150 likes | 247 Views
Network Engineering @ SLAC. S. Luitz, D. Millsom, D. Salomoni, J.Y. Kim, A. Zele. Summary. Introduction Major Issues Network Architecture Performance Retrospective. Introduction. SLAC - Stanford Linear Accelerator Center High Energy Physics Stanford Synchrotron Radiation Laboratory
E N D
Network Engineering @ SLAC S. Luitz, D. Millsom, D. Salomoni, J.Y. Kim, A. Zele CHEP2000 - Padova, February 2000
Summary • Introduction • Major Issues • Network Architecture • Performance • Retrospective CHEP2000 - Padova, February 2000
Introduction • SLAC - Stanford Linear Accelerator Center • High Energy Physics • Stanford Synchrotron Radiation Laboratory • 1300 full-time employees, 700 on-site collaborators • Collaborate with 200 institutions internationally • Mixture of real-time data acquisition, numerical analysis, business services/administration • Very large quantities of data, e.g. 1-2 petabytes/year for the BaBar experiment CHEP2000 - Padova, February 2000
Major Issues • Bandwidth demand doubles every 1.5 years • High reliability and availability requirement, both for experimental work and business services • Network performance requirements dictate use of leading-edge technology • Leading-edge technology challenges reliability • International collaboration dictates need for open network • Security - DOE requirements, open network is more prone to hacking CHEP2000 - Padova, February 2000
Major Issues... • Network services have become so essential that failures can bring organizations to a standstill • They are often more critical than the phone • One reason: critical information (data and applications) has moved into the (often-times central) computer/storage facilities • SLAC: particular issue - very high bandwidth/availability for data acquisition CHEP2000 - Padova, February 2000
Bandwidth Growth CHEP2000 - Padova, February 2000
Network Architecture • Layer one • Star topology • Fiber/Copper • Redundant • Ethernet Full/Half Duplex, 10/100/1000 Mbps • Backbone almost entirely Gigabit Ethernet (with Gigabit EtherChannel) • Islands • BaBar detector/data acquisition • Main Control Center • Business Services • Layer two • Switched VLAN (~45 switches, ~40 VLANs) • Layer three • Centralized routing CHEP2000 - Padova, February 2000
SLAC Switched LAN Spring 2000 Modems, ISDN xDSL Internet DMZ 10BaseT ESA FDDI/CDDI 100BaseFL Old Servers 100BaseT 1Gbit FL DMZ Switch SSRL 4Gbit FL Legacy Concentrator Monitoring Gigaswitch Routers Core Router Switches Switch Hub BSD Netscout 6 Farm edge switches IR2 4 Server switches 20 Building edge switches MCC1 MCC2 MCC3 SSRL BaBar CHEP2000 - Padova, February 2000
External Connections 45 Mb/s 2 Mb/s 155 Mb/s( 622 Mb/s) 622 Mb/s 155 Mb/s CHEP2000 - Padova, February 2000
Performance • A number of tools developed in-house to monitor the status of the network • E.g., port, backplane, CPU utilization, device reachability, L2/L3 traceroute, DMZ traffic statistics • No components are currently approaching saturation CHEP2000 - Padova, February 2000
Retrospective • The network design has proved to be scalable, highly available and provides high bandwidth in a secure environment • Some lessons learned: • be careful with management and configuration of layer-2 switching and spanning trees (e.g., watch for VTP configuration issues) and with CGMP/IGMP multicast support • do not attempt to mix standards (e.g., Cisco ISL and IEEE 803.1Q) even when theoretically possible • adequate security and openness are often conflicting requirements • Open issues: • effective monitoring (e.g., SPAN) and data gathering in a high-speed switched environment • secure SNMP monitoring (SNMPv3 support) and secure access to the network devices (SSH) CHEP2000 - Padova, February 2000