6VPE router —Provider edge router that provides BGP-MPLS IPv6 VPN service over an IPv4-based MPLS core. It is a IPv6 VPN PE, dual-stack
router that implements 6PE concepts on the core-facing interfaces.
autonomous system —A collection of networks that share the same routing protocol and that are under the same system administration.
—Abstract Syntax Notation One. The data types independent of particular computer structures and representation techniques.
Described by ISO International Standard 8824.
—Border Gateway Protocol. The exterior Border Gateway Protocol used to exchange routing information between routers in separate
autonomous systems. BGP uses TCP. Because TCP is a reliable protocol, BGP does not experience problems with dropped or fragmented
BGP prefixes —A route announcement using the BGP. A prefix is composed of a path of autonomous system numbers, indicating which networks
the packet must pass through, and the IP block that is being routed. A BGP prefix would look something like: 701 1239 42 220.127.116.11/24.
(The /24 part is referred to as a CIDR mask.) The /24 indicates that there are 24 ones in the netmask for this block starting
from the left side. A /24 corresponds to the natural mask 255.255.255.0.
CE router —customer edge router. A router on the border between a VPN provider and a VPN customer that belongs to the customer.
—classless interdomain routing. A technique supported by BGP4 and based on route aggregation. CIDR allows routers to group
routes to reduce the quantity of routing information carried by the core routers. With CIDR, several IP networks appear to
networks outside the group as a single, larger entity. With CIDR, IP addresses and their subnet masks are written as four
octets, separated by periods, followed by a forward slash and a two-digit number that represents the subnet mask.
Cisco Express Forwarding —An advanced Layer 3 IP switching technology. Cisco Express Forwarding optimizes network performance and scalability for networks
with large and dynamic traffic patterns.
—In SNMP, a logical group of managed devices and NMSs in the same administrative domain.
community name —See community string.
community string —A text string that acts as a password and is used to authenticate messages sent between a managed station and a router containing
an SNMP agent. The community string is sent in every packet between the manager and the client. Also called a community name.
—Internet Engineering Task Force. A task force consisting of over 80 working groups responsible for developing Internet standards.
The IETF operates under the auspices of ISOC.
See also ISOC.
—A type of notification message that is more reliable than a conventional trap notification message, because the informs message
notification requires acknowledgment, and a trap notification does not.
—Internet Society. An international nonprofit organization, founded in 1992, that coordinates the evolution and use of the
Internet. In addition, ISOC delegates authority to other groups related to the Internet, such as the IAB. ISOC is headquartered
in Reston, Virginia (United States).
—A short, fixed-length data construct that tells switching nodes how to forward data (packets or cells).
—Label Distribution Protocol. A standard protocol between MPLS-enabled routers that is used for the negotiation of the labels
(addresses) used to forward packets.
—Label Forwarding Information Base. In the Cisco Label Switching system, the data structure for storing information about
incoming and outgoing tags (labels) and associated equivalent packets suitable for labeling.
—label switch router. A device that forwards MPLS packets based on the value of a fixed-length label encapsulated in each
—Management Information Base. A database of network management information that is used and maintained by a network management
protocol such as SNMP or CMIP. The value of a MIB object can be changed or retrieved using SNMP or CMIP commands, usually
through a GUI network management system. MIB objects are organized in a tree structure that includes public (standard) and
private (proprietary) branches.
—Multiprotocol Label Switching. A method for forwarding packets (frames) through a network. It enables routers at the edge
of a network to apply labels to packets (frames). ATM switches or existing routers in the network core can switch packets
according to the labels with minimal lookup overhead.
MPLS interface —An interface on which MPLS traffic is enabled.
MPLS VPN —Multiprotocol Label Switching Virtual Private Network. An IP network infrastructure delivering private network services over
a public infrastructure using a Layer 3 backbone. Using MPLS VPNs in a Cisco IOS network provides the capability to deploy
and administer scalable Layer 3 VPN backbone services including applications, data hosting network commerce, and telephony
services to business customers.
For an MPLS VPN solution, an MPLS VPN is a set of provider edge routers that are connected by means of a common “backbone”
network to supply private IP interconnectivity between two or more customer sites for a given customer. Each VPN has a set
of provisioning templates and policies and can span multiple provider administrative domains (PADs).
—network management system. A powerful, well-equipped computer (typically an engineering workstation) that is used by a network
administrator to communicate with other devices in the network. An NMS is typically used to manage network resources, gather
statistics, and perform a variety of network administration and configuration tasks.
—A message sent by an SNMP agent to a network management station, console, or terminal to indicate that a significant event
within Cisco IOS software has occurred.
See also trap.
PE router —provider edge router. A router on the border between a VPN provider and a VPN customer that belongs to the provider.
—quality of service. A measure of performance for a transmission system that reflects its transmission quality and service
—Routing Information Base. Also called the routing table.
—route target. An extended community attribute that identifies a group of routers and, in each router of that group, a subset
of forwarding tables maintained by the router that can be populated with a BGP route carrying that extended community attribute.
The RT is a 64-bit value by which Cisco IOS software discriminates routes for route updates in VRFs.
—Simple Network Management Protocol. The network management protocol used almost exclusively in TCP/IP networks. SNMP provides
a means to monitor and control network devices, and to manage configurations, statistics collection, performance, and security.
—SNMP Version 2. Version 2 of the popular network management protocol. SNMP2 supports centralized and distributed network
management strategies, and includes improvements in the Structure of Management Information (SMI), protocol operations, management
architecture, and security.
See also SNMP.
—A message sent by an SNMP agent to a network management station, console, or terminal, indicating that a significant event
occurred. Traps (notifications) are less reliable than inform requests, because the receiver does not send an acknowledgment
when it receives a trap. The sender cannot determine if the trap was received.
See also notification.
—Virtual Private Network. A group of sites that, as the result of a set of administrative policies, are able to communicate
with each other over a shared backbone network. A VPN is a secure IP-based network that shares resources on one or more physical
networks. A VPN contains geographically dispersed sites that can communicate securely over a shared backbone.
Seealso MPLS VPN.
—A mechanism that identifies a VPN based on RFC 2685. A VPN ID consists of an Organizational Unique Identifier (OUI), a three-octet
hex number assigned by the IEEE Registration Authority, and a VPN index, a four-octet hex number, which identifies the VPN
within the company.
—VPN routing and forwarding instance. A VRF consists of an IP routing table, a derived forwarding table, a set of interfaces
that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table.
In general, a VRF includes the routing information that defines a customer VPN site that is attached to a PE router.