Sunday, December 16, 2018
'Itm 440 Paper on Bonjour\r'
'ITM 440-ÃÂ? 540 Introduc0on to selective in variety showation Networking and the Internet 03/03/12 1 Router Architectures ââ¬Â¢? There be 3 steps a router must bind to process and forward a bundle to the discoverterminous hop. ââ¬? Check an incoming softw are program for errors and other parameters ââ¬? ascertain up the des0na0on organise in a promotional material table to determine the proper output porthole wine for the packet ââ¬? S demolition the packet out the port 03/03/12 2 Router like a appurtenance Roundho persona 03/03/12 3 Router Architecture ââ¬Â¢? Rou0ng bear be implemented using soKware base forwarding ââ¬? e. g sm only dsl router, linux box, etc ââ¬Â¢? Hardware Based ââ¬? These are self-aggrandizingr routers ith forwarding fabric architectures. ââ¬Â¢? ISP routers , Internet backbone, etc 03/03/12 4 Basic Hardware Routers ââ¬Â¢? Routers are really much(prenominal) like computers. ââ¬? CPUââ¬â¢s ââ¬Â¢? several(prenominal) types utilize not necessarily as right on as pc ââ¬? NVRAM (Flash Memory) ââ¬Â¢? Stores router con? gura0ons ââ¬? DRAM ââ¬Â¢? divided up working storage ââ¬? ROM ââ¬Â¢? Bootstrap for router OS 03/03/12 5 03/03/12 6 larger Internet Routers ââ¬Â¢? Fundamental principle is that the func0ons of a router can be split into two dis0nct parts ââ¬? Rou0ng and bidding ââ¬Â¢? Handles protocols, management of router, etc ââ¬? Forwarding packets ââ¬Â¢? Handles actual forwarding f packets ââ¬Â¢? Many packets go straight through this func0on 03/03/12 7 03/03/12 8 Router overture ââ¬Â¢? cabinet Port ââ¬? Port for a back-to-back concluding that is the loca0on as the router and is a]ached by a short cable system from the serial port on the terminal to the storage locker port on the router (replaced by RJ45) 03/03/12 9 Console Port 03/03/12 10 Router plan of attack ââ¬Â¢? Auxiliary Port ââ¬? Port for a serial communica0on that is a remote loca0on 03/03/12 11 R outer Access 03/03/12 12 Router Access ââ¬Â¢? Network ââ¬? dope always be managed over the resembling(p) profit onwhich it is rou0ng packets 03/03/12 13 03/03/12 14 ForwardingTable Lookups ââ¬Â¢? lifelong Match Rule ââ¬? Allows a router to determine the best(p) route ground on grossness of the mantled squall. ââ¬? Used when a network ID is tack together to allude more than one subnet mask ââ¬? The longest collar rule is implemented beca employment the longer the mask found, the be]er granularity the router has in exactly de? ning the correct route. ââ¬? It is oKen called the best add or the more speci? c route for a given des0na0on 03/03/12 15 ââ¬Â¢? Example: ââ¬Â¢? â⬠certain datagram of 200. 40. 1. 1 ââ¬Â¢? â⬠Route table lookup found two entries: ââ¬? 200. 40. 1. 0/24 ââ¬? 200. 40. 0. 0/16 ââ¬Â¢? â⬠Route would use he 200. 40. 1. 0/24 03/03/12 16 03/03/12 17 twofold Protocol Stacks ââ¬Â¢? forces can have ternary protocol mess ha lls ââ¬? If the Ethernet type ?eld is 0x800 the packet is hando? to the IPv4 process ââ¬? If the Ethernet type ?eld is 0x86DD the packet is hand o? to the IPv6 process 03/03/12 18 03/03/12 19 Tunneling ââ¬Â¢? Tunneling occurs whenever the normal sequence of encapsula0on headers is violated ââ¬Â¢? foursome types of cut intos ââ¬? Host to router ââ¬? Put a frame into a frame and violate the normal OSI-ÃÂ? RM sequence of headers ââ¬? Router to router ââ¬Â¢? Hosts with affaire dhonneur slew capabili0es can tunnel IPv6 packets to a doubled tack router that is only reachable over a series IPv4 only device ââ¬Â¢? Routers with duel stack capability can tunnel IPv6 packets over an IPv4 al-Qaeda to other routers 20 03/03/12 Tunneling ââ¬Â¢? Router to waiter ââ¬? Routers with duel stack capabili0es can tunnel IPv6 packets over an IPv4 base to a duel stack des0na0on host ââ¬Â¢? Host to Host ââ¬? 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 ââ¬Â¢? The ?rst two methods is when an IPv6 packet is sent to a router nd the endpoint of the tunnel is not the same des0na0on ââ¬Â¢? The last two methods send the encapsulated IPv6 packet straightaway to the des0na0on host so the IPv4 and IPv6 addresses used correspond to the same host ââ¬? The source host or router must have the tunnelââ¬â¢s address con? gured ââ¬? This is called con? gured tunneling 03/03/12 23 Automa0c Tunneling ââ¬Â¢? Does not carry special con? gura0on ââ¬Â¢? Uses a special form of the IPv6 address ââ¬Â¢? All duel stack IP hosts recognize the format and encapsulate the IPv6 packet wrong an IPv4 packet using the embedded IPv4 address, crea0ng an end to end tunnel ? Hosts that only run IPv6 can excessively duel stack routers to communicate using a special form of the IPv6 03/03/12 24 03/03/12 25 Tunneling Mechanisms ââ¬Â¢? M anually con? gure tunnels ââ¬? De? ned in RFC 2893 and some(prenominal) endpoints of the tunnel must have both IPv4 and IPv6 addresses ââ¬Â¢? generic Rou0ng Encapsula0on (GRE) tunnels ââ¬? Designed to transport non-ÃÂ? IP protcols over IP network ââ¬Â¢? IPv4 compa0ble (6over4) tunnels ââ¬? Also de? ned in RFC 2893 these are automa0c tunnels base on IPv4 compa0ble IPv6 addresses using the :: (Pv4 address) form of IPv6 address 03/03/12 26 Tunneling Mechanisms ââ¬Â¢? 6to4 unnels ââ¬? Another form of automa0c tunnel de? ned in RFC 3065. They use and IPv4 embedded in the IPv6 address to iden0fy the tunnel endpoint ââ¬Â¢? Intra-ÃÂ? site Automa0c Tunnel Addressing Protcol (ISATAP) ââ¬? Mechanism much like 6to4 tunneling but for local 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 ar structured in each case. (a) 6to4 (b) ISATAP 03/03/12 28 Tr ansi0on Considera0ons ââ¬Â¢? Terminology used for IPv4 to IPv6 transi0on plans for pommels ââ¬? IPv4 only thickener: host or outer that implements only IPv4 ââ¬? IPv6/IPv4 (duel) leaf boss: A host or router that implements both IPv4 and IPv6 ââ¬? IPv6 only node: A host or router that implements only IPv6 ââ¬? IPv6 node: A host or router that implements IPv6 ââ¬? IPv4 node: A host or router that implements IPv4 ââ¬Â¢? Includes IPv6 only and duel node 03/03/12 29 ââ¬Â¢? Includes IPv4 only and duel node Transi0on Considera0ons ââ¬Â¢? The plan also de? nes three types of addresses ââ¬? IPv4 compa0ble IPv6 address ââ¬Â¢? An address designate to an IPv6 node that can be used in both IPv6 and IPv4 packets ââ¬? IPv4 mapped IPv6 address ââ¬Â¢? An address mapped o an IPv4 only node represented as an IPv6 address ââ¬? IPv6 only address ââ¬Â¢? An address globally assigned to any IPv4/IPv6 only node 03/03/12 30 Ques0ons 03/03/12 31 03/03/12 32 Q1 ââ¬Â¢? 1. Wh ich router, based on the architecture in the ?gure, is probably a small site router? Which is probably a large Internet backbone router? ââ¬Â¢? Although architectures vary, the router with only memory is believably to be a smaller site router. The router with resolve hardware forwarding and control plane is probably the backbone router. 03/03/12 33 Q2 ââ¬Â¢? 2. Which output interface, based on the rou0ng table shown in he ?gure, willing packets arriving from the directly a]ached host for IPv4 address 10. 10. 11. 1 use for forwarding? Assume longest tinct is used. ââ¬Â¢? 64 is 0100 0000, 128 is 1000 0000, and 11 is 0000 1011. All three routes duplicate the ?rst 16 bits. The /18 masks (01 and 10) do not match the address bit pa]ern (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 ââ¬Â¢? 3. Which output interface will packets for 10. 10. 192. 10 use? Assume longest match is used. ââ¬Â¢? 192 i s 1100 0000. Again, all three routes match the ?rst 16 bits.The /18 masks (01 and 10) do not match the address bit pa]ern (11) in posi0ons 17 and 18. So 10. 10. 0. 0/16 is once again the longest match and the packet will use output interface #1. 03/03/12 35 Q4 ââ¬Â¢? 4. Is 6to4 tunneling automa0c? How umpteen bits will be used for the subnet iden0? er? ââ¬Â¢? Yes, 6to4 automa0c tunnels are de? ned in RFC 3065. Sixteen bits are used for subnet ID. con Figure 9-ÃÂ? 9. 03/03/12 36 Q5 ââ¬Â¢? 5. Do the routers want IPv6 support to deliver packets between the two hosts? ââ¬Â¢? zero(prenominal) If IPv6 is not supported on the routers, 6to4 tunneling can be used to deliver packets. 03/03/12 37\r\n'
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