Interest Rate Control for Content-Centric Networking Luca Muscariello, Massimo Gallo (France Telecom R&D, Orange Labs), Giovanna Carofiglio (Bell Labs, Alcatel-Lucent), Michele Papalini (University of Lugano, Switzerland and Bell Labs Alcatel-Lucent)

1. Joint Hop-by-hop and Receiver-Driven
Interest Control Protocol for
Content-Centric Networks
Massimo Gallo (Orange labs),
joint work with:
Giovanna Carofiglio (Bell Labs),
Luca Muscariello (Orange labs).
CCNxCon 2012 - September 13th, 2012 - Sophia Antipolis

2. AGENDA
1. Transport issues in CCN
2. Receiver-driven Interest control
3. Hop-by-hop Interest control: design and analysis
4. Performance Evaluation
5. Hop-by-hop Interest control: benefits
6. Conclusions

3. CCN Transport - KEY ASPECTS
UNIQUE ENDPOINT
AT THE RECEIVER
No connection instantiation,
multiple senders for the same
CACHE CACHE
content retrieval, unknown a priori
at the receiver
CACHE
PULL-BASED POINT TO
REPO MULTIPOINT RETRIEVAL
Interests for the same content
retrieval can be forwarded in a
Data point-to-multipoint fashion: better
USER CACHE CACHE throughput, better traffic load
balancing if multiple sources in
Interests parallel
MULTIPLE SOURCES
Data can be retrieved by multiple
CACHE repositories, but also intermediate
caches
CACHE CACHE

4. CCN congestion control mechanisms
@ the receiver
CCN receiver is the unique flow endpoint:
• knows application requirements, end-to-end round trip delay per packet
retrieval, receiver buffer (flow size)
• is the best place where to control content retrieval over multiple paths
@ network nodes
CCN nodes know Interest/Data rates of flows (identified by content name)
per interface:
• Interest/Data traverse the same nodes in opposite directions
• provide hop-by-hop Interest control
• handle bursty traffic and react faster

5. Receiver-driven Interest Control Protocol (ICP)
DESIGN
• One Interest per Data packet, in the order decided by the application
• Window-based Additive Increase Multiplicative Decrease (AIMD):
! W is increased by !/W at each Data packet reception
! W is decreased by "W at each timer expiration (a timer is set
at the receiver for each Interest sent out) and no more than once in
a time interval equal to the timer duration
• Adaptive timer expiration value, ! , based on RTT estimates over a
history of samples
! reflects the average virtual RTT and may be associated to a path

6. Hop-by-Hop Interest Control - OBJECTIVES
Basic Idea
If Interest rate> fair rate at a given interface, one can queue and delay
Interests at output interface to reduce Data queuing at the bottleneck
Interest control at network node:
• anticipate congestion detection by
monitoring Interest/Data rate
• trigger rate reduction via Interest
shaping before timer expiration at the
receiver.
• control PIT entries according to
Upstream resources

7. Hop-by-Hop Interest Control - DESIGN
• One virtual queue per flow at each
output interface, identified by the
content name
• One credit counter per virtual queue
initialized to B Data bytes that the
flow can transmit with no additional
delay
• The counter is:
• incremented at the estimated fair rate
• decremented by forwarded Interests

8. Hop-by-Hop Interest Control - DESIGN (cont’d)
@ interest arrival
Shaping algorithm:
(after CS/PIT/FIB lookup)
No bottlenecked Yes
?
queueInterest in a
send Interest drop tail FIFO served
(no additional delay) at !i(t)
Shaping rate:
• is the rate of non-bottlenecked flows (total rate of non shaped
flows, counting the size of the corresponding Data packets)
• is the # of bottlenecked flows (# of non empty queues)
"

9. Hop-by-Hop Interest Control - ANALYSIS
Main Result
We prove that HR-ICP is stable and converges to the max-min fair rate
of ICP, where the shaping queue Qsi (t) replaces Qi(t) in the ICP system

10. Performance Evaluation
Impact of Interest Control on User Performance
• Implementation oh Interest shaping mechanism in CCNPL-Sim
(C++ event driven simulator for the CCN architecture)
• Two hops network, single content retrieval. ICP vs constant window, w or w/
o Hop by Hop Interest control:
Interest Delivery Time Throughput Losses
Results Window [s] [Mbps] [%]
• Hop-by-hop Interest W [pkts]
With W/o With W/o With W/o
HbH HbH HbH HbH HbH HbH
Shaping is not enough
2 2.42 2.42 16.30 16.30 0 0
• Interest shaping reduces 10 1.00 1.00 39.70 39.60 0 0
Data packet losses 15 1.00 2.08 39.60 19.20 0 11.20
20 1.00 1.90 39.60 20.90 0 15.30
ICP 1.00 1.00 39.80 39.80 0 0

11. Performance Evaluation
The benefits of HR-ICP over ICP
Repositor Three flows:
y • 2 ICP (t1=0s, t1=0.5s)
C1= 100Mbps C2= 40 Mbps
• CBR (t=1s - avg 40Mbps).
Results
• HR-ICP queues Interests before the bottleneck link (Q1s not Q2, Q2 is zero )
• ICP flows almost not affected w H2H, get the fair rate, W slightly reduced
• Greedy CBR flow looses (CBR rate - fair rate)

12. Performance Evaluation
Prioritization of real-time and delay sensitive traffic
Repositor Repositor
y y
C1= 100Mbps C2= 40 Mbps C3= 100 Mbps C4= 20 Mbps
Three flows:
• ICP 1 bottlenecked at 4 (t=0s),
• ICP 2 bottlenecked at 2 (t=0.5s),
• 4 Interests in batch every 10ms
(t=0.5s, avg 5Mbps - peak 100
Mbps).
Results:
• HR-ICP queues Interests before
bottleneck,
• ICP flows almost not affected, while
the new flow gets priority along the
request path.

13. HBH Interest shaping - benefits
" Interest not Data Control
" Early Congestion Detection
" Protection from misbehaving receivers
" Scalability/Feasibility
" Delay-sensitive flows protection
" No interest losses
" Additional traffic control opportunities

14. Conclusions
We show that
# Hop-by-hop Interest shaping enhances rate and congestion control
performance
# Compared to alternative solutions for CCN Interest control, our
proposal brings additional benefits due to:
$ the coupling with a rate/fairness optimal receiver control,
$ the positioning of Interest shaper at output interfaces,
$ the shaping mechanism based on Data max-min fair rate.
Future works
definition of traffic control mechanisms for the management of a multipath
communication, coupled with an Interest forwarding policy.

15. Questions
CCN Simulator soon available at: http://perso.rd.francetelecom.fr/
muscariello/sim
http://code.google.com/p/ccnpl-sim