1. Networking 2012 On inter-domain name resolution for information-centric networks K.V. Katsaros, N. Fotiou, X. Vasilakos, C.N. Ververidis, C. Tsilopoulos, G. Xylomenos, and G. C. Polyzos AUEB

2. Outline Name resolution in ICN Related work An enhanced DHT-based NRS Performance evaluation & results Conclusions

3. Name resolution in ICN ICN has many requirements from name resolution Operation over a flat identifier namespace Scalability –Ability to efficiently handle 10 15 names Fault tolerance and fault isolation –No centralized architecture Low signaling overhead Low latency (low response time) –Efficient routing and load distribution Routing policy compliance

4. Related work DHTs (Chord, Pastry) –Logarithmic number of hops required –Not compliant with routing policies MDHT and (old) PSIRP approach –Multilevel DHT with aggregation at higher levels –Questionable scalability and routing compliance DONA –Hierarchical aggregation of information –Requests are propagated upwards –Strictly follows customer-provider relationships

5. An enhanced DHT-based NRS H-Pastry: hierarchical DHT taking into account –Administrative domain boundaries –Inter-domain routing policies H-Pastry results in –Reduced path stretch (similar to regular Pastry) By 55% (Chord) and 47% (Crescendo) –Confined traffic within administrative boundaries 27% less inter-domain hops (Pastry) 55% shorter intra-domain paths (Pastry) –Reduced valley-free policy violations per path By 56% (Chord), 31% (Pastry) and 36% (Crescendo)

6. An enhanced DHT-based NRS Outline of the H-Pastry based NRS

7. Performance evaluation & results Evaluation dimensions –Load: memory, signaling, processing overhead –Routing performance Particular attention paid to the effects of –Underlying network structure on performance –Popularity characteristics of content on caching Evaluation Setup: Topology –Scaled-down but realistic topology –400 domains, 6-levels, peering and multihoming –Number of RV points: 4400

8. Performance evaluation & results Evaluation Setup: Workload –Original workload generated by GlobeTraff See our paper in IFIP NTMS 2012 –Focus on signaling to locate & start transmission –Data plane traffic mix translated to control plane Νumber of items for each traffic type Data volume / median item size per traffic type –Modeled popularity & temporal evolution 25GB of total traffic –~2.5M subscriptions for ~1M objects

9. Performance evaluation & results Routing stretch in inter-domain hops –Ratio of DHT-NRS / DONA hops –Infinite Cache Size (ICS), m is the DONA median Caching performance –Works for popular items –34% worse than DONA

10. Performance evaluation & results State: item entries per node DHT-NRS considerably better than DONA –Note the log scale for the x-axis! –DHT-NRS achieves better state distribution

11. Performance evaluation & results State distribution across hierarchy levels –Roughly 50% of access networks at level 2 –DHT-NRS achieves a better state distribution –DONA is penalized by topology structure

12. Performance evaluation & results Lookup signaling overhead –Includes terminated + forwarded messages –DONA works better for most of the nodes –In DHT-NRS messages cross more nodes

13. Performance evaluation & results Lookup overhead distribution across hierarchy levels –DONA is problematic at level 1 (as expected) –DHT-NRS is also hit at the topmost level Subscribe/Notify messages often go through level 1

14. Performance evaluation & results Advertisement/registration signaling overhead –Inter-domain hop transmissions per registration –DHT-NRS requires 6.34 transmissions (at 0%m) –DONA requires 35.56 transmissions Excessive inter-domain traffic load for DONA –(Limited) flooding method for registrations –Multihoming plays a critical role Registrations sent to multiple higher levels 56.75% of all domains are multi-homed 2.4 providers on average for them

15. Conclusions Routing efficiency –Caching in DHT-NRS cannot compete with DONA –Stretch values range from 1.95 to 2.84 Memory and lookup processing overhead –DHT-NRS considerably better –DONA has a highly skewed distribution Registration processing overhead –DONA is almost 6 times worse than DHT-NRS The problem with DONA is mainly localized –Large-scale centralized solutions (e.g. cloud)?