Laser / RF Timing (Engineering of Femtosecond Timing Systems) Josef Frisch SLAC.
Network Engineering @ SLAC
description
Transcript of Network Engineering @ SLAC
CHEP2000 - Padova, February 2000
Network Engineering @ SLAC
S. Luitz, D. Millsom, D. Salomoni, J.Y. Kim, A. Zele
CHEP2000 - Padova, February 2000
Summary
IntroductionMajor IssuesNetwork ArchitecturePerformanceRetrospective
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
DMZ
InternetModems,
ISDNxDSL
SLAC Switched LAN Spring 2000
ESA
Legacy
SSRL
OldServers
MCC3
20 Buildingedge switches
BaBar
MCC2
SSRL
MCC1
10BaseT
FDDI/CDDI
100BaseT
100BaseFL
Gigaswitch
Router
Switch
Hub
1Gbit FL
4Gbit FL
Concentrator
IR26 Farm edge switches
4 Server switches
BSD
DMZ Switch
Netscout
Monitoring
CoreRouters
Switches
CHEP2000 - Padova, February 2000
CHEP2000 - Padova, February 2000
CHEP2000 - Padova, February 2000
External Connections
622 Mb/s
155 Mb/s( 622 Mb/s)
45 Mb/s
155 Mb/s
2 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
CHEP2000 - Padova, February 2000
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)