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Switch Router Design & Implementation. Paul C. Huang, Ph.D. ITRI / CCL / N300 pchuang@ccl.itri.org.tw. Teaching Staff. Lecturer 黃肇嘉 ( pchuang@ccl.itri.org.tw ) MIT Generalized Oversampled A/D Converter EECS BS / MS ‘87 U. Tokyo Multicast Routing Algorithms EECS Ph.D. ‘94

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switch router design implementation

Switch Router Design & Implementation

Paul C. Huang, Ph.D.

ITRI / CCL / N300

pchuang@ccl.itri.org.tw

teaching staff
Teaching Staff
  • Lecturer
    • 黃肇嘉 (pchuang@ccl.itri.org.tw)
      • MIT Generalized Oversampled A/D Converter EECS BS / MS ‘87
      • U. Tokyo Multicast Routing Algorithms EECS Ph.D. ‘94
      • Bellcore Optical Switch / Optical Transceiver / High Speed Mux
      • CCL LAN switching
  • Teaching Assistant
    • 魏煥雲 (gis87517@cis.nctu.edu.tw)
    • 張政賢 (chchang@cis.nctu.edu.tw)
  • Guest Lecturer
    • 王耀宗 Switch-Router Testing Methodology
    • 呂國正 Verilog Implementation of Routing function
course grading
Course Grading
  • Assignment Load
    • 25% 3 sets of Homework assignments
    • 30% 2 sets of Labs
    • 15% Presentation
    • 30% Final Project
  • Grading Policy
    • Quality, not quantity
    • Innovativeness
    • Late penalty (15% daily, including weekends & holidays).
course schedule
Course Schedule
  • (2/24) Course Introduction
    • General communications network basics
    • Network market reality (success / failures)
    • Evolution towards Switch Router: Why, Where, When, and How
  • (3/3) The Basic Requirements of Switch Router
    • IEEE / IETF overview
    • Current System and IC product features & specification
    • Current IC product architecture
  • (3/10) Switch-Router Architectures
    • Switch architecture
    • IEEE 802.3 (10/100/1000 Mbps MAC)
    • IEEE 802.3x
  • (3/17) Switch-Router Testing Methodology(王耀宗)
    • Lab I: L2 Performance / Functionality Testing
course schedule5
Course Schedule
  • (3/24) Traffic Management & Implementation Issues and Pitfalls
    • Understanding Traffic Management (RSVP, DiffServ, QoS, Buffering, Routing, Scheduling)
    • Buffer Mgt
  • (3/31) Traffic Management & Implementation Issues and Pitfalls
    • Queue Mgt.
    • Scheduler
  • (4/7) Routing Implementation Issues and Pitfalls
    • Route Forwarding Techniques
    • Implementation Issues at Gbps
    • Example Implementation
  • (4/14) Verilog Implementation of Routing function (呂國正)
    • Lab II: L3 Performance / Functionality Testing
course schedule6
Course Schedule
  • (4/21) Routing Algorithms
    • Basics of Routing
    • Classification of Current Routing Algorithms & Protocols (Unicast / Multicast)
  • (4/28) Implementing Unicast Routing Functions
    • Interior Routing Algorithms (RIP)
    • Interior Routing Algorithms (OSPF)
    • Exterior Routing Algorithms (BGP)
  • (5/5) Implementing Multicast Routing Functions
    • (Multicast Routing (DVMRP)
    • Multicast Routing (PIM)
    • Multicast Routing (CBT)
  • (5/12) Advance Routing Topics
    • ATM Routing Protocol (NHRP)
    • Policy-based / CoS / QoS Route
    • Final Project:
course schedule7
Course Schedule
  • (5/19) Project presentation
    • (50 min / group): Total 3 groups.
  • (5/26) Project presentation
    • (50 min / group): Total 3 groups.
course benefits
Industry focus

Market reality

Standards process

Product concepts

Knowledge focus

Networking fundamentals

Testing fundamentals

Actual design trade-offs

Design concepts

Additional benefits

English comprehension

Interactive (hopefully)

Unfocused on …

Not presentation of protocols

Not theoretical

Not number crunching

Course Benefits

Thanks for being my guinea pigs

teaching philosophy
Teaching Philosophy

Confucius (Eastern)

Socrates (Western)

Knowledge

Knowledge

network engineering

Network Engineering

Why are you interested ?

How is it different ?

Is it your cup of tea?

taiwan s industry
Taiwan’s Industry
  • IT
  • PC Motherboard
  • PC Manufacturer
  • Notebook
  • PC Peripheral
  • Modem / NIC
  • Add-on Cards (Graphics)
  • Scanner / Digital Camera
  • Monitor / LCD Monitor
  • DataComm
  • 10/100/1000 NIC
  • Dual Speed Hub
  • L2 Switch
  • SOHO Router
  • Wireless LAN
  • Systems Integration
  • Switch-Router
  • DSLAM
  • Access Switch
  • Software
  • Internet Middleware
  • OS
  • Protocol
  • Applications
  • CPE
  • Telephone
  • KTS
  • TeleComm
  • xDSL Modem
  • Cable Modem
  • Cellular Phone
  • DLC / HDSL
  • RAS
  • IC Design House
  • PC Chipset
  • Network Chipset
  • Consumer IC
  • Memory

Foundry

LCD

Opto-Electronics

key engineering skills
Telecommunications

Scalability

Reliability

Data communications

Compatibility

Standards conformance

Information Technology

Manufacturing Cost

Logistics

Foundry

Manufacturing Cost

Yield Process

Test Equipment

Accuracy

Speed

Completeness

Manufacturing Equipment

Flexibility

Reproducibility

Mobile

Miniaturization

Low power

Wireless

SNR

Error recovery

Key Engineering Skills
fundamental engineering skills
Theoretical

Mathematics / Physic

Algorithmic

Modeling

Design

Power

Analog Circuit

Digital Logic

Software

Architectural

Protocol

Fundamental Engineering Skills
key engineering value
Key Engineering Value
  • Intellectual Property
    • Patents, copyright, trade secrets
  • Service Differentiation
    • Functional
    • Management
  • Content
    • Information
    • Knowledge
the value chain in networking has changed
The Value Chain in Networking has Changed

Chips

Software

System Design & Integration

Manufacturing

Distribution

Chips

Software

System

Manufacturing

Distribution

  • Already Happened in the PC Business
  • Intel makes the chips; Microsoft makes the software.
  • Dell and Compaq focus on manufacturing, relentless cost cutting, and distribution, not R&D
  • Little system-level innovation, few new system startups
  • Plenty of silicon innovation; plenty of silicon startups
  • Shift from managing scarcity to creating abundance
porter s industry attractiveness model
Porter’s Industry Attractiveness Model

Threat of Competitor

Industry Attractiveness

Supplier Power

Customer Power

Threat of New Entrant

networking ic

10/100M NIC Single Chip

N-Way Switch Single Chip 8/16 ports

1998

1999

2000

Dual-speed Hub Single Chip 8/12 ports

Layer 3 Switch 8/16 ports

國內 Networking IC 現況
  • 網路 IC 戰雲密佈, MB/NIC 卡爭鋒, 瑞昱. 旺宏. 聯傑. 威盛. 上元. 民生. 大智. 矽統及華邦等開始 10/100 Mbps 單晶片量產供貨
  • 雙速集線器 IC 定位成功, 宏三乘勝推出 8 埠新產品, 耘碩. 聯傑. 上元. 凱訊. 亞信. 旺宏. 瑞昱等網路 IC 設計公司打算推出三合一集線器晶片
  • 亞信於台北電腦展展出八埠 N-Way Switch 的嵌入式 DRAM 網路晶片, 此顆 IC 內含 32 位元 RISC 及 2MB SDRAM
  • 瑞昱量產網路交換器 IC, 首批國產四埠交換器 IC 月產能已超過一千顆 (87/12)
  • 上元科技推出台灣第一顆八埠交換器整合單晶片 (87/12)
  • 聯傑購併美商 NETio 獲得先進交換器晶片技術, 目前正研發二埠和八埠高速以太交換器晶片 (88/1)
product line of ethernet lan ic

Octal Port

Layer 3

Switch

8 +1

Layer 3

Switch

Quad Port

Gigabit

Layer 3

Switch

IP

NIC

3 in 1

NIC

Hub

Contr..

Single

Speed

Hub

3 in 1

Dual

Speed

Hub

3 in 1

Dual

Port

Switch

Octal

Port

Switch

8 +1

Layer 2

Switch

Quad Port

Gigabit

Switch

MAC

PHY

Single

PHY

2 in 1

Quad

PHY

PHY

TXVR

Transceiver

10Mbps

100Mbps

1000Mbps

Product Line of Ethernet LAN IC
network technology

Network Technology

Creating abundance

Velocity of change

technology pace has exploded
Technology Pace has Exploded

Technology

Explosion

Technology Applications

CPU / DSP Chips

2D / 3D Graphics Engine

Memory (Rambus)

LCD Displays

10 / 100 / 1000 Ethernet

Multi-Layer Ethernet Switch

xDSL (G.Lite, ADSL, VDSL, etc.)

Cable Modem

Terabit Switch-Routers

Dense WDM

Focus on Technology Innovation,

Not Technology Invention

Transistor

IC Processing / Lithography Technology

Analog IC Design (Spice Modeling)

Technology

Creation

Technology

Creation

Technology

Creation

A/D Conversion

Computing Technology

DSP Algorithm

Digitization

Software Technology

Networking Technology

Packet / Cell Switching

Optical Fiber / Laser Technology

Material Science

technology creating abundance
Technology Creating Abundance
  • Chipsfor networking have twice as many gates every 18 months, thanks to Moore’s Law.
    • We can build network systems on a chip for minimal incremental cost or “free”.
    • We can pack billions of DSP ops/sec on a chip. We
    • We can route 10s of millions of packets/sec on a chip.
  • Opticsperformance doubles every 12 months. Twice as many wavelengths on the same fiber every year. Eventually, that changes everything.
  • Packet switching (IP)is taking over everywhere. Fundamental packet technology performance is doubling every 12 months, outpacing alternatives. outpacing alternatives.
moore s law meets network ics

$45

$40

$35

$30

$25

$20

$15

$10

End’97

Mid’98

End’98

Mid’99

L2 through L7

Managed L2

Moore’s Law Meets Network ICs
  • Cost is dropping to $15/port
  • Full L3 and L4 routing, QoS, accounting, etc. “for free”
  • New standards like DiffServ, RSVP, H.323, IPsec, can all be handled with the same chips at the same cost
  • Total Bill of Materials for 10K boxes/month

Source : MMC networks

dwdm a breakthrough technology

OC-192, 32l

OC-48, 96l

OC-192, 16l

OC-48, 48l

OC-192, 4l

135 Mbps

565 Mbps

1.7 Gbps

OC-48

OC-192, 2l

DWDM: A Breakthrough Technology

350

300

250

200

150

100

50

0

Doubling Each Year:

2000: OC-192, 80 l

2001: OC-192, 160 l

2002: OC-192, 320 l

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

System Capacity (Gbps)

demand growing faster than technology
Demand Growing Faster than Technology

Basic technology Performance doubling time

Moore’s Law -gates/chip 18 months; 59% / yr.

Optical fiber - bps/fiber 12 months; 100% / yr.

Packet switching - $/bps12 months; 100% / yr.

Basic demandTraffic doubling time

Internet users 12 months; 100% / yr.

Data bits7.5 months; 300% / yr.

Internet core4 months; 1,000% / yr.

changing of the era sonet wdm
The SONET Era

“Free” local calls, expensive long distance

Circuit/TDM model

Transmission was king;efficiency was key.

Service was based on multiplexing

Data used existing transmission

Few, legacy carriers with legacy nets

Managing scarcity

The WDM Era

Expensive access to “free” backbone

Packet model

Switching is king; features are key

Service is based on internetworking

Data demands new transmission

Thousands of new carriers with new nets

Creating abundance

Changing of the Era: SONET  WDM
changing of the era network processor
Original Assumptions

IP routing is based on destination address

Routers can maintain only a few queues per port

Fast switching must be very simple

Signaling, traffic management should be done only at call setup

Very fast switching requires fixed length cells

Cell and frame networks are very different

New Assumptions

Can route on SA, DA, port, URL, DS types, etc.

Routers can have tens of thousands of queues

Chips can be application-aware, still run at many Gbps

Its possible to do shaping, policing, WFQ, NAT, tunneling for each packet

It is no harder to switch a packet than a cell

In hardware, cells and frames are interchangeable.

Changing of the Era: Network Processor
changing of the era packetization
Changing of the Era: Packetization

This transition is as fundamental as the shift from analog to digital

changing of the era service networks
Telco Business Model

Regulated monopolies

Protected local / domestic markets

High barriers to entry

Pricing based on usage

Smart network

Stupid end devices

Profits generated by managing scarcity

Internet Business Model

Unregulated providers

Global market with global competitors

Low barriers to entry

Pricing based on access

Stupid network

Smart end devices

Profits generated by creating plenty

Changing of the Era: Service Networks
network service

Network Service

Paradigm Shift

New business model

biggest driving factor internet traffic
Biggest Driving Factor: Internet Traffic

Growth assumes more real-time services including multicast

Users(Millions)

Usage Sizes (KB)

Annual Packet Traffic

(Billion Packets)

5000

100-500,000

200

4,000 - 20,000x

5,000x

40x

35

5

1000

50

25

1

1990

1995

2000e

E-Mail

WebHome-PageSurfing**

Web,VideoInfomercialUsage***

1990

1995

2000e

* Presumes growth in PC-installed base from 1995’s 60 million to 2000’s 475 million ** 5KB/page x 10 Web pages per user** 500KB/seconds x 10 seconds

Source: IDC, Zona Research, Literature Searches, Team Analysis

the current pstn model
The Current PSTN Model

Potential Competitors

Baby Bells, GTE

Connectionless

Signaling Network

SS7

Connection-Oriented

Bearer Network

4ESS, 5ESS

Thin Clients

Thin Clients

the current internet model
The Current Internet Model

Potential Competitors

1000’s ISPs, Telcos, HiNet

IP Routers

Connectionless

Bearer Network

Thick Client

Thick Client

Connection-Oriented

Transport Network

SONET, ATM

a possible future model
A Possible Future Model

Potential Competitors

AT&T (@Home), WorldCom (UUNet), AOL, DirectPC

Internet

Connectionless

Signaling Network

Thick Client

SS7-Aware

Gateway

  • Connection-Oriented
  • Bearer Network
  • Application Specific
  • VPN Capable

Future Nets

Thin Clients

another possible future model
Another Possible Future Model

Potential Competitors

Qwest, Level 3, Delta Three, Concentric, IDT,

Bigger Faster Internet

Thick Client

SS7-Aware

Gateway

Connectionless Signaling Network & Best-effort Data Delivery

  • Connection-Oriented Services:
  • IP Telephony
  • VPN Capability
  • Assured Data Delivery

Thin Clients

network architecture

Enterprise Protocol

IP / IPX / SNA

Enterprise Transport

Ethernet

ATM / FDDI / TR

Conventional Voice

(PBXs & phones)

Analog

IP / ATM

Frame Relay

Access: Protocol

Users want choice

and interoperability

Access: Physical

Cable

xDSL / ISDN

SONET / SDH

Satellite / Wireless

Internet provides

Network Intelligence

Access

Applications provide

the Network Services

Edge

Core

TeleComm / Cable / Wireless provides the Access and the Transport

Network Architecture
network convergence
Network Convergence

Voice

Video

SNA

TDM

RAS

Core

Core

Wireless

Voice

ISDN

Data

EDGE

Service Specific

Vertical Integration

from

Access to Core

Core

  • Deregulation
  • Technology
  • The Internet
  • Global Commerce

Frame

Relay

FTTx

HFC

Data

EDGE

IP

ATM

Voice

Voice

Copper

VPN

Video

Core

Core

Intranet

Data

Data

Any access technology on a Common Edge/Core

Architecture offers great flexibility while reducing cost

service content revenue trends

Content

Managed

Intranets

Electronic

Commerce

VPN

Services

Internet

Services

Frame Relay, Cell Relay

Leased Line Services

10%

7%

10%

3%

20%

25%

25%

30%

1997

2000

25%

45%

Service & Content Revenue Trends

Private

Services

Public Services

Increasing Value

Functional

Differentiation

Quality and

Cost

Relative income from basic services decreasing

- value added services key to profitability

the new business driver the customer
The new business driver . . . THE CUSTOMER

IP/ATM

Services

Regulated

Environment

Standards Bodies

Manufacturers

Service providers

Customers

New Competitive

World

ISDN

The market, not regulators

decide on standards today

market success failures

Market Success / Failures

Why do some succeed & some fail ?

networking a technology timeline

1969

1973

1979

1981

1982

1983

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

Networking : A Technology Timeline

Fore and NET/Adaptive,

among others, announce

first ATM switches;

roughly $5000 per port

Novell demonstrates

first networked

PC LAN

IBM introduces

16Mbps token ring

adapter

Sun

introduces

Iava

Robert Metcalfe

found 3Com

IBM announces

4 Mbps token ring

$830 per node

Frame Relay

Forum founded

Bay Networks

established

Arpanet opens;

50 kbps, 4 hosts

IETF

established

ATM Forum

established

Robert Metcalfe

and David Boggs

build first Ethernet;

2.944Mbps over coax

Cisco ships

AGS router

Ipsilon Networks

ships IP switching

Kalpana ships

first Ethernet switch;

$1450 per port

IEEE approves

802.3 Ethernet

Alteon demos first

gigabit Ethernet switch

and adapter

Synoptic ships

first Ethernet hub

IEEE splits work

on fast Ethernet

into two groups,

100Base-T and 100VG

3Com ships

first 10Mbps

Ethernet adapter;

$950

market tradeoffs
Market Tradeoffs

Cost

Functionality

Time to Market

Winner == Right Product at the Right Time at the Right Cost

strategies and corresponding value propositions
Strategies and Corresponding Value Propositions

Market Segment

Vendor-Created

Market-Created

1

3

Innovative

Evolution

Breakthrough

Product

2

4

Replicative

Differentiation

Reposition

broadband network market

Department

Division

SBU

Corporate

Broadband Network Market

Application

CPE

DataComm provides Network Intelligence

Enterprise Networking

Internet Backbone

SOHO Networking

CO / Cable

RAS (Copper, Cable)

SONET / DWDM

TeleComm / Cable / Wireless provides the Access and the Transport

bridge vs router

Need more Functionality

(VLAN, Multicast, Routing, etc.)

Ethernet

Switch

Bridge

Router

Need for Lower Cost,

Higher Bandwidth

Bridge vs Router
  • Available Approaches
  • Big Fast Router
  • Layer 3 Switch Router
  • IP Forwarding Switch
  • MPLS / IP Switch
  • ATM Switch
  • ???

“ASICs are the technology enabler. Like the introduction of the microprocessor, new chips will revolutionize the networking industry.”

-- David House (Chairman, President, and CEO of Bay Networks)

lan standards
LAN Standards

IEEE 802.2

LLC

Data

Link

Layer

802.3

CSMA

/CD

LAN

802.4

Token

Passing

Bus

LAN

802.5

Token

Passing

Ring

LAN

802.6

Dual Bus

Distributed

Queue

Public

LAN

802.11

Wireless

LAN

802.12

Demand

Priority

LAN

802.14

Cable

TV

WAN

ANSI

FDDI

I & II

Campus

MAC

PHY

high speed networking

IP

IP

Ethernet

Ethernet

Frame Switch

Frame Switch

IP

ATM

ATM

ATM

ATM

IP

Ethernet

Cell Switch

Cell Switch

Cell Switch

Cell Switch

Cell Switch

Frame

Cell

IP

Ethernet

ATM

Frame

ATM

Cell

Frame

Cell

High Speed Networking

10 / 100

Ethernet Access

Gigabit

Ethernet Backbone

IP Edge

Hub

IP Switch

Backbone

IFMP, GSMP, TDP

ATM Edge

Hub

ATM Switch

Backbone

IPOA, LANE, MPOA

CIF Edge

Hub

ATM Switch

Backbone

ATM Edge Switch

ATM Switch

Backbone

ip switching model

Integrated

Routing

3. Multi-Layer Switching Model

(Tag Switching, MPLS)

2. Integrated Model

(IP Switching)

Layered

Routing

1. Overlay Model

(MPOA)

Simplified addressing, Separate routing (NA)

Subnet Addressing

Peer Addressing

IP Switching Model
a taxonomy of ip switching solutions
A Taxonomy of IP Switching Solutions

IP Switching

Peer

Overlay

Layer 3 Switch

Flow

Topology

Flow

Address Resolution

Layer 4 Switch

IFMP/GSMP

Tag Switching

MPOA

Classical IP

Gigabit Routers

CSR/FANP

ARIS

LANE

Terabit Routers

IP Navigator

NHRP

QoS Router

VNS

MARS

MPLS

RFC 1483 PVC

  • Different environments warrant different solutions
  • Factors : scalability, cost, simplicity, extensibility, etc.
club sandwich debate protocols

Demand for Internet applications, plus new packet technologies

VCs for flows, VPNs, Traffic engineering.

Provides reliability, provisioning

IP

Very Uneasy Match

ATM

SONET

Very Simple Match

WDM

Provides cost breakthroughs in bandwidth.

Club Sandwich Debate (Protocols)
other success failure
Physical Interface

Modems / ISDN / xDSL / Cable Modem

ATM

25.6 Mbps, TAXI, SONET/SDH

Network Architecture

DLC

HFC

FTTC / FTTH

WAN Protocol

Frame Relay

SMDS

ATM

Network Management

SNMP vs CMIP

Protocol

OSI vs TCP/IP

ATM Forum vs IETF

Other famous battles

Wintel vs. Macintosh

VHS vs Beta

Battles to come

Terabit Cell vs Terabit Packet switch

Other Success & Failure
key to success
Key to Success
  • An innovation is adopted more quickly if:
    • Big Payoff:It shows an easily measured advantage relative to existing methods, through low cost or great results.
    • Investment Protection:It can be adopted compatibly, without having to discontinue or discard the old approach. Often by eliminating architectural changes and protocol development
      • Simpler interoperability — plug & play
      • Easier adoption — mix & match
      • Faster time to market — no waiting for standards
      • Greatly reduced complexity
    • Low Risk:It lends itself to initial small-scale implementations
fast ethernet is a winner
Fast Ethernet is a Winner

100 Mbps Ethernet

1. Big Payoff ?

2. Investment Protection ?

3. Low Risk ?

Yes -- 10 fold speed-up for little or no cost

Good -- and 10/100 chips enable a mix and match installation

Yes -- very low cost, can be adopted incrementally, can be sensed automatically

frame relay is a winner
Frame Relay is a Winner

Frame Relay

1. Big Payoff ?

2. Investment Protection ?

3. Low Risk ?

Yes -- Good price / performance vs. private lines

Excellent -- just a software upgrade to most boxes

Yes -- very low cost, can be adopted incrementally, can grow to large size / high speed

multi layer switch will be a winner
Multi-Layer Switch will be a Winner

Multi-Layer Switch

1. Big Payoff ?

2. Investment Protection ?

3. Low Risk ?

Yes -- 10X performance for 1/10th the cost

Excellent -- works just like a router, only faster

Yes -- very low cost, can be adopted incrementally, can grow to large size / high speed

network backgrounder

Network Backgrounder

Introduction to various network devices

IP Switching

Tag Switching

today s dominant network model
Routers (Pros)

Broadcast Firewalls

Dynamic Path

Security

Routers (Cons)

Protocol dependence

Application fairness

Performance

Administrative Complexity

Scalability

Bridges / Switches (Pros)

Plug & Play connectivity

Simplicity

Performance

Bridges / Switches (Cons)

Broadcast storms

Bandwidth intensive for WAN

Static Path

Scalability

Today’s Dominant Network Model

B

B

H

R

B

H

B

R

R

evolving networking architecture
Evolving Networking Architecture
  • Bridged network
    • Microsegmentation
  • Collapsed backbone routers
    • Use a router to tie shared-media or switched LAN segments together
  • Switched network
    • Hierarchical network
  • VLANs with “one-armed” routers
    • Used to contain broadcast to within one VLAN.
    • Just like subnets, VLANs are interconnected by routers, except that routers link virtual LANs, not physical LAN segments, leading to the “one-armed” configuration of the router hanging off a switch.
    • Focused on “switch when you can, route when you must” strategy.
evolving network architecture
Evolving Network Architecture
  • Cut-through routing
    • Use route servers + “cut-thru” techniques to avoid the need to detour all intersubet traffic through “one-armed” router bottlenecks, thereby improving network efficiency and performance.
    • Focused on “route once, switch many” strategy.
  • Gigabit Wirespeed Routing in Hardware
    • Use the latest ASIC technology to perform routing in specialized hardware.
    • Focused on “route whenever you need to” without any performance penalties or the need to create multiple VLAN network overlays.
next generation network
Base Technology

Switch-Router

Protocol

IP / IPX

Routing Hops

Many

Pros

It’s a router

Cons

Scalability

Base Technology

ATM Switch

Protocol

IP

Routing Hops

~ 2+

Pros

Looks like a router & performs like a switch

Cons

Non-standard

Next Generation Network

“Best Effort” “Guaranteed”

Datagram

Integrated

Overlay

  • Base Technology
    • ATM Switch
  • Protocol
    • ATM + rest
  • Routing Hops
    • 0 or 1
  • Pros
    • Guaranteed QoS
    • Virtual networking
    • Multi-service
  • Cons
    • Complexity
    • Forklift upgrade
the datagram model
The “Datagram” Model
  • “Router-based” Networks
    • Routers are always in the datapath running common routing protocols
    • All services (Routing, IP Multicast, CoS, etc.) are performed by routers.
    • Latency = n( # hops, services, … ) = independent forwarding decision for each packet
  • Future Enhancements
    • IP forwarding switch, Layer 3 switches, Layer 4 switches, Multi-layer switches
    • Gigabit Switch Routers, Terabit Switch Routers (Tiny Tera)

Performance is optimized within a device; best-effort delivery

historical issues with datagram
Historical Issues with Datagram
  • IP only
    • Doesn’t support multi-service (ATM, Frame Relay)
  • Only “Best Efforts”
    • Shared QoS = no QoS
    • Router-based RSVP not scalable
    • Too much latency for real time data delivery
  • Traditionally, router bandwidth is limited
  • Doesn’t support traffic engineering

But: Many of these issues are being corrected

the overlay model

S

S

S

S

E

S

S

One-arm Router

The “Overlay” Model
  • “Overlay-Model” Networks
    • End-to-end / Edge-to-edge switching model
    • Routing is performed only on connection setup
    • Centralized control via some kind of server
      • either to translate addresses or to provide routes
      • limits the cost and complexity of edge devices
      • IETF Standards: NHRP, MARS
      • ATM Forum: LANE, MPOA

Performance is optimized end-to-end; Guaranteed QoS delivery

the overlay model pros cons
The “Overlay” Model — Pros & Cons
  • Provides a lot of benefits
    • Potentially better latency (QoS), performance (Throughput), and scale (Size)
    • Virtual overlay allows new services to be added without penalty
      • Multi-Service
      • Virtualization (LANE, VPNs)
    • Traffic Engineering
  • But
    • If full “n2-squared” connectivity, limited scalability (in size)
    • If partial connectivity, multiple hops may be needed across backbone
the overlay model edge to edge
Advantages

Runs existing legacy routing protocols over ATM (OSPF, IS-IS, RIP, etc.).

Offers investment protection and risk avoidance for existing networks.

Uses familiar and mature technology.

Segregates router implementation from ATM implementation.

Is a reasonable approach for campus backbones.

Disadvantages

Legacy routers have imperfect topology information about the ATM network:

An ATM net is not a single broadcast LAN.

It is not a single link or N2 links among all routers or just selected links.

It is more than just emulated LANs.

Multiple ATM hops may be needed across backbone.

Routers have no existing software for SVCs.

Suboptimal; no end-to-end QoS.

Server-based solutions raise scalability problems.

The Internet needs a different solution.

The “Overlay” Model — Edge-to-edge
the integrated model
The “Integrated” Model

S

S

S

S

  • “Integrated-Model” Networks
    • Routers are always in the edge of the network
    • Switches are always in the core of the network
    • Tags are used to identify the services required of the network
    • Latency  constant
  • Future Enhancements
    • Ipsilon IP switch, Tag Switch, ARIS, Fast IP, etc.
    • MPLS standardization completion

Performance is optimized within the network core; best-effort or CoS delivery

addressing schemes
Addressing Schemes

There are 2 Alternatives for Addressing ATM Switches and Routers

  • Peer model:
    • The ATM address is treated as a logical internetwork layer address.
    • An algorithm can translate between IP and ATM addresses.
    • Internetwork routing done in ATM switches, which have IP addresses.
  • Subnet or overlay model:
    • ATM and internetworking use separate address spaces (chosen by the ATM Forum).
    • An address resolution protocol is needed.
    • This decouples the efforts of the Forum and IETF.
routing schemes
Routing Schemes

There are 2 Ways for ATM Switch Routing to Work with Internet Routing.

  • Layered routing:
    • Conventional Internet routing runs over ATM routing.
    • Usually involves route or address servers.
  • Integrated routing:
    • ATM routing is used to support internetworking directly, or there is only one algorithm.
    • One choice: have the ATM switches run IP routing protocols.
    • Another choice: have the ATM switches use forwarding tables set up in advance by the IP routers.

¤ Note that this choice is independent of the choice of peer or subnet addressing

gigabit ethernet

Gigabit Ethernet

What it use to be ?

What it has become.

What is the key ?

ethernet what it used to be
Shared Ethernet

CSMA / CD

10 Mb/ s

Half Duplex

Distance Limited

Shared Bandwidth

Latency Under Heavy Loads

Lack of Priority Mechanism

Lack of Bandwidth Management

Ease of Installation

low cost of integration

homogeneous

interoperability

backward compatible

longevity & future proof

Ease of Management

low operations & maintenance cost

minimal hidden cost

Cost

2X ~ 3X cost for 10X performance

Ethernet - what it used to be ...
ethernet where it is going
Ethernet - where it is going ...
  • Multiple Data Rate Options
    • 10 Mbps, 100 Mbps, 1000 Mbps (IEEE 802.3z Gigabit Ethernet)
    • Full Duplex Option (IEEE 802.3x)
    • Trunking (Cisco’s Etherchannel)
    • 10,000 Mbps soon thereafter?
  • No Distance Limitations related to CSMA/CD or Data Rate
    • Media determines distance in Full Duplex
  • Latencies Are Coming Down
    • Very low insertion delay in Gigabit Ethernet
      • 0.5 microsec for short frames
      • 12 microsec for longest frames
    • Very low switch latency in multi-Gigabit switches
      • Under 10 microsec
      • As low as 3 microsec
ethernet where it is going73
Ethernet - where it is going ...
  • Switched Ethernet Is The Norm
    • Mix of 10/100/1000 Mbps ports in same box
    • Switching capacities in the tens of Gigabits/sec
      • Historically, ten-fold capacity increase every two years
    • Cost per switched Mbps coming down
      • Historically, prices dropped to 1/2 or 1/3 every two years
  • Scalability and Fault Tolerant Topologies
    • Area of emphasis in new generation of switches
    • Aggregation of traffic on multiple ports
ethernet where it is going74
Ethernet - where it is going …
  • Ethernet Switches Have Multiple Queues
    • Priority of packet determines latency
    • IEEE 802.1p, IETF ISSLL
  • Bandwidth Management Added
    • Flow Control specified in IEEE 802.3x
      • XON / XOFF
      • Switch to Switch, or Switch to End-node Signaling
    • Virtual LANs specified in IEEE 802.1q
      • Frames are tagged to indicate VLAN association
      • Switches interpret the tags and create campus- wideVLANs
    • Advanced Filtering IEEE 802.1p - Multicast
      • Protocol defined for dynamic registrations / deregistration for multicast session - GARP/ GMRP (802.1p) and GVRP (802.1q)
networking where it is going
Networking - where it is going …
  • Layer 3 Routing capabilities
    • Wire-speed routing
    • Performance points as high as 100X relative to traditional routers
    • Eliminates the complicated “route once, switch many”
    • QoS routing
  • Layer 3 Bandwidth Mgt.
    • RSVP
    • SBM
    • CoS (Class of Service)
    • Policy-based QoS
      • QoS Policies set centrally by network administrator
      • Network flows identified in real time
      • No changes required at the end station
      • No changes required to the applications
networking where is it going
Networking - where is it going ...
  • Layer 4 switching
    • Flow based switching: A flow is a stream of packets exchanged between two (or more) users for any application.
    • Flows can be established with RSVP, CLI or SNMP
    • Allows route engineering and service differentiation, facilities that ISPs need and love to have.
    • Allows fine- grained traffic control and enterprise wide policy controls
networking still to come
Networking - still to come
  • End-to-End Standardized Congestion Management
    • Beyond 802.3x Flow Control
  • “Contract based” Guarantees on
    • Latency
    • Latency Variation / Jitter
    • Available bandwidth
  • Security
    • Firewall
    • SYN attack prevention
network standards status
Network - standards status
  • IEEE Standards
    • IEEE 802.3x - Standard in 1997
    • IEEE 802.3z - Standard in Q3 1998
    • IEEE 802.1p - Standard in Q2 1998
    • IEEE 802.1q - Standard in Q3 1998
  • IETF Standards
    • ISSLL - Integrated Services Over Specific Link Layers
      • IS to IEEE 802.1p service mappings
      • Layer 2 Ethernet switches will be able to participate in call-admission control and traffic policing
    • IGMP for Next Generation of Layer 2 Ethernet Switches
so is this still ethernet
So, is this still Ethernet ?
  • Preservation of the Ethernet Frame Format is Key
    • Allows backward compatibility
    • Enables high performance low cost switching (no need for frame translations or segmentations)
    • Best fit to what is on the majority of desktops
  • Other Than the Frame Format...
    • It certainly is very different from the original 10Base5, coax based,shared, CSMA/ CD Ethernet!
  • It is Winning Because...
    • We got here through a series of pragmatic, reality based, improvements (that took 17 years)
    • Successful technologies are not about perfection, but about compromise between complexity, performance, ease of deployment and cost
ip switch concept

ATM STATUS

SYSTEM STATUS

ATM STATUS

ETHERNET STATUS

SYSTEM STATUS

ETHERNET STATUS

ITRI

CCL

Ethernet to ATM Switching Hub

--------------------------------------------

EAS - 3000

ITRI

CCL

Ethernet to ATM Switching Hub

--------------------------------------------

EAS - 3000

POWER

LINE DETECT

. . . . . .

P1

P2

P3

P4

P5

P6

P7

P8

POWER

LINE DETECT

. . . . . .

P1

P2

P3

P4

P5

P6

P7

P8

RUN/DIAG

Rx SIGNAL Tx

Rx

RUN/DIAG

Rx SIGNAL Tx

Rx

. . . . . .

Rx LE Tx

Tx

. . . . . .

Rx LE Tx

Tx

. . . . . .

A2E E2A

COL

. . . . . .

A2E E2A

COL

IP Switch -- Concept

IP Switch

IP Switch Gateway

IP Switch Gateway

IP Switch Controller

Ipsilon Flow

Management Protocol

Ipsilon Flow

Management Protocol

General Switch

Management Protocol

ATM

155 Mbps

ATM

155 Mbps

ATM

155 Mbps

ATM Switch

ip switch configuration
IP Switch -- Configuration

IP switching Ignores all

of the ATM Forum

Software Applications

IP

Software

ATM Forum

Software

IP

Software

MAC Layer

Transport

ATM H/W

ATM H/W

IP Switching combines

the best of IP software

and ATM H/W

ipsilon protocols
Ipsilon Protocols

GSMP - General Switch Management Protocol

  • Simple protocol that provides call setup, tear down & call status
  • Less than 2000 lines of code
  • Capable of operating with any ATM Switch

ATM IP Switch

IP Switch

Controller

GSMP

Downstream

Node

Upstream

Node

ATM

Switch

IFMP

IFMP

  • IFMP - Ipsilon Flow Management Protocol
  • Protocol between multiple IP Switches or hosts
  • Less than 10000 lines of code
  • Protocol used to send flow redirection messages
flow vs connection oriented traffic

Flow-Oriented Traffic

  • FTP data
  • Telnet
  • HTTP
  • Web Image downloads
  • Multimedia audio/video
  • Short-lived Traffic
  • Name Look-ups (DNS)
  • Simple Mail - SMTP
  • POP
  • SNMP
Flow vs. Connection Oriented Traffic
  • A Flow is a sequence of packets sent from a particular source to a particular destination that are related in terms of their routing and any local handling policy they may require
  • It performs a similar function in a connectionless network to the role the connection plays in a connection oriented network.
  • Two packets belong to the same flow if the type of service, protocol, source/destination addresses/ports are the same.
  • short-lived traffic is ideal for forwarding
  • long-lived flows are ideal for "cut-through" switching
ip switch operations

ATM IP Switch

ATM IP Switch

IP Switch

Controller

IP Switch

Controller

ATM

Switch

ATM

Switch

Downstream

Node

Downstream

Node

Upstream

Node

Upstream

Node

ATM IP Switch

ATM IP Switch

IP Switch

Controller

IP Switch

Controller

ATM

Switch

ATM

Switch

Downstream

Node

Downstream

Node

Upstream

Node

Upstream

Node

IP Switch Operations
  • (IFMP)

(vpi/vci

= 0/15)

GSMP

  • (IFMP)
ip switch campus departmental backbones

IP

IP

IP

Switch

Switch

Switch

IP Switch

Gateway

IP Switch--Campus, Departmental Backbones

Direct Attached

Servers

IP Switch of Departments

  • Very-high IP throughput
  • Gbps of switching performance with IP routing functionality
  • Complements existing routed networks and LAN switching
  • IP Gateway used for LAN connection
  • Supports direct attached ATM servers

OC-3

OC-3

OC-3

OC-3

OC-3

OC-3

IP Switch

IP Switch

IP Switch

FDDI

Gateway

Gateway

Gateway

Conventional

Router

10

Mbps

100

Mbps

10

Mbps

100

Mbps

10

Mbps

100

Mbps

ip switching
IP Switching
  • Approach
    • Flow-driven IP switching
    • Integrated routing and switching
    • per-flow classification and mapping to establish dynamic shortcut paths
stated advantages of ip switch
Stated Advantages of IP Switch
  • Simplicity, Flexibility, and Robustness of IP
    • Discards the complexity of ATM protocols (signaling, new routing protocol, new addressing scheme, LANE, MPOA, etc.)
    • Uses well known, well debugged, and heavily tested standard IP routing
    • Backward compatible to existing network and network mgt. tools
  • Scalability and Speed of Switching
    • Uses flexible, scalable ATM hardware whose cost are decreasing rapidly
    • Allows connection-less and flow-oriented traffic
    • Functions like a traditional router, except 4.5 times faster throughput
    • Supports QoS capability for future RSVP compatibility
    • Support multicast functionality for future IP multicast services
potential disadvantages of ip switch
Potential Disadvantages of IP Switch
  • RSVP may not be as simple or low cost
    • still requires massive changes to the network (new adapters, new switches, new routers); (new softwares [ODI, NDIS, Winsock 2.0, etc.])
    • QoS guarantees by RSVP is only a subset of ATM’s
      • Only nrt-VBR
      • No CBR, rt-VBR, ABR
    • Requires signaling (similar to Q.2931?)
    • Requires new routing protocols (not available yet)
    • RSVP is not ready; 2 ~ 3 years behind ATM
mpls tag switching overview

Tag Distribution Protocol

Tag Switches

(ATM Switch or Router)

Tag Edge Router

Existing Routing

Protocol

MPLS (Tag) Switching Overview
cell interleaving problem
Cell Interleaving Problem
  • Solution 1:
    • Use different VPI for each label space and different VCI to maintain source identity (unique VCI range for each ingress node)
    • Limited scalability to 4096 unique VPI labels
  • Solution 2:
    • VC Merging
mpls tag switching
MPLS (Tag) Switching
  • Tag Approach:
    • Topology-driven, not traffic-driven
    • No connection setup; prepopulate tags, distributed before traffic arrival
    • Map IP traffic to a switched path via control protocol information
    • Enhanced forwarding performance via label-swap paradigm
    • Generalized for any media encapsulation: ATM, FR, PPP, etc.
    • Agnostic to network layer services: allows any number of different network-layer functions to map to a simple and fast forwarding mechanism
      • Leverages existing routing protocol
      • Multiprotocol: IPv4, IPv6, IPX
      • Allows future features
        • Diffserv, RSVP, IP Multicast
        • CoS / QoS Routing, Policy-based Routing
mpls tag switching pros cons
MPLS (Tag) Switching — Pros & Cons
  • Advantage
    • Combines L3 flexibility & scalability w/ L2 performance and traffic management
      • Internal routing flexibility (OSPF)
      • External routing scalability (BGP)
    • Log(n) scalability
    • Existing ATM networks
      • Allows IP to integrate with ATM
      • Integrated multi-service networks
      • Reduce complexity due to multiple peer router networks
      • Co-exist with ATM protocols or eliminate them all together
  • Potential Problem
    • Loop creation due to topology changes
      • Forwarding loop formed at L2 goes undetected by L3 loop mitigation mechanism
      • Lack TTL field in an ATM cell header.  consumes both link and TSR resource
potential refinements to mpls
Potential Refinements to MPLS
  • Potential Refinements to MPLS
    • Two-level or multi-level tags can be pushed onto a stack, and popped off as the packet travels.
    • Explicit routes can override destination-based routing for QoS or traffic engineering.
    • Flow-driven short cuts can be used at the edge, with topology-driven short cuts in the core.
  • Tags or Labels can have Varying Granularity
    • A tag represents a forwarding equivalence class.
    • Fine granularity, for example:
      • One class per address prefix in routing table or per source-destination pair
    • Medium granularity, for example:
      • One class for each output port in the network or for each Web URL
    • Coarse granularity, for example:
      • One class for each node in the network or for each external network
router accelerator
Router Accelerator

IP

Forwarding

Switch

Router

Router

route accelerator advantages

No Infrastructure Impact

No new protocols

  • Implementation Cost

A little higher than LAN switch

  • Reduced Price

1/10th of router price

($500 vs. 5,000/100M port)

  • Increased Performance

10~20x Boost

  • Maximum Scalability

Routing protocols - not Spanning

Tree

Route Accelerator — Advantages
learning forwarding in ip forwarding switch
Learning/Forwarding in IP Forwarding Switch

Learning: packets from router ports

Forwarding: packets from network ports and router ports

IP

Forwarding

Switch

Network Ports

Router

Router Ports

sending ip packets
Sending IP Packets

Inter-Subnet

Router

Host1

Intra-Subnet

Host2

  • Intra-Subnet Communication
    • Test under Mask is “true”.
    • Next hop’s address is exactly the destination MAC address.
  • Inter-Subnet Communication
    • Test under Mask is “false”.
    • Next hop’s address is the router’s MAC address.
an example of inter subnet communication

FF

aa

aa

AA

??

RR

aa

rr

aa

AA

rr

RR

FF

aa

aa

AA

??

RR

rr

aa

AA

BB

cc

rr

AA

BB

An Example of Inter-Subnet Communication

1

to destination IP: BB

Test under Mask: false

IP

Forwarding

Switch

2

Network

Ports

Router

Ports

3

4

DA2

SA2

Router

port 4

(ARP_Req)

source Ethernet address (SA3)

source IP address (SIP)

destination Ethernet address (DA3)

destination IP address (DIP)

(ARP_Res)

port 4

IP

MAC

HOST

ARP cache

BB

rr

port 4

Router

HOST

send a packet

(IP Pkt)

IP

MACsub

port

port 3

IP Forwarding Switch

IP cache

BB

cc

3

route once switch many
Route Once, Switch Many

switching

routing

IP

Forwarding

Switch

Router

Inter-Subnet traffic: Switched rather than Routed

route advertisements rip and ospf
Route Advertisements: RIP and OSPF
  • RFC-1388
    • Send RIP-1 packets in broadcast mode.
    • Send RIP-2 packets in broadcast mode.
    • Send RIP-2 packets in multicast mode.
  • RFC-2178
    • Send OSPF packets in broadcast mode.
ip learning process
IP Learning Process

if (a unicast packet && an IP packet)

learn (DIP-DA2) pair and tag proper port ID;

else

do nothing.

IP Forwarding Process

if (a unicast packet && DA2 = router’s MAC address)

lookup IP Table (cache) and forward the packet to

destination port with proper MAC substitution;

else

forward the packet to corresponding router port.

issue of dynamic routing

4

3

2

1

1

2

4

4

3

2

1

1

2

3

4

Issue of Dynamic Routing
  • IN-BAND route refresh

3

IP

Forwarding

Switch

Router

  • OUT-BAND route refresh

null

IP

Forwarding

Switch

Router

cells in frame concept

Multiple ATM Cells w/ Same VC

ATM Hdr

Ethernet Hdr

Cells-In-Frame Concept

Workstation

Ethernet-to-ATM CIF Edge Switch

Applications

Winsock 2.0

SIG

SIG

NULL

IP

CIF

ATM

NDIS

SHIM

Driver

ATM Functionality (QoS / Flow Control over Ethernet

ATM Cells over Ethernet Wire

cells in frames reference model
Cells-In-Frames Reference Model

CIF Workstations

CIF Switch

ATM Switch

ATM Workstation

Upper Layers

Upper Layers

SSCS

SSCS

CIF Mapping Function

CPCS

CPCS

CIF

CIF

SAR

SAR

DLL

DLL

ATM

ATM

ATM

Ethernet

ATM

ATM

PHY

PHY

PHY

PHY

PHY

cif abr flow control
CIF ABR Flow Control

RM Cells passed onto Workstation at reduced rates to convey ABR rate to SHIM, TCP, and source

CIF Ethernet Switch

SHIM uses ABR rate from the RM cells to control the transmission rate for each VC’s queue and then controls TCP to send at the same rate instead of guessing and oscillating

Switch acts as a source and destination for ABR, turning around the RM cells

functions in cif switches
Functions in CIF Switches
  • Signaling Functions
    • The CIF switch will appear as a single device with multiple ATM addresses, one for each of the Ethernet attached workstations
  • Management Functions
    • The CIF switch will intercept, examine, and forward ILMI messages
  • Traffic Shaping Functions
    • The CIF switch will act as a virtual source / virtual destination (VS/VD) on behalf of each workstation
stated advantages of cif
Stated Advantages of CIF
  • Inexpensive and ubiquitous
    • Uses existing Ethernet adapters (saves $$)
    • Large installed Ethernet base (add new ATM software)
    • Cost (CIF switches) @ Cost (Ethernet switches)
  • Provides ATM functionality right away.
    • Guaranteed QoS over standard Ethernet (new services)
    • Allows voice over Ethernet (saves $$)
    • Allows flow / congestion control (better than TCP/IP)
potential disadvantages of cif
Potential Disadvantages of CIF
  • Software SHIM (CIF driver) will hurt performance
    • No pipelining to optimize performance
    • Per packet interrupt results in large delays, low throughput
  • Requires new equipments anyway
    • New CIF switches are required
      • CIF switches could be as complicated as ATM switches (requires QoS support, WFQ, ILMI, Signaling, P-NNI routing, etc.), so may not be cheaper than Ethernet switches
    • Eventually Ethernet adapters and drivers needs to be changed.
      • Why not go straight to ATM adapters.
lan emulation model

Initialization

  • Registration
  • Address Resolution
  • Initialization
  • Registration
  • Address Resolution

LE Server (LES)

LE Server (LES)

  • Data Forwarding
  • Data Forwarding

Broadcast & Unknown

Server (BUS)

Broadcast & Unknown

Server (BUS)

LAN Emulation Model

LE Configuration Server

LECS

LE Client (LEC)

ATM Server

ATM

Network

LE Client (LEC)

Bridge

Legacy LANs

LUNI

LE Client (LEC)

ATM Server

le service components
LE Service Components
  • LE Client (LEC)

* provide a MAC level emulated IEEE 802.3 or 802.5

service interface

  • LE Server (LES)

* registration

* resolving MAC addresses to ATM addresses

  • Broadcast and Unknown Server (BUS)

* send the broadcast MAC address frame

* send all multicast traffic

* send unicast frames (before data direct VCC has been established)

  • LE Configuration Server (LECS)

* provide configuration information, address of LES

luni protocol overview
LUNI Protocol Overview
  • Initialization
  • Configuration
  • Joining
  • Registration and BUS Initialization
  • Data Movement
initialization
Initialization
  • Must determine the ATM address of the LECS
  • Use SNMP ILMI to get address from a table in the switch and place call to that address
  • Use well-known ATM address
  • If that fails, use the VPI/VCI 0/17 PVC as the connection to the LECS
  • If LECS is not available, try the LES
configuration
Configuration
  • LEC provides:
    • ATM address
    • MAC address
    • LAN types and frame sizes requested
  • LECS returns:
    • LES address
    • LAN type and frame size to use
joining
Joining
  • Create Control Direct bi-directional VCC
  • Transmit Join Request (ATM address, LAN info, proxy indication, optional MAC address)
  • Possibly accept Control Distribute VCC before Join Response is received
  • May timeout or fail
registration and bus initialization
Registration and BUS Initialization
  • Register any MAC addresses
  • Resolve 0xffffffffffff MAC address to get ATM address of BUS
  • Create bi-directional Multicast Send VCC to BUS
  • Accept unidirectional Multicast Forward VCC from BUS
data movement
Data Movement
  • When a data frame is available for transmission, check internal cache
  • If unknown, ask the LES
  • While waiting for response, any transmit frame(s) via BUS
  • Establish direct connection when response is received
lec connections across luni
LEC Connections across LUNI

Workstation

LEC

Bridge

LEC

Config Direct VCC

LECS

Config Direct VCC

Control Direct VCC

Control Direct VCC

LES

Control Distribute VCC

Multicast Send VCC

Multicast Send VCC

BUS

Legacy LAN

Multicast Forward VCC

Data Direct VCC

address resolution frames
Address Resolution Frames
  • IP_ARP frames (RFC 826, Nov. 1982)

IP --> 48-bit MAC address

  • LE_ARP frames (ATM-Forum/LAN emulation over ATM Spec)

48-bit MAC address --> 20-byte ATM address

  • ATM_ARP frames (RFC 1577, Jan. 1994)

IP --> 20-byte ATM address

le arp flow

Network

LE_ARP Flow

LES

LEC 1

2

1, 4

A

3

3, 5

4

3, 5

LEC 2

1

B

BUS

1. LEC2 sends and LE-ARP request to find ATM addr of MAC A via Control Direct VCC

2. LES does not find the corresponding ATM address of MAC A in the REG-DB

3. LES sends the LE-ARP request to all Proxies via PROXY-DB

4. Upon receiving the LE-ARP request, LEC1 looks for its filtering table to find MAC A. LEC1 sends back the LE-ARP response with ATM LEC1

5. LES sends the LE-ARP response to LEC2 via LECID-DB

message flow atm to atm
Message Flow / ATM to ATM

Control direct VCC

Multicast send VCC

Multicast forward VCC

Signalling

Data direct VCC

LES

4a, 4b

3a, 3b

1

2, 4

2, 4

IP A

MAC A

ATM A

IP B

MAC B

ATM B

BUS

ES A

ES B

3

3

3c

5, 4c

/* to find MAC B */

1. ES A sends an IP-ARP request, looking for MAC B

2. ES A sends the IP-ARP request to ES B, via BUS-ES B

3. ES B sends the IP-ARP response to ES A, via BUS-ES A

-------------------------------------------------------------------------

/* to find ATM addr of MAC A */

3a ES B sends LE-ARP request to find ATM addr of MAC A

3b. LES sends the LE-ARP response to ES B

3c. ES B sets up a direct VCC to ES A

-------------------------------------------------------------------------

4. ES A begins to transfer data to ES B, via BUS

/* to find ATM addr of MAC B */

4a. ES A sends an LE-ARP request to find ATM addr of MAC B

4b. LES sends the LE-ARP response to ES A

4c. ES A knew it has a direct VCC to ES B. Before using it,

ES A sends a flush message to ES B

-----------------------------------------------------------------------------

5. After ES A receives the ack of flush message, the data flow

is ES A-ATM network-ES B