BY

Broadband Multiplay Wing

DNW, Bangalore

Presentation on BSNL IPTV SERVICES

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During this session the participants will be able to acquire knowledge in the following

• What is IPTV ?• Network Components of IPTV Services • Basic architecture and Call flow of IPTV in Broadband

Multiplay network• View configurational parameters for extending IPTV

services by logging on to the BNG of Broadband Multiplay.

• Configuration of DSLAM port for IPTV Services through a script

• IP Multicasting and Multicast routing protocols PIM DM and PIM SM

• Provisioning of IPTV Services in BSNL

Objectives

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WHAT is IPTV ?

– IPTV (Internet Protocol Television) is a system where a digital television service is delivered using Internet Protocol over a network infrastructure, which may include delivery by a broadband connection

– BSNL IPTV service is delivering the favorite broadcast channels and other video content transmitted over broadband network via a digital set top box.

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COMPONENT OF IPTV DELIVERY SERVICE

CONTENT HEAD END CDN NETWORK

MIDDLEWARE MULTICAST SERVERS BILLING SERVERS DRM SERVERS

DELIVERY NETWORK MPLS MULTIPLAY NETWORK:

BNGRPRDSLAM

LAST MILE CPE STB

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Components of IPTV Delivery services

Content Head End:• The CDN network operation center houses content

comprising of varied videos and broadcast channels. Here TV channels are received and encoded.

Delivery network: • BSNL's Broadband network.

Last Mile

ADSL Line: Copper Access to Subscriber with CPE

Set Top Box with a remote: The Set Top Box is required at the customers premise to convert the IP signal back to TV signal. With every set top box you get a remote.

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SCHEMATIC VIEW OF IPTV SERVICE.

IP Streamer

Video Middleware ServerEncoder

Content Server

Video Traffic

Voice Traffic

Data Traffic

CPESTB

TV

PC

Phone

3 PVCs for 3 Services

MCASTVLAN

MCASTVLAN

VIDEOVLAN

DSLAM

RPR – T2

RPR – T2 RPR – T2

RPR – T2

RPR – T1

BNG

MPLS COREMPLS CORE

TV over IP Services

MCASTVLAN

L3PE

2. DSLAM adds Corresponding Multicast VLAN to the Video Traffic

1. CPE configured to sent Data / Voice / Video Traffic as specific ATM PVCs

3. RPR / OCLAN Switch forwards the traffic in Multicast VLAN with proper QoS Mapping

4. BNG Removes the Multicast VLAN tag, maps the traffic to corresponding context and forwards to L3PE with proper upstream VLAN Tag

5. Video Traffic forwarded to Content Server by L3PE through MPLS Core

BNG

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IPTV NETWORK ARCHITECTURE

CDN END

BSNL END

BNG

TIER 1

DSLAM

LASTMILE

PIM SPARSE/DENSE

1 G CONNECTIVITY

ADSL +2 modem

STB/IPTV

Phone

172.16.1.156/30

CDN-SWITCH

IGMP-Snooping

SPLITTER

172.16.1.160/30

PIM Sparse-Mode

STB Interface/Sparse Mode

PE -MPLS

TIER-II

TIER-IITIER-II

L2 domain

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• L3 communication has been established between the CDN NOC and the PE of BSNL

• PIM Protocol has been enabled between the CDN NOC –MCR-BNG for multicasting

• The Downlink interface of BNG is the STB interface for IPTV for the entire ring

• IGMP snooping is enabled at the RPR ring• IGMP snooping is enabled at the DSLAM• From DSLAM the Multicast stream is flows to the

ADSL +2 modem at the Last mile• AT the CPE a separate VPI-VCI is configured for

IPTV.

How IPTV is extended to customers premises ?

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• Analog Signals are received from the Antenna to the receivers • Receivers convert the Analog signal to the Digital signal • Encoders convert the Digitized signals to UDP traffic• The multicast traffic pump by the Encoder are in MPEG-4

format• Middle-ware performs different functions which are as follows:• Channel Management• User Management• STB Management• VOD – Video On Demand • Storage• Real-Time Synchronization Management

Functions of CDN

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SCHEMATICAL VIEW OF CDN NOC

MIDDLEWARE/BILLING203.110.223.32/27

DRM203.110.223.64/28

MULTICAST SERVER203.110.223.1/27

CDN SWITCH

ENCODERASI

ANALOG SIGNALRECEIVER

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• Digital Right Management are for Securing the packets from Hacking and Blocks Customer from unauthorized access to any movie or Channel stream.

• DRM – Perform RC 4 Encryption • Generates Key to encrypt the Multicast stream and

Video Stream• Database server for database management and user

authentication• Database communicate with the Middleware to

maintain the User database and STB authentication

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IPTV Call Flow• The STB Ethernet interface is connected to ADSL CPEs Ethernet

port, which in turn is port mapped to 0/100 PVC configured in bridge mode.

• The DSLAM ADSL port maps PVC 0/100 to a unique IPTV VLAN. IGMP snooping need to be enabled on DSLAM ADSL cards and uplink cards, RPR / OC LAN switches interfaces so that the IPTV stream is forwarded / pruned on receipt of IGMP REPORT / LEAVE messages.

• IPTV traffic / IGMP messages are carried up to BNG in a single VLAN. In order to prevent MAC security issues MAC force forwarding is implemented on DSLAM uplink by resolving all arp request with BNG interface MAC address and dropping 192.168.1.0/24 arp requests. Further STB DHCP client needs to be configured to accept IP address only by CDN DHCP sever in order to avoid IP address assigned by other CPEs in the IPTV VLAN. All the devises below BNG work in Layer-2 mode by extending the IGMP packets from STB up to BNG.

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IPTV Call Flow• When a subscriber request for TV channel using STB remote, the

STB sends IGMP REPORT message requesting for the IPTV channel by indicating the multicasting address of that channel.

• The ADSL card of DSLAM receives the IGMP Report message, checks its IGMP table for that stream. If that channel is already extended up to ADSL card. The multicasting stream shall be forwarded on PVC 0/100 of the subscriber and the entry is made in the IGMP table. If not the same process is repeated at every hop i.e. DSLAM uplink, RPR / OC LAN Switch and BNG input interfaces.

• If the stream is not available in BNG, on receipt of IGMP message from STB BNG sends PIM JOIN message to PE router. If stream is available on PE router it forwards to BNG, which in turn forwards the stream on interface over which IGMP report is received. This process continues hop by hop up to CDN Layer-3 switch if the stream is not available in PE, P and PE routers.

• .

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IPTV Call Flow• A separate IPTV context is configured in BNG without any AAA

services. PIM SM proxy is configured on BNG interface towards RPR Tier-I switches in order to associate IGMP table with PIM multicasting routes. PIM SM feature is enabled on BNG uplink connected to PE router with PIM RP pointing to CDN layer-3 switch IP address.

• The CDNLayer-3 switch that aggregates the streaming servers is connected to MPLS PE router on GE port. In MPLS a separate multicasting enabled VRF is created for carrying IPTV streams.

• Powering on the STB, the STB contacts the CDN server and gets authenticated based on its MAC address. The CDN DHCP server allots IP address to the STB. The CDN server pushes the TV Channel description along with its associated multicasting ip address.

•

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IPTV Call Flow• With MPEG-4 video code each channel occupies around 3 mbps.

For IPTV service 8 mbps ADSL profile is assigned to the ADSL port on DSLAM. Uplink and Down link policing profile as in case of internet service is not applied on BNG link towards the subscribe for IPTV service.

• When a subscriber changes channel, IGMP Leave message for the previous channel is sent followed by IGMP Report message for new channel. If there is no other subscriber watching the channel in that ADSL card for which it has received IGMP Leave message, the ADSL card forwards the IGMP leave message to the DSLAM uplink card so that it stops receiving the channel. This process continues hop by hop up to BNG. The same process continues from BNG to CDN Layer-3 switch by means of PIM Prune message in lieu of IGMP Leave message

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IP MULTICASTING

• IP Multicast is a protocol for transmitting IP datagrams from one source to many destinations

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Protocol Independent Multicast Sparse Mode (PIM SM)

• PIM Sparse Mode (PIM-SM) is a multicast routing protocol designed on the assumption that recipients for any particular multicast group will be sparsely distributed throughout the network.

• It is assumed that most subnets in the network will not want any given multicast packet. In order to receive multicast data, routers must explicitly tell their upstream neighbors about their interest in particular groups and sources. Routers use PIM Join and Prune messages to join and leave multicast distribution trees.

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PIM SM

• With PIM-SM, the neighboring router knows about the RP. • The neighboring router forwards the multicast data to the RP by

encapsulating it in a unicast Register message or messages. • Normal routing delivers the Register to the RP. • The RP de-encapsulates the multicast and forwards copies down

any Shared Tree • This connects the Source to the RP with a Source Tree, the (S, G)

Shortest Path Tree (SPT). Once the RP receives multicasts along this SPT, it sends a Register-Stop to tell the router by the Source to stop sending Register packets. The reason for this behavior is that no multicast packets are lost, if there are receivers already present.

• By the way, if there are no receivers present, the Register-Stop message is sent. Then when a receiver subsequently shows up (IGMP to neighbor router, PIM Join from neighbor router back to RP), then the RP sends the PIM Join to the Source at that time.

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PIM SM

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Protocol Independent Multicast Dense Mode (PIM DM)

• PIM Dense Mode (PIM-DM) is a multicast routing protocol designed with the opposite assumption to PIM-SM, namely that the receivers for any multicast group are distributed densely throughout the network.

• It is assumed that most (or at least many) subnets in the network will want any given multicast packet. Multicast data is initially sent to all hosts in the network. Routers that do not have any interested hosts then send PIM Prune messages to remove themselves from the tree.

• When a source first starts sending data, each router on the source's LAN receives the data and forwards it to all its PIM neighbors and to all links with directly attached receivers for the data. Each router that receives a forwarded packet also forwards it likewise, but only after checking that the packet arrived on its upstream interface. If not, the packet is dropped. This mechanism prevents forwarding loops from occurring. In this way, the data is flooded to all parts of the network.

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PIM -DM

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Show commands for multicast trouble shooting

• show ip mroute • show ip pim interface • show ip pim neighbor • show ip rpf

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Understanding IGMP

• One router periodically broadcasts IGMP Query messages onto the link.

• Hosts respond to the Query messages by sending IGMP Report messages indicating their group memberships.

• All routers receive the Report messages and note the memberships of hosts on the link.

• If a router doesn't receive a Report message for a particular group for a period of time, the router assumes there are no more members of the group on the link.

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IGMP Snooping

• IGMP snooping is the process of listening to IGMP network traffic. IGMP snooping, as implied by the name, is a feature that allows a layer 2 switch to "listen in" on the IGMP conversation between hosts and routers by processing the layer 3 IGMP packets sent in a multicast network.

• When IGMP snooping is enabled in a switch it analyzes all IGMP packets between hosts connected to the switch and multicast routers in the network. When a switch hears an IGMP report from a host for a given multicast group, the switch adds the host's port number to the multicast list for that group. And, when the switch hears an IGMP Leave, it removes the host's port from the table entry.

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Purpose of IGMP Snooping

• IGMP snooping is designed to prevent hosts on a local network from receiving traffic for a multicast group they have not explicitly joined. It provides switches with a mechanism to prune multicast traffic from links that do not contain a multicast listener (IGMP client)

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IPTV service Provisioning in BSNL

• Presently IPTV services are being provided to the BSNL Broadband users through franchisees

• Each franchisee will be signing the agreement to provide IPTV services in the prescribed number of cities

• He will provide the content to BSNL Broadband network for delivering the same to the users

• The franchisee is responsible for providing / installing the STB at the customers premises

• Authentication request for IPTV will be processed at the Franchisee end.

• BSNL is responsible all configurations on the NEs and DSLAMs for extending IPTV services to the customer premises

• IPTV has been tested in about 76 cities from 3 active franchisees. In about 20 cities it is commercially launched.

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