Chapter 5 Cisco Netacad study guide
Store-and-forward
-always stores the entire frame -checks the CRC before forwarding -checks the frame length before forwarding
Cut-through
-has low latency -may forward runt frames -begins forwarding when the destination address is received
What is the minimum Ethernet frame size that will not be discarded by the receiver as a runt frame?
64 bytes
What are two sizes (minimum and maximum) of an Ethernet frame?
64 bytes & 1518 bytes
Which destination address is used in an ARP request frame?
FFFF.FFFF.FFFF
What is a characteristic of port-based memory buffering?
Frames are buffered in queues linked to specific ports.
A switch with a default configuration connects four hosts. The ARP table for host A is shown. What happens when host A wants to send an IP packet to host D?
Host A sends out a broadcast of FF:FF:FF:FF:FF:FF. Every other host connected to the switch receives the broadcast and host D responds with its MAC address.
What statement describes Ethernet?
It defines the most common LAN type in the world.
Two statements that describe the features and functions of the Logical Link Control (LLC) sublayer in Ethernet standards
LLC is always implemented in software and the data link layer uses LLC to communicate with the upper layers of the protocol suite.
The ARP table in a switch maps which two types of addresses together?
Layer 3 address to a Layer 2 address
What are two potential network problems that can result from ARP operation?
On large networks with low bandwidth, multiple ARP broadcasts could cause data communication delays and network attackers could manipulate MAC address and IP address mappings in ARP messages with the intent of intercepting network traffic.
PC1 has sent a frame addressed to PC3. What will the switch do with the frame?
The switch will forward the frame to all ports except port 4.
PC1 issues an ARP request because it needs to send a packet to PC2. In this scenario, what will happen next?
PC2 will send an ARP reply with its MAC address.
A collision fragment, also known as a _______ frame, is a frame of fewer than 64 bytes in length.
RUNT
What statement is true about MAC addresses?
The first three bytes are used by the vendor assigned OUI.
What happens to runt frames received by a Cisco Ethernet switch?
The frame is dropped
What addressing information is recorded by a switch to build its MAC address table?
The source Layer 2 address of incoming frames.
Which statement describes the treatment of ARP requests on the local link?
They are received and processed by every device on the local network.
When a device is sending data to another device on a remote network, the Ethernet frame is sent to the MAC address of the default gateway.
True
What is auto-MDIX?
a feature that detects Ethernet cable type
MAC addresses must be _____________________
globally unique
The switches are in their default configuration. Host A needs to communicate with host D, but host A does not have the MAC address for its default gateway. Which network hosts will receive the ARP request sent by host A?
only hosts B, C, and router R1
On a Cisco switch, _____________ memory buffering is used to buffer frames in queues linked to specific incoming and outgoing ports.
port-based
ARP _____________ is a technique that is used to send fake ARP messages to other hosts in the LAN. The aim is to associate IP addresses to the wrong MAC addresses.
spoofing
Which switching method uses the CRC value in a frame?
store-and-forward
What is the aim of an ARP spoofing attack?
to associate IP addresses to the wrong MAC address
