Presentation on theme: "Addition of Virtual Interfaces in NetFlow Probe for the NetFPGA Muhammad Shahbaz Zaheer Ahmed Habibullah Jamal Asrar Ashraf Nadeem Yousaf Raania."— Presentation transcript:
1 Addition of Virtual Interfaces in NetFlow Probe for the NetFPGA Muhammad Shahbaz Zaheer Ahmed Habibullah Jamal Asrar Ashraf Nadeem Yousaf Raania Naeem Khan
2 Presentation Organization NetFlow OverviewVirtual Interfaces in NetFlowHardware Architecture of NetFlow probeSoftware Architecture of NetFlow probeSample Netflow RecordExtended ApplicationsConclusionDemonstration SetupQuestions / Answers
3 NetFlow OverviewNetwork Protocol developed by Cisco for Collecting IP traffic informationCisco proprietary but supported by other platforms like Juniper, Linux etc.Netflow enabled routers/probes generate netflow recordsExported via UDP or SCTP to data-collectorsNetflow record identified traditionally by 7-Tuple keys formed by combiningSource IPDestination IPSource port for UDP or TCP and 0 for other protocolsDestination port for UDP or TCP and 0 for other protocolsIP protocolIngress interfaceIP Type of Service(TOS)Netflow Records contain extensive information regarding traffic flow including Version, Sequence number, ingress interface, timestamp and other data statistics of particular data flow.A netflow is a network analysis protocol designed by the Cisco systems for collecting IP traffic information. Though initially developed by Cisico, netflow is now supported by various platforms like Juniper and Linux etc. Netflow enabled routers and probes generate netflow records that are exported to different local and remote data-collectors over UDP or SCTP protocol. A netflow record is normally identified as a 7-tuple key formed by a combination of …. . These netflow records contain extensive information regarding the IP traffic flowing through the network. Information includes IP version, TCP packet sequence number, input interface, timestamp and various other information regarding the data flow. Currently the implemented design only provides support for IPv4 packets.
4 NetFlow Overview (contd. ) Net Flow Applications Network PlanningRMON ProbeRMON ApplicationAccounting/BillingNetFlow FlowCollector:Data CollectionData FilteringData AggregationData StorageNetFlow Data Export:Data SwitchingData AggregationData ExportNetwork Data Analyzer:Data PresentationFlow Control and ConfigurationPartner ApplicationsImage From NetFlow PPT by Michael Lin, Cisco Systems
5 NetFlow Overview (contd.) Standalone NetFlow Architecture In order to avoid the limitations laid down by the router-based approach for netflow analysis a new approach using dedicated probes is becoming very popular. The implementation of NetFlow on NetFPGA is an example of such probe. In the standalone netflow architecture these probes are connected to the monitored links as a totally passive entity using TAPs. These probes export netflow information over a dedicated link established between the collectors and the probes themselves, making them completely invisible to the monitored links.Image From Wikipedia, NetFlow
6 Virtual Interfaces in NetFlow Virtual interfaces are usually found in technologies likeLayer 2 Tunneling Protocol (L2TP)Generic Routing Encapsulation (GRE) tunnelsMultiprotocol Label Switching over Virtual Private Network (MPLS-VPN)Collect network flow information from L2TP, GRE and MPLS enabled networksVirtual interfaces are usually found in technologies like L2TP, GRE, and MPLS-VPN. … . … . Our purpose is to demonstrate the scalability and flexibility of the implemented architecture to support any new protocol in the existing netflow design for flow analysis.
7 Hardware Architecture of NetFlow Probe Here is the hardware architecture of our NetFlow probe design. The IO Queues for Ethernet and PCI, the input arbiter and Output Queues are taken from the netFPGA platform. We have used the user data path of the original netFlow probe design as reference. The major modification is the addition of multi-layer protocol extraction block in the output port lookup. The record wrapper module in refer has been replaced with the OPL processor. Another modification is the placement of Timestamp module outside the output port lookup, just after the input arbiter. This is done to make the timestamp block independent of the main pipeline i.e. output port lookup.
8 Multi-Layer Protocol Extraction Block Composed of following protocols:original L3/L4 block provided with the reference NetFlow designMPLS block for the extraction of multi protocol label switched packets with support for only two labels,GRE block for the parsing of GRE encapsulated protocol packetsL2TP block for mining layer 2 tunneled PPP packetsFuture protocols.Architecture of Multi-Layer Protocol Extraction consists ofPacket Monitor that tracks the state of the packet during the extraction processa configurable stack of protocol combinationsa Multi-stage Priority Multiplexer.The multi-layer protocol extraction block is the heart of our design. The extraction of exact and accurate flow records from different combination of layers is a crucial task. Currently the protocols supported by the extraction block are: (1) the L3L4 protocol (2) multi-protocol label switching MPLS protocol with support for only two labels (3) Generic Routing Encapsulation protocol and (4) layer 2 tunneled PPP packet L2TP protocol.The architecture of the Multi-layer protocol extraction block consists of (1) a Packet monitor that tracks the state of the packet during the extraction process (2) a configurable stack of protocol combinations and (3) a multi-stage priority MUX.
9 Multi-Layer Protocol Extraction Block (contd.) Multi-Stage Protocol Extraction PipelinePacket Monitor broadcasts packet words to all components with a latency of 2 cyclesHeader Information extracted after n+2 cycles delayn is either total number of words taken by the protocol combination with largest header or size of incoming packet which ever is smaller.Total latency for the example shown below is be n+7 cyclesHere you can see the complete pipeline of the protocol extraction block. The Packet Monitor broadcasts the received packets to all the protocol combination blocks with a latency of 2 cycles. These blocks extract the flow information from the packet header in n+2 cycles. Here n is equal to the total number of words taken by the largest protocol combination i.e. supported packet with largest header however, if the incoming packet is smaller than the size of the largest protocol combination then n is equal to the size of the incoming packet. The total latency observed for the configuration shown in the diagram is n+7 cycles, including the 3 cycles latency for the Multiplexer.
10 Multi-Layer Protocol Extraction Block (contd.) MPLS Decoding and ExtractionMultiple Protocol Label Switching (MPLS) tunnels are detected based on lower layer protocol type field as 0x8847Detection of Upper Layer Protocol is not defined in MPLS Standard DocumentsUpper Layer Protocols are detected based on byte pattern detection and verification.Currently IP Protocol Detection is supported as MPLS upper layer protocol.Flow for IP DetectionCheck for final MPLS header from ‘Bottom of Label Stack’ fieldCheck top nibble of first byte after MPLS header (0x4 for IPv4 and 0x6 for IPv6).Check Lower Nibble as Header LengthTreat it as IPv4 or IPv6 Packet and verify Length of remaining packet from expected Total Length field of IP headerIf verified, Upper Layer Protocol is IPv4 or IPv6Else It is treated as Ethernet packetSupport for Any other Protocol above MPLS can be very easily added due to the scalable architecture of the design.MPLS tunnels are detected on the basis of lower layer protocol type field with value 0x8847. The detection of upper layer protocol is not defined in the MPLS standard documents. So in order to find out the type of protocol we have adopted a byte pattern and verification model. Currently the system supports only IP protocol detection as MPLS upper layer protocol.
11 Multi-Layer Protocol Extraction Block (contd.) MPLS with IP as upper layer protocolMPLS DetectionBottom of Label Stack as 1Values extracted from 1st ByteIPv4, Header length=20Verification from Total length field confirms whether IP packet or not.Here is an example of MPLS packet with IP as an upper layer protocol. From the Ethernet type field we see that the next protocol in the stack is MPLS. Next we look for the MPLS bottom of the label stack with value 1, indicating that it’s the last MPLS header. The next nibble just after the last MPLS header is checked for IP version (4 for IPv4). If result is true, as in our case it is, we calculate the sum of all the header lengths and the total length from the IP header field and compare it with the byte count calculated by the receive queue at the reception of the packet. If its verified the upper layer is marked as IP.
12 Multi-Layer Protocol Extraction Block (contd.) GRE Decoding and ExtractionGeneric Routing Encapsulation (GRE) tunnels detected based on lower layer protocol type field as 0x2fSample GRE packetGRE DetectionGRE Upper Layer protocolThe decoding of GRE packets is very straight forward. The GRE tunnels are detected on the basis of lower layer protocol type field. The upper layer protocol is detected using the protocol type field in the GRE header.
13 Multi-Layer Protocol Extraction Block (contd.) L2TP Decoding and ExtractionL2TP Decoding Performed only on UDP Port Number 1701Sample L2TP PacketL2TP DetectionL2TP tunneled packets are always encapsulated in UDP. The L2TP decoding is performed only on the basis of UDP port number as Normally L2TP carries Point to point protocol as its upper layer protocol. The presence of the IP layer is then detected by the protocol type field of the PPP header.
14 Software Architecture of NetFlow probe The host software provided with the original netflow design has been upgraded to provide support for virtual interfaces (GRE, L2TP, and MPLS). The other basic functionalities like configuration, statistical interfaces and information collection remain the same.
15 Resource UtilizationOnly about 3% extra resources were used to incorporate the support for GRE, MPLS and L2TP ProtocolsTable 1: Resource utilization of the Current Architecture with Virtual Interfaces (MPLS, L2TP, and GRE) plus l3l4 protocolTable 2: Resource utilization of the Original NetFlow probe Architecture with only l3l4 protocolResourcesXC2VP50UtilizationUtilization PercentageSlicesout of 2361677%4 - Input LUTS25165 out of 4723253%Flip Flops21244 out of 4723244%Block RAMs200 out of 23286%ResourcesXC2VP50UtilizationUtilization PercentageSlicesout of 2361674%4 - Input LUTS23319 out of 4723249%Flip Flops19504 out of 4723241%Block RAMs200 out of 23286%The resource utilization of the original NetFlow probe architecture and the current architecture is shown in Table 1 and Table 2 respectively. Even though three different technologies of virtual interfaces (GRE, L2TP and MPLS) have been incorporated in the current design, yet there is only an average increase of 3% in the overall utilization of the resources.
16 Sample Netflow (Cflow) Record NetFlow (CFlow) PacketsUsing UDP as Export TransportTop Header of NetFlow RecordThis is a sample output generated from our system. As Shown in Packet, UDP is used for tranporting netflow records. Main Netflow Header contains basic fields like version, count, timestamp and other standard fields. At the end, there is pdu containing statistics regarding a particular flow.Data PDU NetFlow Record
17 Extended Applications Deep Packet Inspection (DPI) based VoIP MonitoringTelecom Regulatory Authorities PerspectiveVoIP Header and RTP Monitoring for illegalV oIP Identification and MitigationScalability Tested for upto 40G Data Rates using HighTech Global CardsFlexible Protocol addition
18 ConclusionPresented a generic protocol extraction layer for Netflow probe architecturePrimary focus on extraction mechanism for technologies supporting virtual interfaces i.e. MPLS, L2TP and GREThe architecture finds applications inDeep Packet Inspection (DPI)Voice over IP (VoIP) monitoringAccounting /BillingIn this paper we presented an architecture of a generic protocol extraction layer for NetFlow Probe with primary focus on the extraction of technologies supporting virtual interfaces like MPLS, L2TP and GRE. The architecture finds applications in Deep packet inspection, Voice over IP monitoring and other applications like accounting and billing.
19 System Demonstration Setup for Multi-Gigabit networks NetFPGA(Traffic Generator)NetFPGA(Netflow Probe)Remote CollectorThis is the demonstration setup for our netFPGA netFlow probe with virtual interfaces. We have a netfgpa card mounted on a linux system acting as a standalone netflow probe. The remote collector is connected to the probe through an ethernet interface.We have used another netfpga card for traffic generation in order to simulate traffic for L2TP, GRE and MPLS. The traffic generator communicates with the probe using an ethernet interface.
20 System Demonstration Setup for Multi-10Gigabit networks Avnet PCIe Card(10G Traffic Generator)Remote CollectorI would like to mention here that at CASE, we have also implemented the similar architecture of netFlow probe using a hitech global PCIE card with 4 10g interfaces. The configuration of the board is similar to the netFPGA excpet that now we have 10g interfaces instead of 1G and a PCIe interface instead of PCI for host connectivity.For simulating network traffic for MPLS, L2TP and GRE we have used an Avnet PCIe card as a 10G traffic generator.Hitech Pcie 40G Card(Netflow Probe)
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