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Christophe Jelger – CS221 Network and Security - Universität Basel - 20051 Christophe Jelger Post-doctoral researcher IP Multicasting.

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Presentation on theme: "Christophe Jelger – CS221 Network and Security - Universität Basel - 20051 Christophe Jelger Post-doctoral researcher IP Multicasting."— Presentation transcript:

1 Christophe Jelger – CS221 Network and Security - Universität Basel Christophe Jelger Post-doctoral researcher IP Multicasting and Mobile IP

2 2Christophe Jelger – CS221 Network and Security - Universität Basel Plan IP Multicast General concept Subscriptions (IGMP, MLD) Multicast routing Shared trees Source-based trees Mobile IP General concept Mobile IPv4 Mobile IPv6

3 3Christophe Jelger – CS221 Network and Security - Universität Basel IP Multicast Group communications at the network layer IP MulticastMobile IP

4 4Christophe Jelger – CS221 Network and Security - Universität Basel Unicast streaming

5 5Christophe Jelger – CS221 Network and Security - Universität Basel Multicast streaming Multicast Tree

6 6Christophe Jelger – CS221 Network and Security - Universität Basel IPv4 Class-D addresses: to ( /28, or 16 Class-A networks !) Some special addresses … = all multicast-capable hosts = all multicast routers = all PIM routers IPv6 ff0x::/8 where x is the scope (2=local, 5=site, e=global) Some special addresses … ff02::1 all nodes on link, ff02::2 all routers on link ff02::16 all MLDv2 multicast routers ff02::d all PIM multicast routers IP Multicast: address range (see

7 7Christophe Jelger – CS221 Network and Security - Universität Basel IPv4 Ethernet multicast (first 24 bits): 01:00:5E + 0 for 25 th bit 23 bits available to map the IPv4 address to an Ethernet address the least significant bits are mapped Ex: :00:5E:01:2F:17 IPv6 Ethernet multicast (first 16 bits): 33:33 32 bits available to map the IPv6 address the least significant bits are mapped Ex: ff05::207:85ff:fe92:7ff8 33:33:fe:92:7f:f8 In both cases, the Ethernet layer acts as an imperfect filter IP Multicast: IP to Ethernet mapping

8 8Christophe Jelger – CS221 Network and Security - Universität Basel IPv4 : Internet Group Membership Protocol (IGMP) IPv6 : Multicast Listener Discovery (MLD) Objective: a multicast router must periodically discover nodes that want to join a certain group The router can then join the appropriate multicast delivery tree The router only needs to know if there is some interest for a group: it does not need to know exactly how many nodes are interested There exists different versions of IGMP and MLD: the main difference is the ability to perform "source-filtering" (so that only the traffic sent by a (some) given source(s) is received) IP Multicast: Step 1 group subscription

9 9Christophe Jelger – CS221 Network and Security - Universität Basel IP Multicast: group subscription with MLD (subscription with IGMP is similar) Group: ff0e::1234:5678/64 MAC : 33:33:12:34:56:78 MLD Query Multicast router MLD Report ff0e::1234:5678 JOIN multicast group ff0e::1234:5678 Multicast DATA sent to 33:33:12:34:56:78 / ff0e::1234:5678

10 10Christophe Jelger – CS221 Network and Security - Universität Basel Objective is to build the multicast delivery tree(s) Two families of trees: Shared-trees (*,G): the tree is shared by all (*) multicast sources sending to group G Source-based trees (S,G): only a given source S can send multicast data on the delivery tree for group G There has been many protocols for multicast routing, but today the only protocol deployed is PIM: Protocol Independent Multicast PIM-SM: Sparse-Mode (shared trees) PIM-SSM: Source-Specific Multicast (source-based trees) IP Multicast: Step 2 Multicast routing

11 Christophe Jelger – CS221 Network and Security - Universität Basel Shared tree (PIM-SM) IP Multicast: Step 2 Multicast routing Source-based tree (PIM-SSM) Source S1 PIM router with group member(s) PIM JOIN message Source S1 Source S Rendez-Vous Point (S1,G) (S2,G) (*,G)

12 12Christophe Jelger – CS221 Network and Security - Universität Basel IP Multicast is very suitable for Group communications with multiple sources and receivers (shared tree): known as N-to-M communication Video-conferencing, network games Group communications with one source and multiple receivers (source-based tree): known as 1-to-M communication TV and radio streaming, content distribution Current deployment of IP Multicast is not large Lack of security: a misbehaving user can create forwarding states by joining hundreds of groups Billing: who should pay for what ? Source discovery accross AS (Autonomous Systems) is complex IP Multicast: some conclusions

13 13Christophe Jelger – CS221 Network and Security - Universität Basel Mobile IP Adding mobility at the network layer IP MulticastMobile IP

14 14Christophe Jelger – CS221 Network and Security - Universität Basel Users are becoming mobile World-wide availability of popular wireless communication technologies More and more portable wireless devices are also available, and they become really powerful

15 15Christophe Jelger – CS221 Network and Security - Universität Basel Problems introduced by mobility When a mobile node moves to a visited network, how is it possible to reach it again ? What about current on-going connections ? (with TCP, IP addresses partly identifies a connection) Objectives of Mobile IP To permit that a mobile node becomes reachable when it is in a visited network To allow on-going connections to be maintained when the mobile node is moving Mobile IP

16 16Christophe Jelger – CS221 Network and Security - Universität Basel Mobile IPv6: basic mechanisms Home network Internet Binding Update Message CoA) Visited network Home agent Correspondant Sending to Access point The mobile node main address is the home address The mobile node obtains an address in the visited network: the care-of address (CoA)

17 17Christophe Jelger – CS221 Network and Security - Universität Basel Mobile IPv6: route optimization Home network Internet Visited network Home agent Correspondant Access point Correspondant Sending to via CoA Binding Update Message CoA)

18 18Christophe Jelger – CS221 Network and Security - Universität Basel IPv4: tunneling A packet sent by or to the mobile node's home address is encapsulated in another packet sent by or to the CoA IPv6: routing header and home address option Via the home agent, tunneling is used With route optimization, a packet sent to the mobile node's home address is replaced by a packet sent to the CoA which also contains a routing header equal to the A packet sent by the mobile node always uses the CoA as source address, and it contains a home address option equal to Mobile IP: maintaining TCP connections

19 19Christophe Jelger – CS221 Network and Security - Universität Basel Deployment Mobile IP has failed to be widely deployed because until recently it suffered from serious security problems: authentication is indeed critical so that a malicious user cannot register a bogus CoA with a home agent Usage The "always-on" paradigm is not a reality yet The need for Mobile IP is not mature enough Mobile IP: some conclusions


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