Free Trial

Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.

  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Part 2: Part Two > Acronyms

Acronyms


2G

Second-generation mobile network


3G

Third-generation mobile network


6PE

A scheme to allow IPv6 traffic to be carried over an IPv4 MPLS network


AAL

ATM Adaptation Layer


ABR

Area Border Router. A router used to connect two OSPF areas


AC

Attachment Circuit. In the context of Layer 2 VPNs, the physical or logical circuit used to connect a CE to a PE


AF

Assured Forwarding DiffServ class


AFI

Address Family Identifier. In BGP, the identity of the network layer protocol associated with the network layer reachability information being advertised


AIS

Alarm Indication Signal. In SONET/SDH networks and ATM networks, a means of signaling in the downstream direction the existence of a fault


APS

Automatic Protection Switching. A method for providing protection at the SONET/SDH layer by moving the traffic to a standby link


ARP

Address Resolution Protocol


AS

Autonomous System. A collection of routers belonging to the same administrative entity and having a common external routing policy


ASBR

Autonomous System Border Router. A router used to connect two ASs


ATM

Asynchronous Transfer Mode


ATM PVC

ATM Permanent Virtual Channel


BC

Bandwidth Constraint. In DiffServ Aware Traffic Engineering, BCs determine the bandwidth availability on a link for a Class Type or group of Class Types


BE

Best Effort DiffServ class


BECN

Backward Explicit Congestion Notification. In Frame Relay networks, a message sent towards the transmission source indicating the existence of congestion in the network


BFD

Bidirectional Forwarding Detection. A protocol to detect faults in the bidirectional path between two forwarding engines


BGP

Border Gateway Protocol. An interautonomous system routing protocol. The current version of BGP is BGP-4, described in RFC 4271


BGP-MP

BGP Multiprotocol extensions, documented in RFC 4760


BSC

Base Station Controller, used in 2G mobile networks


BSR

Broadband Services Router


BTS

Base Transceiver Station, used in 2G mobile networks


CAC

Call Admission Control


CAPEX

CAPital Expenditure


CBR

Constant Bit Rate. An ATM service category having a constant maximum bandwidth allocation. Often used for real-time applications


CCC

Circuit Cross Connect. A scheme for the transport of Layer 2 frames over an MPLS network


CE

Customer Edge (usually designates equipment at the edge of the customer's network)


CIR

Committed Information Rate. In Frame Relay networks, the bandwidth associated with a logical connection.


CLI

Command Line Interface


CLNS

ConnectionLess Network Service. A service defined by the Open Systems Interconnect (OSI) that does not require the existence of a connection in order to send data


CLP

Cell Loss Priority. A bit in the ATM cell header that indicates whether the cell is a candidate for being dropped in the presence of congestion


CoC

Carrier of Carriers. In the context of BGP/MPLS L3VPN, a carrier providing VPN transit to a customer who is himself a carrier


CoS

Class of Service


CPE

Customer Premise Equipment


CPU

Central Processing Unit


CR-LDP

Constrained-based Routing LDP


CsC

Carrier's Carrier - see CoC


CSPF

Constrained Shortest Path First. In traffic engineering, the algorithm used to compute the paths of MPLS LSPs


CSV

Circuit Status Vector. In BGP-signaled L2VPNs, a means for a PE to communicate to remote PEs the state of its connectivity


CT

Class Type. In Differentiated Services Aware Traffic Engineering, a set of classes that have a common aggregate bandwidth requirement of the network


CV

Connection Verification


DCN

Data Communications Network


DE

Discard Eligible. A bit in the Frame Relay header that indicates whether the cell is a candidate for being dropped in the presence of congestion


DiffServ

Differentiated Services


DiffServ-TE

Differentiated Services Aware Traffic Engineering


DLCI

Data Link Connection Identifier. In Frame Relay networks, the means by which a logical circuit is identified


DoS

Denial of Service


DSCP

DiffServ Code Point. A 6-bit field in the IP packet header that determines the class-of-service treatment received by the packet


DSL

Digital Subscriber Line


DSLAM

Digital Subscriber Line Access Multiplexer


EBGP or eBGP

External Border Gateway Protocol


ECMP

Equal Cost Multi-Path


EF

Expedited Forwarding DiffServ class


EIGRP

Enhanced Interior Gateway Routing Protocol


E-LSP

EXP-inferred LSP (LSP for which the DiffServ behavior is inferred from the EXP bits in the MPLS header)


ERO

Explicit Route Object (used in RSVP-TE to encode path information)


Ethernet OAM

An Operations and Maintenance scheme for Ethernet


EXP

Experimental bits in the MPLS header


FA

Forwarding Adjacency


FA LSP

Forwarding Adjacency LSP, used in LSP hierarchy as a container for other LSPs


FCS

Frame Check Sequence. A set of bits added to a frame in order to detect errors in the frame


FEC

Forwarding Equivalence Class. Packets that are to be forwarded to the same egress point in the network along the same path and with the same forwarding treatment along that path are said to belong to the same FEC


FEC 128

The FEC originally used for signaling pseudowires with LDP. This has now been superseded by FEC 129


FEC 129

The FEC now specified for signaling pseudowires with LDP. It superseded FEC 128


FECN

Forward Explicit Congestion Notification. In Frame Relay networks, a message sent towards the receiver indicating the existence of congestion in the network


FR

Frame Relay


FRR

Fast ReRoute. The process of quickly routing traffic around the point of failure


FTP

File Transfer Protocol


GFP

Generic Framing Procedure. A mechanism to encapsulate packets into SONET/SDH frames


GRE

Generic Routing Encapsulation. A protocol for encapsulation of an arbitrary network layer protocol over another arbitrary network layer protocol


HDLC

High-level Data Link Control


H-VPLS

Hierarchical VPLS


IBGP or iBGP

Internal Border Gateway Protocol


ICMP

Internet Control Message Protocol


IETF

Internet Engineering Task Force: www.ietf.org


IGMP

Internet Group Management Protocol. A protocol to enable the host to join or leave a multicast group. Described in RFC3376


IGMP snooping

A scheme by which routers can inspect the contents of IGMP packets in order to determine the location of receivers and optimize traffic forwarding to only those destinations


IGP

Interior Gateway Protocol


IP

Internet Protocol


IPsec

IP security


IPX

Internetwork Packet eXchange. The network layer protocol in the NetWare operating system


IS-IS

Intermediate System-to-Intermediate System. A link-state IGP described in RFC1195


ISO

International Organization for Standardization


ISP

Internet Service Provider


ITU-T

International Telecommunications Union - Telecommunications


LAN

Local Area Network


LDP

Label Distribution Protocol. LDP is documented in RFC5036


LER

Label Edge Router


L-LSP

Label-inferred LSP. An LSP for which the DiffServ behavior is inferred from the label in the MPLS header


LMI

Local Management Interface. A set of enhancements to the basic Frame Relay specification


LOM

Local Overbooking Multiplier. In the context of DiffServ-TE, it is a factor by which the bandwidth for one particular CT is overbooked


LSA

Link State Advertisement. The advertisement sent by a link-state IGP such as OSPF or IS-IS, containing information about the state of the links


LSP

Label Switched Path


LSPing

LSP ping. A mechanism for detecting MPLS data plane failures, based on similar concepts as ping


LSPtrace

A mechanism based on LSPing, which provides failure localization through a traceroute-like capability


LSR

Label-Switching Router. A router that can forward packets based on the value of a label attached to the packet


MAC address

Media Access Control address. A unique 48-bit identifier that represents the physical address of a device


MAM

Maximum Allocation Model. A bandwidth constraint model for DiffServ-TE. The model enforces strict separation between the bandwidth allocated to the different CTs


Mbps

Mega bits per second


MD5

Message digest 5. The MD5 algorithm is documented in RFC1321. Its purpose is to take as input a message of arbitrary length and produce as output a 128-bit fingerprint (signature)


MDT

Multicast Distribution Tree. In the context of VPN multicast, these are the multicast trees in the provider network that provide connectivity to all the PE servicing sites of a multicast-enabled VPN. Conceptually, the MDT creates the abstraction of a LAN to which all the PEs belonging to a particular VPN are attached. This property is very important for the C-instance PIM sessions between the PEs, which can consider each other as directly connected neighbors over this LAN


MIB

Management Information Base. A formal description of a set of objects that can be managed using SNMP


MP

Merge Point. In the context of MPLS FRR, it is the tail end of the backup tunnel and the point where traffic from the backup merges back into the protected LSP


MP2MP

MultiPoint to MultiPoint. An LSP is MP2MP if it has multiple ingress and egress points


MP-BGP

BGP with multi-protocol extensions, as described in RFC 2858, that allow BGP to carry routing information for multiple network layer protocols


MPLS

MultiProtocol Label Switching. A set of IETF standards to allow traffic to be forwarded based on labels rather than destination addresses


MPLS-TE

MPLS Traffic Engineering. The traffic engineering capabilities of MPLS, implemented through a combination of source-based routing and constrained-based routing.


MSAN

Multi-Service Access Node


MSDP

Multicast Source Discovery Protocol, described in RFC 3618


MTU

Maximum Transmission Unit. The largest physical packet size (measured in octets) that can be sent in a packet or frame-based network


mVPN

Multicast VPN. A VPN that carries multicast traffic


NG m VPN

Next-generation m VPN. The BGP/MPLS-based scheme for supporting multicast in a VPN. Also referred to as next generation to differentiate it from the PIM/GRE-based scheme, which was originally proposed for solving this problem


NLRI

Network Layer Reachability Information. In BGP terminology, a route prefix is referred to as NLRI. Different AFI/SAFI pairs are considered to be different NLRI types


Node B

Base station for 3G mobile networks


NSAP

Network Service Access Point. Type of addressing used by ISO network layer protocols


OAM

Operations And Management, or Operations, Administration and Management. A set of network management functions covering fault detection, performance data and diagnosis capabilities


OPEX

OPerational Expenditure


ORF

Outbound Route Filtering. A method for minimizing the number of BGP advertisements between two peers. The main difference between ORF and RTF is in the scope of the filtering: ORF operates between two peers while RTF can propagate filtering information across multiple hops


OSPF

Open Shortest Path First link-state IGP. OSPFv2 (version 2) is documented in RFC2328


P device

Provider device. Designates a router in the core of a provider's network


P2P

Point to Point. An LSP is P2P if it has exactly one ingress and one egress point


P2MP

Point to MultiPoint. An LSP is P2MP if it has one ingress and multiple egress points


PABX

Private Automatic Branch eXchange. A telephone switch used inside a corporation. It connects internal extensions with each other and provides access (by dialing an access number) to the public telephone network


PBX

Private Branch eXchange. Same as PABX.


PCC

Path Computation Client. A client of a PCE. The PCC may be either a router or another PCE


PCE

Path Computation Element. A network element that can compute TE LSPs for which it is not the head end. For example, an ABR or ASBR can play the role of a PCE. The PCE may also be an independent device in the network.


PCEP

PCE Protocol. Protocol for PCE-PCC and PCE-PCE communication, developed in the PCE working group in the IETF


PDH

Plesiochronous Digital Hierarchy


PDU

Protocol Data Unit


PE device

Provider Edge device. Designates equipment at the edge of the provider's network, providing aggregation of the different CE devices


PHB

Per-Hop Behavior. In the context of DiffServ, defines the packet scheduling, queuing, policing or shaping behavior on a particular node


PHP

Penultimate Hop Popping. The act of removing the MPLS label one hop before the LSP egress


PIM

Protocol Independent Multicast. Defined in RFC2362, RFC3973 and in several documents in the pim Working Group in the IETF


PIM-SM

PIM sparse mode, documented in RFC 4601


PIM-SM ASM

See PIM-SM. In the any-source multicast (ASM) mode of operation, PIM-SM provides a service model where there are multiple sources and multiple receivers for the same group.


PIM-SM SSM

See PIM-SM. In the SSM mode of operation, PIM-SM provides a service model where there is a single multicast source and multiple receivers for each group


PLR

Point of Local Repair. In the context of MPLS FRR, it is the head end of the backup tunnel and the point at which traffic from the protected LSP is locally rerouted around the failed resource using the backup tunnel


PMSI

Provider multicast service interface. An abstraction used in the m VPN architecture document in the IETF. A packet sent over a PMSI by a PE router servicing a certain m VPN will arrive to all or some of the other PEs in the m VPN, and the receiving PEs will know which m VPN the packet belongs to


PoP

Point of Presence. Physical location at which a carrier establishes itself for obtaining local access and transport


PPP

Point-to-Point Protocol


PP VPN

Provider-provisioned VPN. VPNs for which the service provider (SP) participates in the management and provisioning of the VPNs


PSTN

Public Switched Telephone Network


PVC

Permanent Virtual Channel


PWE

Pseudowire. A method of emulating a Layer 2 service (such as FR or ATM) over an MPLS backbone by encapsulating the Layer 2 information and then transmitting it over the MPLS backbone


QoS

Quality of Service. A measure of performance that reflects both the quality of the service and its availability


RAN

In the context of mobile networks, the Radio Access Network


RD

Route distinguisher. In the context of BGP/MPLS L3VPNs, an 8-byte string that is concatenated to the VPN-IP prefixes, for the purpose of making them unique before advertising them over the common provider core


RDM

Russian Dolls Model. A bandwidth constraint model for DiffServ-TE. The model allows sharing of a bandwidth across different CTs


RFC

Request For Comments. A type of IETF document. An overview of the IETF process can be found in RFC1718


RIPv2

Routing information protocol version 2, described in RFC2453


RP

Rendezvous point. In the context of PIM-SM, a meeting point for multicast sources and receivers


RPT

RP tree. Tree rooted at the RP


RR

Route reflector. In the context of BGP, a route reflector acts as a focal point for iBGP sessions, eliminating the need for a full mesh of sessions. Instead of peering with each other in a full mesh, routers peer with just the reflector


RRO

Record Route Object. Object used in RSVP-TE to track the path along which traffic is forwarded


RSTP

Rapid Spanning Tree Protocol


RSVP

Resource reSerVation Protocol. The base specification of the protocol is in RFC2205


RSVP-TE

RSVP with traffic engineering extensions. The RSVP extensions for setting up LSPs are defined in RFC3209


RT

Route Target. In the context of BGP/MPLS L3VPN, the route target is an extended BGP community, which is attached to a VPN route. The RT is what accomplishes the constrained route distribution between PEs that ends up defining the connectivity available between the VPN sites


RTF

Route Target Filtering. A method for constraining VPN route distribution to only those PEs interested in the RT with which the route is tagged. The method relies on each PE advertising the RTs for which it is interested in receiving updates and can achieve significant savings in the number of advertisements sent and received


(S, G)

In the context of multicast, a combination of source S and group G


S-VLAN

Service VLAN


SAFI

Subsequent Address Family Identifier. In combination with an AFI it defines an NLRI type


SDH

Synchronous Digital Hierarchy


SDP

Service Delivery Point


SE

Shared Explicit. A reservation style used by RSVP that allows an LSP to share resources with itself


SLA

Service-Level Agreement


SNA

Systems Network Architecture. A set of network protocols originally designed to support mainframe computers


SNMP

Simple Network Management Protocol


SONET

Synchronous Optical NETwork


SP

Service Provider


SPF

Shortest Path First. The shortest path computation performed by the IGPs


SPT

Shortest path tree


SRLG

Shared Risk Link Group. A group of links that is affected by the same single event


STP

Spanning Tree Protocol


TCP

Transmission Control Protocol. Reliable transport protocol used in IP


TDM

Time Division Multiplexing


TE

Traffic Engineering. The ability to steer traffic on to desired paths in the network


TED

Traffic Engineering Database. Database created from the traffic engineering information distributed by the IGPs


TE LSP segment

In the context of setting up an interdomain TE LSP using the stitching method, these are the smaller LSPs that get stitched together


TLV

Type-Length-Value. Type of encoding of information in protocol messages


ToS

Type of Service. A field in the IP header designed to carry information that would allow deployment of QoS


TTL

Time To Live


UDP

User Datagram Protocol. Unreliable transport protocol used in IP


VC

Virtual Circuit


VCI

Virtual Channel Identifier


VCCV

Virtual Circuit Connection Verification. The connection verification protocol for pseudowires set up using LDP


VE ID

VPLS Edge Identifier. In BGP-signaled VPLS, a means of uniquely identifying a site within a VPLS


VLAN

Virtual LAN


VoD

Video on Demand


VoIP

Voice over IP


VP

Virtual Path


VPI

Virtual Path Identifier


VPLS

Virtual Private LAN Service. A scheme in which a service provider's customer site appear to be attached to the same LAN


VPN

Virtual Private Network. A private network realized over a shared infrastructure.


VRF

VPN Routing and Forwarding. The per-VPN routing and forwarding tables that ensure isolation between different VPNs


VSR

Video Services Router


WAN

Wide Area Network


WiMAX

Worldwide Interoperability for Microwave Access


xDSL

DSL stands for Digital Subscriber Line. There are several variants of DSL, such as Asymmetric DSL (ADSL), High-speed DSL (HSDL) and Very high-speed DSL (VDSL). xDSL is used as a generic term to cover all the DSL variants

  • Safari Books Online
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint