week4 eetp bbt final

8/16/2019 Week4 Eetp Bbt Final

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Broadband Technology (BB) VLAN, DSLAM & BB Services

4 VLAN, DSLAM & BROADBAND SERVICES

4.1 INTRODUCTION

4.2

OBJECTIVE

4.3 BROADCAST CONTROL

4.4 LAYER – 2 SWITCH

4.5 VLAN BOUNDARIES

4.6 VLAN MEMBERSHIP

4.7 VLAN TAGGING

4.8 VLAN TRUNK

4.9 FEATURES OF DSLAM

4.10 IMPLEMENTATION OF DSLAM

4.11 CONNECTIVITY OF DSLAM

4.12 ARCHITECTURE OF DSLAM

4.13 AN 2000-IB IP DSLAM

4.14 IP VIRTUAL PRIVATE NETWORKING

4.15

BROADBAND SERVICES

4.16 APPLICATIONS OF BROADBAND

4.17 SUMMARY

4.18 SELF ASSESSMENT QUESTIONS

4.19 REFERENCES AND SUGGESTED FURTHER READINGS

4.1 INTRODUCTION

Virtual LANs (VLANs) offer a method of dividing one physical network into multiple

broadcast domains. This document discusses the concept of VLAN and different types ofVLANs.

4.2 Objective After completion of the topic, the participants will be able to

EETP/BSNL Gold Certification Course/Ver.02/Jan’2015 Page 1 of 26

For Restricted Circulation


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Understand concept of VLAN

Understand the importance of VLAN

Understand the different Types of VLAN

What is DSLAM

Function of DSLAM

Components of DSLAM

Application of DSLAM Requirement for broadband connection

Why broadband is so important

Services available through broadband

Applications of Broadband

4.3 BROADCAST CONTROL

Broadcasts occur in every protocol; but how often they occur depends upon the protocol, the application(s) running on the internetwork, and how these services are

used. Routers, by default, send broadcasts only within the originating network, butswitches forward broadcasts to all segments.

As an administrator, we must make sure the network is properly segmented tokeep problems on one segment from propagating through the internetwork. The mosteffective way of doing this is through a pure switched network and VLANs. All traffic,including broadcasts, are filtered from all of the ports on a switch that are not membersof the same VLAN.

Routers (or layer-3 switches), should be used in conjunction with switches to provide connections between networks (VLANs), which stop broadcasts from propagating through the entire internetwork.

Security

By using VLANs and creating multiple broadcast groups, administrators

have control over each port and user. Users can no longer just plug their workstationinto any switch port and have access to network resources. The administrator controlseach port and whatever resources it is allowed to use. If inter-VLAN communicationneeds to take place, restrictions on a router can also be implemented. Restrictions alsocan be placed on hardware addresses, protocols and applications.

Flexibility and Scalability

By assigning switch ports or users to VLAN groups on a switch or group of

connected switches, we have the flexibility to add only the users we want in the broadcast domain regardless of their physical location. When a VLAN gets too big, wecan create more VLANs to keep the broadcasts from consuming too much bandwidth.The fewer users in a VLAN, the fewer affected by broadcasts.

4.4 Layer – 2 Switch




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A layer-2 switched network is referred to as a flat network topology with single broadcast domain. This means every broadcast packet transmitted is seen by everydevice on the network, regardless of whether the device needs to receive the data or not.The larger the number of users and devices per segment, the more broadcasts andgeneral traffic each device must handle. Another problem with a layer-2 network issecurity, as all users can see all devices. We cannot stop devices from broadcasting andusers trying to respond to broadcasts.

To overcome the problems with single broadcast domain, switched networks can be subdivided into Virtual Local Area Network (VLANs). A VLAN is a logicalgrouping of network devices connected to administratively defined ports on a switch.Using virtual LANs, we’re no longer confined to physical locations. VLANs can beorganized by location, function, department, or even the application or protocol used — regardless of where the resources or users are located. By creating VLANs, we cansolve many of the problems associated with layer-2 networks.

4.5 VLAN Boundaries When building the switch block, there are two basic methods to

understand when defining the VLAN boundaries: End-to-end VLANs

Local VLANs

End-to-End VLANs

End-to-end VLANs are VLANs that span over a number of switches from end-to-end, and where all switches are aware of all configured VLANs. End-to-end VLANsare configured to allow for the extension of the VLAN domain to span over multipleswitches. The best feature of end-to-end VLANs is that users can be placed in a VLANregardless of their physical location, or physical switch connection.

The administrator defines the switch and port the user is connected into as a

VLAN member. If the user moves, the administrator defines their new switch and portas a member of their existing VLAN. The goal of an administrator in defining end-to-end VLANs is to maintain 80 percent of the network traffic as local, or within theVLAN. Only 20 percent or less should extend outside the VLAN.

Local VLANs

Local VLANs are configured by geographic location and these locations can bea building, or just a block in a building, depending on switch size. Geographicconsiderations regarding configured VLANs are designed around the fact that the business or corporation is using centralized resources on a shared backbone. The userswill spend most of the time utilizing these backbone-centralized resources, and 20 percent or less on the local VLAN. Since layer-3 devices are becoming faster and faster,

we must design a geographic VLAN with a fast layer-3 device. The benefit of thisdesign is that it will allow the users a deterministic, consistent method of accessingresources. However, we cannot create this design with a lower end layer-3 model.

Designs of VLAN

In a VLAN, computers are assigned to LAN segments by software. VLANs areoften faster and provide more flexible network management than traditional LAN. Theyare also more complex and so far usually used for larger networks. The two basicdesigns of VLAN are single switch VLANs and multi-switch VLANs.




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Single Switch VLANs: Computers are assigned to individual VLANs in one of four ways using a single

switch :

Port-based VLANs assign computers according to the VLAN switch port to which they are attached.

MAC-based VLANs assign computers according each computer’s data linklayer address

IP-based VLANs assign computers using their IP-address

Application-based VLANs assign computers depending on the application that the computer typically uses.

Multi-Switch VLANs:

VLANs in separate locations can be possible by Multi-Switch VLANsinterconnected by Trunk Links. Multi-switch VLANs can be implemented by two ways:

Proprietary protocols such as Inter Switch Link (ISL) are used to envelope theEthernet frame, which is then sent to its destination switch, where the Ethernet packet is released and sent to its destination computer.

Modify the Ethernet packet to include VLAN information (802.1q) by adding 16 bytes of overheads. When the IEEE 802.1q packet reaches its destination switch,its header is stripped off and the Ethernet packet inside is sent to its destinationcomputer.

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4.6 VLAN Membership:

When a VLAN is implemented at a LAN switch, an end user must have amembership to it. Two methods of assigning membership exist on LAN switches:

Static VLANs and

Dynamic VLANs.

Static VLANs:

Static VLANs offer port-based membership, where switch ports are assigned tospecific VLANs. End user devices become members in a VLAN based on which physical switch port they are connected to. The ports on a single switch can be assigned

and grouped into many VLANs.

4.7 VLAN Trunks

At the access layer, end user devices connect to switch ports (a single VLAN).An additional Layer 3 router/switch is needed to communicate between the VLANs. Atrunk link, however, can transport more than one VLAN through a single switch port.Trunk links are most beneficial when switches are connected to other switches orswitches are connected to routers.

4.8 VLAN Tagging

VLAN Tagging is used when a link needs to carry traffic for more than one VLAN.

The packet is then forwarded to the appropriate switches or routers based on the VLANidentifier and MAC address through a trunk link after adding a tag. This is known as a trunklink or VLAN trunking. Upon reaching the destination Switch the VLAN ID is removedfrom the packet by the adjacent switch and forwarded to the attached device.

VLAN Tagging is used when a link needs to carry traffic for more than oneVLAN. Tagging is used so the receiving switch knows which ports in should flood broadcast. Frame tagging is defined in Standard IEEE 802.1Q.




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Trunking protocols were developed to effectively manage the transfer of framesfrom different VLANs on a single physical line. Trunk links may carry traffic for allVLANs or only specific VLANs.

It is important to understand that a trunk link does not belong to a specific VLAN.The responsibility of a trunk link is to act as a pipe for VLANs between switches

Dynamic VLANs

Dynamic VLANs are used to provide membership based on the MAC address ofan end user device. When a device is connected to a switch port, the switch must querya database to establish VLAN membership. A network administrator must assign aVLAN using the database of a VLAN Membership Policy Server (VMPS). DynamicVLANs allow a great deal of flexibility and mobility for end users.

4.9 FEATURES OF DSLAM

To enable DSL technology, service providers must have a DSLAM located in theirnetworks to interact with the customer premises equipment (CPE) at the end userlocation.

DSLAM is an integrated hardware and software system that allows the user toaccess Broadband services as well as originate and terminate telephone calls over thesame single pair of copper wires. A Digital Subscriber Line Access Multiplexer(DSLAM) delivers exceptionally high-speed data transmission over existing copper




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telephone lines. A DSLAM separates the voice-frequency signals from the high-speeddata traffic and controls and routes digital subscriber line (xDSL) traffic between thesubscriber's end-user equipment (router, modem, or network interface card [NIC]) andthe network service provider's network. A DSLAM takes connections from manycustomers and aggregates them onto a single, high-capacity connection to the Internet.DSLAMs are generally flexible and able to support multiple types of DSL in a single

central office, and different varieties of protocol and modulation, both CAP and DMT,in the same type of DSL. The DSLAM may provide additional functions includingrouting or dynamic IP address assignment for the customers.

The DSLAMs is in general be collocated with existing PSTN exchanges which provide last mile access to customers over copper wire up to average span lengths of 3kms.

A digital subscriber line access multiplexer (DSLAM) delivers exceptionally high-

speed data transmission over existing copper telephone lines. A multiservice DSLAM is a broadband-access network element (NE) that combines support for multiple DSL

transmission types. When coupled with high-capacity asynchronous transfer mode (ATM)

switching, multiservice DSLAMs deliver scalability, port density, and a redundantarchitecture for reliability. Multiservice DSLAMs, together with various CPE elements, can

enable the relatively efficient deployment of broadband networks for high-speed Internet

access as well as voice and video applications. Such DSLAMs often allow for full ATM

switching, traffic management, and quality of service (QoS), in addition to the delivery of afull range of services. These services include analog, ISDN, IDSL, SDSL, rate-adaptive

DSL – competitive access provider (RADSL – CAP), and RADSL – discrete Multitone (DMT)

on a single platform. The basic features of Digital Subscriber Line Access Multiplexer

(DSLAM) are describes below: -

DSLAM aggregates the subscriber lines

A Digital Subscriber Access Multiplexer delivers exceptionally high speed datatransmission over existing copper telephone lines

DSLAM separates Voice and Data of the Subscriber i.e. it separates the voicefrequency signal from High Speed data traffic

Routes and Controls Digital Subscriber Line (xDSL) traffic between thesubscriber’s end-user equipment (Router, Modem, or Network Interface Card (NIC)and the Network Service Provider’s network.

Voice is given to the exchange switch

Data is fed to the IP Network through the LAN Switch

DSLAMs have been categorized in to 6 types based on no. of ports (480, 240,120,

64, 48 & 24) provided and planned for deployment based on the expected demand

DSLAM provides Access from 128Kbps to 8Mbps

DSLAM supports for QOS features such as Committed Access Rate betweenCPE and DSLAM, Traffic Policing per port




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DSLAM works Satisfactory without any degradation in performance andwithout using any repeater/regenerator over a distance for various access speeds for0.5mm copper pair.

Distance wise downstream bit rate in DSLAM

1.1.1.1.1.1.1.1.1 Downstream 1.1.1.1.1.1.1.1.2 Distance

bit rate

6 Mbps

1.5 Kms

2 Mbps

3.5 Kms

1 Mbps

4.0 Kms

4.10 IMPLEMENTATION OF DSLAM

Broadband connectivity is extended to these DSLAM through the core network via

the LAN switch. Commonly it is available with 960, 480, 240, 120, 64, 48 and 24 ports.DSLAMs are generally aggregated through a Fast Ethernet or Gigabit Ethernet Interface.

The connectivity of these DSLAM according to the location and capacity is planned in NIB-II Project 2.2. DSLAMs are available with different types of access modules and capacities.

The FX or GBIC module in DSLAM and LAN switch should be capable of driving up to 10

km on a single mode fibre. The SX or GBIC module in LAN Switch used for connecting

Tier2 to Tier1 will support 40 km. In bigger cities like A1, A2, A3 and A4, one BBRAS percity will be deployed initially. There will be no BBRAS at B1 and B2 cities. The DSLAMsin B1&.B2 and other lower hierarchical cities will be




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aggregated through Layer 2 switches, and will be connected to the nearest BBRAS of Acities on Ethernet over SDH.

M/s HTL and M/s UTStar Comm. have supplied DSLAM equipments for Project 2.2 of NIB-II. Following types of DSLAMs are introduced: -

Huawei SMARTEX MA 5300 480, 240, 120 ports DSLAM

Huawei SMARTEX MA 5300 64, 48 and 24 ports DSLAM

UTStarComm AN2000 IB IPDSLAM 480, 240, 120 ports DSLAM

UTStarComm AN2000 B-100 Mini DSLAM 64, 48, 24 ports DSLAM

4.11

CONNECTIVITY OF DSLAM

DSLAM is connected to ATM or IP based core network through the networkingelements. It aggregates the data traffic of all the users provided to it and extends to corenetwork. The telephone traffic of each user is separated by splitter available in it andtransmits to PSTN network. DSLAM provides user access through user access layer andConnectivity to IP backbone is provided through IP convergence layer.




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Description of DSLAM equipment

DSLAM cabinet consists of various modules in the form of boards and provides theconnectivity to ADSL modem and network. Broadband Access Equipment, DSLAM,developed by M/s Huawei Technologies Co. Ltd. is implemented in Broadband service.Model named as MA5300 and MA5105 are briefly described in this section.

4.12 ARCHITECTURE OF DSLAM

Broadband Access Equipment MA5300 is a piece of L2/L3 IP DSLAM equipment.

There are two types of MA5300 frames: -




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Service frame

MA5300 service frame is 10U high (including a 1U fan frame). It measures436.00 mm (width) x 420.00 mm (depth) x 444.50 mm (height). Figure belowshows the MA5300 service frame. The MA5300 service frame has 16 slots,numbered from 0 to 15. Among them,

Slots 7 and 8 are for the main control board (ESM) exclusively.

Other 14 slots can hold any service board (EAD/EVD/ESH).

Slot 14 and 15 can also hold the Intelligent Service Unit (ISU) or the Ethernetuplink port board (EIU).

In the service frame, the backplane and the ESM are mandatory. Other service boards are flexibly configured based on service types and traffic volumes. All boards adopt front access mode, in which cables are led out from the front panel.

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

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MA5300 service frame

SPL frame.

The MA5300 SPL frame is 9U high, which have the same appearance as theservice frame. The SPL frame is used to hold the splitter boards (ESP). There are twotypes of SPL frame i.e. active SPL frame and passive SPL frame. Active SPL frame isequipped with the main control board (SPMA). Passive SPL frame is not equipped withthe main control board. A SPL frame provides 16 slots, which can hold 14 ESP boards.




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MA5300’s Passive SPL frame MA5300’s Active SPL frame

The SPMA communicates with the MA5300’s ESM board through the serial port using APP. It also controls the ESPC board to capture lines.

In addition, the SPMA provides ports to connect to the external test meter and broadband test management system. In this way, the SPM facilitates line capture underthe control of broadband test management system, as well as test of xDSL lines captured

through an external tester meter.

MA5300’s boards can be divided to the following types:

Main control board

Service board

Built-in ISU board

Ethernet uplink board (EIU)

Splitter board

Table below describes the functions and external ports of various boards.

Type Name Port Description

One network port Provides two sub slots for various

One serial port FE or GE sub boards as required.

One environment (Note: ESME/ESMB is always

monitor port equipped with a 4xFE electrical sub

Main ESMA/ESME: Up to 8 ESMA/ES

board E4FA at sub slot 2; and

control FE ports, or 4 FE ports

ME/ESMB

ESMA is always configured with a

board + 2 GE ports 4xFE optical sub board).

ESB: Up to 8 FE ports,

The FE/GE port serves as either the

uplink port or the local/remote or 4 FE ports + 2 GE

subtending port. ports




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Broadband Technology (BB)

VLAN, DSLAM & BB Services


Coordinates with the ESP (configuration ratio is 2:1),

supporting:

VDSL over POTS in

VDSL

coordination with ESPA/ESPC; EVDA

24 VDSL ports

board VDSL over ISDN and line

capture in coordination with

ESPB.

Connects to the ESP’s xDSL port through a cable.

Coordinates with the ESP

48 ADSL over ADSL

(configuration ratio is 1:1) to EADA

support line capture;

Over POTS ports Connects to the ESP’s xDSL port

through a cable.


EADI

24 ADSL Over ISDN

(configuration ratio is 1:1);

ports Connects to the ESP’s xDSL port through a cable.

ADSL/AD Coordinates with the ESP SL2+

board

(configuration ratio is 1:1);

48 ADSL Over ISDN Built-in protection circuit;

EADJ

Connect to the main distribution

ports

frame (MDF) through a cable.

Note: it can also coordinates with a

third-party splitter board.


EADB

48 ADSL Over ISDN (configuration ratio is 1:1);

ports Connects to the ESP’s xDSL port through a cable.

SHDSL

ESHA 24 SHDSL ports Connects to the MDF, in which the

board

splitter board is not required.

Ethernet

ETHA

12 FE ports

Provides Ethernet access.

board


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Broadband Technology (BB)

VLAN, DSLAM & BB Services


ESPA: applies to xDSL over POTS; ESPB: applies to VDSL over

ISDN;

ESPC: applies to xDSL over POTS

and implements line capture in

coordination with the SPMA;

ESPI: applies to ADSL over ISDN;

LINE port: connects to the MDF

Splitter

48 Line ports

through a subscriber cable to output

ESP 48 xDSL ports POTS and VDSL mixed signals to board

48 PSTN ports the RTU.

xDSL port: connects to the VDSL/ADSL ports of the

EVDA/EADA board though a

cable. PSTN port: connects to the MDF

through a subscriber cable to introduce POTS signals from the

PSTN.

1 communication

serial port SPMA

2 test ports

Line capture

No subtending test

Main

port

control 1 communication board of

SPMB

serial port Line capture

the active

2 test ports

SPL frame

4 subtending test ports

1 communication

SPMC serial port

Line capture 2 test ports

8 subtending test ports

Provides two subslots for various FE or GE subboards as required.

Intelligenc

1 network port

(But the ISUE is always equipped

1 serial port with a 4xFE electrical subboard e service ISUA/ISUE

Up to 8 FE ports +2

E4FA).

unit

GE ports

The FE/GE port serves as either the uplink port or the local/remote

subtending port.

Ethernet When the MA5300 is equipped with

1 GE subslot

active/standby ESM boards, the

Interface EIUA 1 FE subslot

EIU board can be used to provide

Unit

uplink ports.


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POWER SUPPLY

Power supply to the MA5300 can be either AC or DC supply. or. In AC supply,220 V/110 V AC, primary power modules are mounted to the top of the cabinet. Thenumber of primary power modules to be used is subject to the power consumption of thedevice.

In DC supply the MA5300 is powered by external – 48 V DC using the powerdistribution box. It does not need a primary power module. Each board is equipped witha secondary power converter which converts the voltage from – 48 V into 3.3 V or 5 V,enabling distributed power supply.

4.13 AN 2000-IB IP DSLAM

The AN-2000 IB™ is a carrier class IP-based DSLAM that delivers always-on,high-speed Internet data and video services to subscribers over a wire line network. TheAN-2000 IB interfaces directly with the IP MAN (metropolitan area network) to deliver broadband data services cost-effectively and eliminate the need for costly ATMinfrastructure. Service providers to protect their investment and strengthen customer

relationships by offering their customers a wide variety of creative interactive servicesand applications.

The AN-2000 IB solution offers the following advantages:

Unlimited Scalability

Build out the network as needed with the AN-2000 IB modular, high-density architecture.

The product scales gracefully from 24 to 2,424 subscribers per system. All subscribers

can be provisioned easily through dynamic provisioning.

Open Interface

Interoperate with third-party gear and networks as needed; the AN-2000 IB solution uses

an open architecture interface and supports multiple xDSL standards.

New Revenue-Generating Services


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Support IP multicasting for video and value-added services, and deliver always-on broadband data and video, high-speed Internet access, VPNs, distance learning, andenterprise networking to business and residential customers.

High-Speed Remote Access

Provide the satellite-to-headquarters connectivity many of your business customers needwith an economical AN-2000 IB high-speed LAN-interface solution that delivers highernetwork speeds than leased-line or dial-up.

In recent years, worldwide DSL deployment has experienced significant growthdue to increasing customer demand. Today, the DSL access network is evolving fromthe traditional ATM-based access technology to the more cost effective IP-based accesstechnology. With traditional end-to-end ATM-based DSL access networks, manyservice providers experienced problems in provisioning and maintenance, equipmentcost, and network scalability. When the subscriber base grows to hundreds of thousandsand millions of subscribers, network scalability becomes a critical issue to many service providers. In the global DSL broadband market, UTStarcom is a leading provider ofDSLAM equipment and the leading provider of IP-based DSL access solutions.UTStarcom’s AN-2000 IP-DSLAM product not only offers advanced IP basedsolutions, but also provides interfaces to traditional ATM-based backbone networks toallow service providers to gradually transition from ATM to IP. The AN-2000 IP-DSLAM gives service providers the ability to offer true IP-based DSL services and to better utilize each network component to maximize return on investment.

Architecture of AN-2000 IP-DSLAM The AN-2000 IP-DSLAM consists of three types of service modules:-

IP Concentration Module (ICM)

IP Services Module (ISM)

DSL Line Card Module.

The AN-2000 IP-DSLAM chassis consists of two controller slots and 16network/line module slots for user data traffic. These slots can contain three types ofmodules: Internet Concentration Modules (ICM), IP Service Modules (ISM) and LineCard Modules (L/C). The ICM provides Ethernet switching capability for 24 FastEthernet interfaces and two Gigabit Ethernet interfaces. It aggregates all upstreamtraffic from DSL line cards (Fast Ethernet) to the WAN uplink (Gigabit Ethernet) andsegregates the downstream traffic from the WAN to DSL line cards. The ISM providesB-RAS functionality and WAN uplink through its Ethernet and ATM interfaces. TheL/C comprises 24 DSL ports for DSL connections to subscriber CPE. Multiple types ofADSL and SHDSL L/C modules are supported to provide different line standards and

line rates for various market needs.

This system is capable of supporting up to 384 DSL ports per chassis with mixedADSL and SHDSL line cards. DSL subscribers are served with SLA-specific bandwidthand QoS . For example, subscribers who want to use data, voice and video services overthe same DSL connection can subscribe a Triple Play service that provides the required bandwidth and QoS. Other subscribers may use low-bandwidth connections with best-effort QoS. The flexible QoS capabilities of the AN-2000 IP-DSLAM enable




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simultaneous support of different types of customizable services within a single system.On the WAN side, the IP-DSLAM may be configured for ATM, Ethernet or both.

IP SERVICES MODULE (ISM)

The ISM is an IP application blade that enables the service provider to offeradvanced IP services to DSL subscribers. It brings advanced bridging and routingfunctions, layer-two and layer-three QoS features, and subscriber managementcapabilities to the AN-2000 IP-DSLAM. Most importantly, the unique features offered by the ISM bring excellent scalability to the IP access network. ISM also providesinterfaces to traditional ATM-based access network to allow service providers togradually migrate from ATM to IP.

Advanced IP Features

BRIDGING

The ISM supports full-featured bridging functions at layer 2. It supports both802.1d and 802.1q bridging with up to 4095 bridge groups. Additionally, the ISMsupports VLAN aggregation where subscriber traffic carried on different VLANs can bemerged onto a single VLAN.

ROUTING

At layer three, the ISM supports static, dynamic (RIP and OSPF), and policy- based routing. Policy-based routing is implemented through multiple Virtual Routing

Domains (VRDs). Each VRD is a separate routing context in which the routing decisionfor a subscriber packet is based on the routing entries of the VRD that the subscriber belongs to. The ISM also supports inter-VLAN routing.

ACCESS CONTROL AND SESSION TRACKING

The ISM has a rich set of subscriber authentication and session trackingcapabilities. The subscriber is authenticated either through a local user database on theISM or through a RADIUS server.




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At layer two, ISM can apply access control based on the subscriber’s MACaddress. The ISM supports IEEE 802.1x port-based access control and RADIUS proxyfor IEEE 802.1x based wireless access points. With these capabilities, the AN-2000 IP-DSLAM can be deployed to offer wireless hotspot services in conference rooms, coffeeshops, hotels, airports, and elsewhere.

Layer-three access controls are more appropriate when service providers find itdifficult to control subscriber MAC addresses. The ISM supports PPP AuthenticationProtocol (PAP) and Challenge Handshake Authentication Protocol (CHAP) for PPPsubscribers, and IP address authentication for static IP subscribers. Layer-three accesscontrols are difficult to apply in cases where DHCP is utilized because IP addresses aretypically shared among DHCP subscribers. The ISM’s web authentication mechanismsolves this problem by forcing the user to provide their login and password through asecurity portal after receiving an IP address via DHCP.

In addition, when desired by the service provider, the ISM also provides thecapability to track and limit the number of concurrent subscriber sessions. The ISMkeeps track of each admitted subscriber session and collects usage information such as

subscriber MAC addresses, IP addresses, DHCP lease times, and PPPoA/PPPoEsessions. It also maintains a set of counters that tracks each subscriber’s byte counts andonline times. The statistics collected by ISM can be accessed via SNMP and RADIUSaccounting. The ISM also supports sophisticated packet filters via the Access ControlList (ACL) function, allowing the service provider to block unauthorized subscriberapplications.

SUBSCRIBER ISOLATION

Subscriber isolation is one of the capabilities most frequently requested byservice providers. To support security and billing, they typically require that theDSLAM prevent cross-talk between DSL subscribers and forward all subscriber traffic

to the aggregation router. The ISM can provide subscriber isolation at both layer twoand layer three. When layer-two subscriber isolation is enforced in the AN-2000 IP-DSLAM, two subscribers cannot communicate with each other without going throughthe upstream aggregation router, even if they are in the same bridge group. At layerthree, VRDs can also provide subscriber isolation. Subscribers belonging to differentVRDs are prohibited from communicating with each other within the DSLAM.

In addition, similar to layer two subscriber isolation, the ISM can enforce strictisolation between two (or more) subscribers belonging to the same VRD. When strictsubscriber isolation is enforced, two subscribers in the same VRD can onlycommunicate with each other through the upstream aggregation router.

4.14

IP VIRTUAL PRIVATE NETWORKING

A Virtual Private Network (VPN) is a private network constructed using a publicnetwork infrastructure such as the global Internet. The fundamental motivation for usingVPNs lies in the economics of communications. A collection of virtual networksimplemented on a common public network infrastructure is cheaper to operate than anequivalent collection of smaller physically discrete communications infrastructures, eachservicing a single network client. VPNs must enforce traffic segregation such that theinformation carried within a VPN is restricted to a defined set of entities, and third partiescannot gain access. VPNs also allow for private addressing and routing across the public




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Internet. It is important to mention that Service Level Agreements (SLAs) have becomea key aspect of VPN deployments. SLAs are negotiated contracts between service providers and their subscribers. SLAs specify the QoS attributes of each VPN — packetloss, jitter, latency, throughput and more. The AN-2000 IP-DSLAM supports both layer2 (link-layer) and layer 3 (network-layer) IP VPNs.

LINK-LAYER VPN

At the link layer, the AN-2000 IP-DSLAM supports VLAN-based VPNs. TheAN-2000 IP-DSLAM enforces traffic segregation by selectively applying VLAN tags togroups of DSL subscribers that belong to the same VPN. VLAN tags are applied whensubscriber traffic enters the DSLAM. Priority queuing and traffic policing is applied toeach VLAN to ensure conformance to the SLA provided to the VPN subscribers.

Figure 1. Link-layer VPN

NETWORK-LAYER VPN

Network-layer VPNs are most commonly implemented through tunnelingtechniques. The ISM supports three types of network-layer VPNs: L2TP, IP-IP, and IP-GRE. Subscriber traffic is transported by VPN tunnels when it leaves the DSLAM.




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4.15 Broadband Services

A trend of changes in telecommunication technology is very fast. In the presentscenario there is a demand of large bandwidth and its optimum utilization in lower cost.High speed unlimited Internet for a fixed charge on the same line on which yourtelephone works - telephone can be used simultaneously and Internet is always ON - nodialup required), Webfone (Internet Telephony - buy Webfone card and makeinternational calls at very cheap rate) etc. fulfilled the demand of customer. The new erain Telecommunications has started with the Introduction of Convergent Services i.e. a bouquet of services like Television, high speed Internet, Video on Demand, Audio onDemand, Videoconferencing and voice telephony through a single telephone line.

The services are to be provided on the existing copper/optic fiber access networkwithout affecting the existing voice services to the customers.

The optical fiber link would make it easy to provide value-added Internet,entertainment services and Broadband services (BBS). Additional value added services

include audio conferencing (family reunion package), broadcast digital TV, video ondemand, school curriculum on 3D interactive learning mode and personal website fordomestic users, and managed LAN service for commercial users are the main featuresof broadband services (BBS). Broadband service is a kind of service in which one canget multiple telecom services through a single copper cable pair on which the telephoneline is working. Initially the broadband package includes the following services ontelephone line: -

Telephone

Satellite TV channels

Internet

Video on Demand (VoD)

Audio on Demand (AoD)

Video conferencing

Any person who is having a telephone connection can go for a broadbandconnection.

Requirement for providing Broad Band connection

1. Personal Computer2. ADSL Modem3. Land Line Connection4. Splitter for separating telephone from Personal computer.

Why is Broadband Important?

Broadband can provide you with the technical capability to access a wide range ofresources, services and products that can enhance your life in a variety of ways. Theseresources, services and products include,

Education, Culture, & Entertainment

o Broadband can overcome geographical and financial barriers to provide access to awide range of educational, cultural and recreational opportunities and resources.




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Tele-health & Telemedicine

o Broadband can facilitate provision of medical care to unserved andunderserved populations through remote diagnosis, treatment, monitoring andconsultations with specialists.

Economic Development/E-Commerce

o Broadband can promote economic development and revitalizationthrough electronic commerce (e-commerce) by:

Creating new jobs and attracting new industries.

Providing access to regional, national and worldwide markets.

Electronic Government (E-Government)

o Electronic government can help streamline people’s interaction with governmentagencies and provide information about government policies, procedures, benefitsand programs.

Public Safety and Homeland Security

o Broadband can help protect the public by facilitating and promoting publicsafety information and procedures, including, but not limited to:

Early warning/public alert systems and disaster preparation programs.

Remote security monitoring and real time security background checks.

Backup systems for public safety communications networks.

Broadband Communications Services

o

Broadband provides access to new telecommunications technologies such as VoiceOver Internet Protocol (VoIP) allowing voice communication using the Internet.

Communications Services for People With Disabilities

o Broadband permits users of Telecommunications Relay Services (TRS) to useVideo Relay Services (VRS) to communicate more easily, quickly andexpressively with voice telephone users.

DIFFERENT BROADBAND SERVICES

BSNL has a world class, multi-gigabit, multi-protocol, convergent IP infrastructure

through National Internet Backbone – II (NIB-II), that provides convergent servicesthrough the MPLS based backbone and broadband access network. The high speedBackbone comprises of powerful Core Routers connected with high speed 2.5 Gbps(STM-16) on DWDM links.

MPLS VPN is a technology that allows a service provider like BSNL to have completecontrol over parameters that are critical to offering its customers service guarantees withregard to bandwidth throughputs, latencies and availability.




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The Broadband service are available on DSL technology (on the same copper cable thatis used for connecting telephone), on a countrywide basis spanning more than 690 cities.

Services available through Broadband

High speed Internet Access: This is the always-on Internet access service with speed ranging from 256 kbps to 8 Mbps.

Bandwidth on Demand: This will facilitate customer to change bandwidth as per his / her requirement. For example a customer with 256 kbps can change to 1Mbps during the video Conferencing session.

Multicasting: This is to provide video multicast services, video-on-demand etc. for application in distance education, telemedicine etc.

Dial VPN Service: This service allows remote users to access their private network securely over the NIB-II infrastructure.

Video and Audio Conferencing:

Content based Services: Like Video on Demand, Interactive Gaming, Live and time shifted TV

Video on Demand: Customers can view any movie of their choice from a poolof movies stored in a central server. The movies can be viewed either on a TV or

a PC.Audio on Demand: It is a similar service where person can listen to any musicof his choice.

TV channels through broadband connection: The TV channels may be available in the broadband connection. In fact, there may be other new channels, particularly the educational and scientific channels, depending on demand.Additional equipments required in the customer's premises are

Set Top Box (STB) - The STB converts the digital IP based signal to aform compatible with the TV set.

PC and TVThe TV services envisaged are:

i. S-VoD : Subscription based Video Content, as in Pay Channels.

ii.

Video-On-Demandiii. N-VoD : Near Video-On-Demand. NVOD provides playouts on

fixed time bands which people can watch against payment.iv. T-VOD : Transaction or Pay-Per-View service.

The video contents have Hindi, international and regional movies, music, soapsand serials, sports, news, interactive gaming, e-learning and niche channels."The driver in entertainment is on-demand movies, interactive gaming, broadband Internet connectivity and e-learning,"

Billing: To provide a means to bill for the aforesaid services by either time- based or volume-based billing. It shall provide the customer with the option toselect the services through web server To provide both pre-paid and post paid

broadband servicesIP Telephony

Messaging: plain and feature rich,

Multi-site MPLS VPN with Quality of Service (QoS) guarantees.

Wi-Fi




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Web hosting & web co-location.

Lease line service.

Broadcast (BTV) & Time-shifted TV (TVOD)

Besides regular BTV services, TVoDSL provides subscribers with virtual DVD controlsto pause, start, stop, rewind and fast forward live TV programs

Users also have the flexibility to watch any previous broadcasted programs without pre-recording (nPVR)

Pay-Per-View (PPV) /near-Video on Demand (nVOD)

Programs broadcast according to a pre-set schedule with subscribers having the optionof watching and paying for individual programs

Interactive TV (iTV)

Video Phone / Video Conferencing / WebCam

Additional VAS (t-commerce, etc.)

Advertising [Targeted, Multicast]

IPTV

i.) TVOIP (or IPTV) delivers television programming to households via broadband connection using Internet protocols. IPTV is digital television program deliveredto subscribers through the Internet. It is a completely interactive experience.

ii.)

It requires a subscription and IPTV set-top box (STB). The box will connect to thehome DSL line and is responsible for reassembling the packets into a video streamand then decoding the contents. The video stream is broken up into IP packets and




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dumped into the core network, which is a massive IP network that handles all sortsof other traffic (data, voice, etc.)

iii.)

IPTV is typically bundled with other services like Video on Demand (VOD),Voice Over IP (VOIP) or digital Phone, and Web access.

iv.) IPTV viewers have full control over functionality such as rewind, fast-forward, pause, and so on. If you've ever watched a video clip on your computer, you've

used an IPTV system in its broadest sense.

v.) Microsoft is one of the many companies developing solutions to support the IPTVmarket.

VOIP i.) The technology used to transmit voice conversations over a data network using the

Internet Protocol.

ii.) A category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls.

iii.) VoIP works through sending voice information in digital form in packets, iv.) VoIP also is referred to as Internet telephony, IP telephony, or Voice over the

Internet (VOI)

Benefits of VoIP i.)

Cost reduction

a. Toll by-pass b. WAN Cost Reduction

ii.) Operational Improvement c. Common network infrastructured. Simplification of Routing Administration

iii.)

Business Tool Integration

e. Voice mail, email and fax mail integrationf. Web + Callg. Mobility using IP

VPNoBB

Virtual private Network over Broadband is a cost effective solution for VPN needs.It is secured and allows organizations to scale up as the requirement increases. It is




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an add-on service on Broadband and the organization has the option to have bothinternet and VPN connectivity. It can be used to expand the organization’s MPLS VPNconnectivity to other sites where MPLS VPN is not feasible and also as a backup forMPLS VPN at critical sites. The Capex & Opex are affordable.

Salient features of VPNoBB

Cost effective solution for networking

Add-on service on broadband

Very low Capex & Opex Widely available in 900 cities/towns

Scalable Both Internet & VPN possible

Can be used as Backup also No need to purchase costly equipment

4.16 Broadband Applications

1. Personal Services

High Speed Internet Access

Multimedia

2.

Govts. Public services

E-governance

E-education

Tele-medicine

3.

Commercial services

E-commerce

Corporate Internet

Videoconferencing

4. Video & Entertainment services

Broadcast TV

Video on Demand

Interactive gaming

Music on Demand

Online Radio

4.17 Summary

In a VLAN, computers are assigned to LAN segments by software. VLANs are oftenfaster and provide more flexible network management than traditional LAN and BNdesigns. They are also more complex and so far usually used for larger networks.The two basic designs are single switch and multi-switch VLANs. Triple Playservice deployment has imposed a plethora of new functional, performance andcapacity requirements on the key devices that make up DSL




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networks – IP-DSLAMs and B-RASs. Although the complete list of DSLAMmanufacturers would be too long to include, the leading positions are clearlyoccupied by very few manufacturers who represent the de-facto industrystandards. Specifically, Alcatel holds first place at appr. 32.5% of the marketwith Huawei being distant second at appr. 17% and Lucent and Siemens battlingfor the third place. Broadband has numerous applications, starting from voice to

data & video services. Services also include contents based services, on-demandservices, Tele & Electronic version of services & facilities. Hence, broadbandhas penetrated into rural areas & it is proving a technology as a enabler ofremotely available facilities to villages, thereby helping in bridging the Digital-Divide between urban & rural.

4.18 SELF ASSESSMENT QUESTIONS

1. Which type of VPN can be provided using IP DSLAM?

2. What is used to separate Voice and Data at DSLAM?

3.

Which device aggregates subscriber lines?

4. What minimum setup we need for accessing Broadband service?

5. What are different services possible over broadband platform?

6. Can we watch TV or talk over a broadband connection?

4.19 REFERENCES AND SUGGESTED FURTHER READINGS www.en.wikipedia.org/wiki/Virtual_LAN

www.cse.wustl.edu/~jain/cis788-97/ftp/virtual_lans/index.htm

Cisco Switched Internetworks: VLANs, ATM & Voice/Data Integration by Chris Lewis Understanding Digital Subscriber Line Technology by Thomas Starr

http://en.wikipedia.org/wiki/Digital_subscriber_line_access_multiplexer

Broadband Network Architectures: Designing and Deploying Triple-PlayServices By: Chris Hellberg; Dylan Greene; Truman Boyes

Broadband Services: Business Models and Technologies for Community Networks by Imrich Chlamtac, Ashwin Gumaste, Csaba Szabo

Broadband Access Technology, Interfaces, and Management by Alex gillespie

Broadband Last Mile: Access Technologies for Multimedia Communications by Nikil Jayant

Broadband Telecommunications Handbook by Regis B J Bates

Advances in Broadband Communication and Networks by J. I. Agbinya, OyaSevimli

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