User guide

Glossary of Terms
SCE 1000 2xGBE Release 2.0.10 User Guide
2 OL-7117-02
In addition, a subscriber associated with the
attack may be notified about the attack.
The SCE 1000 maintains a list of the most
active IP addresses flowing through it, with
a measure of the activity of each IP address.
(Activity is measured by number of flows
opened to/from that address). If there are IP
addresses in the table whose number of
flows is above the configured threshold,
these IP addresses are assumed to be
attacking, or being attacked. If the SCE
1000is configured to block the attack, it
drops the attack packets.
Duplex
Duplex refers to the bi-directional capacity
of the link, that is, the link can both receive
and transmit.
Full duplex data transmission means that
data can be received and transmitted
simultaneously.
Half duplex data transmission means that the
line can transmit in only one direction at a
time. When data is being transmitted, it
cannot be received and vice versa.
F
Flow
All packets travelling in both directions on a
single application layer connection (such as
a TCP or UDP connection). A flow is
identified by the tuple information: <Source
IP, Destination IP, Source Port, Destination
Port, IP Protocol>. (Note that if the IP
protocol is neither TCP or UDP, the port
number is defined as '0'.)
IN this guide, the term 'flow' represents bi-
directional flows (packets from both the
client and server of each connection). When
referencing a uni-directional flow, this is
explicitly mentioned.
Flow Bundle
A group of one or more flows comprising
the set of application-layer connections (
such as a TCP or UDP connection) used in a
single, logical application session. The
semantics of flow-bundles are application
dependant, and relate to the way each
application spawns and negotiates additional
flows as part of a single session. A few
common examples are:
• An SIP (VoIP) flow bundle comprises
the signaling flow as well as all the
RTP/UDP flows containing the actual
media data (voice).
• An RTSP (Streaming) flow bundle
comprises the signaling flow as well as
the RTP/UDP flows containing the audio
and/or video transmissions.
• AN FTP (file transfer) flow bundle
comprises the control flow (used to login
an FTP server) and the actual file-
transfer flows
In each of these cases, the SCE 1000 tracks
the application communication to identify
new connections created and bundle them
into a single context. This is important for
classification and accounting purposes, as
otherwise these spawned flows would be
unclassifiable.
I
Inline connection mode
The SCE 1000 physically resides bump-in-
the-wire on the data links between the
subscriber and the network
L
Link mode
A specified behavior that may be enforced
on the link. This may be useful during
installation and for debugging the network.
The available link modes are:
• forwarding
• bypass