Cisco CRS-1 - Carrier Routing System Router Getting Started Manual page 268

Glossary
modular services card. Module where the ingress and egress packet processing and queueing functions
MSC
are carried out in the Cisco CRS-1 Series router architecture. Up to 16 MSCs are installed in a line card
chassis; each MSC must have an associated Physical Line Interface Module (PLIM) (of which there are
several types to provide a variety of physical interfaces). The MSC and PLIM mate together on the line
card chassis midplane. See also PLIM.
MSCs are also referred to as line cards.
maximum transmission unit. Maximum packet size, in bytes, that a particular interface can handle.
MTU
Multicast is a feature that refers to single packets copied by the network and sent to a specific subset
multicast
of network addresses. These addresses are specified in the Destination Address Field. See also
broadcast and unicast.
Intradomain multicast routing protocol used in OSPF networks. Extensions are applied to the base
multicast OSPF
OSPF unicast protocol to support IP multicast routing. See also OSPF.
A multicast router is used to send Internet Group Management Protocol (IGMP) query messages on
multicast router
attached local networks. Host members of a multicast group respond to a query by sending IGMP
reports noting the multicast groups to which they belong. The multicast router takes responsibility for
forwarding multicast datagrams from one multicast group to all other networks that have members in
the group. See also IGMP.
N
Loading software images from a network server, such as TFTP.
netboot
A card installed and running on a Cisco CRS-1 Series routing system.
node
nonstop forwarding. Packets keep flowing during events such as failover, process restarts, and the
NSF
upgrade or downgrade of software packages. Nonstop forwarding is the ability of a router to continue
to forward traffic toward a router that may be recovering from a transient failure and the ability of a
router recovering from a transient failure in the control plane to continue correctly forwarding traffic
sent to it by a peer.
Network Time Protocol. Protocol built on top of TCP that ensures accurate local time-keeping with
NTP
reference to radio and atomic clocks located on the Internet. This protocol is capable of synchronizing
distributed clocks within milliseconds over long time periods.
nonvolatile RAM. Static random access memory that is made into nonvolatile storage by having a
NVRAM
battery permanently connected.
O
Optical carrier where x=3, 12, 48, or 192, relating to the various speeds within a SONET network.
OC-x
online insertion and removal. Feature that permits the addition, the replacement, or the removal of cards
OIR
without interrupting the system power, entering console commands, or causing other software or
interfaces to shut down. Sometimes called hot-swapping or power-on servicing.
Cisco CRS-1 Series Carrier Routing System Getting Started Guide
GL-10