Cisco Cisco IOS Software Release 12.2(27)SBC

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. 

NetFlow v9—NetFlow export format Version 9. A flexible and extensible means for carrying NetFlow 
records from a network node to a collector. NetFlow Version 9 has definable record types and is 
self-describing for easier NetFlow Collection Engine configuration.

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.

P router—provider backbone router. A router that is part of a service provider's backbone network and 
is connected to the provider edge (PE) routers. 

PE router—provider edge router. A router that is part of a service provider’s network connected to a 
customer edge (CE) router. All Virtual Private Network (VPN) processing occurs in the PE router.

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.

Refer to the Cisco 

 for terms not included in this 

glossary.