Transcript Multicasting IPv6 By : Kaveri Bhaumik IIT Kanpur

IPv6 Multicasting
By : Kaveri Bhaumik
IIT Kanpur
Topics covered are
Definition of multicasting
Multicast addresses
Comparison between IPv4
multicasting & IPv6 multicasting
VideoLAN Client (VLC) media player
Advantage of using multicasting in
VLC
Installing VLC
UDP Streaming With VLC using the
GUI
Definition of Multicasting
 Multicast is communication between a
single sender and multiple receivers on a
network.
 Together with anycast and unicast,
multicast is one of the packet types in the
Internet Protocol Version 6 (IPv6).
Graphical Representation Of
Multicasting
Sending
Entity
Receiving
Entity
Service Provider
Receiving
Entity
IPv6 ADDRESSING
There are three types of addresses:
 Unicast: An identifier for a single interface.
 Anycast: An identifier for a set of interfaces and is
delivered to one of the interfaces identified by that address.
 Multicast: An identifier for a set of interfaces and is
delivered to all interfaces identified by that address.
Note :-> There are no broadcast addresses in IPv6, their
function being superseded by multicast addresses.
Multicast addresses
• Multicast addresses always start with (xx is
the scope value)
ffxy:
• Multicast addresses format:
|
8
| 4| 4 |
112 bits
|
+-------------+---+------+---------------------------------------+
|11111111|flgs|scop|
group ID
|
+------------+----+------+--------------------------------------+
• Multicast addresses are split into scopes
and types
Multicast addresses format…
•
11111111 at the start of the address identifies the address as
being a multicast address.
+ - + - + -+ - +
| 0|0|0|T |
+ - + - + -+ - +
•
flgs is a set of 4 flags:
•
The high-order 3 flags are reserved.
T = 0 indicates a permanently-assigned ("well-known") multicast
address, assigned by the global internet numbering authority.
T = 1 indicates a non-permanently-assigned ("transient") multicast
address.
Multicast scopes






ffx1: node-local
ffx2: link-local
ffx5: site-local
ffx8: organization-local
ffxe: global scope
others are reserved
Multicast types
 All Nodes Address:
ID = 1h, addresses all hosts on the local node
(ff01:0:0:0:0:0:0:1) or the connected link
(ff02:0:0:0:0:0:0:1).
 All Routers Address:
ID = 2h, addresses all routers on the local node
(ff01:0:0:0:0:0:0:2), on the connected link
(ff02:0:0:0:0:0:0:2), or on the local site
(ff05:0:0:0:0:0:0:2).
Comparison between IPv4
multicasting & IPv6 multicasting



Although the basic notion of multicasting is common to IPv4
and IPv6, several new characteristics are introduced in IPv6
multicasting.
In IPv4,multicasting was extension of the basic specification,
while specifications of IPv6 require that all IPv6 nodes
support multicasting.
IPv6 explicitly limits the scope of a multicast address by
using a fixed address field, whereas the scope was specified
using TTL (Time to Live) of a multicast packet in IPv4.
Comparison…


In IPv4, multicast tunnels were introduced to deploy
multicasting .In IPv6,all routers should be multicast-capable,
which means that we do not have to use multicast tunnels to
deploy IPv6 multicasting.
IPv4 multicasting use unicast addresses to identify a network
interface. However, this is not suitable for IPv6,as an IPv6capable node may assign multiple addresses on a single
interface, which tends to cause a configuration mismatch. In
IPv6 ,to identify the interface the user must use specified
interface index.
Implementation of multicasting
We have practically tested multicasting over
IPv6 in IITK .
Muticasting in IPv6 has also been tested across
the router using the global scope address .
For multicast testing we have used VideoLan
Client media player which is a freeware.
VideoLAN Client (VLC) media player
VLC - the cross-platform media player and streaming
server.
VLC is a multimedia player for various audio and video
formats (MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg,
...) as well as DVDs, VCDs, and various streaming
protocols.
It can also be used as a server to stream in unicast or
multicast in IPv4 or IPv6 on a high-bandwidth network.
Advantage of using multicasting
in VLC
Problems encountered using unicast or
broadcast are :
• with unicast, when a lot of clients want to receive the
stream, the network interface of the server becomes
saturated.So the number of clients is very limited,
especially when the stream is big.
• with broadcast, the machines that do not want to
receive the stream are polluted and some devices do
not like to receive huge broadcasts. If you want to send
several streams at the same time, the network
becomes oversaturated.
Advantage of using multicasting
in VLC…
 With multicast, the packets are sent on the network to a
multicast IP group which is designated by its IP address.
 The machines can join or leave a multicast group by
sending a request to the network. The request is usually
sent by the kernel of the operating system.
 The VLC takes care of asking the kernel of the operating
system to send the join request.
 It is possible for one client to belong to several groups.
Showing a scenario giving example
of multicasting



Server(vlc)
Network
Clients(vlc)
stream --------------> ff1e::1 ---------------> client n°1
|-------------> client n°2
Server(vlc)
Network
Clients(vlc)
<--------------- client n°3 join
join ff1e::1
Server(vlc)
Network
Clients(vlc)
|-------------> client n°1
stream --------------> ff1e::1 ---------------> client n°2
|-------------> client n°3
Scenario of multicasting…

Server(vlc)

Server(vlc)
Network
Clients(vlc)
stream ---------------> ff1e::1 ---------------> client n°2
|-------------> client n°3
Network
Clients(vlc)
<--------------- client n°1 leave
leave ff1e::1
Installing VLC
For Fedora Core 3 :
Download the VLC Binaries packages
vlc-binary.tar.gz
For Windows :
Download the self-extracting package
vlc-0.8.1-win32.exe
Above packages are available in
http://www.videolan.org/
To run the VLC
Type the following command to run VLC:
$vlc
This is the VLC media player:
UDP Streaming With VLC
using the GUI
Server – Send the Data
 Select File – Open File, and Browse to select a file.
 Select the “Stream output” checkbox, then the
Settings button – this opens a Stream Output
window.
Output Methods
For multicasting, select UDP and write following :
address : ff1e and port : 1234
Select the checkbox : Play locally
UDP Streaming…
Stream Output window
UDP Streaming…
Client – Receive the Data
 Open VLC on the receiving PC.
 Select File – Open Network Stream.
To join the session of multicast as sent by
the server do the following :
Select UDP/RTP multicast and write :
address : ff1e and port : 1234
 Click the OK button, and the VLC display window
should open.
Reference
Further information about VLC can be
obtained from :
http://www.videolan.org/
THANK YOU FOR YOUR ATTENTION
Any Questions?