Upload
husnain-ahmad
View
230
Download
0
Embed Size (px)
Citation preview
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
1/36
MULTICASTING
Concepts, Algorithms and Protocols
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
2/36
Introduction
What is Multicasting?
Real Life Applications of Multicasting
Multicasting
Online TV, Radio
Video
Conferencing
Stock MarketUpdates
Internet Gaming
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
3/36
Concepts
Groups in Multicasting
Multicasting Addressing
Managed by IANA(Internet Assigned Numbers Authority)
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
4/36
IANA Approvedaddress Range
224.0.0.0-239.255.255.255
Special Purposese.g.(to exchange linkstate information)
224.0.0.0-224.0.0.255
Globally ScopedAddresses
224.0.1.0-238.255.255.255
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
5/36
Ethernet MAC Address Mapping Technique using
Multicast IP address
IANA owned block of Ethernet MAC addresses start
with 01:00:5E in hexadecimal and half of this block isallocated for multicast addresses
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
6/36
IGMP(Internet Group Management Protocol)
For Dynamically Registration of the Hosts in
Multicast Network
IGMP Packet Format
Type field (indicating different types of IGMP packets) Type 11 is the IGMP membership query.
Type 12 is the IGMP version 1 membership report.
Type 16 is the IGMP version 2 membership report.
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
7/36
Versions of IGMP
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
8/36
Algorithms
Multicasting Routing Algorithms
Flooding
Spanning Trees
Reverse Path Forwarding (RPF)
Truncated Reverse Path Forwarding (TRPF)
Core Based Trees (CBT)
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
9/36
Flooding
Simplest Algorithm
Serious Drawbacks
Pointless Duplicate Copies
Bandwidth Wastage
Inefficient usage of Router Memory
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
10/36
Spanning Trees
Efficient than Flooding Algorithm
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
11/36
Spanning Trees
Advantage
Router will have to keep track of only 1 field
Disadvantages
Centralizes all Traffic on a single link
Doesn't consider the Group Membership
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
12/36
Reverse Path Broadcast (RPF)
Modified form of Spanning Trees
Implicitly Spanned Trees for each source
A more refined approach for improvingR
PB
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
13/36
RPB
Advantage
Very Fast
Better Utilization of Network
Disadvantage
Doesnt take into account the Multicast GroupMembership info.
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
14/36
Truncated Reverse Path Broadcast(TRPB)
Proposed to overcome some of the limitations of
RPB algorithm
IGMP practiced
Concept of Leaf Router
Drawback
Unnecessary traffic on Non-Leaf Subnets which dont
have the group member
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
15/36
Reverse Path Multicasting(RPM)
An enhancement to RPB and TRPB
Delivery Tree spans only if:
Subnetwork has a Group Member
Routers and Subnetworks along shortest path
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
16/36
RPM
Prune Message
Truncation of a Delivery Tree
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
17/36
RPM
Prune State should be Refreshed at regular
intervals
Drawback
Relatively Large Router Memory Space needed for
maintaining state information
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
18/36
Core Based Trees(CBT)
Most Latest Algorithm
One of its kind
Creates a single delivery tree for each group
Core of CBT
Unicast system is also used
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
19/36
CBT In Service
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
20/36
CBT
Advantage
Routers will have to keep less info
Network Bandwidth Conserved
Disadvantage
Single Tree may lead to Traffic concentration
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
21/36
Protocols
Distance Vector Multicast Routing Protocol (DVMRP)
Multicast Extension to OSPF (MOSPF)
Protocol Independent Multicast (PIM)
PIM-DM (for densely spaced Members)
PIM-SM (for sparsely spaced Members)
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
22/36
Distance Vector Multicast Routing Protocol(DVMRP)
Formulated from RIP(Routing Information Protocol)
Difference Between RIP and DVMRP
Earlier Versions Uses RPB and TRPB
Latest Tactic is to useRPM
Grafting Back in case of new Joining
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
23/36
Multicast Extension to OSPF (MOSPF)
Build on top of OSPF
Delivery Tree Constructed using IGMP and OSPF
database
Most significant aspect:
Support of Hierarchal Routing
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
24/36
MOSPF
Hierarchal Routing
Intra-Area Routing
Inter-Area Routing
Inter-AS Routing
Internet
AS-1
Area-1 Area-2
AS-2
Area
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
25/36
MOSPF
Intra-Area Routing
OSPF link state database is used
Group-Membership-LSA
Forwarding Cache at each Router
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
26/36
MOSPF
Inter-Area Routing
ABRs as inter-area multicast forwarders
Wild-Card Multicast Receivers
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
27/36
MOSPF
Inter-AS Routing
The technique used is very similar to Inter-Area Routing
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
28/36
Protocol-Independent Multicast(PIM)
Being Developed by IDMR a working group of IETF
Objective is to develop a Multicast Routing Protocol
independent of any particular Unicast Protocol
Deficiency of DVMRP and MOSPF
No good for sparsely distributed group members
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
29/36
PIM
To address the issue of sparsely spaced members
PIM introduces 2 protocols:
PIM-DM (efficient for dense distributions)
PIM-SM (efficient for sparse distributions)
Both use same control messages
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
30/36
PIM-DM(DENSE MODE)
Uses a push model
Very efficient if active members on each subnet
Flood and Prune Mechanism
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
31/36
PIM-SM(SPARSE MODE)
Uses a pull model
Major Difference between PIM-SM and other stated
Protocols
Introduction of Rendezvous Point (RP)
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
32/36
PIM-SM(SPARSE MODE)
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
33/36
PIM-SM(SPARSE MODE)
Source to Group Sends
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
34/36
MBone(Multicast Backbone)
Launched in 1992
At Start: 40 subnets in 4 countries
Now-a-Days: 3400 subnets in 25 different countries
November 1994 Rolling Stones concert at the CottonBowl in Dallas with 50,000 fans was the "first majorcyberspace multicast concert" Mick Jagger opened theconcert by saying,
"I wanna say a special welcome to everyone that's, uh, climbed into the Internet tonightand, uh, has got into the M-bone. And I hope it doesn't all collapse."
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
35/36
8/8/2019 MultiCasting Concepts,Algoritms,Protocols
36/36