Network Cost Services for Network-Aware FI Applications EC FIARCH WORKSHOP GEORGE XILOURIS, NCSR “DEMOKRITOS”

Network Awareness 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

Network Awareness 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.

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

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 realtime 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.

Generic Architecture

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

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)

Proof-of-concept implementation

Considerations Security and Network Operator Privacy; authentication of the querying entity, anti-(D)DoS protection etc. Inter-domain operation – “assembling” NCs across different domains Including 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

Thank you! www.medianetlab.gr xilouris@iit.demokritos.gr +30 210 650 3166