The document discusses a workshop on enhancing network-layer metrics for optimizing application performance through explicit network awareness, shifting from host-centric to content-centric communication. It emphasizes the need for scalable and efficient methods to assess network costs between endpoints, facilitating better peer selection and content distribution in contemporary architectures like P2P and CDNs. The proposed framework includes active measurements and addresses security and privacy concerns for querying entities.

1. EC FIARCH WORKSHOP
GEORGIOS GARDIKIS, GEORGE XILOURIS, NCSR “DEMOKRITOS”

2. • 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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3. • 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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4. • 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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5. • 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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6. • 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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8. • 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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9. • 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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11. • 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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12. • 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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13. www.medianetlab.gr
xilouris@iit.demokritos.gr
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