Switch Router Design & Implementation

Switch Router Design & Implementation
Paul C. Huang, Ph.D. ITRI / CCL / N300

Teaching Staff Lecturer Teaching Assistant Guest Lecturer
黃肇嘉 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 魏煥雲張政賢 Guest Lecturer 王耀宗 Switch-Router Testing Methodology 呂國正 Verilog Implementation of Routing function

Course Grading Assignment Load Grading Policy
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 (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 (10/100/1000 Mbps MAC) IEEE 802.3x (3/17) Switch-Router Testing Methodology (王耀宗) Lab I: L2 Performance / Functionality Testing

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 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 Schedule (5/19) Project presentation
(50 min / group): Total 3 groups. (5/26) Project presentation

Course Benefits Thanks for being my guinea pigs 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 Thanks for being my guinea pigs

Teaching Philosophy Confucius (Eastern) Socrates (Western) Knowledge

Why are you interested ? How is it different ? Is it your cup of tea?
Network Engineering Why are you interested ? How is it different ? Is it your cup of tea?

Taiwan’s Industry IT PC Peripheral DataComm Systems Integration
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 Yield Process Test Equipment Accuracy Speed Completeness Manufacturing Equipment Flexibility Reproducibility Mobile Miniaturization Low power Wireless SNR Error recovery

Fundamental Engineering Skills
Theoretical Mathematics / Physic Algorithmic Modeling Design Power Analog Circuit Digital Logic Software Architectural Protocol

Key Engineering Value Intellectual Property Service Differentiation
Patents, copyright, trade secrets Service Differentiation Functional Management Content Information Knowledge

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
Threat of Competitor Industry Attractiveness Customer Power Supplier Power Threat of New Entrant

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) 1999 2000 1998 10/100M NIC Single Chip N-Way Switch Single Chip 8/16 ports Dual-speed Hub Single Chip 8/12 ports Layer 3 Switch 8/16 ports

Product Line of Ethernet LAN IC
1000Mbps Transceiver 100Mbps 10Mbps PHY MAC IP NIC 3 in 1 Single Speed Hub TXVR Dual 2 in 1 Quad Port Switch Octal Contr.. Octal Port Layer 3 Quad Port Gigabit 8 +1 Layer 2

Creating abundance Velocity of change
Network Technology Creating abundance Velocity of change

Technology Pace has Exploded
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
Chips for 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. Optics performance 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
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 $10 $15 $20 $25 $30 $35 $40 $45 End’97 Mid’98 End’98 Mid’99 L2 through L7 Managed L2 Total Bill of Materials for 10K boxes/month Source : MMC networks

DWDM: A Breakthrough Technology
350 300 250 200 150 100 50 135 Mbps 565 Mbps 1.7 Gbps OC-48 OC-192, 4l OC-192, 2l OC-48, 48l OC-192, 16l OC-192, 32l OC-48, 96l 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
Basic technology Performance doubling time Moore’s Law -gates/chip 18 months; 59% / yr. Optical fiber - bps/fiber 12 months; 100% / yr. Packet switching - $/bps 12 months; 100% / yr. Basic demand Traffic doubling time Internet users 12 months; 100% / yr. Data bits 7.5 months; 300% / yr. Internet core 4 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: 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: 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

Paradigm Shift New business model
Network Service Paradigm Shift New business model

Biggest Driving Factor: Internet Traffic
Growth assumes more real-time services including multicast Users (Millions) Usage Sizes (KB) Annual Packet Traffic (Billion Packets) 5000 200 ,000 5,000x 4, ,000x 40x 35 5 50 1000 1 25 1990 1995 2000e Web Home-Page Surfing** Web,Video Infomercial Usage*** 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

Internet’s Exponential Growth & Changes

Potential Competitors
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
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
Potential Competitors AT&T 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
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 Applications provide the Network Services
Enterprise Protocol IP / IPX / SNA Enterprise Transport Ethernet ATM / FDDI / TR Conventional Voice (PBXs & phones) Access Edge Core Access: Physical Cable xDSL / ISDN SONET / SDH Satellite / Wireless Analog IP / ATM Frame Relay Access: Protocol Users want choice and interoperability TeleComm / Cable / Wireless provides the Access and the Transport Applications provide the Network Services Internet provides Network Intelligence

Network Convergence Wireless Service Specific Vertical Integration
Video Voice SNA TDM RAS Core Core Wireless Voice ISDN Data EDGE Service Specific Vertical Integration from Access to Core Deregulation Technology The Internet Global Commerce Core Frame Relay Data FTTx HFC EDGE IP ATM Voice Voice Copper Core Core VPN Video Intranet Data Data Any access technology on a Common Edge/Core Architecture offers great flexibility while reducing cost

Service & Content Revenue Trends
Private Services Public Services Frame Relay, Cell Relay Leased Line Services VPN Services Internet Managed Intranets Electronic Commerce Content Increasing Value Functional Differentiation Quality and Cost 1997 7% 3% 20% 25% 45% 2000 10% 25% 30% Relative income from basic services decreasing - value added services key to profitability

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
Why do some succeed & some fail ?

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 1969 1973 1979 1981 1982 1986 1987 1990 1989 1991 1992 1994 1996 1995 1993 1988 1985 1983 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

Cost Functionality Time to Market Market Tradeoffs
Winner == Right Product at the Right Time at the Right Cost

Strategies and Corresponding Value Propositions
Market Segment Vendor-Created Market-Created 1 3 Innovative Breakthrough Evolution Product 2 4 Replicative Differentiation Reposition

Broadband Network Market
Corporate SBU Division Department 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

LAN vs. WAN

Need more Functionality (VLAN, Multicast, Routing, etc.)
Bridge vs Router Bridge Router Need for Lower Cost, Higher Bandwidth Ethernet Switch Need more Functionality (VLAN, Multicast, Routing, etc.) 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) 4 4 9

LAN Standards IEEE 802.2 LLC Data Link Layer MAC PHY 802.3 CSMA /CD
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 Frame Switch Ethernet IP Frame Switch Ethernet
10 / 100 Ethernet Access Gigabit Ethernet Backbone Frame Ethernet IP Cell Cell Switch IP IP Edge Hub IP Switch Backbone IFMP, GSMP, TDP Frame Ethernet IP Cell ATM Cell Switch ATM ATM Edge Hub IPOA, LANE, MPOA ATM Switch Backbone Frame Cell ATM Cell Switch ATM CIF Edge Hub ATM Switch Backbone Cell Switch ATM Cell Switch ATM ATM Edge Switch ATM Switch Backbone

IP Switching Model Integrated Routing Layered
3. Multi-Layer Switching Model (Tag Switching, MPLS) 2. Integrated Model (IP Switching) 1. Overlay Model (MPOA) Simplified addressing, Separate routing (NA) Subnet Addressing Peer Addressing

A Taxonomy of IP Switching Solutions
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. IP WDM ATM SONET Provides reliability, provisioning Very Uneasy Match Very Simple Match Provides cost breakthroughs in bandwidth.

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 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

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
100 Mbps Ethernet 1. Big Payoff ? 2. Investment Protection ? 3. Low Risk ? Yes 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 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
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

Introduction to various network devices IP Switching Tag Switching
Network Backgrounder Introduction to various network devices IP Switching Tag Switching

Today’s Dominant Network Model
B B R H B H B R R 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

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
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
“Best Effort” “Guaranteed” Next Generation Network Datagram Integrated Overlay 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 Base Technology ATM Switch Protocol ATM + rest Routing Hops 0 or 1 Pros Guaranteed QoS Virtual networking Multi-service Cons Complexity Forklift upgrade

Performance is optimized within a device; best-effort delivery
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
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

Performance is optimized end-to-end; Guaranteed QoS delivery
The “Overlay” Model S One-arm Router E “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
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 “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

There are 2 Alternatives for Addressing ATM Switches and Routers
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.

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

What it use to be ? What it has become. What is the key ?
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 - 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 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 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 …
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 ...
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
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
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 ?
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

IP Switch -- Concept IP Switch IP Switch Gateway IP Switch Gateway
IP Switch Controller Ipsilon Flow Management Protocol Ipsilon Flow Management Protocol CCL ITRI Ethernet to ATM Switching Hub EAS SYSTEM STATUS ATM STATUS ETHERNET STATUS LINE DETECT Rx LE Tx A2E E2A Rx SIGNAL Tx Rx COL Tx P1 P2 P3 P4 P5 P6 P7 P8 POWER RUN/DIAG CCL ITRI Ethernet to ATM Switching Hub EAS SYSTEM STATUS ATM STATUS ETHERNET STATUS LINE DETECT Rx LE Tx A2E E2A Rx SIGNAL Tx Rx COL Tx P1 P2 P3 P4 P5 P6 P7 P8 POWER RUN/DIAG General Switch Management Protocol ATM 155 Mbps ATM 155 Mbps ATM 155 Mbps ATM Switch 23 28 23

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 11 11 29

Ipsilon Protocols GSMP - General Switch Management Protocol
ATM IP Switch IP Switch Controller GSMP Upstream Node ATM Switch Downstream Node IFMP IFMP IFMP - Ipsilon Flow Management Protocol Protocol between multiple IP Switches or hosts Less than lines of code Protocol used to send flow redirection messages 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 13 30 13

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. Flow-Oriented Traffic FTP data Telnet HTTP Web Image downloads Multimedia audio/video 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 Short-lived Traffic Name Look-ups (DNS) Simple Mail - SMTP POP SNMP 5 31 5

IP Switch Operations ATM IP Switch ATM IP Switch ATM IP Switch
Upstream Node Downstream ATM IP Switch ATM Switch IP Switch Controller Upstream Node Downstream ATM IP Switch ATM Switch IP Switch Controller (IFMP) (vpi/vci = 0/15) Upstream Node Downstream ATM IP Switch ATM Switch IP Switch Controller Upstream Node Downstream ATM IP Switch ATM Switch IP Switch Controller (IFMP) GSMP 18 18 32

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 IP Switch OC-3 OC-3 OC-3 IP Switch IP Switch OC-3 OC-3 OC-3 Gateway IP Switch IP Switch IP Switch IP Switch FDDI Gateway Gateway Gateway Conventional Router 10 Mbps 100 Mbps 10 Mbps 100 Mbps 10 Mbps 100 Mbps 27 33 25

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
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
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) Switch

MPLS (Tag) Switching Overview
Tag Distribution Protocol Tag Switches (ATM Switch or Router) Existing Routing Protocol Tag Edge Router

MPLS (Tag) Switching Example

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 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
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
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

Route Accelerator

Router Accelerator IP Forwarding Switch Router Router

Route Accelerator — Advantages
No Infrastructure Impact Reduced Price Increased Performance Maximum Scalability Implementation Cost No new protocols 1/10th of router price ($500 vs. 5,000/100M port) 10~20x Boost Routing protocols - not Spanning Tree A little higher than LAN 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 Intra-Subnet Communication
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
1 to destination IP: BB Test under Mask: false 2 IP Forwarding Switch Network Ports Router Ports 3 4 DA2 SA2 FF aa AA ?? RR port 4 FF aa AA ?? RR (ARP_Req) Router source Ethernet address (SA3) source IP address (SIP) destination Ethernet address (DA3) destination IP address (DIP) (ARP_Res) aa rr AA RR HOST ARP cache IP MAC port 4 BB rr rr aa AA BB port 4 HOST send a packet Router (IP Pkt) cc rr AA BB IP MACsub port IP Forwarding Switch IP cache port 3 BB cc 3

Route Once, Switch Many switching routing IP Forwarding Switch Router Inter-Subnet traffic: Switched rather than Routed

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 Forwarding 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
IN-BAND route refresh 4 3 2 1 3 IP Forwarding Switch Router 1 2 4 OUT-BAND route refresh 4 3 2 1 null IP Forwarding Switch Router 1 2 3 4

Cells-in-Frame

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 Multiple ATM Cells w/ Same VC ATM Hdr Ethernet Hdr

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 Ethernet Switch
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
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
Inexpensive and ubiquitous Uses existing Ethernet adapters (saves $$) Large installed Ethernet base (add new ATM software) Cost (CIF Cost (Ethernet switches) Provides ATM functionality right away. Guaranteed QoS over standard Ethernet (new services) Allows voice over Ethernet (saves $$) Allows flow / congestion control (better than TCP/IP)

Potential Disadvantages of CIF
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

LE Configuration Server
LAN Emulation Model LE Configuration Server LECS LE Client (LEC) Data Forwarding Broadcast & Unknown Server (BUS) Initialization Registration Address Resolution LE Server (LES) ATM Server ATM LE Client (LEC) Network Bridge Data Forwarding Broadcast & Unknown Server (BUS) Initialization Registration Address Resolution LE Server (LES) Legacy LANs LUNI LE Client (LEC) ATM Server 15

LE Service Components LE Client (LEC) LE Server (LES)
* provide a MAC level emulated IEEE 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 16

LUNI Protocol Overview
Initialization Configuration Joining Registration and BUS Initialization Data Movement 17

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 18

Configuration LEC provides: LECS returns: ATM address MAC address
LAN types and frame sizes requested LECS returns: LES address LAN type and frame size to use 19

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 20

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 21

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 22

LEC Connections across LUNI
Workstation LEC Bridge LEC Config Direct VCC LECS Config Direct VCC Control Direct VCC LES Control Direct VCC Control Distribute VCC Multicast Send VCC Multicast Send VCC BUS Legacy LAN Multicast Forward VCC Data Direct VCC 23

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 24

LE_ARP Flow LEC 1 LES 2 A 1, 4 3 3, 5 4 Network 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 25

Message Flow / ATM to ATM
Control direct VCC Multicast send VCC Multicast forward VCC Signalling Data direct VCC LES 4a, 4b 3a, 3b 1 IP A MAC A ATM A 2, 4 2, 4 IP B MAC B ATM B ES A BUS 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 26

Switch Router Design & Implementation

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