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Internet TechnologyNETW 902Tutorial 3

Mohamed Esam

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Outline

1. SONET/SDH2. ATM 3. ISDN4. Dialup5. DSL6. IP Addressing

Exercise 3.

Access Network

Core Network

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Main Points for Problems 1. ALOHA2. Slotted ALOHA3. CSMA/CD4. Token Ring, Token BUS & Ring Types. (last Tutorial)5. BUS Segments6. WLAN7. FDDI8. Spanning Tree9. Performance of (Aloha, CSMA & Token Ring)

10. SONET/SDH11. ATM12. Virtual Connections13. ISDN14. Dial up15. DSL

Ch’s 1&2Till page: 200

Ch’s 3Till page: 255

Ex.1:LAN-Inter working& Spanning TreeEx.2:MAC protocols Performance

Ex.3:IP Addressing, ATM& Access Networks

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16.Internet Arch. & IP Addressing.17.ARP18.MTU19.Routing Functions20.Forwarding21.Routing Principles22.Distance Vector Algor.23.Link State Algor.24.Path Vector Algor.25.Routing in Internet.26.Internet Routing Protocols27.ARQ28.UDP29.TCP30.QoS

Some of Ch’s 4&5Till page: 554

Ex.4:Distance Vector &Link State Routing

Ex.5:TCP

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IP Addressing

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IP Addressing

• IP Addressing:– Subnetting: a network is divided into smaller subnets with

each subnet having its own subnet address.• Classless• Classful

– Benefits:• Faster routing• Smaller broadcast domains• Reduced network traffic• Simplified management

– Supernetting

• IP v4 4 Bytes (Dotted decimal x.x.x.x)• IP v6 16 Bytes (128 bits)

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Classless Subnetting

• The IP address is divided into two part:– Network Addr. (n bits)– Host Addr. (32 – n bits for IPv4)– IP Address with Prefix Notation: ex. 120.112.2.1/n

• Subnet Mask:– Example if n=26 subnet mask is:– 11111111 11111111 11111111 1100000– And gate is used to get the Network address using the

subnetmask

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Classful Subnetting

• Special case of classless subnetting when n has defined values.

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Supernetting

• Opposite to subnetting• Example:

– If A0(Network 0 Address)=00000000.11111111.00000000.00000000/2

4– & A1(Network 1 Address)=00000000.11111111.11111111.00000000/2

4 Aagg=

00000000.11111111.00000000.00000000/16

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IP Static Routing

• Assume 2 BUS topology networks connected by router. The router is the gateway for each network to the other one.

• Station (1.1) will send data to station 2.3.• Next Hop station is the first station will receive the data from the Tx.• Interface is the station in the network domain that will send to the next hop

or the Rx station. • Router knows that address (1.x) is in network 1 and (2.x) is in network 2

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Exerc.3 Prob.1

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Asynchronous Transfer Mode (ATM)

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WAN Definition

• WAN can be divided into:– Core Networks:

Connects cities or countries. (ATM or SONET)

– Access Networks: Connects clients with network operators by IWU. (DSL or Dialup)

• IWU: Interworking Unit (Bridge, Router or gateway)

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ATM

• Is designed to integrate all communication services with different traffic classes:– Constant bit rate (phones)– Variable bit rate (video)– Packetized traffic

• By: – Packetization into small

constant size cells.– Asynchronous multiplexing into

high transmission channels.

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MUX

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Wasted bandwidth

ATM

TDM

4 3 2 1 4 3 2 1 4 3 2 1

4 3 1 3 2 2 1

Voice

Data packets

Images

Figure 7.37Leon-Garcia & Widjaja: Communication NetworksCopyright ©2000 The McGraw Hill Companies

Asynchronous Multiplexing

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Virtual Path & Virtual Connections

• ATM is a Connection Oriented Technology.• Virtual Channel (VC): the channel of ATM cell identified by

VCI (VC ID)• Virtual Channel Connection (VCC): sequence of VC’s links

to establish a path between terminal equipments (TEs).• Virtual Path (VP): group of VC’s identified by a (VPI)• Virtual Path Connection (VPC): sequence of VC’s links to

establish a path between terminal equipments (TEs).• Each cell carriers both transmission VPI and VCI

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ATM Cell

• Header details in Page 233

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Cell Switching• Base on the

connection establishment phase, switching tables are used.

• In the switching table, each input VCI /VPI is mapped to another output VCI/VPI and the corresponding output port number.

Exer.3Prob. 2, Part 1 ATM based access network

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AAL

ATM

User information

User information

AAL

ATM

PHYPHY

ATM

PHY

ATM

PHY

…

End system End systemNetwork

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Ethernet Frame

Ethernet FrameCS-header Pad CS-trailer

Cellheader

Cellpayload

SAR-PDUheader

SAR-PDUpayload

SAR-PDUtrailer

SAR-PDUheader

SAR-PDUpayload

SAR-PDUtrailer

Higherlayer

Convergence Sub-layer (CS)layer

Segmentation & Reassembly (SAR)layer

ATMlayer

Cellheader

Cellpayload

Adaptation Layer : A detailed view

AAL

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AAL5

• The most Common used AAL type.• CPCS payload: The actual information that is sent by the user. • Pad: Padding bytes to make the entire packet (including control and CRC)

fit into a 48-byte boundary. • UU: CPCS user-to-user indication to transparently transfer CPCS user to

user information.• CPI: Common part indicator is a filling byte (of value 0). This field is to

be used in the future for layer management message indication. • Length: Length of the user information without the Pad (65535). • CRC: CRC-32. Used to allow identification of corrupted transmission.

1216

User Data

Divided into 53 bytes

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Synchronous Digital Hierarchy (SDH)

• SDH is used to integrate ATM cells in the transmission system

• Synchronous Optical Network (SONET) is the protocol for North America and Japan by ANSI while SDH is the definition for Europe by ITU-T.

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Synchronous TDM• In Synchronous TDM, the time slots are

preassigned to sources and fixed.– The time slots for each source are

transmitted whether or not the source has data to send

– capacity is wasted to simplify the hardware implementation

– It is possible for a synchronous TDM device to handle sources of different data rates. • For example:

– the slowest input device could be assigned one slot per cycle,

– faster devices are assigned multiple slots per cycle.

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Synchronous TDMStation A is Faster

Asynchronous (Statistical) TDMStation B&D are idle

Normal TDM

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SDH- Standard Frame Representation

• All frames are:– 9 rows Matrix– 125 us

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Overhead

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Check slides4, 7

Given in the problem Encapsulation Headers ATM CS layer

sizeheaderlengthframetheisbits16),12( 16 n

Preamble and SFD are not considered as given in the problem

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Part 2 Ethernet based access network

• ATM technology in DSLAM is replaced by an Gigabit Ethernet interface.

• Ethernet frames in the VLAN switch are encapsulated using the Generic Framing Procedure (GFP).

• GFP adds a header of 8 bytes, but does not include the preamble and the start frame delimiter of the Ethernet frame.

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For EncapsulationGiven in the problem

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