Networking Devices and Initial Configuration Module 4 - 6 Checkpoint Exam

IPv4

12 basic header fields 20 octets header 32-bit address space

IPv6

128-bit address space 40 octets header 8 header fields

A network engineer subnets the network 192.168.100.0 /24 into 16 subnets. How many usable host addresses will be available on each of the subnets?

14 When network 192.168.100.0 /24 is subnetted into 16 subnets, each subnet will have a new network mask of 255.255.255.240. This new mask will leave four bits of the address available for hosts. Four host bits yield 16 host addresses. However, two of those addresses are reserved, the lowest for the subnet and the highest for the subnet broadcast. This leaves 14 addresses for host configuration.

When a computer assembles a frame to be sent over the network, what is the maximum size of an Ethernet frame?

1518 bytes Ethernet standards define a frame size with a minimum of 64 bytes and a maximum of 1518 bytes including fields of destination MAC address, source MAC, Length/Type, data payload, and FCS.

Consider the group of five IPv4 addresses each with the subnet mask of 255.255.255.0. Which two IPv4 addresses belong to the same local network? (Choose two.)

192.168.10.56 192.168.10.2 The subnet mask determines which part of the IP address is the network number. Because the subnet mask is 255.255.255.0, the first three sets of numbers in each IPv4 address indicate the network number. IPv4 addresses with the same network number are considered in the same local network.

What subnet mask would be associated with the IPv4 prefix of /28?

255.255.255.240 /28 represents the number of consecutive 1s in the subnet mask. 24 1s makes the 255.255.255 part of the subnet mask. The last 4 1s in the mask is where it gets a little tricky. Add the values that these 4 1s represent to get the last octet of the mask: 128 + 64 + 32 + 16 = 240. /28 = 255.255.255.240

Which two hosts exist on the same subnet? (Choose two.)

Hosts 172.16.100.4/23 and 172.16.101.199/23 both exist in network 172.16.100.0/23. This network includes all addresses from 172.16.100.1 through 172.16.101.255.

What is correct in relation to NAT for IPv6?

It is a temporary mechanism to assist in the migration from IPv4 to IPv6.

What IPv6 header field is used to indicate the upper layer protocol or extension header that is included in the packet?

Next Header There are eight fields in an IPv6 header. 1. Version 2. Traffic Class 3. Flow Label Payload Length Next Header Hop Limit Source Address 8. Destination Address The next header field contains an 8-bit value that indicates the upper layer or extension header that is contained within the IPv6 packet.

Which IPv4 header field is responsible for defining the priority of the packet?​

differentiated services Differentiated services (DiffServ) is an IPv4 header field that is used to define the priority of each packet. The first 6 bits identify the value that is used by the QoS mechanism, and the last 2 bits identify the value that can be used to avoid packet dropping during network congestion. Traffic class is an IPv6 header field that is equivalent to the IPv4 differentiated services (DiffServ) field. Flow label is also an IPv6 header field that can be used to tell routers and switches to keep the same path for the packet flow to avoid packet reordering. Flags is an IPv4 header field that identifies how the packet is fragmented.

What is one advantage that the IPv6 simplified header offers over IPv4?

efficient packet handling The IPv6 simplified header offers several advantages over IPv4:· Better routing efficiency and efficient packet handling for performance and forwarding-rate scalability· No requirement for processing checksums· Simplified and more efficient extension header mechanisms (as opposed to the IPv4 Options field)· A Flow Label field for per-flow processing with no need to open the transport inner packet to identify the various traffic flows

Which field in the IPv6 header points to optional network layer information that is carried in the IPv6 packet?

next header

What are two functions that are provided by the network layer? (Choose two.)

providing end devices with a unique network identifier The network layer is primarily concerned with passing data from a source to a destination on another network. IP addresses supply unique identifiers for the source and destination. The network layer provides connectionless, best-effort delivery. Devices rely on higher layers to supply services to processes.

Which information does a switch use to populate the MAC address table?

the source MAC address and the incoming port To maintain the MAC address table, the switch uses the source MAC address of the incoming packets and the port that the packets enter. The destination address is used to select the outgoing port.

Why does a Layer 3 device perform the ANDing process on a destination IP address and subnet mask?

to identify the network address of the destination network ANDing allows us to identify the network address from the IP address and the network mask.

When would a switch record multiple entries for a single switch port in its MAC address table?

when another switch is connected to the switch port When another switch or a hub is connected to a switch port then frames could be received from the multiple nodes connected to the other switch or the hub. This will result in the MAC address for each of those multiple nodes to be recorded in the MAC address table against that one port. When a router is connected to a switch port, only the MAC address of the router interface would be recorded against the switch port. ARP broadcasts are used to associate MAC addresses with IP addresses and such broadcasts would not directly result in multiple MAC addresses being recorded against a single switch port. Configuring the switch to perform Layer 3 switching will not result in multiple MAC addresses being recorded against a single switch port. The ARP table associated with the Layer 3 switch port may contain multiple IP address to MAC address mappings but this is to enable the correct framing of Layer 3 packets, not the Layer 2 frame switching function.