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Networking@desy. Volker Gülzow, Kars Ohrenberg. Computing Seminar. Zeuthen, 23.04.2013. Network Topology Hamburg. Topology. Zeuthen inbound. Zeuthen outbound. Bandwidth Evolution @ DFN. DFN is upgrading the optical platform of the X-WiN
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Networking@desy Volker Gülzow, Kars Ohrenberg Computing Seminar Zeuthen, 23.04.2013
Bandwidth Evolution @ DFN • DFN is upgrading the optical platform of the X-WiN • Contract awarded to ECI Telecom (http://www.ecitele.com) • Migration work is currently underway • High Bandwidth Capabilities • 88 wave length per fiber • Up to 100 Gbps per wave length • thus 8.8 Tbps per fiber! • 1 Tbps Switching Fabric (aggregation of 10 Gbps lines on single 100 Gbps line)
Bandwidth Evolution @ DFN • Significant cheaper components for 1 Gbps and 10 Gbps components -> reduced cost for VPN connections, new DFN pricing • New DFN conditions starting 1.7.2013 • DESYs contract of 2 x 2 GBits will go to 2 x 5 Gbps without additional costs • New cost model for Point-to-point VPNs • 1) Initial installation payment • 10 GBps ~ 11.400 €, 40 GBps ~ 38.000 €, 100 GBps ~ 94.000 € • 2) Annual fee now depends on the distance • Hamburg <> Berlin at ~ 20% of the current costs (for 10 Gbps) • Hamburg <> Berlin at ~ 80% of the current costs (for 40 Gbps) • Hamburg <> Karlsruhe at ~ 45% of the current costs (for 10 Gbps) • Hamburg <> Karlsruhe at ~ 150% of the current costs (for 40 Gbps)
LHC Computing Infrastructure • WLCG in brief: • 1 Tier-0, 11 Tier-1s, ~ 140 Tier-2s, O(300) Tier-3s worldwide
The LHC Optical Private Network • The LHCOPN (from http://lhcopn.web.cern.ch) • The LHCOPN is the private IP network that connects the Tier0 and the Tier1 sites of the LCG. • The LHCOPN consists of any T0-T1 or T1-T1 link which is dedicated to the transport of WLCG traffic and whose utilization is restricted to the Tier0 and the Tier1s. • Any other T0-T1 or T1-T1 link not dedicated to WLCG traffic may be part of the LHCOPN, assuming the exception is communicated to and agreed by the LHCOPN community • Very closed and restricted access policy • No Gateways
Data transfers CERN Tier 1s Global transfers Ian.Bird@cern.ch Global transfer rates are always significant (12-15 Gb/s) – permanent on-going workloads CERN export rates driven (mostly) by LHC data export By Ian Bird, CRRB,4/13
Resource usage: Tier 0/1 By Ian Bird Ian.Bird@cern.ch
Resource use vs pledge CERN Tier 1s CCRC F2F 10/01/2008
Resource vs pledges: Tier 2 By Ian Bird Ian.Bird@cern.ch
Connectivity (100 Gb/s) By Ian Bird Latency measured; No problems anticipated Ian.Bird@cern.ch
Computing Models Evolution • The original MONARC model was strictly hierarchical • Changes introduced gradually since 2010 • Main evolutions: • Meshed data flows: Any site can use any other site as source of data • Dynamic data caching: Analysis sites pull datasets from other sites „on demand“, including from Tier-2s in other regions • Remote data access • Variations by experiment • LHCOPN only connects T0 and T1
LHC Open Network Environment • With the successful operation of the LHC accelerator and the start of the data analysis, there has come a re-evaluation of the computing and data models of the experiments • The goal of LHCONE (LHC Open Network Environment) is to ensure better access to the most important datasets by the worldwide HEP community • Traffic patterns have altered to the extent that substantial data transfers between major sites are regularly being observed on the General Purpose Networks (GPN) • The main principle is to separate the LHC traffic from the GPN traffic, thus avoiding degraded performance • The objective of LHCONE is to provide entry points into a network that is private to the LHC T1/2/3 sites. • LHCONE is not intended to replace LHCOPN but rather to complement it
LHCONE Activities • With the above in mind, LHCONE has defined the following activities: • VRF-based multipoint service: a “quick-fix” to provide multipoint LHCONE connectivity, with logical separation from R&E GPN • Layer 2 multipath: evaluate use of emerging standards such as TRILL (IETF) or Shortest Path Bridging (SPB, IEEE 802.1aq) in WAN environments • Openflow: There was wide agreement that SDN is the most probable candidate technology for LHCONE in the long-term (but needs more investigations) • Point-to-point dynamic circuits pilots • Diagnostic Infrastructure: each site to have the ability to perform E2E performance tests with all other LHCONE sites
Software-Defined Networking (SDN) • Is a form of network virtualization in which the control plane is separated from the data plane and implemented in a software application • This architecture allows network administrators to have programmable central control of network traffic without requiring physical access to the network's hardware devices • SDN requires some method for the control plane to communicate with the data plane. One such mechanism is OpenFlow which is a standard interface for controlling computer networking switches
LHCONE VRF • Implementation of multiple logical router instances inside a physical device (virtualized Layer 3) • Logical control plane separation between multiple clients • VRF in LHCONE: regional networks implement VRF domains to logically separate LHCONE from other flows • BGP peerings used inter-domain and to end-sites
Multipath in LHCONE • Multipath problem: • How to use the many (transatlantic) paths at Layer 2 among the many partners, e.g. USLHCNet, GEANT, SURFnet, NORDUnet, ... • Layer 3 (VRF) can use some BGP techniques • MED, AS padding, local preference, restricted announcements • works in a reasonably small configuration, not clear it will scale up to O(100) end-sites • Some approaches to Layer 2 mulitpath: • IETF: TRILL (TRansparent Interconnect of Lots of Links) • IEEE: 802.1aq (Shortest Path Bridging) • None of these L2 protocols is designed for WAN! • R&E needed
LHCONE Routing Policies • Only the networks which are announced to LHCONE are allowed to reach the LHCONE • Networks announced by DESY: • 131.169.98.0/24, 131.169.160.0/21, 131.169.191.0/24 (Tier-2 Hamburg) • 141.34.192.0/21, 141.34.200.0/24 (Tier-2 Zeuthen) • 141.34.224.0/22, 141.34.228.0/24, 141.34.229.0/24, 141.34.230.0/24 (NAF Hamburg) • 141.34.216.0/23, 141.34.218.0/24, 141.34.219.0/24, 141.34.220.0/24 (NAF Zeuthen) • e.g. networks announced by CERN: • 128.142.0.0/16 but not 137.138.0.0 • Only these networks will be reachable via the LHCONE • Other traffic uses the public, general purpose networks • Asymmetric routing should be avoided as this will cause problems for traffic passing (public) firewalls
LHCONE - the current status • Currently ~100 network prefixes • German sites currently participating in LHCONE • DESY, KIT, GSI, RWTH Aachen, Uni Wuppertal • Europe • CERN, SARA , GRIF (LAL + LPNHE), INFN, FZU, PIC, ... • US: • AGLT2 (MSU + UM), MWT2 (UC), BNL, ... • Canada • TRIUMF, Toronto, ... • Asia • ASGC, ICEPP, ... • Detailed monitoring via perfSONAR
R&D Network Trends • Increased multiplicity of 10Gbps links in the major R&E networks: GEANT, Internet2, ESnet, various NREN, ... • 100Gbps Backbones in place and transition now underway • GEANT, DFN, ... • CERN - Budapest 2 X 100G for LHC Remote Tier- 0 Center • OpenFlow (Software-defined switching and routing) taken up by much of the network industry and R&E networks
Summary • The LHC computing and data models continue to evolve towards more dynamic, less structured, on-demand data movement thus requiring different network structures • LHCOPN and LHCONE may merge in the future • With the evolution of the new optical platforms bandwidth will get more affordable