1 Internet Technology NETW 902 Tutorial 3 Mohamed Esam

2 Outline 1.SONET/SDH 2.ATM 3.ISDN 4.Dialup 5.DSL 6.IP Addressing  Exercise 3. Access Network Core Network

3 Main Points for Problems 1.ALOHA 2.Slotted ALOHA 3.CSMA/CD 4.Token Ring, Token BUS & Ring Types. (last Tutorial) 5.BUS Segments 6.WLAN 7.FDDI 8.Spanning Tree 9.Performance of (Aloha, CSMA & Token Ring) 10.SONET/SDH 11.ATM 12.Virtual Connections 13.ISDN 14.Dial up 15.DSL Ch’s 1&2 Till page: 200 Ch’s 3 Till page: 255 Ex.1: LAN-Inter working & Spanning Tree Ex.2: MAC protocols Performance Ex.3: IP Addressing, ATM & Access Networks

4 16.Internet Arch. & IP Addressing. 17.ARP 18.MTU 19.Routing Functions 20.Forwarding 21.Routing Principles 22.Distance Vector Algor. 23.Link State Algor. 24.Path Vector Algor. 25.Routing in Internet. 26.Internet Routing Protocols 27.ARQ 28.UDP 29.TCP 30.QoS Some of Ch’s 4&5 Till page: 554 Ex.4: Distance Vector & Link State Routing Ex.5: TCP

5 IP Addressing

6 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)

7 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 /n Subnet Mask: –Example if n=26  subnet mask is: – –And gate is used to get the Network address using the subnetmask

8 Classful Subnetting Special case of classless subnetting when n has defined values.

9 Supernetting Opposite to subnetting Example: –If A0(Network 0 Address)= /24 –& A1(Network 1 Address)= /24  Aagg= / 16

10 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

11 Exerc.3 Prob.1

12 Asynchronous Transfer Mode (ATM)

13 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)

14 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.

15 MUX ` Wasted bandwidth ATM TDM Voice Data packets Images Figure 7.37Leon-Garcia & Widjaja: Communication NetworksCopyright ©2000 The McGraw Hill Companies Asynchronous Multiplexing

16 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

17 ATM Cell Header details in Page 233

18 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 19

20 AAL ATM User information AAL ATM PHY ATM PHY ATM PHY … End system Network

21 Ethernet Frame CS-headerPadCS-trailer Cell header Cell payload SAR-PDU header SAR-PDU payload SAR-PDU trailer SAR-PDU header SAR-PDU payload SAR-PDU trailer Higher layer Convergence Sub-layer (CS) layer Segmentation & Reassembly (SAR) layer ATM layer Cell header Cell payload Adaptation Layer : A detailed view AAL

22 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. User Data Divided into 53 bytes

23 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.

24 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.

25 Synchronous TDM Station A is Faster Asynchronous (Statistical) TDM Station B&D are idle Normal TDM

26 SDH- Standard Frame Representation All frames are: –9 rows Matrix –125 us

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Overhead 29

30 Check slides 4, 7 Given in the problem Encapsulation Headers ATM CS layer 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. 32

33 For Encapsulation Given in the problem

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