Cisco Chpt. 5
What are two potential network problems that can result from ARP operation?
Network attackers could manipulate MAC address and IP address mappings in ARP messages with the intent of intercepting network traffic. On large networks with low bandwidth, multiple ARP broadcasts could cause data communication delays.
What statement describes a characteristic of MAC addresses?
They must be globally unique.
store and forward
always stores the entire frame checks the CRC before forwarding checks the frame length before forwarding
cut through
low latency may forward runt frames begins forwarding when the destination address received
Refer to the exhibit. 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
Which switching method uses the CRC value in a frame?
store-and-forward
What addressing information is recorded by a switch to build its MAC address table?
the source Layer 2 address of incoming frames
What is the aim of an ARP spoofing attack?
to associate IP addresses to the wrong MAC address
What happens to runt frames received by a Cisco Ethernet switch?
The frame is dropped
What is the minimum Ethernet frame size that will not be discarded by the receiver as a runt frame?
64 bytes
What are the two sizes (minimum and maximum) of an Ethernet frame?
64 bytes 1518 bytes
Which destination address is used in an ARP request frame?
FF:FF:FF:FF:FF:FF
What is a characteristic of port-based memory buffering?
Frames are buffered in queues linked to specific ports.
Refer to the exhibit. 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.
The ARP table in a switch maps which two types of address together?
Layer 3 address to a Layer 2 address
Which two statements describe features or functions of the logical link control sublayer in Ethernet standards?
Logical link control is implemented in software. The data link layer uses LLC to communicate with the upper layers of the protocol suite.
Refer to the exhibit. 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.
Which statement is true about MAC addresses?
The first three bytes are used by the vendor assigned OUI.
Refer to the exhibit. The exhibit shows a small switched network and the contents of the MAC address table of the switch. 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.
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
