A generic Network Cost provision framework is described, accompanied with a preliminary proofof-concept implementation. Deployment considerations and open research issues are also discussed.

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.
2

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
3

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.
4

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
5

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.
6

7. 7

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.
8

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)
9

10. 1

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).
1

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
1

13. www.medianetlab.gr
xilouris@iit.demokritos.gr
1