Spirent SmartBits System, Reference Manual

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Glossary of Terms
Features and Terminology
258 SmartBits System Reference
Red triangle LED – card is reserved by another user or by another application
Once cards are owned, you can make a group.
•
In all applications, the default Group is all reserved cards.
•
To assign ports to a subset or a select group of ports, consult your user guide or online
help for each application. Applications have a Reservations command, a Group
assignment column, or Port Selection columns to create groups.
•
In SmartWindow, the Set Group command selects all the cards you have reserved and
proposes them as a default Group. To constitute a Group, you must accept the
proposed Group or changed the selected ports in the
SmartBits Multiport Selection
dialog and click OK . Notice that all unowned cards are grayed out until you reserve
them.
IGMP
IP multicast traffic is used in multimedia and data sharing applications; multicast (IGMP)
is a technology that delivers a stream of traffic from a sender to multiple receivers
simultaneously. Forwarding devices are informed of a host's desire to receive multi-cast IP
traffic through the Internet Group Management Protocol (IGMP). IGMP allows group
information and multi-cast forwarding tables to be dynamically maintained. Hosts send an
IGMP membership report to "join" a group. Once joined, hosts must respond to periodic
router queries to maintain their membership status. If a host fails to respond to queries for
a specified interval, its membership is automatically removed.
An updated version of IGMP (version 2) allows hosts to explicitly leave groups by sending
a
leave request . This is a far more efficient way to leave a group as it minimizes the
amount of unwanted traffic forwarded to the host.
jitter
The variation in latency for a series of packets, measured via the SmartMetrics
mechanism. Low jitter is important in voice transmissions. In SmartFlow, this is known as
“latency standard deviation.”
latency
The time interval between the transmission and reception of a frame.
Multilayer SmartCards
A group of card types also known as first series of SmartMetrics cards.
Multilayer SmartCards include the ML-7710, ML-5710A, and L3-6710.
Multilayer cards allow you to to test the performance and interoperability of both Layer 2
(frame-based) and Layer 3 (stream-based) devices as well as higher layer operations. Each
multilayer SmartCard can generate multilayer, mixed protocol traffic equivalent to one
fully loaded LAN with up to 1000 end-user devices. The single RJ-45 interface can