Network Cost Services for Network-Aware FI ApplicationsEC FIARCH WORKSHOPGEORGIOS GARDIKIS, GEORGE XILOURIS, NCSR “DEMOKRITOS”

Network Awareness

• Promising aspect within the FI scene• On-demand signaling of specific network-layer metrics

to querying applications aiming in optimization of application behavior and performance

• Within the generic “Resource Awareness” FI design principle.

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Current Status

• Present model: implicit derivation of network status (e.g. TCP)

• Applications assume network conditions by observing their own performance

• Implicit network awareness has survived during the years, and works well for most of the applications

• It is also scalable

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Current Status - trends• Gradual paradigm shift from host-centric to content-centric

communication• Existing implicit mechanisms may be not as efficient due to new

communication architectures, beyond the traditional client-server:– peer-to-peer– CDNs/Content-centric networks– in-network clouds etc.

• Content is distributed into the network, rather than concentrated in a single server -> simultaneous communication with tens, hundreds, or even thousands of peers.

• Assessing the communication with each of these peers at application level via the usual in-band methods would pose significant overhead in the network, besides requiring a considerable amount of time.

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A Network Cost Service• A scalable and efficient way to provide explicit Network Awareness• Offered by Network Operators (or third-parties)• “Network Cost” (NC) assessment for any given pair or group of

network endpoints. • NC could be instantly exploited at application level in order to

optimize operations such as in-network content placement, peer selection, prioritization and load balancing.

• A similar approach is promoted by the Application Layer Traffic Optimisation (ALTO) WG of the IETF

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Use cases• peer-to-peer file sharing and streaming - for optimizing p2p

communication via selection of “best peers” i.e. peers with lower NC

• one-to-one and one-to-many real-time audiovisual communication – for a priori optimizing stream format and rate according to NC

• distributed caching, Content-Delivery Networks (CDN) and Information Centric Networking (ICN) – for choosing optimal locations for caching content within the network

• in-network clouds – for efficient load balancing, traffic distribution and resource transfer to optimal locations, including Virtual Machine (VM) migration.

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Generic Architecture

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Generic Architecture• Network Cost Query: pair or group of endpoints’ addresses,

optionally application type (for application-aware networks)• Response: Network Cost vector

where ci(a,b), denotes a certain network metric between endpoints a and b (e.g. hop count, one-way delay, average

packet loss, jitter/delay variation etc.)• Can be transformed to a scalar value, taking into account the

sensitivity wi of the specific application against each of the aforementioned metrics.

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Proof-of-concept implementation• Customised SNMP agents on Linux-based routers• On-demand execution of active end-to-end measurements

according to the OWAMP protocol (RFC 4656)• Configuration of measurements and collection of results over SNMP• Network Cost provided to applications over SOAP/XML protocol• NC elements:

– Number of hops traversed– Average One-Way Delay (OWD)– Average packet loss– Average jitter– Percentage of duplicates

• Also tested on DiffServ-enabled configurations (Network Cost varies upon different DSCP values)

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Proof-of-concept implementation

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Proof-of-concept implementation• OpenSource implementation of the SAM framework is available at

http://medianetlab.gr/opensource

• Technical information available in the work:

G. Gardikis, K. Sarsembagieva, G. Xilouris, A. Kourtis, “An SNMP Agent for Active In-Network Measurements”, in Proc. ICUMT 2012, October 3-5, 2012, St. Petersburg,

Russia (to appear).

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Considerations

• Security and Network Operator Privacy; authentication of the querying entity, anti-(D)DoS protection etc.

• Inter-domain operation – “assembling” NCs across a chain of network domains

• Inclusion of the access network; separate assessment of the access link and combining results with edge/core network statistics so as to form end-to-end cost in a scalable manner

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Thank you!

www.medianetlab.gr

xilouris@iit.demokritos.gr

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