1. WLCG Network Discussion
WLCG Workshop
19-23 June 2018

2. Goal: Identify Missing Effort/Capability
We want to conclude the network session with a quick discussion about what may be missing for network monitoring/diagnosis and use compared with identified needs
We have heard the experiments provide their perspectives on networking
In addition we asked for a 1 page summary of what is needed in network monitoring/diagnosis that follows
WLCG Workshop 2017

3. ALICE Concerns
Comprehensive WAN network picture is essential for efficient data transfers and placement
ALICE depends on and strongly encourages the full implementation of LHCONE at all sites
Plus the associated tool (like perfSONAR), which we can use in our Grid frameworks
A number of sites in well-connected parts of the world still have to join
Entire regions with high local growth of computing resources, in particular Asia, require a lot of further work
WLCG Workshop 2017

4. ATLAS Requirements
ATLAS would like better visibility into our networks to improve our ability to resolve network issues.
Alerting/alarming on network problems:
Large packet loss, low throughput, missing data, infrastructure problems.
perfSONAR 4.0 campaign
Nodes not updating, services not configured properly, services and/or nodes down, problematic test results
ATLAS would like to see network traffic data from RENs
Dashboards to display relevant data together.
Tools to better identify network monitoring infrastructure problems.
WLCG Workshop 2017

5. WLCG Workshop 2017

6. CMS Requirements
Network requirements scale (to first order) with CPU availability
5MB/s/core would satisfy most demanding workflow – but appears not affordable for large sites
Commissioning for 1-2MB/s/core should be the target for LAN capacity
A few thousand remote connections of ~0.5MB/s can be expected (for sites with sizable storage)
“Full” Tier-2: Many CPUs and large disk capacity
Some 10Gbit/s or 100Gbit/s for both LAN and WAN are advisable for sites with several 1000 cores > “CPU-rich” Tier-2: Disk storage for caching only
CMS has no experiences with such a site (yet)
Mainly the same targets like for the “full” T2 apply > 1-2MB/s/core for LAN (reading from cache)
“Good” WAN connectivity (Some 10Gbit/s or more) for filling the cache or reading in (directly) from remote
“Disk-rich” Tier-2: More storage than average, perhaps hosting disk for co-located CPU only site
Good WAN connection even more important
“Disk-poor” Tier-2: Rather similar to “CPU-rich”
WLCG Workshop 2017

7. LHCb
Monitoring, including network monitoring, available from within Dirac
Main use cases:
For “helper data processing” sites check the WAN connectivity to a T1 storage
For data management check WAN quality
WLCG perfSONAR information is included into the DIRAC monitoring infrastructure
Consumed via CERN/ActiveMQ
Example Dirac perfsonar monitoring:
Show packet loss, red if > 5 %

8. GEANT/Mian: Investigating ways to increase ability to differentiate, break dependence on vendors, and provide capabilities to automate / orchestrate multi-domain services
Greater differentiation
Business and operational systems: digital transformation
Service catalogue
Service management
Order management
On-demand request/delivery
Service bundling
Diversified service portfolio
automation / orchestration of multi-domain services
Flow-based services
VPN services
IP services
new service offerings
Disaggregated control and management plane
Multivendor Interoperability
Programmable data plane
Open & Programmable

9. Questions and Discussion
Need to maintain, monitor and develop our network monitoring; we require people to:
Respond to GGUS tickets
Track service and metric status and follow up on down services, mis-configuration, etc.
Evolve the system, implementing new user interfaces, analytics, alerting and new measurements
Coordinate network activities with others
Do we have enough people identified to deliver on the experiment expectations?
WLCG Workshop 2017

10. Questions and Discussion(2)
Are the services we have (operating and planned) sufficient for identifying and resolving network problems?
If not what more is required?
Some interest has been expressed about network programmability, especially in light of foreseen, commercially driven network developments.
Do we have enough research/prototyping planned to ensure we can utilize future network capabilities?
WLCG Workshop 2017

11. References
Pre-GDB on networking meeting
Summary on Pre-GDB
Last LHCONE/LHCOPN meeting
WLCG Workshop 2017