Outlines Received due 13 March %

Homework n Review for Midterm (1 March 2000) n Research Paper n Readings [5] “Virtual Private Networks” [6] “Internet QoS: A Big Picture” [7] “IP Routers: New Tool for Gigabit Networking” [8] “Corporate-Class Internet? Don’t Count on It!”

Bridge n Operates at OSI Layers 1 & 2 Follows MAC n Uses MAC addresses to switch packets n May be capable of minor protocol conversions n If properly placed will improve performance u Filters unneccesary traffic u Improves Efficiency u Increases average Bandwidth to each end user u Tends to increase delay across the bridge

Router n Operates at OSI Layers 1, 2, & 3 n capable of making complex routing decisions ‘peers into’ packets n Very useful on Large Networks with multiple end-to-end paths

Switched Hub n ASK VENDOR!!! n May be a multi-port bridge n May route (OSI Layer 3) first packet of a flow (OSI Layer 5), bridge (OSI Layer 2) remainder

The Internet n VAST collection of interconnected networks n Key Building Block: Routers running IPv4 (Layer 3) n Router link speeds range from 56 Kbps to 2.5 Gbps n Hierarchical Addressing

ISO OSI Seven Layer Model n Layer 7 Application Netscape n Layer 6 Presentation Win95 (API) n Layer 5 Session Win95 (TCP) n Layer 4 Transport Win95 (TCP) n Layer 3 Network Win95 (IP) n Layer 2 Data Link 3Com NIC n Layer 1 Physical 3Com NIC

Internet Service Provider Backbone ISP ‘Cloud’ Trunks use StatMux & Packet Switching Router Trunks Leased Line

11Feb00 Traceroute to n 3 Internal OSU routers n 2 OneNet routers border3-okc-oc3atm.onenet.net n 4 SBC routers edge1-fa0-0-0.okcyok.swbell.net n 2 Williams routers williams1-oc3-gr1.dal2.dbn.net n 7 BBNPlanet routers p1-0.lsanca1-br1.bbnplanet.net p7-3.paloalto-nbr2.bbnplanet.net\ n 2 Cisco routers

11Feb00 Traceroute to LABRATS.COM n 3 Internal OSU routers n 2 OneNet routers u OKC n 7 Williams Routers u OKC u Dallas u Tulsa n 1 Labrat Router

Virtual Circuits n Routing decisions made once when circuit is set up n All packets part of info transfer follow the same path n Frame Relay & ATM use Virtual Circuits n Allows switch resources (buffer space, bandwidth) to be set aside for specific traffic flows

Datagrams n Routing decisions are made “on the fly” multiple times (every time a packet hits a Router) n Packets may follow different paths n IP uses Datagrams n Routers get no ‘advance warning’ of packet flows.

What works* on the Internet? n Non Real Time Data Services Usenet Fax n Interactive Data Based Services File Transfer Protocol Telnet World Wide Web Excellent Good *Provided you’re not trying to sip bandwidth through a straw.

What works* on the Internet? n Interactive Data Based Services White Boarding Application Sharing n Non-Interactive One-Way Audio n Interactive Two-Way Audio n One way motion video n Interactive motion Video Fair Poor *Provided you’re not trying to sip bandwidth through a straw.

TCP, UDP, and IP n 20 year old Protocols Designed for data One Priority & “Best Effort” services No QoS Guarantees Available bandwidth depends on other users n TCP (Layer 4 & 5) provides reliable transfer n UDP (Layer 4 & 5) provides unreliable transfer

Interactive Telephony over the INTERNET “... is a toy until delay and voice-quality problems are overcome” Network World, 19 August 1996 “... is a toy until delay and voice-quality problems are overcome” Network World, 19 August 1996

Interactive VOICE & VIDEO over the INTERNET n Is not ready for Prime Time n Delay & Quality problems not likely to be solved under the current system... n...although throwing Bandwidth at the problem will alleviate n Has a place for the user whose main concern is $$$$ or convenience

Thinking of moving time sensitive traffic over the Internet? Check back in 2-3 years when... n Priorities Enabled (IPv6 and/or DiffServ) n Resources Guaranteed (Resource Reservation Protocol (RSVP) or equivalent is deployed) n Flat rate pricing is gone

Pros of Using the Internet n Any-to-Any Connectivity n It’s Inexpensive (save $$$$) n Tons of valuable information available n Excellent marketing/sales tool

Cons of Using the Internet n Any-to-Any Connectivity puts all attached machines at risk n Slightly higher risk of Theft of Traffic n Tons of Worthless Information Available n No QoS guarantees or Guaranteed Bandwidth May have trouble rapidly moving large files May have trouble reliably moving time sensitive traffic WARNING: SECURITY HAZARD!

Worldwide ISP Revenues $1.35B ‘95$2.40B ‘96$5.28B ‘97 $8.42B ‘98 $12.10B ‘99 $0.19B ‘94 Source: Data Communications

Internet Performance 0% 100% Trunk Offered Load Probability of dropped packets Average Delay for delivered packets

Backbone Engineering n Option A) Deploy ‘best effort’ Routers Rapidly Deploy Trunk Bandwidth Keep Trunks Lightly Loaded u Delays will be small u Dropped packets will be few u Quality fine for Interactive Voice/Video

Backbone Engineering n Option B) Deploy more expensive QoS enabled Routers Deploy fewer, more heavily loaded Trunks Give preferential treatment to Voice/Video n Which is less expensive in the long run?

Connectionless vs. Connection Oriented n Connectionless * Packet delivery may be out of order * Packet delivery NOT guaranteed * Packets may be mangled * End User’s responsibility to fix any problems n Connection Oriented * Packet delivery in order * Packet delivery usually guaranteed