Multicast Networking - National Tsing Hua University
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Transcript Multicast Networking - National Tsing Hua University
Multicast Networking
[email protected]
References
Multicast Networking and Applications
Computer Networking: A Top-Down Approach
Featuring the Internet
Miller, C. Kenneth
Addison-Wesley, 1999
James F. Kurose, Keith W. Ross
http://gaia.cs.umass.edu/kurose/Contents.htm
RFC
2
Introduction
Unicast protocols
Multicast protocols
From one or more senders to a group of
receivers
bulk data, streaming continuous media,
shared data applications, data feeds,
interactive gaming
3
4
Multicast applications
5
Multicast group
address indirection
class D
224. 0. 0. 0 ~ 239.255.255.255
6
IPv6
128 bits
flgs: three higher-order bits are set to zero
scop: 0~F
7
Multicast address allocation
8
Network layer multicast protocol
IGMP
Multicast routing protocol
Transport layer multicast protocol
Reliable multicast protocol
9
10
IGMP
Joining particular multicast group is
receiver-initiated using the Internet
Group Management Protocol (IGMP)
A dialog that occurs between routers
supporting multicast routing and hosts
on a subnet attached to that router
11
IGMP v1
RFC 1112
Nearest router
Query messages
Periodically from router to hosts
Time To Live of 1
Membership reports from hosts
Random back-off to avoid
report messages implosion
12
IGMP v2
RFC 2236
Membership query
General group
Specific group
Membership report
Leave group
13
IGMP v3
Internet draft
Select only specific sources of multicast
traffic to receive
Inclusion group-source report messages
Exclusion group-source report messages
Leave group messages
Specify the IP addresses of any source-group
pairs it wishes to leave
14
Multicast Routing Protocols
Group-shared tree
Steiner tree problem
Source-based tree
Distance vector
Link state
Shared tree
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16
DVMRP
RFC 1075
Distance vector algorithm
Reverse path forwarding(RPF)
Pruning
grafting
17
MOSPF
RFC 1584
Link-state advertisements
Complete topology information
Edge routers with attached hosts belonging to
various multicast groups
18
Protocol Independent Multicast-Dense
Mode
Internet draft
Flood-and-prune
Similar to DVMRP
Protocol independent
19
Core-Based Trees
RFC 2201,2189
Single core
Join
JOIN_REQUEST
JOIN_ACK
Maintain
ECHO_REQUEST
ECHO_REPLY
20
Protocol Independent Multicast-Sparse
Mode
RFC 2117
Rendezvous point
Encapsulate data and unicast to the RP
Switch from a group-shared tree to a
source-specific tree
21
Interdomain Multicast Routing
Interior gateway protocol (IGP)
Exterior gateway protocol (EGP)
Border Gateway Multicast Protocol (BGMP)
Internet draft
Group-shared tree approach
Set up roots by MASC
22
23
Wide Area Networks
Asynchronous transfer mode
Meshes of point-to-multipoint PVCs
ATM-level multicast servers (MCS)
24
One-way satellite
25
Reliable Multicast Technology
TCP : point-to-point (unicast)
UDP : multicast
26
Research Activities and Topics
in Reliable Multicast
Request implosion
Duplicate replies
Recovery latency
Recovery isolation (exposure)
Adaptability to dynamic membership
change
27
Reliable Multicast Protocols
Create a generalized reliable multicast
transport layer that can handle all
reliable multicast applications
timeliness, packet ordering, error
correction, high scalability
Focus the reliable multicast protocol on
solving the needs of particular
applications
28
Generalized Reliable Multicast
Protocols
Scalable Reliable Multicast (SRM)
Repair by any receiver that has the data to
achieve scalability by reducing
administrative back-traffic to the source
Suppression of duplicate requests via a
random time period
A random back-off timer is used before a
repair is sent
29
No scope limit (exposure)
30
Reliable Multicast Transport Protocol
(RMTP)
Designated Receivers (DRs)
Collect status messages from nodes in a local
RMTP domain
Provide repairs
RMTP+
Transmit window
Bit mask (selective repeat retransmission)
31
RMTP
32
Specialized Reliable Multicast
Protocols
Reliable Adaptive Multicast Protocol
(RAMP)
Group sizes less than 100, timeliness
RFC 1458
Break up the data sent into bursts
Burst mode
Idle mode
33
Multicast File Transfer Protocol (MFTP)
Internet draft
NAK-based
Block as large as possible
34