Packet Classification

1. Packet Classification Packet Classification, D.-C. Fleury & D. Francis, 2002-03-14. This document was prepared by Denis-Claude Fleury & Dany Francis in partial fulfillment of the requirements for the course ELG/CEG4183. Packet Classification Packet Classification

2. Presentation Summary What is Packet Classification Application fields of Packet Classification Background and problem definition Classification Example Algorithm of Packet Classification The following points will be covered in the presentation: What is Packet Classification Application fields of Packet Classification Background and problem definition Classification Example Algorithm of Packet Classification The following points will be covered in the presentation: What is Packet Classification Application fields of Packet Classification Background and problem definition Classification Example Algorithm of Packet Classification

3. What is Packet Classification? Packet Classification is: The function of identifying and categorizing packets of data moving across the network. [1] It allows network equipment to recognize the application and determine the Quality of Service (QoS) required. By answering WHY PACKET CLASSIFICATION, we will find what is Packet Classification. So why packet classification: Until recently, Internet routers provided only "best-effort"; service, servicing packets in a first-come-first-served manner. Routers are now called upon to provide different qualities of service to different applications which means routers need new mechanisms such as admission control, resource reservation, per-flow queueing, and fair scheduling. All of these mechanisms require the router to distinguish packets belonging to different flow. So Packet Classification is: Routers classify packets to determine which flow they belong to, and to decide what service they should receive. Classification may, in general, be based on an arbitrary number of fields in the packet header. Those fields include the source and destination IP address of IP header, and the port number of the transport layer. By answering WHY PACKET CLASSIFICATION, we will find what is Packet Classification. So why packet classification: Until recently, Internet routers provided only "best-effort"; service, servicing packets in a first-come-first-served manner. Routers are now called upon to provide different qualities of service to different applications which means routers need new mechanisms such as admission control, resource reservation, per-flow queueing, and fair scheduling. All of these mechanisms require the router to distinguish packets belonging to different flow. So Packet Classification is: Routers classify packets to determine which flow they belong to, and to decide what service they should receive. Classification may, in general, be based on an arbitrary number of fields in the packet header. Those fields include the source and destination IP address of IP header, and the port number of the transport layer.

4. Application fields of Packet Classification Packet classification is important for applications such as: Those that require security features such as Firewalls; Intrusion detection; Internet Telephony; Audio over IP and video over IP; Differentiated services. This is essential to applications that require real-time delivery of data such as Internet Telephony, audio over IP, video over IP, and those that require security features such as VPNs and Firewalls. This is essential to applications that require real-time delivery of data such as Internet Telephony, audio over IP, video over IP, and those that require security features such as VPNs and Firewalls.

5. Background and problem definition Background: Internet: Mesh of Routers [2] Requirements for Routers: Must perform an IP datagram forwarding decision (called forwarding) Must send the datagram out the appropriate interface (called switching) SEE DOCUMENT INTERNET.HTM Optionally: a router MAY choose to perform special processing on incoming packets Requirements for Routers: Must perform an IP datagram forwarding decision (called forwarding) Must send the datagram out the appropriate interface (called switching) SEE DOCUMENT INTERNET.HTM Optionally: a router MAY choose to perform special processing on incoming packets

6. Background and problem definition (Cont’d) Background: Flow-aware router: keeps track of flows and perform similar processing on packets in a flow Flow-unaware router (packet-by-packet router): treats each incoming packet individually Why Flow-aware Router? ISPs want to provide differentiated services Routers require additional mechanisms: admission control, resource reservation, per-flow queueing, fair scheduling etc. Capability to distinguish (classification) and isolate traffic belonging to different flows based on negotiated service agreements (Rules or policies) Why Flow-aware Router? ISPs want to provide differentiated services Routers require additional mechanisms: admission control, resource reservation, per-flow queueing, fair scheduling etc. Capability to distinguish (classification) and isolate traffic belonging to different flows based on negotiated service agreements (Rules or policies)

7. Background and problem definition (Cont’d) Background: Motivation of Packet Classification is the need for Differentiated Services [3]