GL-23
Cisco Router and Security Device Manager 2.5 User’s Guide
OL-4015-12
Glossary
mGRE multipoint GRE.
MTU maximum transmission unit. The maximum packet size, in bytes that an
interface can transmit or receive.
N
NAC Network Admission Control. A method of controlling access to a network in
order to prevent the introduction of computer viruses. Using a variety of
protocols and software products, NAC assesses the condition of hosts when they
attempt to log onto the network, and handles the request based on the host’s
condition, called its posture. Infected hosts can be placed in quarantine; hosts
without up-to-date virus protection software can be directed to o btain updates,
and uninfected hosts with up-to-date virus protection can be allowed onto the
network. See also ACL, posture, and EAPoUDP.
NAD Network Access Device. In a NAC implementation, the device that receives a
host’s request to log on to the network. A NAD, usually a router, works with
posture agent software running on the host, virus protection software, and ACS
and posture/remediation servers on the network to control access to the network
in order to prevent infection by computer viruses.
NAS Network Access Server. Platform that interfaces between the Internet and the
public switched telephone network (PSTN).
Gateway that connects asynchronous devices to a LAN or WAN through network
and terminal emulation software. Performs both synchronous and asynchronous
routing of supported protocols.
NAT
Network Address
Translation
Network Address Translation. Mechanism for reducing the need for globally
unique IP addresses. NAT allows an organization with addresses that are not
globally unique to connect to the Internet by translating those addresses into
globally routable address space.
NBAR Network-based Application Recognition. A method used to classify traffic for
QoS.