Broadcast, ARP, DHCP, Ethernet Frame

Question 1

One sender and One receiver. Most common transmission method. Unicast is addressed to a single device like an email or text message to one person.

Answer 1

Unicast

Question 2

One or more senders & multiple receivers also called multicast stream. It delivers the same transmission to a group. Dedicated addresses or address ranges. The most complex transmission method to manage. Zoom is a good example it is addressed to a group.

Answer 2

Multicast

Question 3

FF-FF-FF-FF-FF-FF it’s all on….hexadecimal or 48 (1’s in binary). Every device must receive the traffic.

Answer 3

Broadcast Address (MAC)

Question 4

Part of the TCP/IP protocol for determining the MAC address based on the IP address. Does have a disadvantage of potentially being used by hackers and cyber attackers. A useful protocol for building the ARP table and is a good troubleshooting tool.

Answer 4

Address Resolution Protocol (ARP) Part 1

Question 5

For a network communication to happen computers need to know both the IP Address and the Mac Address of the destination.

Answer 5

Address Resolution Protocol (ARP) Part 2

Question 6

are received by all devices in a broadcast domain. ff-ff-ff-ff-ff-ff is what gets broadcasted in the broadcast domain.

Answer 6

Broadcasts

Question 7

Can occur when a loop (duplicating frames) is in the network. When bandwidth in the network gets overwhelmed by duplicity and consumed the network begins to choke and either dies/crashes.

Answer 7

Broadcast Storms

Question 8

is a logical division of a computer network. Broadcast domains are connected together with a device called router. Routers (Layer 3) help separate (like a border police) broadcast domains and traffic. Router (Layer 3) is also considered a broadcast domain. Broadcasts cannot leave the broadcast domain. Switches (Layer 2) can also separate broadcast domains with Vlans (virtual local area network).

Answer 8

Broadcast Domain

Question 9

It happens in the Layer 1 and Layer 2 of the TCP/IP and OSI model.
[Parts of the Ethernet Frame as follows: Destination Address, Source Address, Type 0x 8060, (ARP Request or ARP Reply consists of MAC/IP-Source & Destination), Padding, and CRC.]

Answer 9

Ethernet Frame

Question 10

a temporary table (stored in the RAM of the device/s) of all known IP Addresses (routers) to MAC address (switches) relationships that the computer has learned about in the network. Using arp -a in the terminal in Windows or Mac/Linux computer finds Address Resolution Protocol (ARP) cache, which contains recently resolved MAC addresses of Internet Protocol (IP) hosts on the network. Cisco IOS show arp.

ARP cache includes static (manual entry/static broadcast ff-ff-ff-ff-ff-ff) and dynamically (learned entries automatic). If no MAC Address is present then an Arp request is sent to determine the MAC address. After the arp is completed the arp cache is updated. Can find arp cache in switches and routers.

Answer 10

ARP Cache

Question 11

An ARP announcement to update other hosts. ARP tables without the need for an ARP request (Security Risks). Sometimes performed during the computer operating system startup process. Helps to update the network faster when there was a recent change to a hosts IP address (done in static/manual Reboot). It’s an Automatic update after an IP change is made on a host.

Answer 11

Gratuitous ARP

Question 12

Hands out IP Addresses. DHCP is used primarily to automatically assign IP Addresses to hosts on a network.

Answer 12

Dynamic Host Configuration Protocol (DHCP)

Question 13

Burned permanently into the hardware. It is a physical address vs. IP address which is logical.

Answer 13

MAC Address