CS4/MSc Computer Networking. Lecture 4 The network layer: Forwarding, Routing, IP and Internet routing protocols
|
|
- Aubrie Gordon
- 5 years ago
- Views:
Transcription
1 CS4/MSc Computer Networking Lecture 4 The network layer: Forwarding, Routing, IP and Internet routing protocols Computer Networking, Copyright University of Edinburgh 2005
2 Network layer services External view: services the network provides to the transport layer Connection-oriented with quality of service guarantees Connectionless Note that there is no choice; it s one or the other Internal view: the physical interconnection topology of the network How are packets transferred datagrams or virtual circuits Congestion control and flow control (topic of future lecture) Addressing and routing procedures Two major functions Forwarding (or switching) move packet to the right out-port of router Routing determine the correct/best next router for each destination 2
3 The Switching Function Dynamic interconnection of inputs to outputs Enables dynamic sharing of transmission resources Two fundamental approaches: Connectionless Connection-Oriented: Call setup control, Connection control 3
4 Message Switching Message Message Message Source Message Switches Destination Entire messages multiplexed onto shared lines, relayed from switch to switch in store-and-forward fashion Headers for source & destination addresses 4
5 Message Switching Delay Source T Switch 1 τ Switch 2 t t t Destination Delay High utilisation of the transmission line Delay over multiple hops can be long: Whole message has to be received before it can be transmitted on Minimum delay = 3τ + 3T, assuming equal speed lines and no queueing delay Probability of transmission error also increases with length of the block More retransmissions required for correct delivery (for each link) t 5
6 Packet Switching (datagram) Messages broken into smaller units (packets) Source & destination addresses in each packet header Connectionless, packets routed independently (datagram) Packets may arrive out of order and may follow different routes Pipelining of packets across network can reduce delay, increase throughput Packet 2 Packet 1 Packet 2 Packet 1 Packet 2 Lower delay than message switching, suitable for interactive traffic 6
7 Packet-Switching Delay Source Switch 1 Switch 2 τ Destination 3 hops L hops 3τ + 2(T/3) first bit received Lτ + (L-1)P first bit received t t t t 3τ + 3(T/3) first bit released Lτ + LP first bit released 3τ + 5 (T/3) last bit released Lτ + LP + (k-1)p last bit released where T = k P 7
8 Packet-Size Eventually the delay due to the transmission of the header in each packet will reverse the speed-up gained by using ever-smaller packet sizes figure from Stallings, Data & computer communications 7e 8
9 Switching operation in connectionless networks At each switch the (final) destination address is extracted from the header and used in a look-up table to determine the forwarding output port Routing table has an entry for each destination Size of table becomes impractical for very large number of destinations Hierarchical addressing scheme used Routing tables updated dynamically when network failures occur Adjacent routers periodically share link status information Therefore datagram switching is robust 9
10 Connection-Oriented Packet Switching: Virtual Circuits Packet Packet Packet Packet Virtual circuit Call set-up phase sets ups routers in fixed path along network All packets for a connection follow the same path Variable bit rates possible, negotiated during call set-up Delays variable, cannot be less than circuit switching A release procedure required to terminate the session 10
11 Connection Setup Connect request Connect confirm SW 1 Connect request Connect confirm SW 2 SW n Connect request Connect confirm Signaling messages propagate as route is selected Signaling messages identify connection and setup tables in switches Typically a connection is identified by a local tag, Virtual Circuit Identifier (VCI) Each switch only needs to know how to relate an incoming tag in one input to an outgoing tag in the corresponding output Once tables are setup, packets can flow along path Data packet headers are shorter than with datagram switching 11
12 Virtual-Circuit Packet-Switching Delay Connect request CR CR CC CC Connect confirm Release t t t t Connection setup delay is incurred before any packet can be transferred Delay is acceptable for sustained transfer of large number of packets This delay may be unacceptably high if only a few packets are being transferred 12
13 Cut-Through Switching Source Switch 1 Switch 2 Destination Minimum delay = 3τ + T t t t t Some networks perform error checking on header only, so packet can be forwarded as soon as header is received & processed Delays reduced further with cut-through switching Error control for the payload is left for higher layer protocols To be successful, header needs to be processed quickly. Mostly used in VC switching 13
14 Router Architecture Overview 14
15 Input Port Functions Physical layer: bit-level reception Data link layer: e.g., Ethernet Decentralized switching: given datagram dest., lookup output port using forwarding table in input port memory goal: complete input port processing at line speed queuing: if datagrams arrive faster than forwarding rate into switch fabric 15
16 Three types of switching fabrics 16
17 Output Ports Buffering required when datagrams arrive from fabric faster than the transmission rate Scheduling discipline chooses among queued datagrams for transmission 17
18 Input Port Queuing Fabric slower than input ports combined -> queueing may occur at input queues Head-of-the-Line (HOL) blocking: queued datagram at front of queue prevents others in queue from moving forward Queueing delay and loss due to input buffer overflow! 18
19 Inter-networking IP packets transfer information across internet Host A IP router router router Host B IP IP layer in each router determines next hop (router) Network interfaces transfer IP packets across networks Host A Transport Layer Internet Layer Network Interface Router Internet Layer Network Interface Net Net 51 Router Internet Layer Net Net 54 Network Net Net 52 Net Net 53 Interface Router Internet Layer Network Interface Host B Transport Layer Internet Layer Network Interface 19
20 IP datagram format IP protocol version number header length (bytes) type of data max number remaining hops (decremented at each router) upper layer protocol to deliver payload to ver head. len 16-bit identifier time to live type of service upper layer 32 bits flgs data (variable length, typically a TCP or UDP segment) length fragment offset Internet checksum 32 bit source IP address 32 bit destination IP address Options (if any) total datagram length (bytes) for fragmentation/ reassembly E.g. timestamp, record route taken, specify list of routers to visit. 20
21 Fragmentation and Reassembly Each physical link imposes a maximum size of transmission unit (MTU) e.g. ethernet 1500 bytes, FDDI 4464 bytes IP may have to break a large packet into smaller fragments Each fragment is sent independently, as though it were an IP packet Any router may need to fragment packets to smaller sizes again IP Source Router Destination IP Network Network The destination IP is the only entity that reassembles fragments into the original packet 21
22 Fragmentation and Reassembly Operation To reassemble a packet Destination waits until all the fragments have been received If any fragment is lost, the whole original packet is abandoned» Lost fragments detected by using a time-out following arrival of first fragment Identification field in IP header shows which packet a fragment belongs to» Source must not reuse an identification value for a sufficiently long period Flag bits :» DF : don t fragment - if packet is longer than MTU for next hop, discard and send error message» MF : more fragments follow this one Offset field : measures the offset in the packet of this fragment in units of eight bytes (all fragments must be multiples of 8, except the last) Performance: fragment loss means retransmission of all packet fragments again Could be done more efficiently with selective retransmission 22
23 IP Addresses Each host is assigned a unique 32-bit IP address : Network ID + Host ID or multiple IP addresses for hosts with multiple interfaces Host ID allocated locally by network administrator or DHCP Network IDs allocated by RIPE (Réseaux IP Européens) NCC (Network Coordination Centre) in Amsterdam for Europe, Middle East & North Africa One of three Regional Internet Registries: ARIN (Americas), APNIC (Asia Pacific)» Allocation of blocks of IP addresses to Local Internet Registries e.g. ISPs - who further allocate them to their users Routers only need to route packets on basis of the Network ID part» reduces size of routing tables Five address classes : A to E with distinct prefixes» Class D used for multicast services to a group of hosts simultaneously» Class E reserved for experiments 23
24 Subnets portion of a network sharing a particular subnet address subnet /24 subnet /24 IP address: subnet part (high order bits) host part (low order bits) What s a subnet? device interfaces with same subnet part of IP address can physically reach each other without intervening router Subnet mask (a 32-bit combination which describes which portion of address refers to the subnet and which to the host Masks out the hostid part of the address e.g subnet /24 24
25 Classless Inter-Domain Routing (CIDR) Essentially applies the idea of subnetting to the network ID part of the address An arbitrary prefix length indicates the network number Address format: a.b.c.d/x, where x is # bits in subnet portion of address e.g /22 indicates a prefix of 22 bits represented as /16, i.e. the number of left-most contiguous mask bits that are set to one. Allows aggregation of a number of contiguous network addresses into a single entry in a routing table (supernetting) Assuming the next hop router is common Requires that a longest prefix match search scheme be used IP addresses have to be allocated using policies to capitalise on this capability e.g. reflecting the physical hierarchical topology of the network continents use a short prefix, countries slightly longer etc. 25
26 Classless Inter-Domain Routing (CIDR) Each domain takes its IP address from a higher level hierarchical internet architecture This allows for the summarisation of the domains to be done at higher level ISP owns network /16 ISP can offer /24, /24 and so on. To customers When advertising to other providers, ISP need only advertise /16 26
27 Network Address Translation IP addresses can be re-used in separate internal sub-internetworks Each internal sub-network lives behind a NAT-enabled gateway/router Registered IP addresses used outside the gateway to connect to public network» assigned by the usual authorities as normal A set of unregistered IP addresses is used in the private local network» a range of addresses are set aside for this re-use by the authority Hosts on the local network communicate using local unregistered addresses Packets outgoing to the public network have their local IP addresses translated to registered external IP addresses by the gateway and vice versa 27
28 Dynamic NAT example 2: NAT router changes datagram source addr from , 3345 to , 5001, updates table 2 NAT translation table WAN side addr LAN side addr , , 3345 S: , 5001 D: , S: , 3345 D: , : host sends datagram to , S: , 80 D: , : Reply arrives dest. address: , 5001 S: , 80 D: , : NAT router changes datagram dest addr from , 5001 to ,
29 NAT limitations 16-bit port-number field: 60,000 simultaneous connections with a single LAN-side address. Not bad! NAT is controversial: routers should only process up to layer 3 violates end-to-end argument» NAT possibility must be taken into account by app designers, eg, P2P applications address shortage should instead be solved by IPv6 29
30 Dynamic Host Configuration Protocol (DHCP) Provides a method for dynamically assigning temporary IP addresses Also allows clients to acquire IP configuration parameters they need» e.g. subnet mask, broadcast IP address, default router etc. Based on BOOTP protocol, runs on top of UDP (client port 67, server 68) How can you use UDP if you don t know your own IP address? Temporarily use ; host identified by network (e.g. ethernet) address An ISP allocates IP addresses from its assigned set on a per-use basis IP addresses leased for a time from a limited pool Address can be re-used for another client at a later time 30
31 DHCP Operation Host broadcasts DHCP Discover message on its physical network Server replies with Offer message (IP address + configuration information) Host selects one offer and broadcasts DHCP Request message Server allocates IP address for lease time T Sends DHCP ACK message with T, and threshold times T1 (=1/2 T) and T2 (=.875T) At T1, host attempts to renew lease by sending DHCP Request message to original server If no reply by T2, host broadcasts DHCP Request to any server If no reply by T, host must relinquish IP address and start from the beginning 31
32 IP version 6 Introduced to address shortcomings of IPv4 and emerging applications Designed to interoperate with IPv4 during transition period Main features: Longer addresses 128 bits Simpler header format e.g. no header length or fragmentation fields Options provided by more flexible extension headers Flow label capability to identify a packet flow that needs certain QoS Security : supports authentication Large packets : jumbo packets longer than 64Kb Fragmentation at source only: intermediate routers not allowed to fragment No checksum field» Typically physical layers perform error detection» higher layers too 32
33 IPv6 Header Format Version Traffic Class Flow Label Payload Length Next Header Version : 6 for IPv6 Traffic class : priority of packet; zero means best-effort intended to support differentiated services still experimental Flow label : source desires special handling of this flow of packets assigned by the source pseudo-randomly flow requirements specified by a control protocol or within the packets also still experimental Source Address Destination Address Payload length : length of data excluding the header; larger packet though extension header option Next header : Type of next header: extension or payload Hop limit : replaces TTL field in IPv4; now means what it says! Source and destination addresses : 128 bits Hop Limit 33
34 IPv6 Addressing Address Types Unicast : denote a single host the normal understanding of IP address Multicast : a multicast enabled host can join a multicast address group Anycast : like multicast with groups of hosts but only one host gets the packet typically the closest host» Share the same address space as multicast addresses Hexadecimal notation Groups of 16 bits represented by 4 hex digits, separated by colons: 4BF5:AA12:0216:FEBC:BA5F:039A:BE9A:2176 Hierarchical provider-based i.e. ISP, unicast addresses : n bits m bits o bits p bits (125-m-n-o-p) bits 010 Registry ID Provider ID Subscriber ID Subnet ID Interface ID IPv6 must be backwards compatible with IPv4 to be interoperable e.g. IPv4-compatible IPv6 addresses:» 96 bits of zeroes followed by 32 bits of IPv4 address 34
35 IPv6 Extension Headers An arbitrary number of daisy-chained headers to provide extra options Each header has a type field describing what the next header is for Extension headers processed in order of appearance Basic header Next header = routing Routing header Next header = fragment Fragment header Next header = authentication Authentication header Next header = TCP TCP segment Basic header Next header = TCP TCP segment Extension header types: Large jumbo packets» Packet size declared in basic header is replaced with this Fragmentation header» Fragmentation ID, fragment offset, etc Routing header» source routing i.e. the sequence of routers to be visited by each packet 35
36 Migration from IPv4 to IPv6 Gradual transition from IPv4 to IPv6 Dual IP stacks: routers run both IPv4 & IPv6 Type field used to direct packet to IP version IPv6 islands can tunnel across IPv4 networks Encapsulate user packet inside IPv4 packet Tunnel endpoint at source host, intermediate router, or destination host Tunneling can be recursive Source Tunnel head-end Tunnel tail-end Destination Tunnel (a) IPv6 network IPv6 header IPv4 network IPv4 header IPv6 network 36
37 37
38 Routing in Packet Networks An objective function needed to determine the best route e.g. minimum number of hops, minimum end-to-end delay, path with greatest available bandwidth etc. Algorithms should seek certain goals: Rapid and accurate routing Adaptability to network topology changes» due to switch or link failures» must be able to quickly reconfigure routing tables Adaptability to varying loads» must be able to reconfigure best according to the current loads Ability to route packets away from temporarily congested links» load balancing over links desirable Ability to determine connectivity of the network Low overhead of control message interchange between routers 38
39 Classification of routing strategies Centralised routing Single special host calculates shortest paths between all pairs of hosts Distributed routing Each router does a part of the job Static routing Dynamic (or adaptive) routing Routes change as a result of changes in the network 39
40 Shortest-Path Algorithms Each link is associated with a cost value calculated using a cost function Packet delay, congestion, link capacity, Distance vector routing (e.g. Bellman-Ford algorithm) Neighbouring routers exchange list of distances to destinations Routers process this to find better routes through the neighbour and adapt to changes in the network topology as information percolates through the network Link state routing (e.g. Dijkstra algorithm) Each router broadcasts information about the state of its links to neighbours and other routers pass this information on further Each router can therefore construct a map of the entire network and derive a routing table 40
41 Dijkstra s Algorithm Input: the network graph with edges annotated with costs Iteratively find the next closest node from the source let D i be the current minimum cost from source to node i let C ij be the cost of the path from node i to node j Initialisation: N = {s} Find next closest node: Update minimum costs: D j = C sj j s ( = if no direct connection) D s = 0 find node i N such that D i = min D j, j N add i to N if N contains all nodes, stop for each node j N, D j = min { D j, D i + C ij } 41
42 Bellman-Ford Algorithm Initially, distance to self is 0, to all other destinations Each node i periodically broadcasts its vector of costs { D i1, D i2, D i3 } to its neighbours When an update is received, a node compares the minimum cost to each destination and selects the corresponding neighbour as the next hop: D ij = min { C ik + D kj } k i +Good news travel fast - Bad news don t (count to infinity problem) 42
43 Comparison of LS and DV algorithms Message complexity LS: with n nodes, E links, O(nE) msgs sent DV: exchange between neighbors only convergence time varies Speed of Convergence LS: O(n 2 ) algorithm requires O(nE) msgs may have oscillations DV: convergence time varies may be routing loops count-to-infinity problem Robustness: what happens if router malfunctions? LS: DV: node can advertise incorrect link cost each node computes only its own table DV node can advertise incorrect path cost each node s table used by others» error propagate thru network 43
44 Specialised Routing - Flooding Each switch forwards incoming packets to all ports except the one the packet was received from Packet reaches the destination with minimum number of hops Unfortunately flooding may swamp the network with an exponentially increasing number of packets Useful when routing information not available or when survivability is required (e.g. MANETS: mobile ad-hoc networks) Effective when source needs to broadcast to all hosts in the network Flood control: A time-to-live field set to some small number, decremented at each switch and the packet discarded when the count reaches zero Each switch adds its identifier to the packet header before it floods When a switch receives a packet, it records the source address and the sequence number 44
45 Hierarchical routing in the Internet The Internet is a collection of Autonomous Systems (AS) Sets of routers and networks each administered by a single organisation Stub AS : single connection to outside world Transit AS : has connections to more than one other AS Allows itself to be used for transit traffic and needs its own ASN Most large ISP s are transit AS s Multihomed AS : has multiple AS connections but does not allow through traffic Routing protocols Interior Gateway Protocol (IGP)» within an AS Exterior Gateway Protocol (EGP)» communication among ASs Intra-AS Routing algorithm Forwarding table Inter-AS Routing algorithm 45
46 Routing Information Protocol (RIP) IGP protocol based on the distance-vector Bellman-Ford algorithm With split-horizon poisoned reverse Runs on top of UDP port number 520 Distance metric is the number of hops Maximum number of hops limited to 15 i.e. the diameter of the network must be no greater than is regarded as infinity Small infinity number limits the count to infinity problem RIP is not flexible in choice of metric e.g. cannot take account of network load conditions RIP-2 offers improvements: Packets carry a variable-length subnet mask allows CIDR to work and an authentication procedure for trusting distance vectors from other routers 46
47 RIP (v1) Operation RIP router sends an update message to its neighbours every 30 seconds The neighbours can then recalculate their shortest paths Router expects to receive an update message from each of its neighbours at least once every 180 seconds Allows more than 30 seconds since UDP is unreliable If a router does not receive an update within the time limit, it assumes the link to its neighbour has failed Sets the corresponding cost to 16 (infinity) This can be replaced with a correct value if the neighbour eventually responds or another route to it is found Convergence of shortest paths can be slow when topology changes Triggered updates can improve this» update its neighbours immediately rather than wait for next update time 47
48 Open Shortest Path First (OSPF) Specification in RFC 2328 IGP protocol based on link-state methods, using Dijkstra s algorithm Link-state is monitored and flooded to other routers Routers learn the complete network topology: each has an identical link-state database They can apply a shortest path algorithm locally to find optimal routes Link-state database is kept up to date when changes occur and periodically (30min) Designed to be better and much more flexible than RIP Converges to a stable state faster Allows different optimal routes to be calculated for different types of service Allows load balancing over paths of equal cost 48
49 Hierarchical OSPF Two-level hierarchy: local area, backbone Link-state advertisements only in area each node has detailed area topology; only know direction (shortest path) to nets in other areas Area border routers: summarize distances to nets in own area, advertise to other Area Border routers Backbone routers: run OSPF routing limited to backbone. Boundary routers: connect to other AS s 49
50 OSPF Operation Phase 1 : neighbours are discovered using the Hello protocol Router periodically broadcasts a hello packet onto each of its interfaces When a router receives a hello packet, it replies with a hello packet containing the ID of each neighbouring router it knows about Originating router sees a hello packet with its own ID, it knows there is a working bidirectional link between it and the sending router Hello protocol also elects designated routers and backup designated routers for multiaccess networks Phase 2 : Establishment of adjacencies and database synchronisation Routers are chosen to become adjacent=keep link-state data synchronised Link State Advertisement (LSA) headers are exchanged using database description packets A neighbour can then request the full LSA database entry if it does not have it or it is out-of-date 50
51 OSPF Operation (cont) Phase 3 : Maintenance and updating the database A router wanting to update its link state database can send a link state request to its neighbour When a router has a change to propagate, it can update its neighbours with a link state update packet containing (full) LSAs When a router receives an update packet» It sends an acknowledgment» Updates its database» Propagates the information by flooding: forwards the LSAs to all its neighbours except the one it came from OSPF routers are obliged to refresh their LSAs every 30 minutes 51
52 Border Gateway Protocol BGP Pairs of routers (BGP peers) exchange routing info over TCP connections BGP sessions do not correspond to physical links. When AS2 advertises a prefix to AS1, AS2 is promising it will forward any datagrams destined to that prefix towards the prefix. AS2 can aggregate prefixes in its advertisement An internal BGP distributes the new info to AS s routers 3c 3a 3b AS3 1a AS1 1c 1d 1b 2a 2c 2b AS2 ebgp session ibgp session 52
53 Distributing reachability info With ebgp session between 3a and 1c, AS3 sends prefix reachability info to AS1. 1c can then use ibgp do distribute this new prefix reach info to all routers in AS1 1b can then re-advertise the new reach info to AS2 over the 1b-to-2a ebgp session When router learns about a new prefix, it creates an entry for the prefix in its forwarding table. 3c 3a 3b AS3 1a AS1 1c 1d 1b 2a 2c 2b AS2 ebgp session ibgp session 53
54 Path attributes & BGP routes When advertising a prefix, advert includes BGP attributes prefix + attributes = route advert Two important attributes: AS-PATH: contains the ASs through which the advert for the prefix passed: AS 67 AS 17 NEXT-HOP: Indicates the specific internal-as router to next-hop AS. (There may be multiple links from current AS to next-hop-as) Only path changes (new, withdrawn) are exchanged When gateway router receives route advert, uses import policy to accept/decline 54
55 Why different Intra- and Inter-AS routing? Policy: Inter-AS: admin wants control over how its traffic routed, who routes through its net. Intra-AS: single admin, so no policy decisions needed Scale: Hierarchical routing saves table size, reduced update traffic Performance: Intra-AS: can focus on performance Inter-AS: policy may dominate over performance 55
56 Reading list LGW Tanenbaum Stallings 10.6, 12 56
57 EGP routing tasks Suppose router in AS1 receives datagram for which dest is outside of AS1 Router should forward packet towards one of the gateway routers, but which one? 3c 3a 3b AS3 1a 1c 1d 1b AS1 needs: 1. to learn which dests are reachable through AS2 and which through AS3 2. to propagate this reachability info to all routers in AS1 Job of inter-as routing! AS1 2a 2c AS2 2b 57
CS4/MSc Computer Networking. Lectures 6-8 The network layer: Forwarding, Routing, IP and Internet routing protocols
CS4/MSc Computer Networking Lectures 6-8 The network layer: Forwarding, Routing, IP and Internet routing protocols Computer Networking, Copyright University of Edinburgh 2005 Network layer services External
More informationLecture 8. Network Layer (cont d) Network Layer 1-1
Lecture 8 Network Layer (cont d) Network Layer 1-1 Agenda The Network Layer (cont d) What is inside a router Internet Protocol (IP) IPv4 fragmentation and addressing IP Address Classes and Subnets Network
More informationLecture 3. The Network Layer (cont d) Network Layer 1-1
Lecture 3 The Network Layer (cont d) Network Layer 1-1 Agenda The Network Layer (cont d) What is inside a router? Internet Protocol (IP) IPv4 fragmentation and addressing IP Address Classes and Subnets
More informationRouter Architecture Overview
Chapter 4: r Introduction (forwarding and routing) r Review of queueing theory r Router design and operation r IP: Internet Protocol m IPv4 (datagram format, addressing, ICMP, NAT) m Ipv6 r Generalized
More informationHY 335 Φροντιστήριο 8 ο
HY 335 Φροντιστήριο 8 ο Χειμερινό Εξάμηνο 2009-2010 Παπακωνσταντίνου Άρτεμις artpap@csd.uoc.gr 4/12/2009 Roadmap IP: The Internet Protocol IPv4 Addressing Datagram Format Transporting a datagram from source
More informationLast time. Transitioning to IPv6. Routing. Tunneling. Gateways. Graph abstraction. Link-state routing. Distance-vector routing. Dijkstra's Algorithm
Last time Transitioning to IPv6 Tunneling Gateways Routing Graph abstraction Link-state routing Dijkstra's Algorithm Distance-vector routing Bellman-Ford Equation 10-1 This time Distance vector link cost
More informationChapter 4: Network Layer
Chapter 4: Introduction (forwarding and routing) Review of queueing theory Routing algorithms Link state, Distance Vector Router design and operation IP: Internet Protocol IPv4 (datagram format, addressing,
More informationCPSC 826 Internetworking. The Network Layer: Routing & Addressing Outline. The Network Layer
1 CPSC 826 Intering The Network Layer: Routing & Addressing Outline The Network Layer Michele Weigle Department of Computer Science Clemson University mweigle@cs.clemson.edu November 10, 2004 Network layer
More informationLecture 4 - Network Layer. Transport Layer. Outline. Introduction. Notes. Notes. Notes. Notes. Networks and Security. Jacob Aae Mikkelsen
Lecture 4 - Network Layer Networks and Security Jacob Aae Mikkelsen IMADA September 23, 2013 September 23, 2013 1 / 67 Transport Layer Goals understand principles behind network layer services: network
More informationLecture 4 The Network Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it
Lecture 4 The Network Layer Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Network layer functions Transport packet from sending to receiving hosts Network layer protocols in every
More informationinternet technologies and standards
Institute of Telecommunications Warsaw University of Technology 2017 internet technologies and standards Piotr Gajowniczek Andrzej Bąk Michał Jarociński Network Layer The majority of slides presented in
More informationNetworking: Network layer
control Networking: Network layer Comp Sci 3600 Security Outline control 1 2 control 3 4 5 Network layer control Outline control 1 2 control 3 4 5 Network layer purpose: control Role of the network layer
More informationEEC-684/584 Computer Networks
EEC-684/584 Computer Networks Lecture 14 wenbing@ieee.org (Lecture nodes are based on materials supplied by Dr. Louise Moser at UCSB and Prentice-Hall) Outline 2 Review of last lecture Internetworking
More informationNetwork Layer PREPARED BY AHMED ABDEL-RAOUF
Network Layer PREPARED BY AHMED ABDEL-RAOUF Network layer transport segment from sending to receiving host on sending side encapsulates segments into datagrams on receiving side, delivers segments to transport
More informationInternet Routing Protocols, DHCP, and NAT
Internet Routing Protocols, DHCP, and NAT Hwajung Lee Modified from Slides Courtesy of Cisco Networking Academy and the book titled Communication Networks by Leon-Garcia Contents Basic Routing Single Area
More informationEC441 Fall 2018 Introduction to Computer Networking Chapter4: Network Layer Data Plane
EC441 Fall 2018 Introduction to Computer Networking Chapter4: Network Layer Data Plane This presentation is adapted from slides produced by Jim Kurose and Keith Ross for their book, Computer Networking:
More informationChapter 4: network layer
Chapter 4: network layer chapter goals: understand principles behind network layer services: network layer service models forwarding versus routing how a router works routing (path selection) broadcast,
More informationNetwork layer: Overview. Network layer functions IP Routing and forwarding NAT ARP IPv6 Routing
Network layer: Overview Network layer functions IP Routing and forwarding NAT ARP IPv6 Routing 1 Network Layer Functions Transport packet from sending to receiving hosts Network layer protocols in every
More informationBasic Idea. Routing. Example. Routing by the Network
Basic Idea Routing Routing table at each router/gateway When IP packet comes, destination address checked with routing table to find next hop address Questions: Route by host or by network? Routing table:
More informationNetwork layer: Overview. Network Layer Functions
Network layer: Overview Network layer functions IP Routing and forwarding NAT ARP IPv6 Routing 1 Network Layer Functions Transport packet from sending to receiving hosts Network layer protocols in every
More informationRouting by the Network
Routing Basic Idea Routing table at each router/gateway When IP packet comes, destination address checked with routing table to find next hop address Questions: Route by host or by network? Routing table:
More informationCSCE 463/612 Networks and Distributed Processing Spring 2018
CSCE 463/612 Networks and Distributed Processing Spring 2018 Network Layer II Dmitri Loguinov Texas A&M University April 3, 2018 Original slides copyright 1996-2004 J.F Kurose and K.W. Ross 1 Chapter 4:
More informationUNIT III THE NETWORK LAYER
UNIT III THE NETWORK LAYER Introduction-Virtual Circuit and Datagram Networks- Inside a Router- The Internet Protocol (IP): Forwarding and Addressing in the Internet-Routing Algorithms Routing in the Internet-Broadcast
More informationCSCE 463/612 Networks and Distributed Processing Spring 2018
CSCE 463/612 Networks and Distributed Processing Spring 2018 Network Layer IV Dmitri Loguinov Texas A&M University April 12, 2018 Original slides copyright 1996-2004 J.F Kurose and K.W. Ross 1 Chapter
More informationInitial motivation: 32-bit address space soon to be completely allocated. Additional motivation:
IPv6 Initial motivation: 32-bit address space soon to be completely allocated. Additional motivation: header format helps speed processing/forwarding header changes to facilitate QoS IPv6 datagram format:
More informationChapter 4 Network Layer. Network Layer 4-1
Chapter 4 Network Layer Network Layer 4- Chapter 4: Network Layer 4. Introduction 4. Virtual circuit and datagram networks 4. What s inside a router 4.4 IP: Internet Protocol Datagram format IPv4 addressing
More informationChapter 4: network layer. Network service model. Two key network-layer functions. Network layer. Input port functions. Router architecture overview
Chapter 4: chapter goals: understand principles behind services service models forwarding versus routing how a router works generalized forwarding instantiation, implementation in the Internet 4- Network
More information1-1. Switching Networks (Fall 2010) EE 586 Communication and. October 25, Lecture 24
EE 586 Communication and Switching Networks (Fall 2010) Lecture 24 October 25, 2010 1-1 Announcements Midterm 1: Mean = 92.2 Stdev = 8 Still grading your programs (sorry about the delay) Network Layer
More informationCOMP211 Chapter 4 Network Layer: The Data Plane
COMP211 Chapter 4 Network Layer: The Data Plane All material copyright 1996-2016 J.F Kurose and K.W. Ross, All Rights Reserved Computer Networking: A Top Down Approach 7 th edition Jim Kurose, Keith Ross
More informationCSc 450/550 Computer Networks Internet Routing
CSc 450/550 Computer Networks Internet Routing Jianping Pan Summer 2007 7/12/07 CSc 450/550 1 Review Internet Protocol (IP) IP header addressing class-based, classless, hierarchical, NAT routing algorithms
More informationChapter 4: Network Layer, partb
Chapter 4: Network Layer, partb The slides are adaptations of the slides available by the main textbook authors, Kurose&Ross Network Layer 4-1 Interplay between routing, forwarding routing algorithm local
More informationMaster Course Computer Networks IN2097
Chair for Network Architectures and Services Prof. Carle Department for Computer Science TU München Master Course Computer Networks IN2097 Prof. Dr.-Ing. Georg Carle Christian Grothoff, Ph.D. Chair for
More informationSubnets. IP datagram format. The Internet Network layer. IP Fragmentation and Reassembly. IP Fragmentation & Reassembly. IP Addressing: introduction
The Network layer Host, network layer functions: Network layer Routing protocols path selection R, OSPF, BGP Transport layer: TCP, forwarding table Link layer physical layer protocol addressing conventions
More informationRouting Unicast routing protocols
Routing Unicast routing protocols Jens A Andersson Electrical and Information Technology R1 Choosing an Optimal Path R4 5 R7 5 10 40 R6 6 5 B R2 15 A 20 4 10 10 R8 R3 5 10 R5 1 Router A router is a type
More informationETSF05/ETSF10 Internet Protocols. Routing on the Internet
ETSF05/ETSF10 Internet Protocols Routing on the Internet Circuit switched routing ETSF05/ETSF10 - Internet Protocols 2 Routing in Packet Switching Networks Key design issue for (packet) switched networks
More informationData Communication & Networks G Session 7 - Main Theme Networks: Part I Circuit Switching, Packet Switching, The Network Layer
Data Communication & Networks G22.2262-001 Session 7 - Main Theme Networks: Part I Circuit Switching, Packet Switching, The Network Layer Dr. Jean-Claude Franchitti New York University Computer Science
More informationTopics for This Week
Topics for This Week Routing Protocols in the Internet OSPF, BGP More on IP Fragmentation and Reassembly ICMP Readings Sections 5.6.4-5.6.5 1 Hierarchical Routing aggregate routers into regions, autonomous
More informationETSF05/ETSF10 Internet Protocols Routing on the Internet
ETSF05/ETSF10 Internet Protocols Routing on the Internet 2014, (ETSF05 Part 2), Lecture 1.1 Jens Andersson Circuit switched routing 2014 11 05 ETSF05/ETSF10 Internet Protocols 2 Packet switched Routing
More informationChapter 4: Network Layer
Mecanismes d Echange d Informations Chapter 4 Network Layer A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students, readers). They re in PowerPoint
More informationNetwork layer. Network Layer 4-1. application transport network data link physical. network data link physical. network data link physical
Network layer transport segment from sending to receiving host on sending side encapsulates segments into datagrams on receiving side, delivers segments to transport layer network layer protocols in every
More informationRouting. Jens A Andersson Communication Systems
Routing Jens A Andersson Communication Systems R1 Choosing an Optimal Path R4 5 R7 5 10 40 R6 6 5 B R2 15 A 20 4 10 10 R8 R3 5 R5 10 Router A router is a type of internetworking device that passes data
More informationCMPE 150/L : Introduction to Computer Networks. Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 12
CMPE 150/L : Introduction to Computer Networks Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 12 1 Chapter 4: outline 4.1 introduction 4.2 virtual circuit and datagram networks 4.3 what
More informationNetwork Layer: Control/data plane, addressing, routers
Network Layer: Control/data plane, addressing, routers CS 352, Lecture 10 http://www.cs.rutgers.edu/~sn624/352-s19 Srinivas Narayana (heavily adapted from slides by Prof. Badri Nath and the textbook authors)
More informationEEC-484/584 Computer Networks
EEC-484/584 Computer Networks Lecture 13 wenbing@ieee.org (Lecture nodes are based on materials supplied by Dr. Louise Moser at UCSB and Prentice-Hall) Outline 2 Review of lecture 12 Routing Congestion
More informationInternetworking Part 2
CMPE 344 Computer Networks Spring 2012 Internetworking Part 2 Reading: Peterson and Davie, 3.2, 4.1 19/04/2012 1 Aim and Problems Aim: Build networks connecting millions of users around the globe spanning
More informationinternet technologies and standards
Institute of Telecommunications Warsaw University of Technology 2015 internet technologies and standards Piotr Gajowniczek Andrzej Bąk Michał Jarociński Network Layer The majority of slides presented in
More informationNetwork Layer: Internet Protocol
Network Layer: Internet Protocol Motivation Heterogeneity Scale Intering IP is the glue that connects heterogeneous s giving the illusion of a homogenous one. Salient Features Each host is identified by
More informationTDTS06: computer Networks
TDTS06: computer Networks Lecturer: Johannes Schmidt The slides are taken from the book s companion Web site with few modifications: Computer Networking: A Top Down Approach 5 th edition. Jim Kurose, Keith
More informationUnit 3: Dynamic Routing
Unit 3: Dynamic Routing Basic Routing The term routing refers to taking a packet from one device and sending it through the network to another device on a different network. Routers don t really care about
More informationChapter 4 Network Layer
Chapter 4 Network Layer Computer Networking A Top-Down Approach These slides are based on the slides made available by Kurose and Ross. All material copyright 1996-2012 J.F Kurose and K.W. Ross, All Rights
More informationThe Interconnection Structure of. The Internet. EECC694 - Shaaban
The Internet Evolved from the ARPANET (the Advanced Research Projects Agency Network), a project funded by The U.S. Department of Defense (DOD) in 1969. ARPANET's purpose was to provide the U.S. Defense
More informationInternet Technology 3/23/2016
Internet Technology // Network Layer Transport Layer (Layer ) Application-to-application communication Internet Technology Network Layer (Layer ) Host-to-host communication. Network Layer Route Router
More informationCS118 Discussion Week 7. Taqi
CS118 Discussion Week 7 Taqi Outline Hints for project 2 Lecture review: routing About Course Project 2 Please implement byte-stream reliable data transfer Cwnd is in unit of bytes, not packets How to
More informationQuiz. Segment structure and fields Flow control (rwnd) Timeout interval. Phases transition ssthresh setting Cwnd setting
Quiz v 10/30/2013 (Wednesday), 20 mins v Midterm question (available on website) v TCP basics Segment structure and fields Flow control (rwnd) Timeout interval v TCP Congestion control Phases transition
More informationLast time. Network layer. Introduction. Virtual circuit vs. datagram details. IP: the Internet Protocol. forwarding vs. routing
Last time Network layer Introduction forwarding vs. routing Virtual circuit vs. datagram details connection setup, teardown VC# switching forwarding tables, longest prefix matching IP: the Internet Protocol
More informationCS 457 Networking and the Internet. Shortest-Path Problem. Dijkstra s Shortest-Path Algorithm 9/29/16. Fall 2016
9/9/6 S 7 Networking and the Internet Fall 06 Shortest-Path Problem Given: network topology with link costs c(x,y): link cost from node x to node y Infinity if x and y are not direct neighbors ompute:
More informationChapter 4: outline. Network Layer 4-1
Chapter 4: outline 4.1 introduction 4.2 virtual circuit and datagram networks 4.3 what s inside a router 4.4 IP: Internet Protocol datagram format IPv4 addressing ICMP IPv6 4.5 routing algorithms link
More informationEECS 122, Lecture 16. Link Costs and Metrics. Traffic-Sensitive Metrics. Traffic-Sensitive Metrics. Static Cost Metrics.
EECS 122, Lecture 16 Kevin Fall kfall@cs.berkeley.edu edu Link Costs and Metrics Routing protocols compute shortest/cheapest paths using some optimization criteria Choice of criteria has strong effect
More informationChapter 4: Network Layer
Chapter 4: Network Layer 4. 1 Introduction 4.2 Virtual circuit and datagram networks 4.3 What s inside a router 4.4 IP: Internet Protocol Datagram format IPv4 addressing ICMP IPv6 4.5 Routing algorithms
More informationHierarchical Routing. Our routing study thus far - idealization all routers identical network flat not true in practice
Hierarchical Routing Our routing study thus far - idealization all routers identical network flat not true in practice scale: with 200 million destinations: can t store all destinations in routing tables!
More informationChapter 4: Advanced Internetworking. Networking CS 3470, Section 1
Chapter 4: Advanced Internetworking Networking CS 3470, Section 1 Intra-AS and Inter-AS Routing a C C.b b d A A.a a b A.c c B.a a B c Gateways: perform inter-as routing amongst themselves b perform intra-as
More informationHierarchical Routing. Our routing study thus far - idealization all routers identical network flat no true in practice. administrative autonomy
Hierarchical Routing Our routing study thus far - idealization all routers identical network flat no true in practice scale: with 50 million destinations: can t store all dest s in routing tables! routing
More informationCSCI-1680 Network Layer: IP & Forwarding John Jannotti
CSCI-1680 Network Layer: IP & Forwarding John Jannotti Based partly on lecture notes by David Mazières, Phil Levis, Rodrigo Fonseca Administrivia IP out today. Your job: Find partners, get setup with Github
More informationLecture 5 The Network Layer part II. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it
Lecture 5 The Network Layer part II Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it IP datagram format IP protocol version number header length (bytes) type of data max number remaining
More informationCSCI-1680 Network Layer: IP & Forwarding Rodrigo Fonseca
CSCI-1680 Network Layer: IP & Forwarding Rodrigo Fonseca Based partly on lecture notes by David Mazières, Phil Levis, John Janno< Administrivia IP out today. Your job: Find partners and tell us Implement
More informationAnnouncements. CS 5565 Network Architecture and Protocols. Project 2B. Project 2B. Project 2B: Under the hood. Routing Algorithms
Announcements CS 5565 Network Architecture and Protocols Lecture 20 Godmar Back Project 2B due in 2 parts: Apr 29 and May 6 Extra Credit Opportunities: Expand simulator (and your implementation) to introduce
More informationComputer Network Fundamentals Spring Week 4 Network Layer Andreas Terzis
Computer Network Fundamentals Spring 2008 Week 4 Network Layer Andreas Terzis Outline Internet Protocol Service Model Addressing Original addressing scheme Subnetting CIDR Fragmentation ICMP Address Shortage
More informationOutline. Routing. Introduction to Wide Area Routing. Classification of Routing Algorithms. Introduction. Broadcasting and Multicasting
Outline Routing Fundamentals of Computer Networks Guevara Noubir Introduction Broadcasting and Multicasting Shortest Path Unicast Routing Link Weights and Stability F2003, CSG150 Fundamentals of Computer
More informationReview for Chapter 4 R1,R2,R3,R7,R10,R11,R16,R17,R19,R22,R24, R26,R30 P1,P2,P4,P7,P10,P11,P12,P14,P15,P16,P17,P22,P24,P29,P30
Review for Chapter 4 R1,R2,R3,R7,R10,R11,R16,R17,R19,R22,R24, R26,R30 P1,P2,P4,P7,P10,P11,P12,P14,P15,P16,P17,P22,P24,P29,P30 R1. Let s review some of the terminology used in this textbook. Recall that
More informationNetwork layer: Overview. Network layer functions Routing IP Forwarding
Network layer: Overview Network layer functions Routing IP Forwarding 1 Network Layer Functions Transport packet from sending to receiving hosts (processes) Network layer protocols in every host, router
More informationChapter 4 Network Layer
Chapter 4 Network Layer Reti degli Elaboratori Canale AL Prof.ssa Chiara Petrioli a.a. 2014/2015 We thank for the support material Prof. Kurose-Ross All material copyright 1996-2012 J.F Kurose and K.W.
More informationDepartment of Computer and IT Engineering University of Kurdistan. Network Layer. By: Dr. Alireza Abdollahpouri
Department of Computer and IT Engineering University of Kurdistan Network Layer By: Dr. Alireza Abdollahpouri What s the Internet: nuts and bolts view PC server wireless laptop cellular handheld millions
More informationTo contain/reduce broadcast traffic, we need to reduce the size of the network (i.e., LAN).
2.3.3 Routers 2.3.3.1 Motivation Bridges do not stop broadcast traffic. This can lead to broadcast storms (e.g., more than 100 nonunicast frames/sec) which can be catastrophic. This can bring the network
More informationThe Network Layer Forwarding Tables and Switching Fabric
The Network Layer Forwarding Tables and Switching Fabric Smith College, CSC 249 February 27, 2018 1 Network Layer Overview q Network layer services v v Desired services and tasks Actual services and tasks
More informationComputer Networking Introduction
Computer Networking Introduction Halgurd S. Maghdid Software Engineering Department Koya University-Koya, Kurdistan-Iraq Lecture No.15 Chapter 4: outline 4.1 introduction 4.2 virtual circuit and datagram
More informationIP - The Internet Protocol. Based on the slides of Dr. Jorg Liebeherr, University of Virginia
IP - The Internet Protocol Based on the slides of Dr. Jorg Liebeherr, University of Virginia Orientation IP (Internet Protocol) is a Network Layer Protocol. IP: The waist of the hourglass IP is the waist
More informationLecture 19: Network Layer Routing in the Internet
Lecture 19: Network Layer Routing in the Internet COMP 332, Spring 2018 Victoria Manfredi Acknowledgements: materials adapted from Computer Networking: A Top Down Approach 7 th edition: 1996-2016, J.F
More informationRouting. Advanced Computer Networks: Routing 1
Routing Advanced Computer Networks: Routing 1 Gateway To internet or wide area network Metropolitan Area Network (MAN) s s Organization Servers Backbone R S R R Departmental Server s R S R s S R s s s
More informationInternet Routing Protocols Tuba Saltürk
Internet Routing Protocols 15505068 Tuba Saltürk Outline Internet Routers Routing Protocol Interior Gateway Protocol (IGP) Distance- Vector Routing Protocol Routing Information Protocol (RIP) Interior
More informationNetwork Layer: Router Architecture, IP Addressing
Network Layer: Router Architecture, IP Addressing UG3 Computer Communications & Networks (COMN) Mahesh Marina mahesh@ed.ac.uk Slides thanks to Myungjin Lee and copyright of Kurose and Ross Router Architecture
More informationChapter 4: Network Layer. Lecture 12 Internet Routing Protocols. Chapter goals: understand principles behind network layer services:
NET 331 Computer Networks Lecture 12 Internet Routing Protocols Dr. Anis Koubaa Reformatted slides from textbook Computer Networking a top-down appraoch, Fifth Edition by Kurose and Ross, (c) Pearson Education
More informationCSC 4900 Computer Networks: Routing Protocols
CSC 4900 Computer Networks: Routing Protocols Professor Henry Carter Fall 2017 Last Time Link State (LS) versus Distance Vector (DV) algorithms: What are some of the differences? What is an AS? Why do
More informationRouting. Outline. Algorithms Scalability
Routing Outline Algorithms Scalability 1 Internetworking What is internetwork An arbitrary collection of networks interconnected to provide some sort of host-host to packet delivery service A simple internetwork
More informationDongsoo S. Kim Electrical and Computer Engineering Indiana U. Purdue U. Indianapolis
Session 8. TCP/IP Dongsoo S. Kim (dskim@iupui.edu) Electrical and Computer Engineering Indiana U. Purdue U. Indianapolis IP Packet 0 4 8 16 19 31 Version IHL Type of Service Total Length Identification
More informationInformation Network Systems The network layer. Stephan Sigg
Information Network Systems The network layer Stephan Sigg Tokyo, November 1, 2012 Error-detection and correction Decoding of Reed-Muller codes Assume a second order (16, 11) code for m = 4. The r-th order
More informationInter-AS routing. Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Addison-Wesley
Inter-AS routing Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Addison-Wesley Some materials copyright 1996-2012 J.F Kurose and K.W. Ross, All Rights Reserved Chapter 4:
More informationIntroduction to Computer Networking. Guy Leduc. Chapter 4 Network Layer: The Data Plane. Chapter 4: Network Layer Data Plane
Introduction to Computer Networking Guy Leduc Chapter 4 Network Layer: The Data Plane Computer Networking: A Top Down Approach, 7 th edition. Jim Kurose, Keith Ross Addison-Wesley, April 2016. From Computer
More informationECE 428 Internet Protocols (Network Layer: Layer 3)
ECE 428 Internet Protocols (Network Layer: Layer 3) 1 Done so far MAC protocols (with PHYsical layer) Transport bits from one node to another. Key element: Determine WHEN to transmit DLC protocol (running
More informationCSC 4900 Computer Networks: Network Layer
CSC 4900 Computer Networks: Network Layer Professor Henry Carter Fall 2017 Chapter 4: Network Layer 4. 1 Introduction 4.2 What s inside a router 4.3 IP: Internet Protocol Datagram format 4.4 Generalized
More informationCMPE 80N: Introduction to Networking and the Internet
CMPE 80N: Introduction to Networking and the Internet Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 17 CMPE 80N Spring'10 1 Announcements Next class: Presentation of fun projects
More informationLecture 16: Network Layer Overview, Internet Protocol
Lecture 16: Network Layer Overview, Internet Protocol COMP 332, Spring 2018 Victoria Manfredi Acknowledgements: materials adapted from Computer Networking: A Top Down Approach 7 th edition: 1996-2016,
More informationCS555, Spring /5/2005. April 12, 2005 No classes attend Senior Design Projects conference. Chapter 4 roadmap. Internet AS Hierarchy
CS555, Spring 2005 April 12, 2005 No classes attend Senior Design Projects conference Network Layer 4-1 Chapter 4 roadmap 4.1 Introduction and Network Service Models 4.2 VC and Datagram Networks 4.3 What
More informationCS 43: Computer Networks Internet Routing. Kevin Webb Swarthmore College November 16, 2017
CS 43: Computer Networks Internet Routing Kevin Webb Swarthmore College November 16, 2017 1 Hierarchical routing Our routing study thus far - idealization all routers identical network flat not true in
More information2/22/2008. Outline Computer Networking Lecture 9 IP Protocol. Hop-by-Hop Packet Forwarding in the Internet. Internetworking.
Outline 5-44 Computer Networking Lecture 9 Protocol Traditional addressing CIDR addressing Peter Steenkiste Departments of Computer Science and Electrical and Computer Engineering Forwarding examples 5-44
More informationCS 43: Computer Networks. 21: The Network Layer & IP November 7, 2018
CS 43: Computer Networks 21: The Network Layer & IP November 7, 2018 The Network Layer! Application: the application (e.g., the Web, Email) Transport: end-to-end connections, reliability Network: routing
More informationCOMPUTER NETWORK. Homework #3. Due Date: May 22, 2017 in class
Computer Network Homework#3 COMPUTER NETWORK Homework #3 Due Date: May 22, 2017 in class Question 1 Host A and B are communicating over a TCP connection, and Host B has already received from A all bytes
More informationCSC 401 Data and Computer Communications Networks
CSC 401 Data and Computer Communications Networks Network Layer IPv4, Format and Addressing,, IPv6 Prof. Lina Battestilli Fall 2017 Chapter 4 Outline Network Layer: Data Plane 4.1 Overview of Network layer
More informationOpen Shortest Path First (OSPF)
CHAPTER 42 Open Shortest Path First (OSPF) Background Open Shortest Path First (OSPF) is a routing protocol developed for Internet Protocol (IP) networks by the interior gateway protocol (IGP) working
More informationComputer Networking Introduction
Computer Networking Introduction Halgurd S. Maghdid Software Engineering Department Koya University-Koya, Kurdistan-Iraq Lecture No.13 Chapter 4: outline 4.1 introduction 4.2 virtual circuit and datagram
More informationChapter 4 Network Layer: The Data Plane
Chapter 4 Network Layer: The Data Plane Chapter 4: outline 4.1 Overview of Network layer data plane control plane 4.2 What s inside a router 4.3 IP: Internet Protocol datagram format fragmentation IPv4
More information