IT 276 Test 2 (Layer 3)
Internet vs internet
(I)nternet is meant for the public internet (i)nternet is typically used for local intranets
2 benefits of IPV4 over IPV6
-Legacy compatability -Takes up less space in routing table -Easier for humans to read
Layer 3 Switch vs Router
-Switch can perform most of what a router does except connect to public internet -Router can run any routing protocol or most code a computer can
2 Benefits of IPV6 ove IPV4
-Unlimited public addressing -improved end-to-end encryption
The subnet mask 255.255.255.0 is written as ____________ in CIDR notation.
/24
Is /24 subnet bigger or smaller than /25?
/24 is bigger and holds twice as many subnets as /25 Same goes for all, each +1 to /xx is halving the amount of hosts/networks
10.0.0.0 /8 Private IPV4 range
10.0.0.0 - 10.255.255.255
private IPv4 address ranges
10.0.0.0 /8 Addresses 172.16.0.0 /12 Addresses 192.168.0.0 /16 Addresses
loopback address
127.0.0.1; special address that hosts use to direct traffic to themselves; you can ping this address to test the configuration of TCP/IP on the local host. Porgrammers use to test networking as to not mess with actual networks
An IPv6 address is _________ bits long.
128 bits
IPV6 Address Length
128 bits
APIPA (Automatic Private IP Addressing)
169.254.0.1 - 169.254.255.254 Acts as a DHCP fail-safe. Allows a system to assign itself an IP address when DHCP might not be operational
172.16.0.0 /12 Private IPV4 Range
172.16.0.0 - 172.31.255.255
192.168.0.0 /16 Private IPV4 Range
192.168.0.0 - 192.168.255.255
The default subnet mask for a Class A network is____________.
255.0.0.0
VLSM (Variable Length Subnet Mask)
A classless subnet mask that can be customized to a different length for each subnet based on the number of nodes on that subnet. gives you flexibility to choose a subnet size (/24 or /25) that you want
classless addressing
A concept in IPv4 addressing that defines a subnetted IP address as having two parts: a prefix (or subnet) and a host. Introduced CIDR notation to split up IP ranges into subnets
Point-to-Point Topology
A network of two single devices communicating with each other over one connection
What is fragmentation?
A packet is broken into pieces in order to fit through networks on its way to the final destination
BGP (Border Gateway Protocol)
A path-vector protocol makes routing decisions based on paths, network policies, or rule-sets configured by a network administrator and is involved in making core routing decisions.
Network Address Translation (NAT)
A technique that allows private IP addresses to be used on the public Internet. Provider gives you one public IP for multiple devices
Should a packet be fragmented by the sender or on transit?
By the host, doing so in the network by whatever means is extremly inefficient and slow
________allows classless IP routing, and is notated with a slash.
CIDR
CIDR notation
Classless Inter Domain Routing (CIDR) is a method for assigning IP addresses without using the standard IP address classes like Class A, Class B or Class C. Ex. /24 /32 /16 /x means x number of bits are locked to the network portion
What is supernetting?
Combine similar small subnets into one larger supernet to condense a router table
Where is a packet sent if no match on a router table exists?
Default Gateway
Mesh Topology
Devices are connected with many redundant interconnections between network nodes. Multiple links between nodes
What is DHCP?
Dynamic Host Control Protocol A protocol used to automate the assignment of IP Address.
How does NAT keep devices seperate?
Each device is sent its own local IP address Router changes header when communicating to match public IP address
What part is the checksum for?
Header
________ is a companion protocol to IP that lives at the Network layer. It provides services such as error reporting, operational info, and is often used to check if a device is online.
ICMP
ICMP
Internet Control Message Protocol. Where ping and trace route work Provide error message if say TTL has expired
When a packet is encapsulated in a frame, the total size of the packet must be less than the _______ to prevent fragmentation.
MTU
ping options
Make it ping continuously Change the payload size Mark as unfragmentable which is used to determine where fragmentation occured
What technology delayed the extinction of IPV4 addressing?
NAT
_________ allows a site to use a set of private addresses for internal communication and a set of global/public IPs for communication with the rest of the world.
NAT
IP addresses are hierarchical. A portion of the IP address designates the _________, and the rest of the IP address designates the _____________.
Networks Hosts
Can a switch connect to public internet?
No only a router can
Does checksum remain the same until it reaches its final destination?
No, each time it hits a router is is recalculated because the TTL value as been changed
Is there an urgent need for North America to switch over to IPV6?
No, things right now work well with IPV4 due to NAT
Does Layer 3 provide error control?
No, this is found in say TCP but Layer 3 does have error reporting like ICMP
_________ can be used to monitor/verify that a system or device remains connected to the network and reachable.
Ping and ICMP
What is ping used for?
Ping is used to test network connectivity and if two devices can communicate
Where are dynamic routes learned?
Routing protocols
In IPV4, the _______ value is decremented by one each time a packet passes through a router.
TTL
Global Unicast
The term for a public IPv6 address. min == 2000 max == 3FFF Similar to CIDR, the first 4 bits are the prefix to describe what range
What is TTL?
Time to Live TTL is determined at send time, total number is # of routers it can pass through until being discarded Each time it hits a router it is decremented by one until reaching 0
How does NAT know what device to send incoming message to?
Use of PAT (Packet address translation) Maps internal socket to outside socket Client sides request random port number and router keeps track of a translation table
classful addressing
Used until 1993 Split into 5 classes by 4 leading bits (A, B, C, D, E) Not used anymore because we were running out of IPV4 addresses. Some places given wayyyyy too many IPs due to classless addressing
__________ is subnetting a network into smaller, different sized networks.
VLSM (variable-length subnet mask)
IP is a _________ protocol
connectionless, unreliable
OSPF is an example of a (an) __________ routing protocol.
interior
Most important variable in bgp
length of subnet mask match
Functions the network layer provides are___________.
logical addressing delivery of data to the destination fragmentation and reassembly
What is a trace route?
records the route through the Internet between your computer and a specified destination computer. calculates and displays the amount of time each hop took. Traceroute is a handy tool both for understanding where problems are in the Internet network
A __________ route never changes, and is manually configured.
static
What is subnetting?
strategy used to partition a single physical network into more than one smaller logical sub-networks (subnets). An IP address includes a network segment and a host segment.
