INFSO-RI-508833 Enabling Grids for E-sciencE Institution of SLAs TNLC Meeting ― Athens,...

INFSO-RI-508833

Enabling Grids for E-sciencE

www.eu-egee.org

Institution of SLAs

TNLC Meeting ― Athens, 2005-04-21Afrodite Sevasti (SA2, GRNET)

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Model• Network Service Instance (NSI) refers to every instance of a

distinct flow or aggregate of EGEE traffic being transported between two end-points located in two distant EGEE RCs.

• NSIs are active between two EGEE RCs at a specific point in time, as a result of corresponding equal in number requests made by the EGEE middleware.

•

• The GEANT/NREN community can currently offer two types of border-to-border services:– Best-Effort IP service– Premium IP service

NREN 2

GEANT

NREN 1

EGEE RC A

EGEE RC B

MAN/ Campus/Institutionnetwork

border-to-border connectivity

end-to-end connectivity

MAN/ Campus/Institutionnetwork



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Services

• It is recommended that all EGEE NSIs are served using Premium IP service. However, there is also the possibility for an NSI to be served using the Best-Effort IP service

• All domains involved in network services provisioning to EGEE as part of the existing network infrastructure hierarchy have to be categorized as to whether they– Compliant with the Premium IP service– Supportive of the Premium IP service– Indifferent to the Premium IP service



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PIP compliant domain

• A domain provides Premium IP service to an EGEE NSI by following a set of basic principles as listed here:– IP traffic belonging to a single NSI and served by Premium IP

service is classified and its packets are being policed – Each router of the domain serves packets of PIP-served NSIs

via a dedicated router queue;– Each router queue dedicated to serving Premium IP traffic must

be able to accommodate the maximum of Premium IP traffic that can be routed through it;

– For Premium IP traffic of NSIs, it is possible to measure the achievable bandwidth and provide statistical measurements for a set of quality metrics between two edges of the domain.

– It must be capable of performing admission control on each new NSI request from an ingress interface to an egress interface of the domain.



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Non PIP compliant domains• Definition of a PIP supportive domain

– Preserving marking of PIP packets– Operating in an over-provisioned manner. – Monitoring of performance

• Definition of a PIP indifferent domain– Might alter the DSCP field value in packet headers– Might serve NSI traffic over congested links (and thus

compromise NSI requested guarantees such as guaranteed bandwidth)

– Lack of monitoring infrastructure• A Premium IP indifferent domain can be part of the

end-to-end path that the packets of an NSI traverse, however this automatically degrades the IP connectivity network service provided to the NSI from PIP to Best-Effort.



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NSI establishment

• For every case where it is required that an amount of data is transferred from one EGEE RC to another either in bulk transfer mode or in a real-time transmission mode an NSI request is made.

• If the NSI request is accepted, the NSI is established• For each NSI an end-to-end SLA is established that

provides all the technical and administrative details for maintaining, monitoring and troubleshooting the NSI.

• This SLA is formed using the individual SLAs provided by all domains along the end-to-end path



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Scenarios



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Responsibilities• GEANT-NRENs cloud

– NIS request processing by each domain along the border-to-border part of the path.

– If all three domains are able to confirm that the NSI request can be honored, the acceptance of the request together with a border-to-border SLA will be returned to the ENOC responsible, for each specific NSI

• Non-GEANT/NREN cloud domains– In case of a PIP compliant or PIP supportive domain:

use its admission control mechanism to examine whether the appropriate resources are available in order to accommodate the request

perform necessary configurations (in the case of a PIP compliant domain) to serve the NSI

fill in the corresponding SLA template (depending on whether the domain is PIP compliant or PIP supportive) for the NSI and return it to the ENOC contact point

– In case of a PIP indifferent domain: ENOC is notified as part of the normal process of collecting per-domain

SLAs to produce the end-to-end SLA. The end-to-end SLA is still established by the ENOC however it provides

Best Effort IP service to the particular NSI



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SLA templates

• SLA template for a Premium IP compliant domain• SLA template for a Premium IP supportive domain• SLA template for a Premium IP indifferent domain• EGEE end-to-end SLA template

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Establishment of SLAs

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End-to-end SLA establishment & the EGEE middleware

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Other issues• Monitoring of SLAs

– Each domain is responsible for monitoring its network services’ provisioning according to the SLA it offers and whether it is a PIP compliant, PIP supportive or PIP indifferent domain

– It is left to the EGEE RCs to install and/or run application oriented tests to verify the performance of the end-to-end path

• Fault reporting and troubleshooting of SLAs– In case of faults or degradation of performance, usually

perceived by by those involving in an NSI VOs/RCs, the problem must be directly reported to the ENOC

– The ENOC is responsible for deciding where the problem might be located and notifying the Technical Contact(s) of one or more of the domains along the path.

• Quotas• Disqualifying a domain

INFSO-RI-508833 Enabling Grids for E-sciencE Institution of SLAs TNLC Meeting ― Athens,...

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