AToM --Any Transport over MPLS. A protocol that provides a common framework for encapsulating and transporting supported Layer 2 traffic types over a Multiprotocol Label Switching (MPLS) network core.
BGP --Border Gateway Protocol. An interdomain routing protocol that replaces Exterior Gateway Protocol (EGP). A BGP system exchanges reachability information with other BGP systems. It is defined by RFC 1163.
CE router --customer edge router. A router that is part of a customer network and that interfaces to a provider edge (PE) router. CE routers do not have routes to associated VPNs in their routing tables.
core router --In a packet-switched star topology, a router that is part of the backbone and that serves as the single pipe through which all traffic from peripheral networks must pass on its way to other peripheral networks.
EGP --Exterior Gateway Protocol. Internet protocol for exchanging routing information between autonomous systems. It is documented in RFC 904. This term is not to be confused with the general term exterior gateway protocol. EGP is an obsolete protocol that was replaced by Border Gateway Protocol (BGP).
export packet --(NetFlow) A packet from a device (for example, a router) with NetFlow services enabled that is addressed to another device (for example, a NetFlow collector). This other device processes the packet (parses, aggregates, and stores information on IP flows).
FEC --Forward Equivalency Class. A set of packets that can be handled equivalently for the purpose of forwarding and thus is suitable for binding to a single label. The set of packets destined for an address prefix is one example of an FEC. A flow is another example.
flow --A unidirectional set of packets (IP or Multiprotocol Label Switching [MPLS]) that arrive at the router on the same subinterface and have the same source and destination IP addresses, the same Layer 4 protocol, the same TCP/UDP source and destination ports, and the same type of service (ToS) byte in the IP header.
IPv6 --IP Version 6. Replacement for the current version of IP (Version 4). IPv6 includes support for flow ID in the packet header, which can be used to identify flows. Formerly called IPng (next generation).
label --A short, fixed-length identifier that tells switching nodes how the data (packets or cells) should be forwarded.
label imposition --The act of putting a label or labels on a packet.
LDP --Label Distribution Protocol. A standard protocol that operates between Multiprotocol Label Switching (MPLS)-enabled routers to negotiate the labels (addresses) used to forward packets. The Cisco proprietary version of this protocol is the Tag Distribution Protocol (TDP).
LFIB --Label Forwarding Information Base. A data structure and way of managing forwarding in which destinations and incoming labels are associated with outgoing interfaces and labels.
LSR --label switch router. A router that forwards packets in a Multiprotocol Label Switching (MPLS) network by looking only at the fixed-length label.
MPLS --Multiprotocol Label Switching. A switching method in which IP traffic is forwarded through use of a label. This label instructs the routers and the switches in the network where to forward the packets. The forwarding of MPLS packets is based on preestablished IP routing information.
MPLS flow --A unidirectional sequence of Multiprotocol Label Switching (MPLS) packets that arrive at a router on the same subinterface and have the same source and destination IP addresses, the same Layer 4 protocol, the same TCP/UDP source and destination ports, and the same type of service (ToS) byte in the IP header. A TCP session is an example of a flow.
packet header -- (NetFlow) The first part of an export packet that provides basic information about the packet, such as the NetFlow version, number of records contained within the packet, and sequence numbering. The header information enables lost packets to be detected.
PE router --provider edge router. A router that is part of a service provider's network connected to a customer edge (CE) router. All VPN processing occurs in the PE router.
P router --provider core or backbone router. A router that is part of a service provider's core or backbone network and is connected to the provider edge (PE) routers.
TDP --Tag Distribution Protocol. The Cisco proprietary version of the protocol (label distribution protocol) between Multiprotocol Label Switching (MPLS)-enabled routers to negotiate the labels (addresses) used to forward packets.
TE --traffic engineering. Techniques and processes that cause routed traffic to travel through the network on a path other than the one that would have been chosen if standard routing methods were used.
TE tunnel --traffic engineering tunnel. A label-switched tunnel that is used for traffic engineering. Such a tunnel is set up through means other than normal Layer 3 routing; it is used to direct traffic over a path different from the one that Layer 3 routing could cause the tunnel to take.
VPN --Virtual Private Network. 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.