on the processing time for detection of skype traffic
DESCRIPTION
On the processing time for detection of Skype traffic. P.M. Santiago del Río , J. Ramos, J.L. García-Dorado , J. Aracil Universidad Autónoma de Madrid A. Cuadra-Sánchez , M. Cutanda-Rodríguez Indra Sistemas. International Workshop on TRaffic Analysis and Classification TRAC 2011 - PowerPoint PPT PresentationTRANSCRIPT
On the processing time for detection of Skype traffic
P.M. Santiago del Río, J. Ramos, J.L. García-Dorado, J. Aracil
Universidad Autónoma de MadridA. Cuadra-Sánchez, M. Cutanda-Rodríguez
Indra Sistemas
International Workshop on TRaffic Analysis and Classification TRAC 2011Istanbul July, 7th 2011
2
Contents Introduction. Skypeness. Performance Evaluation. Conclusion and Future work.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
3
Contents Introduction.
• Detecting Skype.• Motivation.
Skypeness. Performance Evaluation. Conclusion and Future work.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
4
How to detect Skype traffic? Skype:
• Proprietary, obfuscated and encrypted protocol.• Random ports.• UDP packets (TCP only used in presence of UDP-restricted
firewalls). Traffic Classification Techniques:
• Port numbers:– Not valid (random port numbers).
• DPI:– Computationally expensive (payload inspection).– Insufficient accuracy (encrypted content).
• Machine-learning:– Sufficient accuracy.– Sufficient performance (from a computational viewpoint)
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
5
Motivation Why detect Skype traffic?
• Popularity:– Users (increasing thanks to mobile smartphones).– Profits.
• Security reasons:– Lawful interception.– e.g. EU directive 2006/24/EC.
• Quality of Service (QoS).• Billing/accounting and restrictions.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
6
Motivation Why so fast?
• Increase in data transmissions speeds:– 10 Gb/s (and even faster…).– A lot of sorts of traffic.
• Current traffic classifications applications:– Accuracy: – Processing speed:
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
7
Motivation Why in commodity hardware?
• Alternative to specialized hardware (e.g. FPGAs):– Less flexibility.– More cost.
• Low-cost integration and minimal interference with current infrastructure.
• Good performance and limited cost.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
8
Contents Motivation. Skypeness.
• Detector Fundamentals• HW & SW Architecture
Performance Evaluation. Conclusion and Future work.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
9
Skypeness Goals:
1. Accurate
2. Fast
3. Cheap
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
10
Detector Fundamentals Based on Tstat Skype classifier:
• Packet length.• Interrarival times.• Bit rate.• Chi Square Test (packet payload inspection required)
UDP packets.• TCP only used in presence of UDP-restricted firewalls.
Smooth data (moving average).
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
11
Detector Fundamentals Detection algorithm:
• Proportion of packet windows whose mean packet size/inter-arrival/bit-rate are inside the valid intervals.
• If these proportions are greater than the threshold, the flow is marked as Skype.
• Ground-truth obtained in several scenarios (wired and wireless, real and emulated networks conditions, etc).
• Thresholds values optimized with C4.5 trees.On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
Characteristic Interval ThresholdPacket size [Bytes] [30,200] 0.75
Interarrival [ms] [in-1±15] 0.6
Bit rate [Kb/s] [0,150] 0.75
12
Software Architecture 3 modules:
• Capturing and parsing packets.• Creating and updating flows.• Detecting Skype.
Modular architecture:• Provides flexibility.• Makes possible adding other tests.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
13
Software Architecture Capturing module details:
• Raw socket and mmap functions to map NIC receive queues at user-space.
• Parse IP/TCP-UDP headers, obtaining:– 5-tuple (IP src/dst, port src/dst, transport protocol).– Packet size– Arrival timestamp
Flow-builder module details:• Unidirectional flows.• Hash-based table.• Pre-allocated memory pool.• Sorted.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
14
Hardware Architecture Commodity hardware:
• 4 AMD Opteron processors.• 32x4 GB DDR3 memory.• Intel 10 Gigabit NIC:
– Multiqueue Tx and Rx (up to 16 per interface).
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
15
Hardware Architecture NUMA: Non Uniform Memory Access
• Memory split in several groups.• The lower the distance, the higher the performance.
Ubuntu Server 10.04 64 bits, 2.6.35 kernel
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
16
Contents Motivation. Skypeness. Performance Evaluation.
• Accuracy results.• Processing performance results.
Conclusion and Future work.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
17
Accuracy results Using 3 traces:
• T1 and T2: from 96-hour of only Skype traffic (PoliTo).• T3: Synthetic P2P (and no Skype) traffic (UAM).
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
Trace Skype Other FP(%) FN(%)
T1Bytes ~8GB 0 - 0.41
Packets ~40M 0 - 0.79
Flows ~1K 0 - 11.33
T2Bytes ~230M 0 - 5.88
Packets ~3M 0 - 6
Flows ~160 0 - 6.29
T3Bytes 0 ~1GB 0 -
Packets 0 ~5.3K 0 -
Flows 0 ~50 0 -
18
Processing performance results Receiving real traffic:
• Variable rate (100 Mb/s … 1 Gb/s).• Tcpreplay limitation to 1 Gb/s.• 1 Rx queue and 1 Skypeness instance:
– Only using 2 cores: 1 for receiving and 1 for detecting.– Located in NUMA nodes 1 and 4 respectively (worst case in
terms of distance).• Using Trace 4:
– 3G real traffic.– ~70M packets.– ~12M TCP/UDP flows.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
19
Processing performance results Receiving real traffic:
• No packet loss at 1 Gb/s. But… how about 10 Gb/s?
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
Bit rate [Mbps]
Packet rate [Kpps]
Max. Flow rate per second
Total Packet Loss Rate
100 30 ~26K 0
250 75 ~53K 0
500 150 ~90K 0
750 225 ~120K 0
1000 300 ~170K 0
20
Processing performance results Assigning a Rx queue per socket:
• Up to16 Rx queues and 16 detecting processes. Offline experiments:
• Read from memory (instead offrom the NIC).
– Bandwidth of DDR3: 170.6 Gb/s » Much greater than a backbone link.
• Skypeness instances and traces are located in memory as far as possible in terms of NUMA distance (worst case).
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
21
Processing performance results 3.7 Gb/s a single instance. 45 Gb/s using 16 instances. No perfect scaling due to serialized access to
shared memory by NUMA.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
22
Contents Motivation. Skypeness. Performance Evaluation. Conclusion and Future work.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
23
Conclusion Skypeness detects Skype traffic:
• With sufficient accuracy:– False negative rate of 6%.– False positive rate of zero.
• At high speed:– 1Gb/s and up to 3.4 Gb/s per instance (from NIC and
memory respectively).– Total throughput of 45 Gb/s with 16 instances.
• Using commodity hardware. Feasibility of Skype traffic detection at high-
speed networks (10-40 Gb/s) using commodity hardware.
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
24
Future (and present) work Capturing packets from a 10 Gb/s NIC:
• Using PacketShader capture engine. Online experiments at 10 Gb/s Apply methodology to
• other classes of traffic:– RTP (done!)– P2P
• other classification techniques:– DPI
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th
Thank you for your attention!
Questions?
On the processing time for detection of Skype trafficTRAC 2011 Istanbul, July 7th