All
If you care about LHCOPN/LHCONE then this is so that everyone is fully aware of the
recent request from outside the UK and the GridPP response.
Pete
Begin forwarded message:
From: Peter Clarke <[log in to unmask]>
Subject: Re: Moving T1-T1 traffic off of LHCOPN?
Date: 20 June 2015 09:04:46 BST
To: Edoardo Martelli <[log in to unmask]>
Cc: "project-lhcopn-routing (IP routing design for the LHC Optical Private Network)" <[log in to unmask]>, <[log in to unmask]>
Resent-From: <[log in to unmask]>
Dear Edoardo
Here is a UK position statement concerning LHCONE for both T1 and T2. The full position statement is attached.
The high level summary is that the UK is not in favour, as within the UK we have no explicit need for LHCONE
for any reason of T1 capacity planning, but to implement it involves additional complexity and possibly cost.
The current system works fine and we therefore see no overriding reason to remove T1-T1 transit via LHCOPN.
We note that it would have to be agreed by both the experiments and WLCG managements as being an official WLCG requirement.
This is because it is not a purely technical question as it potentially affects reachability (and hence computing models) if some sites cannot,
or do not wish to move.
Of course we understand that the situation may be different in other countries, and that they may have a real imperative
to only use LHCONE. The UK is sensitive to the “collective” needs of the community, and as a general statement we would always seek to address
any legitimate request agreed by the WLCG MB in order to play our role in meeting international expectations.
Happy to discuss further, and im sure there will be a good session on this in Amsterdam.
Pete (on behalf of GridPP)
--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
On 17 Jun 2015, at 13:42, Edoardo Martelli <[log in to unmask]> wrote:
Hello
At the last LHCOPN meeting it was proposed to move Tier1-Tier1 traffic off of the LHCOPN (https://indico.cern.ch/event/376098/contribution/25/material/slides/1.pdf).
One of the reason behind the proposal was that most of the LHCOPN Tier1-Tier1 direct links have disappeared. As well, Tier1-Tier1 traffic is already allowed in the LHCONE and it may be confusing for operational teams to understand where the traffic is actually flowing, or it was flowing in a given moment in the past, or whether it is symmetric.
Against the proposal there were the facts that not all the Tier1s are connected to LHCONE or they don't have the same amount of bandwidth in LHCONE as in the LHCOPN.
Since not many Tier1 were represented at the meeting, it was decided to follow up the discussion on the mailing lists. So I would urge the Tier1s to voice their opinion for or against the proposal.
All the slides presented at the last LHCOPN/ONE meeting can be found here: https://indico.cern.ch/event/376098/
cheers
Edoardo
|