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The Intersection of Grids and Networks: Where the Rubber Hits the Road

The Intersection of Grids and Networks: Where the Rubber Hits the Road. William E. Johnston ESnet Manager and Senior Scientist Lawrence Berkeley National Laboratory. Objectives of this Talk. How a production R&E network works

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The Intersection of Grids and Networks: Where the Rubber Hits the Road

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  1. The Intersection of Grids and Networks:Where the Rubber Hits the Road William E. JohnstonESnet Manager and Senior Scientist Lawrence Berkeley National Laboratory

  2. Objectives of this Talk • How a production R&E network works • Why some types of services needed by Grids / widely distributed computing environments are hard

  3. Outline • How do Networks Work? • Role of the R&E Core Network • ESnet as a Core Network • ESnet Has Experienced Exponential Growth Since 1992 • ESnet is Monitored in Many Ways • How Are Problems Detected and Resolved? • Operating Science Mission Critical Infrastructure • Disaster Recovery and Stability • Recovery from Physical Attack / Failure • Maintaining Science Mission Critical Infrastructurein the Face of Cyberattack • Services that Grids need from the Network • Public Key Infrastructure example

  4. How Do Networks Work? • Accessing a service, Grid or otherwise, such as a Web server, FTP server, etc., from a client computer and client application (e.g. a Web browser_ involves • Target host names • Host addresses • Service identification • Routing

  5. How Do Networks Work? • When one types “google.com” into a Web browser to use the search engine, the following takes place • The name “google.com” is resolved to an Internet address by the Domain Name System (DNS) – a hierarchical directory service • The address is attached to a network packet (which carries the data – a google search request in this case) which is then sent out of the computer into the network • The first place that the packet reaches is a router that must decide how to get that packet to its desitnatiion (google.com)

  6. How Do Networks Work? • In the Internet, routing is done “hot potato” • Routers are in your site LANs and at your ISP, and each router typically communicates directly with several other routers • The first router to receive your packet takes a quick look at the address and says, if I send this packet to router B that will probably take it closer to its destination. So it sends it to B without further adieu. • Router B does the same thing, and so forth, until the packet reaches google.com • What makes this work is routing protocols that exchange reachability information between all directly connected routers – “BGP” is the most common such protocol in WANs

  7. How Do Networks Work? • Once the packet reaches its destination (the computer called google.com) it must be delivered to the google search engine, as opposed to the google mail server that may be running on the same machine. • This is accomplished with a service identifier that is put on the packet by the browser (the client side application) • The service identifier says that this packet is to be delivered to the Web server on the destination system – on each system every server/service has a unique identified called a “port number” • So when someone says that the Blaster/Lovsan worm is attacking port 135 on the system called google.com, they mean that a worm program somewhere in the Internet is trying to gain access to the service at port 135 on google.com (usually to exploit a vulnerability).

  8. Role of the R&E Core Network: Transit (Deliver Every Packet) • core routers • focus on high-speed packet forwarding LBNL ESnet (Core network) router core router router • peering routers • implement/enforce routing policy for each provider • provide cyberdefense border router core router gateway router peering router • border/gateway routers • implement separate site and network provider policy (including site firewall policy) peeringrouter Big ISP(e.g. SprintLink) router router router router router Google, Inc. router

  9. Outline • How do Networks Work? • Role of the R&E Core Network • ESnet as a Core Network • ESnet Has Experienced Exponential Growth Since 1992 • ESnet is Monitored in Many Ways • How Are Problems Detected and Resolved? • Operating Science Mission Critical Infrastructure • Disaster Recovery and Stability • Recovery from Physical Attack / Failure • Maintaining Science Mission Critical Infrastructurein the Face of Cyberattack • Services that Grids need from the Network • Public Key Infrastructure example

  10. What is ESnet • ESnet is a large-scale, very high bandwidth network providing connectivity between DOE Science Labs and their science partners in the US, Europe, and Japan • Essentially all of the national data traffic supporting US open science is carried by two networks – ESnet and Internet-2 / Abilene (which plays a similar role for the university community) • ESnet is very different from commercial ISPs (Internet Service Providers) like Earthlink, AOL, etc. • Most big ISPs provide small amounts of bandwidth to a large number of sites • ESnet supplies very high bandwidth to a small number of sites

  11. ESnet Connects DOE Facilities and Collaborators GEANT - Germany - France - Italy - UK - etc. Sinet (Japan) Japan – Russia(BINP) CA*net4 KDDI (Japan) France Switzerland Taiwan (TANet2) Australia CA*net4 Taiwan (TANet2) Singaren PNNL NERSC SLAC BNL ANL MIT INEEL LIGO LBNL LLNL SNLL JGI TWC Starlight GTN&NNSA 4xLAB-DC ANL-DC INEEL-DC ORAU-DC LLNL/LANL-DC JLAB PPPL AMES FNAL ORNL SRS LANL SNLA DOE-ALB PANTEX SDSC ORAU NOAA OSTI ARM ALB HUB YUCCA MT BECHTEL GA Allied Signal KCP ELP HUB DC HUB ATL HUB NYC HUB CHI HUB NREL SNV HUB CA*net4 CERN MREN Netherlands Russia StarTap Taiwan (ASCC) PNWG SEA HUB ESnet IP Abilene Japan Abilene Chi NAP NY-NAP QWEST ATM Abilene MAE-E SNV HUB PAIX-E MAE-W Fix-W PAIX-W Euqinix Abilene 42 end user sites Office Of Science Sponsored (22) International (high speed) OC192 (10G/s optical) OC48 (2.5 Gb/s optical) Gigabit Ethernet (1 Gb/s) OC12 ATM (622 Mb/s) OC12 OC3 (155 Mb/s) T3 (45 Mb/s) T1-T3 T1 (1 Mb/s) NNSA Sponsored (12) Joint Sponsored (3) Other Sponsored (NSF LIGO, NOAA) Laboratory Sponsored (6) ESnet core ring: Packet over SONET Optical Ring and Hubs peering points ESnet hubs

  12. RTR RTR RTR RTR RTR RTR Current Architecture ESnet site site LAN Site – ESnet network policy demarcation (“DMZ”) Site IP router ESnet IP router ESnet hub • Wave division multiplexing • today typically 64 x 10 Gb/s optical channels per fiber • channels (referred to as “lambdas”) are usually used in bi-directional pairs • Lambda channels are converted to electrical channels • usually SONET data framing or Ethernet data framing • can be clear digital channels (no framing – e.g. for digital HDTV) 10GE 10GE ESnet core optical fiber ring A ring topology network is inherently reliable – all single point failures are mitigated by routing traffic in the other direction around the ring.

  13. Peering – ESnet’s Logical Infrastructure –Connects the DOE Community With its Collaborators NY-NAP STARLIGHT CHI NAP EQX-SJ EQX-ASH PAIX-E MAE-E GA CA*net4 CERN MREN Netherlands Russia StarTap Taiwan (ASCC) Australia CA*net4 Taiwan (TANet2) Singaren GEANT - Germany - France - Italy - UK - etc SInet (Japan) KEK Japan – Russia (BINP) KDDI (Japan) France PNW-GPOP SEA HUB 2 PEERS Distributed 6TAP 19 Peers Abilene Japan 1 PEER CalREN2 NYC HUBS 1 PEER LBNL Abilene + 7 Universities SNV HUB 5 PEERS Abilene 2 PEERS PAIX-W 26 PEERS MAX GPOP MAE-W 22 PEERS 39 PEERS 20 PEERS FIX-W 6 PEERS 3 PEERS LANL CENIC SDSC Abilene ATL HUB TECHnet ESnet provides complete access to the Internet by managing the full complement of Global Internet routes (about 150,000) at 10 general/commercial peering points + high-speed peerings w/ Abilene and the international networks. Commercial ESnet Peering (connections to other networks) University International Commercial

  14. What is Peering? • Peering points exchange routing information that says “which packets I can get closer to their destination” • ESnet daily peeringreport(top 20 of about 100) • This is a lot of work peering with this outfitis not random, it carriesroutes that ESnet needs(e.g. to the Russian Backbone Net)

  15. What is Peering? • Why so many routes? So that when I want to get to someplace out of the ordinary, I can get there. For example:http://www-sbras.nsc.ru/eng/sbras/copan/microel_main.html (Technological Design Institute of Applied Microelectronics of SB RAS 630090, Novosibirsk, Russia)

  16. ESnet is Engineered to Move a Lot of Data ESnet is currently transporting about 250 terabytes/mo. ESnet Monthly Accepted Traffic TBytes/Month Annual growth in the past five years has increased from 1.7x annually to just over 2.0x annually.

  17. Who Generates Traffic, and Where Does it Go? ESnet Inter-Sector Traffic Summary,Jan 2003 / Feb 2004 (1.7X overall traffic increase, 1.9X OSC increase)(the international traffic is increasing due to BABAR at SLAC and the LHC tier 1 centers at FNAL and BNL) 72/68% 21/14% Commercial DOE is a net supplier of data because DOE facilities are used by universities and commercial entities, as well as by DOE researchers 14/12% ESnet ~25/18% 17/10% R&E (mostlyuniversities) DOE sites 10/13% Peering Points 53/49% 9/26% International DOE collaborator traffic, inc.data 4/6% Note that more that 90% of the ESnet traffic is OSC traffic ESnet Appropriate Use Policy (AUP) All ESnet traffic must originate and/or terminate on an ESnet an site (no transit traffic is allowed) Traffic coming into ESnet = Green Traffic leaving ESnet = Blue Traffic between sites % = of total ingress or egress traffic

  18. ESnet Top 20 Data Flows, 24 hrs., 2004-04-20 A small number of science users account for a significant fraction of all ESnet traffic SLAC (US)  IN2P3 (FR) 1 terabyte/day Fermilab (US) CERN SLAC (US) INFN Padva (IT) Fermilab (US)  U. Chicago (US) U. Toronto (CA)  Fermilab (US) CEBAF (US)  IN2P3 (FR) INFN Padva (IT)  SLAC (US) DFN-WiN (DE)  SLAC (US) Fermilab (US)  JANET (UK) SLAC (US)  JANET (UK) DOE Lab  DOE Lab Argonne (US)  Level3 (US) DOE Lab  DOE Lab Fermilab (US)  INFN Padva (IT) Argonne  SURFnet (NL) IN2P3 (FR)  SLAC (US)

  19. Top 50 Traffic Flows Monitoring – 24hr – 1 Int’l Peering Point 10 flows> 100 GBy/day More than 50 flows> 10 GBy/day

  20. Scalable Operation is Essential • R&E networks typically operate with a small staff • The key to everything that the network provides is scalability • How do you manage a huge infrastructure with a small number of people? • This issue dominates all others when looking at whether to support new services (e.g. Grid middleware) • Can the service be structured so that its operational aspects do not scale as a function of the use population? • If not, then it cannot be offered as a service

  21. Scalable Operation is Essential • The entire ESnet network is operated by fewer than 15 people Core Engineering Group (5 FTE) 7X24 On-Call Engineers (7 FTE) Science Services(middleware andcollaboration tools) (5 FTE) 7X24 Operations Desk (2-4 FTE) Management, resource management,circuit accounting, group leads (4 FTE) Infrastructure (6 FTE)

  22. Automated, real-time monitoring of traffic levels and operating state of some 4400 network entities is the primary network operational and diagnosis tool Network Configuration Performance OSPF Metrics (internalrouting and connectivity) SecureNet IBGP Mesh (WAN routing and connectivity) Hardware Configuration

  23. How Are Problems Detected and Resolved? GEANT - Germany - France - Italy - UK - etc Sinet (Japan) Japan – Russia(BINP) CA*net4 KDDI (Japan) France Switzerland Taiwan (TANet2) Australia CA*net4 Taiwan (TANet2) Singaren PNNL SEA HUB NERSC SLAC Brandeis Nevis Yale MIT BNL ANL LIGO INEEL LBNL LLNL SNLL TWC JGI GTN&NNSA 4xLAB-DC ANL-DC INEEL-DC ORAU-DC LLNL/LANL-DC FNAL AMES JLAB PPPL ORNL SRS LANL SNLA DOE-ALB PANTEX SDSC NOAA ORAU OSTI ARM ALB HUB YUCCA MT BECHTEL GA SNV HUB Allied Signal Allied Signal ELP HUB ATL HUB DC HUB CHI HUB NYC HUB NREL When a hardware alarm goes off here, the 24x7 operator is notified CA*net4 CERN MREN Netherlands Russia StarTap Taiwan (ASCC) ESnet IP Japan QWEST ATM International (high speed) OC192 (10G/s optical) OC48 (2.5 Gb/s optical) Gigabit Ethernet (1 Gb/s) OC12 ATM (622 Mb/s) OC12 OC3 (155 Mb/s) T3 (45 Mb/s) T1-T3 T1 (1 Mb/s)

  24. ESnet is Monitored in Many Ways ESnet configuration Performance OSPF Metrics SecureNet Hardware Configuration IBGP Mesh

  25. Drill Down into the Configuration DB to Operating Characteristics of Every Device e.g. cooling air temperature for the router chassis air inlet, hot-point, and air exhaust for the ESnet gateway router at PNNL

  26. Problem Resolution • Let’s say that the diagnoistics have pinpointed a bad module in a router rack in the ESnet hub in NYC • Almost all high-end routers, and other equipment that ESnet uses, have multiple, redundant modules for all critical functions • Failure of a module (e.g. a power supply or a control computer) can be corrected on-the-fly, without turning off the power or impacting the continued operation of the router • Failed modules are typically replaced by a “smart hands” service at the hubs or sites • One of the many essential scalability mechanisms

  27. ESnet is Monitored in Many Ways ESnet configuration Performance OSPF Metrics SecureNet Hardware Configuration IBGP Mesh

  28. Drill Down into the Hardware Configuration DBfor Every Wire Connection Equipment rack detail at AOA, NYC Hub(one of the10 Gb/s core optical ring sites)

  29. The Hub Configuration Database • Equipment wiring detail for two modules at the AOA, NYC Hub • This allows “smart hands” – e.g., Qwest personnel at the NYC site – to replace modules for ESnet)

  30. What Does this Equipment Actually Look Like? Equipment rack detail at NYC Hub, 32 Avenue of the Americas (one of the 10 Gb/s core optical ring sites) Picture detail

  31. Typical Equipment of an ESnet Core Network Hub Qwest DS3 DCX Sentry power 48v 30/60 amp panel ($3900 list) AOA Performance Tester ($4800 list) Sentry power 48v 10/25 amp panel ($3350 list) DC / AC Converter ($2200 list) Cisco 7206 AOA-AR1 (low speed links to MIT & PPPL) ($38,150 list) Lightwave Secure Terminal Server ($4800 list) ESnet core equipment @ Qwest 32 AofA HUB NYC, NY (~$1.8M, list) Juniper T320 AOA-CR1 (Core router) ($1,133,000 list) Juniper OC192 Optical Ring Interface (the AOA end of the OC192 to CHI ($195,000 list) Juniper OC48 Optical Ring Interface (the AOA end of the OC48 to DC-HUB ($65,000 list) Juniper M20 AOA-PR1 (peering RTR) ($353,000 list)

  32. Outline • How do Networks Work? • Role of the R&E Core Network • ESnet as a Core Network • ESnet Has Experienced Exponential Growth Since 1992 • ESnet is Monitored in Many Ways • How Are Problems Detected and Resolved? • Operating Science Mission Critical Infrastructure • Disaster Recovery and Stability • Recovery from Physical Attack / Failure • Maintaining Science Mission Critical Infrastructurein the Face of Cyberattack • Services that Grids need from the Network • Public Key Infrastructure example

  33. Operating Science Mission Critical Infrastructure • ESnet is a visible and critical piece of DOE science infrastructure • if ESnet fails,10s of thousands of DOE and University users know it within minutes if not seconds • Requires high reliability and high operational security in the systems that are integral to the operation and management of the network • Secure and redundant mail and Web systems are central to the operation and security of ESnet • trouble tickets are by email • engineering communication by email • engineering database interfaces are via Web • Secure network access to Hub routers • Backup secure telephone modem access to Hub equipment • 24x7 help desk and 24x7 on-call network engineer trouble@es.net (end-to-end problem resolution)

  34. BNL LBNL TWC PPPL AMES ELP HUB SNV HUB CHI HUB NYC HUBS DC HUB ATL HUB SEA HUB ALB HUB Disaster Recovery and Stability • Engineers, 24x7 Network Operations Center, generator backed power • Spectrum (net mgmt system) • DNS (name – IP address translation) • Eng database • Load database • Config database • Public and private Web • E-mail (server and archive) • PKI cert. repository and revocation lists • collaboratory authorization service • Remote Engineer • partial duplicate infrastructure DNS Remote Engineer Duplicate Infrastructure Currently deploying full replication of the NOC databases and servers and Science Services databases in the NYC Qwest carrier hub • Remote Engineer • partial duplicate infrastructure • The network must be kept available even if, e.g., the West Coast is disabled by a massive earthquake, etc. • high physical security for all equipment • non-interruptible core - ESnet core operated without interruption through • N. Calif. Power blackout of 2000 • the 9/11/2001 attacks, and • the Sept., 2003 NE States power blackout • Reliable operation of the network involves • remote Network Operation Centers (3) • replicated support infrastructure • generator backed UPS power at all critical network and infrastructure locations

  35. Recovery from Physical Attack / Core Ring Failure normal traffic flow We can route traffic either way around the ring, so any single failure in the ring is transparent to ESnet users New York (AOA) X reversed traffic flow Chicago (CHI) break in the ring Washington, DC (DC) The Hubs have lots of connections(42 in all) ESnet backbone(optical fiber ring) Atlanta (ATL) Sunnyvale (SNV) El Paso (ELP) The local loops are still single points of failure Hubs(backbone routers and local loop connection points) Local loop (Hub to local site) Site gateway router ESnet border router SiteLAN DMZ Site

  36. Maintaining Science Mission Critical Infrastructurein the Face of Cyberattack • A Phased Security Architecture is being implemented to protects the network and the ESnet sites • The phased response ranges from blocking certain site traffic to a complete isolation of the network which allows the sites to continue communicating among themselves in the face of the most virulent attacks • Separates ESnet core routing functionality from external Internet connections by means of a “peering” router that can have a policy different from the core routers • Provide a rate limited path to the external Internet that will insure site-to-site communication during an external denial of service attack • Provide “lifeline” connectivity for downloading of patches, exchange of e-mail and viewing web pages (i.e.; e-mail, dns, http, https, ssh, etc.) with the external Internet prior to full isolation of the network

  37. Cyberattack Defense ESnet third response – shut down the main peering paths and provide only limited bandwidth paths for specific “lifeline” services ESnet first response – filters to assist a site ESnet second response – filter traffic from outside of ESnet peeringrouter X X router ESnet router LBNL attack traffic router X borderrouter • Lab first response – filter incoming traffic at their ESnet gateway router gatewayrouter peeringrouter border router Lab gatewayrouter Lab • Sapphire/Slammer worm infection created a Gb/s of traffic on the ESnet core until filters were put in place (both into and out of sites) to damp it out.

  38. ESnet WAN Security and Cybersecurity • Cybersecurity is a new dimension of ESnet security • Security is now inherently a global problem • As the entity with a global view of the network, ESnet has an important role in overall security 30 minutes after the Sapphire/Slammer worm was released, 75,000 hosts running Microsoft's SQL Server (port 1434) were infected. (“The Spread of the Sapphire/Slammer Worm,” David Moore (CAIDA & UCSD CSE), Vern Paxson (ICIR & LBNL), Stefan Savage (UCSD CSE), Colleen Shannon (CAIDA), Stuart Staniford (Silicon Defense), Nicholas Weaver (Silicon Defense & UC Berkeley EECS) http://www.cs.berkeley.edu/~nweaver/sapphire ) Jan., 2003

  39. ESnet and Cybersecurity Sapphire/Slammer worm infection hits creating almost a full Gb/s (1000 megabit/sec.) traffic spike on the ESnet backbone

  40. Outline • Role of the R&E Transit Network • ESnet is Driven by the Requirements of DOE Science • Terminology – How Do Networks Work? • How Does it Work? – ESnet as a Backbone Network • ESnet Has Experienced Exponential Growth Since 1992 • ESnet is Monitored in Many Ways • How Are Problems Detected and Resolved? • Operating Science Mission Critical Infrastructure • Disaster Recovery and Stability • Recovery from Physical Attack / Failure • Maintaining Science Mission Critical Infrastructurein the Face of Cyberattack • Services that Grids need from the Network • Public Key Infrastructure example

  41. Network and Middleware Needs of DOE Science August 13-15, 2002 Organized by Office of Science Mary Anne Scott, Chair Dave Bader Steve Eckstrand Marvin Frazier Dale Koelling Vicky White Workshop Panel Chairs Ray Bair and Deb Agarwal Bill Johnston and Mike Wilde Rick Stevens Ian Foster and Dennis Gannon Linda Winkler and Brian Tierney Sandy Merola and Charlie Catlett • Focused on science requirements that drive • Advanced Network Infrastructure • Middleware Research • Network Research • Network Governance Model • The requirements for DOE science were developed by the OSC science community representing major DOE science disciplines • Climate • Spallation Neutron Source • Macromolecular Crystallography • High Energy Physics • Magnetic Fusion Energy Sciences • Chemical Sciences • Bioinformatics • Available at www.es.net/#research

  42. Grid Middleware Requirements (DOE Workshop) • A DOE workshop examined science driven requirements for network and middleware and identified twelve high priority middleware services (see www.es.net/#research) • Some of these services have a central management component and some do not • Most of the services that have central management fit the criteria for ESnet support. These include, for example • Production, federated RADIUS authentication service • PKI federation services • Virtual Organization Management services to manage organization membership, member attributes and privileges • Long-term PKI key and proxy credential management • End-to-end monitoring for Grid / distributed application debugging and tuning • Some form of authorization service (e.g. based on RADIUS) • Knowledge management services that have the characteristics of an ESnet service are also likely to be important (future)

  43. Grid Middleware Services • ESnet provides several “science services” – services that support the practice of science • A number of such services have an organization like ESnet as the natural provider • ESnet is trusted, persistent, and has a large (almost comprehensive within DOE) user base • ESnet has the facilities to provide reliable access and high availability through assured network access to replicated services at geographically diverse locations • However, service must be scalable in the sense that as its user base grows, ESnet interaction with the users does not grow (otherwise not practical for a small organization like ESnet to operate)

  44. Science Services: PKI Support for Grids • Public Key Infrastructure supports cross-site, cross-organization, and international trust relationships that permit sharing computing and data resources and other Grid services • DOEGrids Certification Authority service provides X.509 identity certificates to support Grid authentication provides an example of this model • The service requires a highly trusted provider, and requires a high degree of availability • The service provider is a centralized agent for negotiating trust relationships, e.g. with European CAs • The service scales by adding site based or Virtual Organization based Registration Agents that interact directly with the users • See DOEGrids CA (www.doegrids.org)

  45. Science Services: Public Key Infrastructure • DOEGrids CA policies are tailored to science Grids • Digital identity certificates for people, hosts and services • Provides formal and verified trust management – an essential service for widely distributed heterogeneous collaboration, e.g. in the International High Energy Physics community • This service was the basis of the first routine sharing of HEP computing resources between US and Europe • Have recently added a second CA with a policy that supports secondary issuers that need to do bulk issuing of certificates with central private key management • NERSC will auto issue certs when accounts are set up – this constitutes an acceptable identity verification • A variant of this will also be set up to support security domain gateways such as Kerberos – X509 – e.g. KX509 – at FNAL

  46. Science Services: Public Key Infrastructure • The rapidly expanding customer base of this service will soon make it ESnet’s largest collaboration service by customer count Registration Authorities ANL LBNL ORNL DOESG (DOE Science Grid) ESG (Climate) FNAL PPDG (HEP) Fusion Grid iVDGL (NSF-DOE HEP collab.) NERSC PNNL

  47. Grid Network Services Requirements (GGF, GHPN) • Grid High Performance Networking Research Group, “Networking Issues of Grid Infrastructures” (draft-ggf-ghpn-netissues-3) – what networks should provide to Grids • High performance transport for bulk data transfer (over 1Gb/s per flow) • Performance controllability to provide ad hoc quality of service and traffic isolation. • Dynamic Network resource allocation and reservation • High availability when expensive computing or visualization resources have been reserved • Security controllability to provide a trusty and efficient communication environment when required • Multicast to efficiently distribute data to group of resources. • How to integrate wireless network and sensor networks in Grid environment

  48. Transport Services • network tools available to build services • queue management • provide forwarding priorities different from best effort • e.g. • scavenger (discard if anything behind in the queue) • expedited forwarding (elevated priority queuing) • low latency forwarding (highest priority – ahead of all other traffic) • path management • tagged traffic can be managed separately from regular traffic • policing • limit the bandwidth of an incoming stream

  49. Priority Service: Guaranteed Bandwidth bandwidth 1000 available for elevated priority traffic reserved for production, best effort traffic 0 network pipe bandwidth management model ? bandwidthbroker usersystem1 flag traffic from user system1 forexpedited forwarding site A borderrouter usersystem2 borderrouter site B

  50. ? bandwidthbroker usersystem1 borderrouter usersystem2 borderrouter Priority Service: Guaranteed Bandwidth • What is wrong with this? (almost everything) there may be several users that want all of the premium bandwidth at the same time this is at least three independent networks, and probably more the user may send data into the high priority stream at a high enough bandwidth that it interferes with production traffic (and not even know it) a user that was a priority at site A may not be at site B site A site B

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