Glossary
GL-7
Cisco 10000 Series Router Software Configuration Guide
OL-2226-23
N
NAS
Network access server. Cisco platform (or collection of platforms) that interfaces between the packet
world (for example, the Internet) and the circuit world (for example, PSTN).
NetFlow
A Cisco-proprietary IP statistics collection feature that collects information on IP flows passing
through a router.
NVRAM
Non-Volatile Random Access Memory. The router uses this memory to store configuration information.
The contents of this memory are not lost after a reboot or power cycle of the unit.
O
OAP
Overlapping Address Pool. An IP address group that supports multiple IP address spaces and still
allows for the verification of nonoverlapping IP address pools within a pool group.
ODAP
A block of addresses managed by a central server such as a Radius server or DHCP server. Each pool
is divided into subnets of various sizes. The server assigns the subnets to PE routers upon request.
on-demand address
pool
See ODAP.
OSI
Open Systems Interconnection. An international standardization program to facilitate communications
among computers from different manufacturers.
overlapping address
pool
See OAP.
P
PAP
Password Authentication Protocol. Authentication protocol that allows PPP peers to authenticate one
another. The remote router attempting to connect to the local router is required to send an authentication
request. Unlike CHAP, PAP passes the password and host name or user name in the clear (unencrypted).
PAP does not itself prevent unauthorized access, but merely identifies the remote end. The router or
access server then determines if that user is allowed access. PAP is supported only on PPP lines.
Compare with CHAP.
PCR
Peak cell rate. Parameter defined by the ATM Forum for ATM traffic management.
permanent virtual
circuit
A fixed virtual circuit between two users. The public data network equivalent of a leased line. No call
setup or clearing procedures are needed.
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.
