CCENT Concepts Pt. 6 Flashcards
connection establishment
The process by which a connection-oriented
protocol creates a connection. With TCP, a
connection is established by a three-way
transmission of TCP segments
firewall
A device that forwards packets between the less
secure and more secure parts of the network,
applying rules that determine which packets are
allowed to pass, and which are not.
Forward acknowledgement
A process used by protocols that do error recovery
in which the number that acknowledges data lists
the next data that should be sent, not the last data
that was successfully received.
Intrusion Detection System
A security function that examines more complex traffic patterns against a list
of both known attack signatures and general characteristics of how attacks
may be carried out, rating each perceived threat and reporting the threats.
Intrusion Prevention System
A security function that examines more complex traffic patterns against a list
of both known attack signatures and general characteristics of how attacks
may be carried out, rating each perceived threat and reacting to prevent the
more significant threats.
Positive Acknowledgement and
Retransmission (PAR)
A generic reference to how the error recovery feature works in many
protocols, including TCP, in which the receivef must send an acknowledgment
that either implies that the data was (positively) received, or send an
acknowledgement that implies that some data was lost, so the sender can
then resend the lost data.
sliding windows
For protocols such as TCP that allow the receiving device to dictate the
amount of data the sender can send before receiving an acknowledgment– a
concept called a window–a reference to the fact that the mechanism to gran
future windows is typically jsut a number that grows upwards slowly after each
acknowledgment, sliding upward.
Virtual private network (VPN)
The process of securing communication between two devices whose packets
pass over some public and unsecure network, typically the Internet. VPNs
encrypt packets so that the communication is private and authenicate the
identity of the endpoints.
web server
Software running on some computer,
that stores web pages and sends
those web pages to web clients (web
browsers) that request the web pages.
Switching Logic
Deciding when to forward a frame or when to filter (not forward) a frame,
based on the destination MAC address.
Learning MAC addresses by examining the source MAC address of each
frame received by the bridge.
Create a (Layer 2) loop-free environment with other bridges by using
Spanning Tree Protocol (STP)
Switching Method - Store and
forward
The switch fully receive all bits in the frame (store)
before forwarding the fram (forward). This allows
the switch to check the FCS before forwarding the
frame.
Cut-through
The switch forwards the frame as soon
as it can. This reduces latency but
does not allow the switch to discard
frames that fail the FCS check.
Fragment-free
The switch forwards the frame after
receiving the first 64 bytes of the
frame, thereby avoiding forwarding
frames that were errored due to a
LAN Switching Summary
Switch ports connected to a single device microsegment the LAN, providing
dedicated bandwidth to that single device.
Switches allow multiple simultaneous conversation between devices on
differeent ports.
Switch ports connected to a single device support full duplex, in effect
doubling the amount of bandwidth available to the device.
Switches support rate adaption, which means that devices that use different
Ethernet speeds can communicate through the switch (hubs cannot).
Collision Domain
a set of network interface cards (NIC) for which a
frame sent by one NIC could result in a collision
with a fram sent by any other NIC in the same
collision domain.
Broadcast Domain
A set of NICs for which a broadcast
frame sent by one NIC is received by
all other NICs in the same broadcast
domain.
Flooding
The result of the LAN switch forwarding process for broadcasts and unknown
unicast frames. Switches forward these frames out all interfaces, except the
interface in which the frame arrived. Switched also forward multicasts by
default, although this behaviour can be changed.
Spanning Tree Protocol (STP)
A bridge protocol that uses the Spanning Tree algorithm, allowing a switch to
dynamically work around loops in a network topology by creating a spanning
tree. Switches exchange bridge protocol data unit (BPDU) messages with
other bridges to detect loops and then remove the loops by shutting down
selected bridge interfaces.
virtual LAN
A group of devices, connected to one or more switches, with the devices
grouped into a single broadcast domain through switch configuration. VLANs
allow switch administrators to separate the devices connected to the switches
into separate VLANs without requiring separate physical switches, gaining
design advantages of separating the traffic without the expense of buying
additional hardware.
Default console port settings
9600 bits/second
No hardware flow control
8-bit ASCII
No parity bits
Global Configuration Mode
Enable
configure terminal
Cisco Switch Memory Type - RAM
Working Memory and running
configuration
Cisco Switch Memory Type -
Flash
Cisco IOS Software
Cisco Switch Memory Type - ROM
Bootstrap Program
Cisco Switch Memory Type -
NVRAM
Startup Configuration
