10/100/1000copper ports. CANA offers improved controlover the autonegotiation process. Thesystem advertises all port capabilities that fortri-speed ports include 10 Mb/s, 100 Mb/s,1000 Mb/s speeds and duplex and half-duplexmodes of operation. This advertisementresults in autonegotiation between the localand remote end that settles on the highestcommon denominator. CANA can advertise auser-defined subset of the capabilities that settleon a lower or particular capability.

customer edge (CE)A router or switch located at a customer site thatconnects to a provider edge (PE) router.

customer premise equipment (CPE)Equipment or inside wiring at the customer sitethat connects to telecommunications equipment.

cyclic redundancy check (CRC)Ensures frame integrity is maintained duringtransmission. The CRS performs a computationon frame contents before transmission andon the receiving device. The system discardsframes that do not pass the CRC.


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D

Data Encryption Standard (DES)A cryptographic algorithm that protectsunclassified computer data. The NationalInstitute of Standards and Technology publishesthe DES in the Federal Information ProcessingStandard Publication 46-1.

Data Communications Equipment (DCE)A network device (such as a modem) thatestablishes, maintains, and terminates a session.

Data Terminating Equipment (DTE)A computer or terminal on the network that is thesource or destination of signals.

database description (DD) packetsExchanged when a link is initially establishedbetween neighboring routers that synchronizestheir link state databases. The Open ShortestPath First (OSPF) protocol uses DD packets.

daemon/servera program that services network requestsfor authentication and authorization, verifiesidentities, grants or denies authorizations, andlogs accounting records.

dampenIndicates that routes which exhibit instability arenot advertised until the routes become stable fora minimum time period.


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22 D

denial-of-service (DoS)Attacks that prevent a target server or victimdevice from performing its normal functionsthrough flooding, irregular protocol sizes (forexample, ping requests aimed at the victimserver) and application buffer overflows.

dense wavelength division multiplexing (DWDM)A technology that uses many optical signals(4 or more) with different wavelengths tosimultaneously transmit in the same directionacross one fiber, and then separates bywavelength at the distant end.

demultiplexingThe wavelength separation in a wavelength-division multiplexing system. The opposite ofmultiplexing.

designated router (DR)A single router elected as the designated routerfor the network. In a broadcast or nonbroadcastmultiple access (NBMA) network running theOpen Shortest Path First (OSPF) protocol, a DRensures all network routers synchronize witheach other and advertises the network to the restof the autonomous system (AS). In a multicastnetwork running Protocol Independent Multicast(PIM), the DR acts as a representative router fordirectly connected hosts. The DR sends controlmessages to the rendezvous point (RP) router,sends register messages to the RP on behalf ofdirectly connected sources, and maintains RProuter status information for the group.

Device Manager (DM)A graphical user interface (GUI) used toconfigure and manage the Nortel EthernetRouting Switch 8600.

DiffServ (DS) boundary or access pointThe edge of a DS domain in which classifiersand traffic conditioners are deployed.


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DS fieldFormerly called the IPv4 Type of Service (TOS)octet or the IPv6 Traffic Class octet. The DSfield provides the Differentiated Services CodePoint (DSCP) that is used for packet forwarding.These fields are part of the standard IPv4header.

Differentiated Services Code Point (DSCP)The first six bits of the DS field. The DSCP usespacket marking to guarantee a fixed percentageof total bandwidth to each of several applications(guarantees Quality of Service).

digital subscriber line (DSL)In Integrated Services Digital Networks (ISDN),equipment that provides full-duplex service ona single twisted metallic pair at a rate sufficientto support ISDN basic access and additionalframing, timing recovery, and operationalfunctions.

digital subscriber line access multiplexer (DSLAM)A network device, at a telephone companycentral office, that receives signals frommultiple customer digital subscriber line (DSL)connections and uses multiplexing techniques toplace the signals on a high-speed backbone line.

Dual port controller (DPC)A Field Programmable Gate Array (FPGA)device on the R module.

dispersionThe broadening of input pulses as they travel thelength of an optical fiber. The following types ofdispersion exist:

• modal dispersion-caused by the many opticalpath lengths in a multimode fiber

• chromatic dispersion-caused by thedifferential delay at various wavelengths in anoptical fiber

• waveguide dispersion-caused by lighttraveling through both the core and claddingmaterials in single-mode fibers


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24 D

Distance Vector Multicast Routing Protocol (DVMRP)A dense mode routing protocol that floodsmulticast data to all internetwork routers.

Distributed MultiLink Trunking (DMLT)Allows you to aggregate similar ports fromdifferent modules. MLT provides moduleredundancy through Distributed MultiLinkTrunking.

distribution treeA set of multicast routers and subnetworks thatallow the group members to receive traffic from asource.

Domain Name System (DNS)A system that maps and converts domain andhost names to IP addresses.

downstream nodeRefers to the node that the packet enters on thedownstream node.

downstream-on-demand (DoD)A label switch router (LSR) distributes a forwardequivalence class (FEC) label binding inresponse to an explicit request from anotherLSR. The Nortel Ethernet Routing Switch 8600does not support downstream-on-demand.

downstream unsolicited (DU)An LSR distributes label bindings to LSRs thatdo not explicitly request them.

dual inline memory module (DIMM)A module that contains one or several randomaccess memory (RAM) chips on a small circuitboard with pins that connect it to the computermotherboard.

Duplicate Address Detection (DAD)A method used to discover duplicate addressesin an IPv6 network.


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Dynamic Host Configuration Protocol (DHCP)A standard Internet protocol that dynamicallyconfigures hosts on an Internet Protocol (IP)network. DHCP extends the Bootstrap Protocol(BOOTP).


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E

Electromagnetic Interference (EMI)Electromagnetic radiation released from anelectronic device that disrupts the operation orperformance of another device.

Electrostatic Discharge (ESD)The discharge of stored static electricity thatcan damage electronic equipment and impairelectrical circuitry that results in complete orintermittent failures.

emulated LAN (ELAN)A virtual LAN (VLAN) for Asynchronous TransferMode (ATM).

encoder-decoder (CODEC)Compresses and decompresses audio and videodata.

equal cost multipath (ECMP)Distributes routing traffic among multipleequal-cost routes.

Ethernet switches (ES)A family of frame-based computer networkingtechnologies for local area networks (LANs).

Ethernet Services Module (ESM)The ESM serves as the demarcation pointbetween the enterprise customer and the serviceprovider and utilizes an Ethernet user-to-networkinterface (UNI).


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explicit route (ER)Defines one or more hops in the label switchedpath (LSP) in a Multiprotocol Label Switching(MPLS) network.

explicit pathA Resource Reservation Protocol (RSVP) hop-byhop tunnel that terminates on an interface IPaddress on the egress Label Edge Router (LER).

Extended Unique Identifier (EUI)A 64-bit format used in assigning addressesautomatically to IPv6 interfaces.

Extensible Authentication Protocol over LAN (EAPoL)A port-based network access control protocol.EAPoL provides security in that it prevents usersfrom accessing network resources before theyare authenticated.

External BGP (EBGP)A BGP session between two BGP speakers indifferent ASs.

Exterior BGP (EBGP)A Border Gateway Protocol (BGP) used byrouters that exchange information between twodifferent Autonomous Systems.


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F

far end fault indication (FEFI)Determines that one of two unidirectional fibers,that form the connection between two switches,fails.

Feedback Output Queue (FOQ)A mechanism that helps the Nortel EthernetRouting Switch 8600 avoid switch fabriccongestion.

FEC to NHLFE table (FTN)A lookup table that is consulted for incoming,unlabeled packets to determine which labelvalues to use when encapsulating the packet.(See also Next Hop Label Forwarding Entry[NHLFE]).

file allocation table (FAT)A table that the operating system uses to locatefiles on a disk.

File Transfer Protocol (FTP)A protocol that governs transferring files betweennodes, as documented in RFC 959. FTP is notsecure. FTP does not encrypt transferred data.Use FTP access only after you determine it issafe in your network.

forward equivalence class (FEC)Specifies which packets map to a label switchedpath (LSP) in a Multiprotocol Label Switching(MPLS) network.

Frame Check Sequence (FCS)


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Generalized Regular Expression Parser (GREP)A Unix command used to search files for linesthat match a given regular expression (RE).

get nearest server (GNS)A request used by Internetwork PacketExchange (IPX) clients to find a login server.

gigabit Ethernet (GE)Ethernet technology with speeds up to 1 Gbit/s.

Gigabit Interface Converter (GBIC)A hot-swappable input/output enhancementcomponent designed for use with Nortel productsto allow Gigabit Ethernet ports to link with otherGigabit Ethernet ports over various media types.

Global routing engine (GRE)The base router or routing instance 0 in theVirtual Router and Forwarder (VRF).

global server load balancing (GSLB)Serves content from several points to overcomescalability, availability, and performance issuesinherent in distributing content across multiplegeographic locations.

graphical user interface (GUI)A graphical (rather than textual) computerinterface.


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High Availability (HA)Activates two CPUs simultaneously. The CPUsexchange topology data so, if a failure occurs,either CPU can take precedence in less than 1second with the most recent topology data.

Hypertext Transfer Protocol (HTTP)Communications protocol for the Web.

Hypertext Transfer Protocol, Secure (HTTPS)Communications protocol used to access asecure Web server.


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incoming label map (ILM)An index used to map an incoming labeledpacket to an NHLFE.

Institute of Electrical and Electronics Engineers (IEEE)An international professional society that issuesstandards and is a member of the AmericanNational Standards Institute and the InternationalStandards Institute, and the InternationalStandards Organization.

integrated service director (ISD)The processor PCI Mezzanine Card (PrPMC)and disk drive on a firewall module.

Interior BGP (IBGP)Routers that use the Border Gateway Protocol(BGP) within an autonomous system. The routerredistributes BGP information to Interior GatewayProtocols (IGPs) that run in the autonomouspath.

Interior Gateway Protocol (IGP)Distributes routing information between routersthat belong to a single autonomous system (AS).

internal router (IR)A router with interfaces only within a single areainside an Open Shortest Path First (OSPF)network.


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Internet Assigned Numbers Authority (IANA)The central registry for various assignednumbers, for example, Internet protocolparameters (such as port, protocol, andenterprise numbers), options, codes, and types.

Internet Control Message Protocol (ICMP)A collection of error conditions and controlmessages exchanged by IP modules in bothhosts and gateways.

Internet Engineering Task Force (IETF)A standards organization for IP data networks.

Internet Group Management Protocol (IGMP)A host membership protocol used to arbitratemembership in multicast services.

Internet Group membership Authentication Protocol(IGAP)

An authentication and accounting protocol forclients that receives multicast streams.

Internet Protocol Control Packet (IPCP)Establishes and configures Internet Protocol datatransmission over a Point-to-Point Protocol link.

Internet Protocol Flow Information eXport (IPFIX)An IETF standard that improves the Netflow V9protocol. IPFIX monitors IP flows on the NortelEthernet Routing Switch 8600 platforms, and onother Nortel switching platforms.

Internet Protocol multicast (IPMC)The technology foundation for audio andvideo streaming, push applications, softwaredistribution, multipoint conferencing, and proxyand caching solutions.

Internet Protocol security (IPsec)A secure version of the Internet Protocol (IP) thatprovides optional authentication and encryptionat the packet level.


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Internet Protocol version 4 (IPv4)The protocol used to format packets for theInternet and many enterprise networks. IPv4provides packet routing and reassembly.

Internet Protocol version 6 (IPv6)An improved version of the IP protocol. IPv6improves the IPv4 limitations of security and useraddress numbers.

Internetwork Packet Exchange (IPX)A network layer protocol. IPX is similar to IP butdoes not guarantee packet delivery.

interswitch trunking (IST)A feature that uses one or more parallelpoint-to-point links to connect two aggregationswitches. The two aggregation switches use thischannel to share information and operate as asingle logical switch. Only one interswitch trunkcan exist on each Split Multilink Trunking (SMLT)aggregation switch.

internal spanning tree (IST)Runs in a given multiple spanning tree (MST)region. Within an MST region, you can configuremultiple spanning instances. Instance 0 within aregion is the IST.


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jitterThe delay variance between received packets.Packets may not arrive at the destinationaddress in consecutive order, or on a timelybasis, and the signal can vary from its originalreference timing. This distortion damagesmultimedia traffic.


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labelA fixed length header that an LSR uses toforward packets along a Label Switched Path(LSP). A label represents a FEC.

label bindingAn association between a label and a FEC,which can be advertised to neighbors toestablish an LSP.

label advertise modeThis mode (downstream unsolicited ordownstream on demand) determines when theinterface distributes label mappings to the nexthop upstream.

label distribution modeThis mode (independent or ordered) specifieshow an LSR binds a label to a FEC.

Label Distribution Protocol (LDP)Provides a mechanism for dynamic hop-by-hoplabel distribution between routers in aMultiprotocol Label Switching (MPLS) network.LDP assigns labels to IGP-learned routes anddistributes the label bindings to its peers, toestablish label switched paths (LSP) through thenetwork.

LDP target addressIP address of the remote peer to which atargeted LDP session is formed. On the EthernetRouting Switch 8600, this address is equivalentto the MPLS router ID of the remote peer and theCLIP address of the egress LER.


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label edge router (LER)Resides at the network edge to initiate andterminate label switched paths and assignpackets to forward equivalence class (FEC) astraffic enters the Multiprotocol Label Switching(MPLS) network.

label information base (LIB)A table of incoming labels, outgoing labels, andinterface mappings.

label retention modeThis mode (liberal or conservative) specifieswhether or not the interface retains labelbindings that it receives

label stackMPLS uses a label stack, which can containmultiple labels. For example, in a stackcontaining two labels, the bottom labelrepresents the egress Peripheral Equipment(PE) and the top label represents the next hopalong the LSP. To move a packet across thenetwork, LSRs swap out the top label to forwardthe packet to the next hop.

label switched path (LSP)An end-to-end unidirectional tunnel betweenMPLS-enabled routers. Data travels throughthe MPLS network over LSPs from the networkingress to the network egress.

label switched router (LSR)A core router that operates between the sourceand destination LERs in an MPLS network.LSRs strip off the existing label and applies anew label that tells the next-hop LSR how toforward the packet.

label use modeThis mode (immediate or not immediate)specifies when the interface uses the label forthe next hop.


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last member query interval (LMQI)The time between when the last IGMP memberleaves the group and the stream stops.

latencyThe time between when a node sends amessage and receipt of the message by anothernode; also referred to as propagation delay.

Layer 2 (L2)The Data Link Layer of the Open SystemInterconnection (OSI) model. Examples of Layer2 protocols are Ethernet and Frame Relay.

Layer 3 (L3)The Network Layer of the OSI model. Examplesof Layer 3 protocols are Internet Protocol (IP)and Internetwork Packet Exchange (IPX).

light emitting diode (LED)A semiconductor diode that emits light when acurrent passes through.

Lightweight Directory Access Protocol (LDAP)A network protocol designed to work on TCP/IPstacks to extract information from a hierarchicaldirectory such as X.500.

line cardA card that goes into slots 1 to 4 or 7 to 10 of aNortel Ethernet Routing Switch 8600 chassis.The card provides network connectivity forvarious media (Layer 0) and protocol types. Acard is also called a module.

Link Aggregation Control Protocol (LACP)A protocol that exists between two bridgeendpoints.

Link Aggregation Control Protocol Data Units(LACPDUs)link aggregation group (LAG)

A group that increases the link speed beyond thelimits of any one single cable or port, and alsoincreases the redundancy for higher availability.


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44 L

link-state advertisement (LSA)Packets that contain state information aboutdirectly connected links (interfaces) andadjacencies. Each Open Shortest Path First(OSPF) router generates the packets.

link-state database (LSDB)A database built by each OSPF router to storeLSA information. The router uses the LSDB tocalculate the shortest path to each destination inthe autonomous system (AS), with itself at theroot of each path.

load balancing (LB)The practice of splitting communication into two(or more) routes or servers.

local access transport area (LATA)A geographical area where an operatingcompany offers telecommunication-relatedservices.

Local Area Network (LAN)A data communications system that lies within alimited spatial area, uses a specific user groupand topology, can connect to a public switchedtelecommunications network (but is not one).

Logical Link Control (LLC)A protocol used in LANs to transmit protocoldata units between two end stations. This LLClayer addresses and arbitrates data exchangebetween two endpoints.

Logical Provider Edge (LPE)The LPE distributes the processing of VPNsacross the Ethernet Routing Switch 8600.


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management information base (MIB)Defines system operations and parameters usedfor the Simple Network Management Protocol(SNMP).

markingA process that uses defined rules to assign theDifferentiated Services Code Point (DSCP) in apacket.

maskA bit string that is used along with an IP addressto indicate the number of leading bits in theaddress that correspond with the network part.

maximum burst size (MBS)One of a set of traffic characterization valuesthat defines traffic characteristics through thetraffic descriptor types. MBS defines the lengthin cells of a traffic burst relative to the peak cellrate (PCR), which it cannot exceed, and thesustained cell rate (SCR), which it can exceedbut only for a time period defined by bursttolerance (BT).

maximum transmission unit (MTU)The largest number of bytes in a packet—theMaximum Transmission Unit of the port.

mediaA substance that transmits data betweenports; usually fiber optic cables or category 5unshielded twisted pair (UTP) copper wires.


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Media Access Control (MAC)Arbitrates access to and from a shared medium.

media access unit (MAU)The equipment in a communications systemthat adapts or formats signals, such as opticalsignals, for transmission over the propagationmedium.

media dependent adapter (MDA)An independent module, that features an input oroutput port that interfaces to a media connector.

Message Digest 5 (MD5)A one-way hash function that creates a messagedigest for digital signatures.

metropolitan area network (MAN)A broadband network that covers an area largerthan a Local Area Network.

microflowA single instance of an application-to-applicationpacket flow identified by source address,destination address, protocol ID, and sourceport.

Minimum Link (MinLink)Minimum Link defines the minimum number ofactive links required for a LAG to remain in theforwarding state.

mirrored portThe port to mirror. The port is also called thesource port.

mirroring portThe port to which all traffic is mirrored, alsoreferred to as the destination port.

mirroring multilink trunkThe multilink trunk to which the traffic is mirrored.

mirroring VLANThe virtual Local Area Network (VLAN) to whichthe traffic is mirrored.


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multicast group ID (MGID)A hardware mechanism in the egress path thatdirects data to several ports simultaneously.

multihomed ASAn AS that has multiple connections to one ormore ASs and does not carry transit traffic.

Multicast Link Discovery (MLD)An asymmetric protocol. MLD specifies separatebehaviors for multicast address listeners andmulticast routers.

multicast router discovery (MRDISC)Provides the automatic discovery of multicastcapable routers. By listening to multicast routerdiscovery messages, Layer 2 devices candetermine where to send multicast sourcedata and Internet Group Management Protocol(IGMP) host membership reports.

Multicast Router Discovery Protocol (MRDP)Discovers multicast routers in a Layer 2 bridgeddomain configured for IGMP snooping.

Multicast Router Learning Protocol (MRLP)Provides basic information between two coreswitches, for example, neighbor informationlearning for edge switches, messages thatdetermine the forwarder, and multicast treebuilding information related to the edge switch.

Multicast Source Discovery Protocol (MSDP)A mechanism that connects multiple IP version4 Protocol Independent Multicast Sparse-Mode(PIM-SM) domains. Rendezvous points (RPs) indifferent domains use MSDP to know multicastsources for a group. Each PIM-SM domain usesits own independent RP and does not depend onRPs in other domains.

MultiLink Trunking (MLT)A method of link aggregation that uses multipleEthernet trunks aggregated to provide a singlelogical trunk. A multilink trunk provides the


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combined bandwidth of multiple links and thephysical layer protection against the failure of asingle link.

multimode fiber (MMF)A fiber with a core diameter larger than thewavelength of light transmitted that allowsmany modes of light to propagate. Commonlyused with LED sources for low speed and shortdistance lengths. Typical core sizes (measuredin microns) are 50/125, 62.5/125 and 100/140.

multiplexingCarriage of multiple channels over a singletransmission medium; a process where adedicated circuit is shared by multiple users.Typically, data streams intersperse on a bit orbyte basis (time division), or separate by differentcarrier frequencies (frequency division).

multiplexer (MUX)A device that combines two or more signals intoa signal composite data stream for transmissionon a single channel.

multiple spanning tree bridgeA bridge that supports the common spanningtree (CST) and one or more multiple spanningtree instances (MSTI) and selectively mapsframes classified in a VLAN to the CST or anMSTI.

multiple spanning tree configuration identifierA name for the revision level and summary of agiven allocation of VLANs to spanning trees.

multiple spanning tree configuration tableAllocates every possible VLAN to the CST or aspecific MSTI.

multiple spanning tree instance (MSTI)One of a number of spanning trees calculatedby the Multiple Spanning Tree Protocol (MSTP)within an MST Region, to provide a simple andfully connected active topology for frames thatbelong to a VLAN mapped to the MSTI.


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Multiple Spanning Tree Protocol (MSTP)Configures multiple instances of the RapidSpanning Tree Protocol (RSTP) on the switch.

multiple spanning tree regionA set of LANs and MST bridges physicallyconnected by ports on the MST bridges.

Multiprotocol Label Switching (MPLS)A technique promoted by the InternetEngineering Task Force (IETF) that integratesthe label-swapping paradigm with network-layerrouting to flexibly provide high-speed serviceswith quality-of-service guarantees over IP andATM networks.


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nanometer (nm)One billionth of a meter (109 meter). A unitof measure commonly used to express thewavelengths of light.

neighbor discovery (ND)Used by IPv6 nodes (routers and hosts) on thesame link to discover link layer addresses andobtain and advertise various network parametersand reachability information.

Network Access Server (NAS)any client, such as an Ethernet Routing Switch5500 Series box, that makes TACACS+authentication and authorization requests, orgenerates TACACS+ accounting packets.

Network Address Translation (NAT)Provides access to the Internet for networkports by using one or more globally uniqueIP addresses. Use NAT on a network to useone set of network addresses internally and adifferent set externally.

Network Basic Input/Output System (NetBIOS)An application programming interface (API) thataugments the DOS BIOS by adding specialfunctions for Local Area Networks (LANs).

Network Interface Card (NIC)A network interface device (NID) in the form ofa circuit card installed in an expansion slot of acomputer to provide network access.


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Network Time Protocol (NTP)A protocol that works with TCP that assuresaccurate local time keeping with reference toradio and atomic clocks located on the Internet.NTP synchronizes distributed clocks withinmilliseconds over long time periods.

network-to-network interface (NNI)An interface between two networks in differentmanagement domains.

next hopThe next hop to which a packet can be sent toadvance the packet to the destination.

Next Hop Label Forwarding Entry (NHLFE)n index used to forward a labeled packet.It contains the next hop of the packet andinstructions of what to do, either swap the labelor pop the label stack.

nonbroadcast multiaccess (NBMA)Interconnects multiple devices over a broadcastnetwork through point-to-point links. NBMAreduces the number of IP addresses required forpoint-to-point connections.

nondispersion-shifted fiber (NDSF)A type of optical fiber optimized for the 1310 nmtransmission window.

NonVolatile Random Access Memory (NVRAM)Random Access Memory that retains its contentsafter electrical power turns off.

nonzero-dispersion-shifted fiber (NZDSF)A type of optical fiber optimized for high bit-rateand dense wavelength-division-multiplexingapplications.

Nortel Networks command line interface (NNCLI)Nortel Networks command line interface (NNCLI)is a common CLI that follows the industrystandard. NNCLI is a common user interface fordevice management across Nortel products.


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not so stubby area (NSSA)Prevents the flooding of external link-stateadvertisements (LSA) into the area by providingthem with a default route. An NSSA is aconfiguration of the Open Shortest Path First(OSPF) protocol.


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O

Open Shortest Path First (OSPF)A link-state routing protocol used as an InteriorGateway Protocol (IGP).

Open Systems Interconnection (OSI)A suite of communication protocols, networkarchitectures, and network managementstandards produced by the InternationalOrganization for Standardization (ISO).OSI-compliant systems can communicate withother OSI-compliant systems for a meaningfulexchange of information.

operation, administration, and maintenance (OAM)All the tasks necessary for providing,maintaining, or modifying switching systemservices.

Optical Ethernet (OE)Provides seamless Layer 2 Ethernet connectivityfor enterprise customers across bothmetropolitan area networks (MAN) andwide area networks (WAN).

Optical Ethernet Auto Discovery Mechanism (OE-ADM)In the LPE, auto-discovery and distributionof VPN memberships are facilitated by theOE-ADM. The OE-ADM is a set of simplemessages that are sent by the PE-Edges to thePE-Core, which result in provisioning actions onthe PE-Core.


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Optical Carrier-level 3 concatenation (OC-3c/STM-1)An optical fiber transmission system thatcarries Synchronous Transport Signal(STS)-3c/Synchronous Transport Module(STM)-1 frame structures at 155 Mbit/s.Concatenation means only one logical datastream (rather than supporting a channelizedstructure) exists.

Optical Carrier-level 12 concatenation (OC-12c/STM-4)An optical fiber transmission system that carriesSTS-12c/STM-4 frame structures at 622 Mbit/s.Concatenation means only one logical datastream (rather than supporting a channelizedstructure) exists.

Optical Time Domain Reflectometer (OTDR)Device used to inspect optical fiber links bysending optical pulses down the link andmonitoring the light reflected back to the device.Can calculate overall fiber attenuation andhighlight points of loss or breaks in the fiber.

out of band (OOB)The capacity to deliver information using amodem or other asynchronous connection.


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P

Packet Capture Tool (PCAP)A data packet capture tool that captures ingressand egress (E-modules only) packets onselected I/O ports. You can analyze capturedpackets for troubleshooting purposes.

packet lossExpressed as a percentage of packets droppedover a specified interval. Keep packet loss to aminimum to deliver effective IP telephony and IPvideo services.

Packet over SONET (PoS)A technology that carries IP packets directlyover Synchronous Optical Network (SONET) formetropolitan area networks (MAN) and wide areanetworks (WAN) without a data-link facility.

packet transmission opportunities (PTO)Used to assign weights to the eight egressqueues. The switch assigns additional PTOsto high priority queues so time sensitivetransmissions forward with minimum latency.

Password Authentication Protocol (PAP)A procedure used by Point-to-Point Protocol(PPP) servers to validate a connection request.The PAP is the simplest method of enablingsecurity on PPP links. During link establishment,the peer (caller) sends its peer ID and passwordto the authenticator. If the ID and passwordmatch the values stored by the Authenticator, theconnection proceeds.


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peak cell rate (PCR)The upper limit on the time interval between twoconsecutive ATM cell emissions.

penultimate routerPenultimate means next-to-last. In this case, itrefers to the next-to-last provider router in thenetwork.

per-hop behavior (PHB)A traffic class forwarding treatment based oncriteria defined in the DiffServ field.

permanent virtual connection (PVC)An ATM channel connection or path connectionconfigured at the network management interface.

Personal Computer Memory Card InternationalAssociation (PCMCIA)

A standard software and hardware interface thataccommodates credit-card-sized hardware cardsinto a personal computer.

physical layer (PHY)Layer 1 of the Open System Interconnection(OSI) model that provides raw informationchannels to Layer 2. Protocols depend onwhether the interface is the basic rate inteface(BRI) or primary rate interface (PRI).

Port Interface Module (PIM)A Field Programmable Gate Array (FPGA)device on the R module.

point of presence (PoP)A physical layer within a local access andtransport area (LATA) at which an interLATAcarrier establishes itself to obtain LATA access,and to which the local exchange carrier providesaccess services.


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Point-to-Point Protocol (PPP)A network protocol used to dial into anInternet Service Provider (ISP). Serial LineInterface Protocol (SLIP) and PPP provide fullTransmission Control Protocol/Internet Protocol(TCP/IP) capabilities to the casual dial-up user.

policingEnsures that a traffic stream follows the domainservice provisioning policy or service levelagreement (SLA).

portA physical interface that transmits and receivesdata.

Port Access Entity (PAE)Software that controls each port on the switch.The PAE, which resides on the Nortel EthernetRouting Switch 8600, supports authenticatorfunctionality. The PAE works with the ExtensibleAuthentication Protocol over LAN (EAPoL).

port mirroringA feature that sends received or transmittedtraffic to a second destination.

port VLAN IDUsed to coordinate VLANs across multipleswitches. When you create a port-based VLANon a switch, assign a VLAN identification number(VLAN ID) and specify the ports that belong tothe VLAN.

PPP over Ethernet (PPPoE)Uses the Point-to-Point Protocol with Ethernet asthe transport protocol.

Pragmatic General Multicast (PGM)A standard transport-level protocol thataddresses the disadvantages inherent in othermulticasting protocols such as unreliable packetdelivery, packet duplication, and networkcongestion.


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prefixA group of contiguous bits, from 0 to 32 bits inlength, that defines a set of addresses.

primary rate interface (PRI)An integrated service digital network (ISDN)interface standard designed in North America ashaving 23 circuit-switched B channels and one Dchannel, which operate at 64 kbit/s.

private virtual circuit (PVC)An ATM channel connection or path connectionconfigured at the network management interface.

Provider Edge (PE) deviceA device owned and operated by the serviceprovider. It maintains knowledge of VPNinformation and enforces service levelagreements. The PE hosts the UNIs that supplyVPN services to customers and is logicallyadjacent to the CE.

Protocol Data Units (PDUs)A unit of data that is specified in a protocol of agiven layer and that consists of protocol-controlinformation of the given layer and possibly userdata of that layer.

programmable I/O module (PIM)A Field Programmable Gate Array (FPGA)device on the R module.

Protocol Independent Multicast multicast border router(PIM MBR)

Connects PIM domains to other multicast routingdomains and to the Internet.

Protocol Independent Multicast, Source Specific(PIM-SSM)

Uses only shortest-path trees to providemulticast services based on subscription to aparticular (source, group) channel.


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Protocol Independent Multicast, Sparse Mode (PIM-SM)Adds a Rendezvous Point router to avoidmulticast-data flooding. Use PIM–SM whenreceivers for multicast data are sparselydistributed throughout the network.

Protocol Independent Multicast, Split MultiLink Trunking(PIM-SMLT)

Builds a virtual switch that represents the twoswitches of the split multilink trunk core.

provider core router (P router)A router in the core of a provider network thatsupports tunnels between provider edge (PE)routers, but is not connected to a customerdevice. P routers do not need to support VPNfunctionality.

provider edge (PE)A router in the provider network that connects tocustomer edge (CE) devices located at customersites. PE routers support VPN functionality.Within a single VPN, pairs of PE routers connectthrough a multiprotocol label switching (MPLS)label switched path (LSP) tunnel. A PE routercan act as a P router.


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quality of service (QoS)The collective effect of service performances thatdetermine the degree of satisfaction of a serviceuser.


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Random Access Memory (RAM)Memory into which you can write and read data.A solid state memory device used for transientmemory stores. You can enter and retrieveinformation from any storage position.

Rapid Spanning Tree Protocol (RSTP)Reduces the recovery time after a networkbreakdown. RSTP enhances switch-generatedTopology Change Notification (TCN) packets toreduce network flooding.

Read Write All (RWA)An access class that lets users access all menuitems and editable fields.

Real-Time Streaming Protocol (RTSP)An application-level protocol that addressesreliability, quality, fidelity, packet loss, andstart and stop commands for audio and videoreal-time data streaming.

record route object (RRO)Describes the actual path taken by a labelswitched path (LSP). An RRO describes all thelinks traversed by the LSP. The RRO containsthe IP addresses of the links traversed and cancontain the link labels. RRO is an option usedby the Resource Reservation Protocol-TrafficEngineering (RSVP-TE) protocol when settingup a path in an MultiProtocol Label Switching(MPLS) network.


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reduced instruction set computer (RISC)A computer that employs a small, simplifiedset of frequently used instructions for rapidexecution.

remarkingChanges the Differentiated Services Code Point(DSCP) of a packet, in accordance with a servicelevel agreement (SLA).

Remote Authentication Dial-in User Service (RADIUS)A protocol that authenticates, authorizes, andaccounts for remote access connections that usedial-up networking and virtual private network(VPN) functionality.

remote defect indication (RDI)A signal transmitted upstream when a systemdetects a downstream fault.

remote login (rlogin)An application that provides a terminal interfacebetween hosts (usually UNIX) that use theTCP/IP network protocol. Unlike Telnet, rloginassumes the remote host is, or behaves like, aUNIX host.

remote mirroringA mirroring port that encapsulates traffic intoa Layer 2 header and transmits it to a remotemirror target (RMT) for decapsulation. Thepacket transmits over a Layer 2 network andpreserves the original packet.

remote mirror source (RMS)The port that generates the mirroredencapsulated traffic.

remote mirror target (RMT)The port that decapsulates the remote mirrortraffic and transmits it out of the Nortel EthernetRouting Switch 8600.


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remote monitoring (RMON)A remote monitoring standard for SimpleNetwork Management Protocol (SNMP)-basedmanagement information bases (MIB). TheInternetwork Engineering Task Force (IETF)proposed the RMON standard to provideguidelines for remote monitoring of individualLAN segments.

rendezvous point (RP)The root of the shared tree. One RP existsfor each multicast group. The RP gathersinformation about available multicast servicesthrough the reception of control messages andthe distribution of multicast group information.Protocol Independent Multicast (PIM) uses RPs.

request for comments (RFC)A document series published by the InternetEngineering Task Force (IETF) that describeInternet standards.

requested shaping rate (RSR)One of a set of ATM traffic characterizationvalues used to define traffic characteristicsthrough the traffic descriptor types.

resilient packet ring (RPR)A shared packet edge ring connection, whereboth paths around the ring carry traffic, thatallows double bandwidth on each ring.

Reverse Address Resolution Protocol (RARP)A protocol that maintains a database ofmappings between physical hardware addressesand IP addresses.

reverse path checking (RPC)Prevents packet forwarding for incoming IPpackets with incorrect or forged (spoofed) IPaddresses.

reverse path forwarding (RPF)Prevents a packet from forging its source IPaddress. Typically, the system examines andvalidates the source address of each packet.


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Report Route Object (RRO)A feature of the RSVP. It allows the path throughthe MPLS cloud to be displayed at the sender ofthe path if RRO is set to true.

Resource Reservation Protocol-Traffic Engineering(RSVP-TE)

A label signaling protocol that establishestraffic-engineered label switched paths (LSP)through the Multiprotocol Label Switching(MPLS) network.

RIP (Routing Information Protocol)A distance vector protocol in the IP suite, usedby IP and IPX network-layer protocols, thatenables routers in the same AS to exchangerouting information by means of periodicupdates. It is most often used as a very simpleIGP within small networks.

route flappingAn instability that is associated with a prefix,where the associated prefix routes may exhibitfrequent changes in availability over a period oftime.

route table manager (RTM)Determines the best route to a destination basedon reachability, route preference, and cost.

route reflectorA BGP speaker that advertises routes learnedfrom its route reflector clients to other IBGPneighbors.

route reflector clientA BGP speaker that advertises its learned routesto a route reflector for readvertisement of itsroutes to the rest of the AS.

Routed SMLT (RSMLT)Provides full redundancy in core networks andrapid failover—eliminating routing protocol timerdependencies when network failures occur.


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Remote Service Provider (RSP)Resource Reservation Protocol-Traffic Engineering(RSVP-TE)

A protocol with traffic engineering extensions,which reserves network resources to establishexplicitly routed MPLS tunnels.

Routing Information Protocol (RIP)Distance-vector-based interior gateway routingprotocol.

Routing policyAny form of routing that is influenced by factorsother than the default algorithmically best route,such as the shortest or quickest path.

RSMLT VLANA virtual Local Area Network (VLAN) withRSMLT enabled for router redundancy andprotected by active-active SMLT aggregationswitch default gateways.


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Source Address and Destination Address (SA/ DA)Secure Copy (SCP)

Securely transfers files between the switch anda remote station.

Secure Shell (SSH)Used for secure remote logons and data transferover the Internet. SSH uses encryption toprovide security.

Secure Sockets Layer (SSL)An Internet security encryption andauthentication protocol for secure point-to-pointconnections over the Internet and intranets,especially between clients and servers.

Serial Line Internet Protocol (SLIP)A network protocol installed in a computer topermit access to communications services, suchas the Internet, e-mail, Telnet, File TransferProtocol (FTP), and the Web.

Service Advertisement Protocol (SAP)Used by printers, file servers, and gatewaysto announce their availability to nodes on thenetwork.

service level agreement (SLA)A service contract that specifies the forwardingservice that traffic receives.


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shimMPLS uses a shim header for Ethernet packetsso they can accommodate a label in theirheader. MPLS uses the shim to make forwardingdecisions. The shim label is a 32-bit identifierused to identify a FEC.

shortest path first (SPF)A class of routing protocols that use Djikstra’salgorithm to compute the shortest path througha network, according to specified metrics, forefficient transmission of packet data.

shortest path tree (SPT)Creates a direct route between the receiver andthe source for group members in a ProtocolIndependent Multicast - Spare Mode (PIM-SM)domain.

signal computing system architectureAn open-system protocol that describes devicesand specifies interfaces for a signal processingsystem for PC-based communicationsprocessing.

Simple Network Management Protocol (SNMP)Administratively monitors network performancethrough agents and management stations.

Simple Loop Prevention Protocol (SLPP)Is used to prevent loops in a SMLT network.

Single Link SMLT (SLT)single mode fiber (SMF)

One of the various light waves transmitted inan optical fiber. Each optical signal generatesmany modes, but in single-mode fiber onlyone mode is transmitted. Transmission occursthrough a small diameter core (approximately 10micrometers), with a cladding that is 10 timesthe core diameter. These fibers have a potentialbandwidth of 50 to 100 GHz per kilometer.

single spanning tree bridgeA bridge that can support only a single spanningtree, the common spanning tree (CST).


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SMLT aggregation switchConnects to multiple wiring closet switches,edge switches, or Customer Premise Equipment(CPE) devices.

SMLT clientA switch located at the edge of the network,such as in a wiring closet or CPE. An SMLTclient switch performs link aggregation but doesnot require Split MultiLink Trunking (SMLT)intelligence.

source path messages (SPM)Allows the network element, a Nortel EthernetRouting Switch 8600 with Pragmatic GeneralMulticast (PGM) enabled, to learn the sourcepath and maintain information about the PGMsession.

spanning treeA simple, fully-connected active topology formedfrom the arbitrary physical topology of connectedbridged Local Area Network components byrelaying frames through selected bridge ports.The protocol parameters and states that areused and exchanged to facilitate the calculationof the active topology and to control the bridgerelay function.

Spanning Tree Group (STG)A collection of ports in one spanning treeinstance.

Spanning Tree Protocol (STP)MAC bridges use the STP to exchangeinformation across Local Area Networks tocompute the active topology of a bridged LocalArea Network in accordance with the SpanningTree Protocol algorithm.

Split MultiLink Trunking (SMLT)A Nortel extension to IEEE 802.3ad, providesnodal and link failure protection and flexiblebandwidth scaling to improve on the level ofLayer 2 resiliency.


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SSL Acceleration Module (SAM)Intelligently accelerates secure businesstransactions and confidential data by off-loadingSSL processing from local servers withoutimposing delays on other traffic in the same datapath.

sustainable cell rate (SCR)The expected rate of cell transmission on anonconstant bit rate (CBR) transmission.

Switch Fabric (SF)In signal computing system architecture(SCSA), the facility that connects two (or more)transmitting or receiving service providers.Network interfaces reside on line cards thatprovide connection between a switch fabric andexternal networks.

Switch Fabric/Central Processor Unit (SF/CPU)The board that resides in slot 5 or 6 of the NortelEthernet Routing Switch 8600 system chassis.

switched multimegabit data service (SMDS)A connectionless, broadband, packet-switcheddata service that provides LAN-like performanceand features in metropolitan or wide areas.

synchronous digital hierarchy (SDH)A European digital transmission hierarchy basedon time division multiplexing.

Synchronous Dynamic Random Access Memory(SDRAM)

A form of dynamic random access memory(DRAM) that can run at higher clock speeds thanconventional DRAM. SDRAM employs a burstingtechnique in which the DRAM predicts theaddress of the next memory location to access.

synchronous optical network (SONET)A family of fiber optic transmission rates thatprovides the flexibility to transport many digitalsignals with different capacities. This American


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National Standards Institute (ANSI) standardprovides transmission from OC-1 to OC-48 andgreater.

System Administration, Networking and SecurityInstitute (SANS)

The research and education organizationfor network administrators and securityprofessionals.


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Terminal Access Controller Access-Control System Plus(TACACS+)

TACACS+ is a security application implementedas a client/server-based protocol that providescentralized validation of users attempting to gainaccess to a router or network access server.TACACS+ is a Transmission Control Protocol(TCP)-based protocol that uses full packetencryption.

TCP (Transport Control Protocol)The main reliable transport protocol used in theInternet (and with BGP).

transparent domain identifier (TDI)A User-to-Network Interface (UNI) portconfigured as transparent service type assignsall traffic to its associated transparent domainusing the TDI.

Transparent LAN Service (TLS)TLS is the component of the Nortel Networks OEsolution that allows a group of customer sites toappear as one single LAN, regardless of theirgeographic location. (See also Virtual PrivateLAN Services [VPLS]).

Time Division Multiplexing (TDM)A method that obtains a number of channelsover a single path by dividing the path into anumber of time slots and then assigning eachchannel its own intermittently repeated time slot.


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time-to-live (TTL)The field in a packet used to determine the validduration for the packet; the TTL determines thepacket lifetime. The system discards a packetwith a TTL of zero.

traffic engineering (TE)A method that guarantees performance in anetwork.

traffic profileThe temporal properties of a traffic stream, suchas rate.

transit ASAn AS that has multiple connections to oneor more ASs and is used (with certain policyrestrictions) to carry both transit and local traffic.

Transmission Control Protocol (TCP)Provides flow control and sequencing fortransmitted data over an end-to-end connection.

Transmission Control Protocol over IP (TCP/IP)A protocol stack designed to connect differentnetworks.

Transparent LAN Services (TLS)A network application that provides a virtualLocal Area Network (VLAN) the ability to transmitcustomer Ethernet packets across a sharednetwork.

Trivial File Transfer Protocol (TFTP)A protocol that governs transferring files betweennodes without protection against packet loss.

trunkA logical group of ports that behaves like a singlelarge port.

trunk portOn the Ethernet Routing Switch 8600, atrunk port is a port that connects to theservice provider network such as the MPLSenvironment.


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type of service (TOS)A field in the IPv4 header that determines theClass of Service prior to the standardization ofDifferentiated Services.

tunnelSee LSP.

tunnel groupsA collection of RSVP tunnels.

Television (TV)A widely used telecommunication system forbroadcasting and receiving moving pictures andsound over a distance.


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universal asynchronous receiver-transmitter (UART)A device that converts outgoing parallel data toserial transmission and incoming serial data toparallel for reception.

Universal/Local (U/L)Determines global and local link addresses; usedwith the Extended Unique Identifier (EUI).

universal resource locator (URL)A standardized method that represents differentdocuments, media, and network services on theWorld Wide Web.

UNIXA powerful and complex computer operatingsystem that runs data processing and telephonesystems. Provides multitasking, multiusercapabilities.

unshielded twisted pair (UTP)A cable with one or more pairs of twistedinsulated copper conductors bound in a singleplastic sheath.

user-based security model (USM)A security model that uses a defined set of useridentities for authorized users on a particularSimple Network Management Protocol (SNMP)engine.

user-based policies (UBP)Establishes and enforces roles and conditions onan individual user basis for access ports in thenetwork.


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82 U

User Datagram Protocol (UDP)In TCP/IP, a packet-level protocol built directlyon the Internet Protocol layer. TCP/IP hostsystems use UDP for application-to-applicationprograms.

user-to-network interface (UNI)An interface between ATM user equipment andATM network equipment.

upstream nodeAn upstream node refers to the node that thepacket exits on its way to the downstream nodeon the next hop LSR.


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83.

V

variable bit rate (VBR)The capability of the encoding algorithm todynamically switch between 32 and 24 kbytes/s.

view-based access control model (VACM)Provides context, group access, and groupsecurity levels based on a predefined subset ofmanagement information base (MIB) objects.

virtual connection (VC)A communication channel that providessequential unidirectional transport ofAsynchronous Transfer Mode (ATM) cellsamong ATM layer entities.

Virtual Link Aggregation Control Protocol (VLACP)A Layer 2 handshaking protocol which can detectend-to-end failure between two physical Ethernetinterfaces.

Virtual Local Area Network (VLAN)Virtual LAN as defined in the IEEE 802.1Qstandard. VLANs divide the LANs into smallergroups without interfering with the physicalnetwork.

Virtual Private LAN Service (VPLS)A multipoint virtual private network (VPN).

Virtual Private Network (VPN)A private communications network that usespublic networks to transfer data. VPN users canbe in geographically separate locations.


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virtual private network identifier (VPN-ID)A globally significant VPN identifier.

virtual router (VR)An abstract object managed by the VirtualRouter Redundancy Protocol (VRRP) that actsas a default router for hosts on a shared LAN.

virtual router forwarding (VRF)Provides traffic isolation between the customersoperating over the same node. Each virtualrouter emulates the behavior of a dedicatedhardware router by providing separate routingfunctionality, and the network treats each VRF asa separate physical router.

Virtual Router Redundancy Protocol (VRRP)A protocol used in static routing configurations,typically at the edge of the network. This protocoloperates on multiple routers on an IP subnetand elects a primary gateway router. When theprimary router fails, a backup router is quicklyavailable to take its place.

Voice over IP (VOIP)The technology that delivers voice informationin digital form in discrete packets using theInternet Protocol (IP) rather than the traditionalcircuit-committed protocols of the public switchedtelephone network (PSTN).


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W

wavelength division multiplexing (WDM)Simultaneously transmits many colors(wavelengths) of laser light down the sameoptical fiber to increase the amount of transferredinformation.

Web Switching Module (WSM)Provides content-intelligent processing ofWeb-based traffic.

weighted round robin (WRR)A mechanism that uses the packet transmitopportunity (PTO) of a queue to determine whichqueue to process first.

well-known attributeA BGP attribute that is required to be known byall BGP implementations.

Wide Area Network (WAN)A network that provides communication servicesto a geographic area larger than that served bya Local Area Network or a metropolitan areanetwork, and that can use or provide publiccommunication facilities.

wiring closet (WC)A central termination area for telephone ornetwork cabling or both.


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87.

Customer serviceVisit the Nortel Web site to access the complete range of services andsupport that Nortel provides. Go to www.nortel.com, or go to one of thepages listed in the following sections.

Navigation• “Updated versions of documentation” (page 87)

• “Getting help” (page 87)

• “Express Routing Codes” (page 87)

• “Additional information” (page 88)

Updated versions of documentationYou can download and print the latest versions of Nortel Ethernet RoutingSwitch 8600 NTPs and Release Notes directly from the Internet atwww.nortel.com/documentation.

Getting helpIf you purchased a service contract for your Nortel product from adistributor or authorized reseller, contact the technical support staff for thatdistributor or reseller for assistance.

If you purchased a Nortel service program, you can get help bycontacting one of the Nortel Technical Solutions Centers found athttp://www.nortel.com/callus; or visit our Technical Support site athttp://www.nortel.com/support.

Express Routing CodesAn Express Routing Code (ERC) is available for many Nortel products andservices.

When you use an ERC, your call is routed to a technical support personwho specializes in supporting that particular product or service. To locatean ERC for a product or service, go to http://www.nortel.com/erc.


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http://www.nortel.com/

http://support.nortel.com/go/main.jsp

http://www.nortel.com/cgi-bin/comments/comments.cgi

http://support.nortel.com/go/main.jsp?cscat=MYSUPPORT=MYSUPPORT

http://www.nortel.com/help/contact/erc/index.html

88 Customer service

Additional informationUse the information in the following table to access other areas of theNortel Web site.

For information about Contact

Contact Us www.nortel.com/contactus

Documentation feedback www.nortel.com/documentfeedback

Products (marketing) www.nortel.com/products

Partner Information Center (PIC) www.nortel.com/pic

Register www.nortel.com/register

Search www.nortel.com/search

Services www.nortel.com/services

Training www.nortel.com/training


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http://www.nortel.com/cgi-bin/comments/comments.cgi

http://www.nortel.com/documentfeedback

http://products.nortel.com/go/product_index.jsp

http://www.nortel.com/prd/picinfo/index.html

https://www161.nortelnetworks.com/Register/RegisterMVCController.jpf

http://www.nortel.com/search

http://products.nortel.com/go/service_index.jsp

http://app97.nortelnetworks.com/cgi-bin/teds/cs/maintc.jsp

Nortel Ethernet Routing Switch 8600

TerminologyCopyright © 2009 Nortel NetworksAll Rights Reserved.

Release: 5.1Publication: NN46205-102Document revision: 02.01Document release date: 16 March 2009

To provide feedback or to report a problem in this document, go to www.nortel.com/documentfeedback.

www.nortel.comLEGAL NOTICEWhile the information in this document is believed to be accurate and reliable, except as otherwise expressly agreed to in writingNORTEL PROVIDES THIS DOCUMENT "AS IS" WITHOUT WARRANTY OR CONDITION OF ANY KIND, EITHER EXPRESSOR IMPLIED. The information and/or products described in this document are subject to change without notice.

THE SOFTWARE DESCRIBED IN THIS DOCUMENT IS FURNISHED UNDER A LICENSE AGREEMENT AND MAY BE USEDONLY IN ACCORDANCE WITH THE TERMS OF THAT LICENSE.

Nortel, the Nortel logo, and the Globemark are trademarks of Nortel Networks.

SANS is a trademark of The SANS Institute.

All other trademarks are the property of their respective owners.

Documents

NN46205-102_02.01_Terminology