Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
csc chp4 flashcards
topic = IP the internet protocol
| Question | Answer |
|---|---|
| IP datagram format diagram | slide 43 |
| what is an IP address | 32-bit identifier associated with each host or router interface |
| what is an interface | connection between host/router and physical link |
| can routers have multiple interfaces | yes |
| how many interfaces does a host have | one or two interfaces (wired ethernet / wireless) |
| what is a subnet | device interfaces that can physically reach each other without passing through anintervening router |
| what are the two IP addresses structures | subnet part and host part |
| what is a subnet part | devices in same subnet have common high order bits |
| what is a host part | remaining low order bits |
| what is the recipe for defining subnets | detach each interface from its host or router creating islands of isolated networks / each isolated network is called a subnet |
| what does CIDR stand for | classless interdomain routing |
| what is the purpose of a CIDR | subnet portion of address of arbitrary length / address format a.b.c.d/x where x is # bits in subnet portion of address |
| what are subnet mask used for | they are used by a computer to determine if any computer is on the same network or on a different network |
| what is a IPv4 subnet mask | 32 bit sequence of ones followed by a block of zeros |
| what do ones in IPv4 subnet mask designate | the network prefix |
| what do zeros in IPv4 subnet mask designate | the host identifier |
| what do we use in shorthand | /24 |
| what does /24 mean | means subnet mask has 24 ones and the rest are zeros |
| how does a host get an IP address | it's hard-coded by sysadmin in config file |
| what does DHCP stand for | dynamic host configuration protocol |
| what is the function of DHCP | dynamically get address from as server (plug-and-play) |
| what's the goal of DHCP | host dynamically obtains IP address from network server when it joins network (can renew its lease on address in use / allows reuse of addressing / support for mobile users who join and leave network) |
| what is the overview of DHCP | host broadcasts DHCP discover msg / DHCP server responds with DHCP offer / host requests IP address = DHCP request msg / DHCP server sends address = DHCP ack msg |
| example of DHCP client-server scenario | slide 54-55 |
| what more can DHCP return on subnet other than an IP address | address of first-hop router for client / name and IP address of DNS server / network mask (indicating network versus host portion of address) |
| example of DHCP | slide 57-58 |
| what is subnetting | dividing a single large network into multiple small networks known as subnets to help relieve network congestion and improve efficiency in utilizing relatively small network address space available |
| what is supernetting | combing multiple networks into a single large network known as supernets to provide route updates in the most efficient way possible by advertising many routes in one ad instead of individually |
| what are the two approaches to subnetting | fixed length subnet mask (FLSM) and variable-length subnet mask (VLSM) |
| describe FLSM subnetting | all subnets are equal in size with an equal number of host identifiers |
| describe VSLM subnetting | subnet design strategy that allows all subnet masks to have variable sizes / network admin can divide an IP address space into subnets of different sizes and allocate it according to individual needs on network |
| how is VSLM efficient | it makes more efficient use of given IP address range (default standard for how every network is designed today) |
| what is VSLM supported by | supported by most used protocols on the internet |
| what are some protocols that support VSLM | open shortest path first / enhanced interior gateway protocol / border gateway protocol... |
| when do you use the same subnet mask for each subnet | in FLSM and all the subnets have the same number of addresses in them (tends to be the most wasteful because it uses more IP addresses than are necessary) |
| in FLSM how does a network get subnet part of IP address | gets allocated portion of its provider ISP' address space |
| example of ISP allocates out its address | slide 62 |
| problem exercise | slid 63 |
| how to solve the solution use subnet mask table | slide 64-69 |
| what is a routing table | summary of all known networks |
| how do routers find the shortest path | routers share routing tables to find new paths and locate the best paths to destinations |
| where is supernetting used | it's used in hierarchical addressing to simplify or summarize network routing decisions with the goal of min processing overheads when matching routes |
| what happens when there is no supernetting | the router will share all routes from routing tables as they are / with supernetting it will summarize them before sharing which reduces the size of routing updates |
| what does hierarchical addressing allow | allows for efficient advertisement of routing information |
| hierarchical addressing example | slide 72-73 |
| how does an ISP get blocked of addresses | ICANN - internet corporation for assigned names and numbers |
| what does ICANN help with | allocates IP addresses, through 5 regional registries (RR) / manages DNS root zone, including delegation of individual TLD |
| what does ICANN allocate | allocates last chunk of IPv4 addresses to RRs in 2011 |
| what's the purpose of NAT | helps IPv4 address space exhaustion |
| how many bit space does IPv6 have | 128-bit address space |
| what does NAT stand for | network address translation |
| what is NAT used for | all devices in local network share just one IPv4 address as far as outside world is concerned |
| how does NAT work for connected devices | all devices in local network have 32-bit addresses in a private IP address space that can only be used in local network |
| what are some advantages of NAT | just one IP address needed from provider ISP for all devices / can change addresses of host in local network without notifying outside world / can change ISP without changing addresses of devices in local network |
| another advantage of NAT | security = devices inside local net not directly addressable, visible by outside world |
| how do you implement NAT | router must have outgoing datagrams = which replace (source IP address, port#) of every outgoing datagram to (NAT IP address, new port#) |
| what do remote clients and servers do when NAT is implemented | they respond using NAT IP address, new port# as destination address |
| what happens in a NAT translation table | every source IP address, new port# to NAT IP address, new port# translation pair |
| what happens when datagrams are incoming | replace NAT IP address, new port# in destination fields of every incoming datagram with corresponding source IP address, port# stored in NAT table |
| how has NAT been controversial | routers should only process up to layer 3 / address shortage should be solved by IPv6 / violates end-to-end argument / NAT traversal = what if client wants to connect to server behind NAT |
| why is NAT here to stay | extensively used in home and institutional nets 4G/5G cellular nets |
| what is the initial motivation for IPv6 | 32-bit IPv4 address space would be completely allocated |
| what are two other additional motivations for IPv6 | speed processing/forwarding = 40-byte fixed length header / enable different network-layer treatment of flows |
| what's the priority of a IPv6 datagram | identify priority among datagrams in flow |
| what is a flow label in an IPv6 datagram | identify datagrams in flow (concept of flow not well defined) |
| how many bits does the source and destination address in IPv6 datagram | 128-bit |
| what's different with IPv6 compared to IPv4 | no checksum (to speed processing at routers) / no fragmentation/reassembly / no options (available as upper-layer, next-header protocol at router) |
| how will network operate with mixed IPv4 and IPv6 routers | tunneling |
| what's tunneling | IPv6 datagram carried as payload in IPv4 datagram among IPv4 routers (packet within a packet) |
| where is tunneling extensively used | 4G/5G |
| what can't all routers do | can't be upgraded simultaneously from IPv4 to IPv6 |
| IPv4 network connection two IPv6 routers diagram | slide 84-87 (IPv4 = root) |
| where is IPv6 adopted from | google = 30% of clients access services via IPv6 / NIST = 1/3 of all US government domains are IPv6 capable |
| how long has IPv6 been deployed for | 25 years and counting (application-level changes in last 25 years = www, social media, streaming media, gaming, telepresence) |
Created by:
NtokozoN
Popular Computers sets