Itm 440 Paper on Bonjour

ITM 440-? 540 Introduc0on to Data Networking and the profit 03/03/12 1 Router Architectures ? There are 3 steps a roadr must borrow to process and forward a computer software to the next hop. ? Check an entree packet for errors and other parameters ? Look up the des0na0on finish in a forwarding dining table to determine the proper output port for the packet ? Send the packet out the port 03/03/12 2 Router uniform a Train Roundho drug abuse 03/03/12 3 Router Architecture ? Rou0ng bum be implemented utilise soKware based forwarding ? e. g small digital subscriber line dispatchr, linux box, etc ? Hardware Based ? These are larger routers ith forwarding fabric architectures. ? ISP routers , cyberspace backbone, etc 03/03/12 4 Basic Hardware Routers ? Routers are very very much like computers. ? CPUs ? Several types used not unavoidably as powerful as pc ? NVRAM (Flash Memory) ? Stores router con? gura0ons ? DRAM ? all overlap working storage ? ROM ? Bootstrap for router OS 03/03/12 5 03/03/12 6 Larger Internet Routers ? Fundamental principle is that the func0ons of a router can be split into two dis0nct parts ? Rou0ng and control ? Handles protocols, counselling of router, etc ? Forwarding packets ? Handles actual forwarding f packets ? Many packets go at present through this func0on 03/03/12 7 03/03/12 8 Router gate ? soothe embrasure ? Port for a serial final stage that is the loca0on as the router and is aached by a short cable from the serial port on the terminal to the console port on the router (replaced by RJ45) 03/03/12 9 console Port 03/03/12 10 Router Access ? Auxiliary Port ? Port for a serial communica0on that is a remote loca0on 03/03/12 11 Router Access 03/03/12 12 Router Access ? Network ? Can always be managed over the same profits onwhich it is rou0ng packets 03/03/12 13 03/03/12 14 ForwardingTable Lookups ? Longest Match Rule ? Allows a router to determine the best route based on granularity of the masked anticipate. ? Used when a network ID is found to twain more than one subnet mask ? The longest match rule is implemented because the longer the mask found, the beer granularity the router has in exactly de? ning the correct route. ? It is oKen called the best match or the more speci? c route for a given des0na0on 03/03/12 15 ? Example ? Received datagram of 200. 40. 1. 1 ? Route table lookup found two entries ? 200. 40. 1. 0/24 ? 200. 40. 0. 0/16 ? Route would use he 200. 40. 1. 0/24 03/03/12 16 03/03/12 17 Dual Protocol hemorrhoid ? Hosts can befuddle dual protocol stacks ? If the Ethernet type ? old age is 0x800 the packet is hando? to the IPv4 process ? If the Ethernet type ?eld is 0x86DD the packet is handed o? to the IPv6 process 03/03/12 18 03/03/12 19 Tunneling ? Tunneling occurs whenever the normal instalment of encapsula0on headers is violated ? Four types of delves ? Host to router ? Put a frame into a frame and violate the normal OSI-? RM sequence of headers ? Router to router ? Ho sts with affaire dhonneur stack capabili0es can turn over IPv6 packets to a dual tack router that is entirely reachable over a series IPv4 only device ? Routers with affaire dhonneur stack susceptibility can tunnel IPv6 packets over an IPv4 infrastructure to other routers 20 03/03/12 Tunneling ? Router to master of ceremonies ? Routers with duel stack capabili0es can tunnel IPv6 packets over an IPv4 infrastructure to a duel stack des0na0on host ? Host to Host ? Hosts with duel stack capabili0es can tunnel IPv6 packets over an IPv4 infrastructure to other duel stack IP hosts without an intervening router 03/03/12 21 03/03/12 22 Tunneling ? The ?rst two methods is when an IPv6 packet is sent to a router nd the expiry of the tunnel is not the same des0na0on ? The last two methods send the encapsulated IPv6 packet directly to the des0na0on host so the IPv4 and IPv6 shell outes used correspond to the same host ? The get-go host or router must have the tunnels address con? gured ? This is called con? gured tunneling 03/03/12 23 Automa0c Tunneling ? Does not require particular(prenominal) con? gura0on ? Uses a special form of the IPv6 address ? All duel stack IP hosts recognize the format and encapsulate the IPv6 packet at heart an IPv4 packet development the embedded IPv4 address, crea0ng an end to end tunnel ? Hosts that only run IPv6 can also duel stack routers to communicate using a special form of the IPv6 03/03/12 24 03/03/12 25 Tunneling Mechanisms ? Manually con? gure tunnels ? De? ned in RFC 2893 and both endpoints of the tunnel must have both IPv4 and IPv6 addresses ? Generic Rou0ng Encapsula0on (GRE) tunnels ? Designed to transport non-? IP protcols over IP network ? IPv4 compa0ble (6over4) tunnels ? Also de? ned in RFC 2893 these are automa0c tunnels based on IPv4 compa0ble IPv6 addresses using the (Pv4 address) form of IPv6 address 03/03/12 26 Tunneling Mechanisms ? 6to4 unnels ? Another form of automa0c tunnel de? ned in RFC 3065. They use and IPv4 embedded in the IPv6 address to iden0fy the tunnel endpoint ? Intra-? site Automa0c Tunnel Addressing Protcol (ISATAP) ? Mechanism much like 6to4 tunneling but for local anesthetic site networks. Uses a special pre? x and the IPv4 address to iden0fy the endpoint 03/03/12 27 6to4 and ISATAP tunnel addressing showing how the 128 bits of the IPv6 address Are structured in each case. (a) 6to4 (b) ISATAP 03/03/12 28 Transi0on Considera0ons ? Terminology used for IPv4 to IPv6 transi0on plans for invitees ? IPv4 only node host or outer that implements only IPv4 ? IPv6/IPv4 (duel) node A host or router that implements both IPv4 and IPv6 ? IPv6 only node A host or router that implements only IPv6 ? IPv6 node A host or router that implements IPv6 ? IPv4 node A host or router that implements IPv4 ? Includes IPv6 only and duel node 03/03/12 29 ? Includes IPv4 only and duel node Transi0on Considera0ons ? The plan also de? nes iii types of addresses ? IPv4 compa0ble IPv6 address ? An a ddress charge to an IPv6 node that can be used in both IPv6 and IPv4 packets ? IPv4 mapped IPv6 address ? An address mapped o an IPv4 only node be as an IPv6 address ? IPv6 only address ? An address globally assigned to any IPv4/IPv6 only node 03/03/12 30 Ques0ons 03/03/12 31 03/03/12 32 Q1 ? 1. Which router, based on the architecture in the ?gure, is plausibly a small site router? Which is probably a large Internet backbone router? ? Although architectures vary, the router with only memory is promising to be a little site router. The router with separate hardware forwarding and control plane is likely the backbone router. 03/03/12 33 Q2 ? 2. Which output interface, based on the rou0ng table shown in he ?gure, leave alone packets arriving from the directly aached host for IPv4 address 10. 10. 11. 1 use for forwarding? Assume longest match is used. ? 64 is 0100 0000, 128 is grand piano 0000, and 11 is 0000 1011. All three routes match the ?rst 16 bits. The /18 masks (01 and 1 0) do not match the address bit paern (00) in posi0ons 17 and 18. So 10. 10. 0. 0/16 is the longest match and the packet will use output interface 1. 03/03/12 34 Q3 ? 3. Which output interface will packets for 10. 10. 192. 10 use? Assume longest match is used. ? 192 is 1100 0000. Again, all three routes match the ?rst 16 bits.The /18 masks (01 and 10) do not match the address bit paern (11) in posi0ons 17 and 18. So 10. 10. 0. 0/16 is over again the longest match and the packet will use output interface 1. 03/03/12 35 Q4 ? 4. Is 6to4 tunneling automa0c? How many bits will be used for the subnet iden0? er? ? Yes, 6to4 automa0c tunnels are de? ned in RFC 3065. Sixteen bits are used for subnet ID. See paradigm 9-? 9. 03/03/12 36 Q5 ? 5. Do the routers require IPv6 support to deliver packets among the two hosts? ? No. If IPv6 is not supported on the routers, 6to4 tunneling can be used to deliver packets. 03/03/12 37