Multi-granular, multi-purpose and multi-Gb/s monitoring on

off-the-shelf systems

TELE9752 Group 3

Agenda

•Introduction

•System Overview

•Performance Evaluation Results

•An Application Sample

•Related Work

•Conclusion

I. Introduction

What is it?• Multi-granular Identify an event in either flow records or packet data or both angles• Multi-purpose perform tasks in parallel different traffic-related purpose sharing granularities between apps

Why use it?• Low-cost• High performance in off-the-shelf systems• Provides flexibility between capturing and processing traffic interaction

TING TAN 2/5

TING TAN 1/3

Features Network trouble shooting• Traffic flows to mornitor the sudden changes(e.g. peaks)• Flow traces (e.g. identify the troublesome agents)• Traffic inspections for futher problem diagnose (e.g. lost packets)

Data Pre-processing• e.g. provides flow records to all apps (skip step of flow record creation)

Performance Conventional approach vs

Optimization techs• Low –level hardware affinities• Allow NIC driver and default stack optimizations• Software optimizations

TING TAN 2/3

3M Omon

Contributions

• API development for Multi-granular apps

• Construct data at different granularities – saving duplicated efforts • Works at multi-Gb/s rates after all Optimization

• Scalability ,available for open-source license

TING TAN 3/3

II. System Overview

HPCAP

• Kernel level module implementing network traffic sniffer, at real time.

• for each NIC to be monitored, a kernel-level thread is instantiated and assigned to its receive queue.

• For new packet, thread makes a copy to a kernel-level packet buffer

• Packet data are accessed on a single-producer/multiple-consumer basis.

M3 - OMON

• Consists of 3 sub modules –• Packet Dumper - reads fixed-size blocks of bytes

(e.g. 1 MB) from the buffer and writes them to disk.- an independent periodic process (e.g. CRON) is in charge of deleting old capture files when the volume is nearly full.

• Flow manager - flow reconstruction and statistic collection.

M3 - OMON

• Flow store - table indexed with a hash over the 5-tuple, handling collisions with linked lists.

• Maintains a list of active flows with each node containing a pointer to the flow record in the hash table.

• Periodically (e.g. every second) generates the MRTG statistics, both writing them to a file and sending them through a multicast socket.

M3 - OMON

• Flow exporter -different thread exports flow records, writing them to disk and using a multicast socket.- Flows may be exported in either an extended NetFlow or standard IPFIX formats.- Each Flow record - 5-tuple - MAC addresses, first/last packet timestamps, counters of bytes and packets, average/standard deviation/minimum/maximum for both packet length and inter-arrival times, TCP statistics (e.g. counters of flags or number of packets with TCP zero-window advertisements), the first 10 packet lengths and inter-arrivals and, if required, the first N bytes of payload, which is configurable.

M3 - Omon’s API

• provides real-time and offline access to the data gathered by the system, namely: raw packets (PCAP format), MRTG statistics and flow records. It has been designed taking as a reference the de facto standard PCAP library.

• Real time pkt data-applications to hook as HPCAP listeners and read packets using a packet loop function similar to pcap_loop implemented in the PCAP library.

• Exported flow recs and MRTG data - loop over the records subscribing to the corresponding multicast group.

III. PERFORMANCE EVALUATION RESULTS

This table shows the mean throughput and standard error of the mean when repeating the 10 min experiments 50 times, for both applications and for fixed-size line-rate synthetic traffic. It also shows both applications only lose packets in the worst-case scenario.

This table shows the mean and standard error of the mean for both system throughput and packet loss when receiving the CAIDA trace at link speed. And it shows the performance obtained by the complete M3Omon system.It also shows the overall performance when instantiating two forensic (offline) applications—one for packets and one for flows—and using all of the available cores for real-time flow record processing.

IV. An application sample: DETECTPRO

• It leverages leverages M3Omon to monitor network traffic without being concerned about lower-level tasks.

• DetectPro reads aggregate statistics to diagnose both short-term and long-term changes and reports the corresponding alarms.

• It selects and inspects packet traces corresponding to the alarm period.

Anomalous increase

The number of connections has increased in this time interval but the increment in the involved bytes and packets is not relevant.

Hosts in the subnets represented as 40.10.0.0/16 and 238.138.39.0/24, in directions A and B respectively, generated a huge number of SYN flag activated packets

V. Related work

• Capturing engines: PacketShader, PF_Ring, netmap, PFQ, and DPDK.

• System: Tstart, TM (time machine).• Hardware-accelerated monitoring center –

HAMOC.• Application: Blockmon, traffic classification,

NIDS.

Conclusion

• Propose a monitoring system architecture consist of three main blocks: – M3Omon– HPCAP– An API allowing Multi-granular data accessibility