Agenda

1. QUIZ 2. HOMEWORK 3. ATM 4. SONET/SDH/OTN 5. NETWORK DEVICES

Pre-amble

To Fromaddr addr

Data Pad Check sum

Bits:7 1 2/6 2/6 2 0 - 1500 0 - 46 4

Start of framedelimiter

Length ofdata field

(Ethernet Frame)

(IP Header)

32 bits

Version IHL Type of service Total length

Identification Fragment offset

Time to live Protocol Header checksum

Source address

Destination address

Options (0 or more words)

DF

MF

(TCP Header)

32 bits

Source port Destination port

Sequence number

Acknowledgement number

Window size

Urgent pointer

Options (0 or more 32 bit words)

Checksum

Data (optional)

TCPheaderlength

URG

ACK

PSH

RST

SYN

FIN

Homework

19-1, 19-3, 19-6, 19-73, 19-82

20-1, 20-6, 20-13, 20-55

21-2, 21-51

Chapter 19

ATM

Figure 19-1

Multiplexing Using Different Packet Sizes

• We have packets as large as 65,545 bytes sharing systems with systems with packets having fewer than 200 bytes• What does the size of X do to A?

Figure 19-2

Multiplexing Using Cells

Cell network overcomes delay problems by using the cell as the basic unit of data exchange, so X becomes X, Y & Z (smaller fixed size blocks).

Figure 19-3

ATM Multiplexing

• Note: Multiplexer output is sequential like token ring

• Call it TDM or CDM?

Figure 19-4

Architecture of an ATM Network Showing User-Network & Network-Network Interface Points

What is the difference?

Figure 19-5

Transmission Path, Virtual Paths, and Virtual Circuits

Virtual Circuit means• Part or all of the paths are the same?• All cells follow the same route for a message or transmission?

Figure 19-6

Example of VPs and VCs

8 end points using 4 virtual circuits

Figure 19-7

Virtual Path & Virtual Circuit Connection Identifiers

Figure 19-8

Virtual Connection Identifiers in UNIs and NNIs

Why does NNI have more Virtual Path Indicator bits?

Figure 19-9

An ATM Cell(One Size Fits All)

Figure 19-10

SVCSetup

Same as X.25& Frame Relay?

What about PVC?

Figure 19-11

Routing with a VP Switch

Virtual Path Switch uses only Virtual path identifiers (like IP table?)

Figure 19-12

A Conceptual View of a VP Switch

Virtual path identifiers change but virtual circuit identifiers don’t.

Figure 19-13

Routing with a VPC Switch(Combining VP & VC Switches)

Figure 19-14

A Conceptual View of a VPC Switch

What does this add to the VP switch? It uses VCIs too & not just VPIs.

Figure 19-15

Crossbar Switch

Figure 19-16Knockout Switch

• Uses distributors & queues to direct cells to different queues at the output.• With n inputs & n outputs you need n2 crosspoints. So?

Figure 19-17 A Banyan Switch

• Multi stage with microswitches at each stage• For n inputs & n outputs you have log2(n) stages & n/2 microswitches• What probability of cell collision?

2

n

Figure 19-19

Batcher-Banyan Switch

Buffer?

Overcomes Banyan by sorting incoming cells by their final destination

Figure 19-20

ATM Layers

Figure 19-21

ATM Layers in End-Point Devices and Switches

Note: Switches use only two bottom layers

Data Types & Sub-layer Functions

Data Types• Constant bit rate (CBR) has no delays & good for real time• Variable bit rate (VBR) at some burst level • Connection oriented packet data like X.25 & TCP• Connectionless packet data like most IP

Sub-layers• Convergence divides the bit stream into 47 byte segments• SAR adds a one byte header so 48 bytes goes to ATM layer

Figure 19-22

AAL Types

Figure 19-23

AAL1

Note: CSI used for signaling while SC for error & flow control

Figure 19-24

AAL2

Note: IT says where in message & LI points to how much padding

Figure 19-25AAL3/4

Figure 19-26

AAL5

What happened to all the control complexity?

Figure 19-27

ATM Layer

Routing, traffic management, switching & multiplexing

Figure 19-28ATM Header

Figure 19-29

Payload Type (PT) Fields

Figure 19-30

Service Classes

Figure 19-31

Service Classes and Capacity of Network

Figure 19-32

QoS

Sustained Cell RatePeak Cell RateMinimum Cell RateCell Variation Delay

Cell Loss RatioCell Transfer DelayCell Delay VariationCell Error Rate

How about a term paper on the value of each of these?

Figure 19-33ATM WAN

Are these routers or gateways?

Figure 19-34

Ethernet Switch and ATM Switch

• Connectionless vs. connection oriententation• Physical address vs. virtual connection identifiers• Broadcast vs.

Figure 19-35

Local Area Network Emulation (LANE) Approach

What do Broadcast/Unknown server & LANE clients add? Connectionless Service

Lane Clients (LEC), Lane Servers (LES), and Broadcast/Unknown Server (BUS)

Chapter 20

SONET/SDH

Figure 20-1

The SONET System Using Synchronous Transport Signal Multiplexers

Figure 20-2

An Example of a SONET Network

Regenerators regenerate & change some header information. So?

Figure 20-3SONET Layers

PL: end-to-end, LL: mux-to-mux, SL: neighbors; like OSI?

Figure 20-4

Device-Layer Relationship in SONET

Figure 20-5

Data Encapsulation in SONET

Note the pretty overhead additions.

Figure 20-6

STS-1 Frame

Is this structure or throughput?

Figure 20-7

STS-1 Frame Overhead(showing SynchronousPayload Envelope)

Figure 20-8

STS-1 Frame Section Overhead

Figure 20-9

STS-1 Frame Line Overhead

Figure 20-10

Payload Pointers

ID location of payload when it is someplace other than the beginning

Figure 20-11

STS-1 Frame Path Overhead

Figure 20-12

Virtual Tributaries

VTs for multiple sources?

Figure 20-13

VT Types

Figure 20-14

STS-n

Figure 20-15

STS Multiplexing

Figure 20-16

ATM in an STS-3 Envelope

• With STS-3 (155.520 Mbps) entire payload can be used for cell transport• 260 octets can carry close to 5 cells (5 X 53 = 265 bytes)• Recall STS-1 is 51.84 Mbps

Broadband’s Future: Optical Networking

• Background:– Over 100 standards are currently on the drafting

table– Networkers should no longer need to purchase

monthly or yearly for one-time capacity– Networks may not be structurally sound:

• Ethernet/IP mentality eschews complex networks

• SONET-voice & security worlds argue for multi-layered networks with all the complexity and protection that implies.

Broadband’s Future: Optical Networking

• Same old conflict:– The SONET successor is the Optical Transport

Network (OTN) which could work across an Automatic Switched Optical Network (ASON)

– The IP-centric approach uses Generalized Multiprotocol Label Switching (GMPLS)

Broadband’s Future: Optical Networking

• SONET’s disadvantages:– Bandwidth efficiency is a problem at higher

capacities. More overhead is required.– It’s a single wavelength solution (so far)– It’s ignorant of the underlying infrastructure

• Providers are left to manage two layers:– The SONET network with its point to point Wavelength

Division Multiplex network

– The layer-2 or layer-3 networks that might be transported across the SONET network.

• SONET’s advantage: It’s circuit switched.

IP to WDM Choices

RPRPHY

10GigELAN PHY

10GigEWAN PHY

GigEPHY

GFP

RPRMAC

Ethernet MAC HDLC ATM

SONET/SDH

Interface for OTN, G.709

Optical fiber/OTN (WDM)

IPIEEE 802.2 LLC IEEE 802.2 LLC PPP AAL 5

POS

WDM, WWDM, DWDM

IP to WDM Choices

• Acronyms:– RPR = Resilient Packet Ring, IEEE 802.17– HDLC = High-level Data Link Control– POS = Packet over SONET/SDH– GFP = Generic Framing Procedure (ANSI T1 X1

driven standard)– OTN = Optical Transport Network– WDM = Wavelength Division Multiplexing– WWDM = Wide WDM– DWDM = Dense WDM

Optical Networking Approaches

• Overlay Model: Maintaining two discrete networks: A layer-1 optical network and a client network. Users access the underlying optical network through User Network Interfaces (UNIs). Devices in the optical network rely on Network-to-Network Interfaces (NNIs).

• Peer-to-peer Model: A single network, equipment at the networks edge decides how bandwidth is allocated at the network core.

Overlay Approach: ITU Plan

– Divide connections into three components (like SONET):

• The path (the logical connection between stations) called optical channels, to provide end-to-end networking.

• The line (the underlying physical link) called optical multiplex sections, to underpin the channels; but these are expanded to have multiple wavelengths when SONET has one.

• The sections (the individual copper or fiber spans that terminate at the amplifiers or regenerators) called the optical transmission section to define the physical interface that details the optical parameters such as frequency (wavelength), power level, signal-to-noise ratio, etc.

– Include a SONET-like hierarchy called the Optical Transport Hierarchy

Chapter 21

Networking and

Internetworking Devices

Figure 21-1

Connecting Devices

Figure 21-2

Connecting Devices and the OSI Model

Figure 21-3

A Repeater in the OSI Model

Figure 21-6

A Bridge in the OSI Model

Figure 21-10

A Router in the OSI Model

Figure 21-12

A Gateway in the OSI Model

Figure 21-16

Switch

Figure 21-17

Example of an Internet

Figure 21-18 The Concept of Distance Vector Routing

Figure 21-24

Concept of Link State Routing

Figure 21-27

Flooding of A’s LSP