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Connect. Communicate. Collaborate
BANDWIDTH-ON-DEMAND SYSTEM CASE-STUDY BASED ON GN2 PROJECT EXPERIENCES
Radosław Krzywania (speaker)
PSNC
Mauro CampanellaGARR
Afrodite SevastiGRNET
Connect. Communicate. CollaborateAgenda
• Introduction• Technology Choice• Domain Privacy• Pathfinding• Advance Reservations
Connect. Communicate. CollaborateJRA3 AutoBAHN – Geant2
• AutoBAHN = Automated Bandwidth Allocation across Heterogeneous Networks
• A ‘Joint Research Activity’ investigating the provision of ‘Bandwidth on Demand’ services to the NREN community
• The environment:– Multi-domain– Multiple technologies– Requirements for:
• end-to-end non-contended capacity • a standardized interface for service requests at end-points• service level indication to end-users• advance reservation (scheduled)
Connect. Communicate. CollaborateArchitecture overview
Client equipment
IP domain
NMS
GE domain
L2 MPLS VPN
SDH domain
Native EthernetGFP over SDH
GMPLS signalling
Technology Proxy
Domain Manager
Inter-Domain Manager
User access module
Request handling logic
DM pathfinding
AAI
Resource modelling
Policy module
Inter-domain pathfinder
User interface
Technology Proxy
Domain Manager
Inter-Domain Manager
User access module
Request handling logic
DM pathfinding
AAI
Resource modelling
Policy module
Inter-domain pathfinder
User interface
Client equipment
JRA
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oD s
yste
mD
ata
plan
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Technology Proxy
Domain Manager
Inter-Domain Manager
User access module
Request handling logic
DM pathfinding
AAI
Resource modelling
Policy module
Inter-domain pathfinder
User interface
Connect. Communicate. CollaborateAgenda
• Introduction• Technology Choice• Domain Privacy• Pathfinding• Advance Reservations
Connect. Communicate. CollaborateTechnology Choice
• European network is heterogeneous
• Each NREN develops its own architecture independently, relying on various technology
• NRENs are interconnected through GEANT2 pan-European network
• NRENs can connect with each other with cross-border links, evading GEANT2 infrastructure
Connect. Communicate. CollaborateTechnology Choice
• AutoBAHN aims at the following technologies:– Layer 1
• lambda circuit management– Layer 2
• MPLS VPNs• Gb Ethernet• SDH• GFP over SDH
• Layer 3 technologies are out of scope, as they belong to the responsibility of other GEANT2 activities.
Connect. Communicate. CollaborateAgenda
• Introduction• Technology Choice• Domain Privacy• Pathfinding• Advance Reservations
Connect. Communicate. Collaborate
• Domain Privacy– AutoBAHN aims at operating
over a federated architecture, where each domain is independent
– The AAI and domain privacy is a key issue
– Each domain would like to hide its internal details from other domains
– The public advertisements are limited to reachablity information only
Connect. Communicate. CollaborateDomain Privacy
• Various representations of abstracted domains– 1 to 1 representation– Aggregated nodes– Edge nodes only (currently
used by AutoBAHN)– Single node
Connect. Communicate. CollaborateDomain Privacy
• Aggregation of attributes issue– If alternative paths will be
abstracted to single one, what attribute values should be used?
– It is impossible to have a 10Gbps path with 10ms delay and cost of 15 points…
Connect. Communicate. CollaborateAgenda
• Introduction• Technology Choice• Domain Privacy• Pathfinding• Advance Reservations
Connect. Communicate. CollaboratePathfinding
• Single point computation – Detailed
– The advertised domain topologies include information about internal nodes and attributes (limited domain privacy, peering model)
– The path contains exact nodes and links in each domain along the reservation path between two end points
– The path is computed in one domain (any domain manager, PCE, etc.)
Connect. Communicate. CollaboratePathfinding• Single point computation – General
– The advertised domain topologies are abstracted, no (or limited) intra-domain details are visible
– The path contains only domains that should be traversed by a path (ingress and egress domain points)
– Each domain must perform local pathfinding to find a detailed part of inter-domain path (this part may be published or hidden due privacy reasons)
– The inter-domain path is computed in single point, the domain details must be computed in each domain
Connect. Communicate. CollaboratePathfinding
• Distributed computation– Inter-domain topologies
provide only routing information
– Instead of defining a full path, each domain defines only the „next hop domain”
– Each domain defines its part of the path in detail, including outgoing inter-domain links
Connect. Communicate. CollaboratePathfinding
• AutoBAHN inter-domain pathfinding is performed based on inter-domain abstracted topology (reachability information between domains + abstracted intra-domain links), which is built with OSPF Quagga daemon.
• Currently Dijkstra algorithm is used to find a potential inter-domain path.
• The information on abstracted topology database are insufficient to perform a reservation, therefore an additional process (negotiation) is required to validate the path.
• During the process each domain is queried for details and validation of inter-domain part of the path. The details are called constraints
• The last domain on a path is responsible to agree all constraints and prepare a final set of reservation attributes, which includes technology specific parameters.
Connect. Communicate. CollaborateAgenda
• Introduction • Technology Choice• Domain Privacy• Pathfinding• Advance Reservations
Connect. Communicate. CollaborateAdvance Reservations
• AutoBAHN allows to perform advance reservations– Each reservation has start and end time attributes
attached– Resources are booked, not configured – a calendar
module is used– At reservation time, involved domains configure the
network to build a circuit– When reservation time expires, domain removes circuit
configuration
Connect. Communicate. CollaborateAdvance Reservations
• Inter-domain centralized approach– Calendar must be aware of
each particular resource in every domain (limited domain privacy)
– One place of data storage (simple maintenance)
– Easy to implement
Connect. Communicate. CollaborateAdvance Reservations
• Inter-domain distributed approach– Each domain has its own
calendar– Domain privacy may be kept– Synchronization of
databases is required (for inter-domain resources)
– More complex solution than centralized approach
Connect. Communicate. CollaborateAdvance Reservations
• Intra-domain centralized approach– There is one calendar
instance per domain– The calendar is aware of
each resource under control of BoD system
– Easy to implement and maintain
– Single point of data storage
Connect. Communicate. CollaborateAdvance Reservations
• Intra-domain distributed approach– Each resource or resource
group has it’s own calendar module
– The synchronization is required between calendars for shared resources (e.g. links)
– Interaction with external domains is more complex than in centralized approach
– Calendars should be part of equipment – vendor support
Connect. Communicate. CollaborateAdvance Reservations
• Pathfinding– Pathfinder (PF) module is
request to find a chain of domains, which should be involved in circuit creation
– Pathfinder takes a snapshot of current abstract topology view (includes other domain information as advertised by Quagga)
– Dijkstra algorithm is executed to find best paths (delay value is used as optimization attribute)
Connect. Communicate. CollaborateAdvance Reservations
• Negotiations– All domains (included in
circuit) are involved in negotiation process
– Each domain checks possible intra-domain paths and validates resource availability for reservation time
– The constraint entities are created, which describe domain requirements for particular reservation (e.g. allowed VLAN range or SDH time slots)
Connect. Communicate. CollaborateAdvance Reservations
• Negotiations– The constraints are collected
from all domains along reservation path
– The destination domain is responsible to concatenate all constraints in order to find common set of configuration attributes
– If such set is found, the resources are booked in all domains’ calendars along the way back to source domain
Connect. Communicate. CollaborateAdvance Reservations
• Reservation– Each domain is responsible
for initialization of circuit configuration, when reservation time starts (calendar module)
– DM configures circuit through Technology Proxy module
– Source domain IDM module is notified about circuit creation in all domains
– Similar proces is executed to remove circuit configuration
Connect. Communicate. CollaborateJRA3 AutoBAHN Partners
• The JRA3 work is a joint effort of the following NRENs & DANTE– CARNET– CESNET– DANTE– FCCN– GARR– GRNET– HEANET– HUNGARNET– PSNC– REDIRIS– RENATER– SURFNET
• This presentation was co-authored by– Mauro Campanella (GARR) – Afrodite Sevasti (GRNET)
Connect. Communicate. CollaborateQ&A
• Thank you for your attention
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