1. QoS ( Intserv & Diffserv) BY ANJALI KULKARNI YI-AN CHEN

2. QoS Current Internet offers best effort service only As the Internet is the ubiquitous communications infrastructure, there is a clear need for providing differentiated classes of service to network traffic

3. What is Intserv Service differentiation in the Internet Focuses on individual packet flows Each flow requests specific levels of service from network Levels of service quantified as a minimum service rate, or a maximum tolerable end-to-end delay or loss rate Network grants or rejects the flow requests, based on availability of resources and the guarantees provided to other flows

4. Interserv Best effort service Real time service Controlled link sharing  Multi-entity link-sharing  Multi-protocol link-sharing  Multi-service sharing

5. Framework of IS Model Packet scheduler Admission control Classifier Reservation setup protocol(RSVP)

6. RSVP Path messages Resv messages PathErr, PathTear, ResvErr, ResvTear, ResvConf Messages Phop, Sender template, Tspec, Adspec Reservation style, Filter specification, Rspec, Tspec

7. Processing and Propagation of Path Messages by Network Routers Update the path state entry Set cleanup timer Create and forward Path message Any change to stored path state or a change in the set of outgoing interfaces in the data forwarding path Every refresh period timeout interval

8. RSVP

9. RSVP Filters

10. Factors Impeding Deployment of Intserv/RSVP Use of per-flow state and per-flow processing raises scalability concerns for large network The necessary policy control mechanisms have only recently become available

11. What is Diffserv Based on a model where traffic entering a network is classified, possibly conditioned at the boundaries of the network, and assigned to different service classes Here, we avoid complexity and maintenance of per-flow state information in core nodes and push unavoidable complexity to the network edges

12. What is Diffserv Provide scalable service differentiated in the internet that can be used to permit differentiated pricing of internet service Separate packet forwarding model from routing model

13. Terminology Per Hop Behavior(PHB) DS Domain( e.g. ISP, intranet) DS Boundary Node(Egress & Ingress) DS Interior Node DS Codepoint(DSCP) DS Behavior Aggregate

14. Terminology Bandwidth Broker (BB) ãLogical entity, can be mapped to a single or multiple physical entity ãA logical entity residing in each administrative domain managing internal demands & resources according to some policy database (who can do what where and when) ãSetting up & maintaining bilateral agreement with neighbor domains

15. Terminology SLA(SLS) & TCA(TCS) ãCustomer/Provider boundaries ãService Level Agreement A set of parameters and their values which together define the service offered to a traffic stream by a DS domain ãTraffic Conditioning Agreement A set of parameters and their values which together specify a set of classifier rules and traffic profile

16. SLA

17. Logical View of Packet Classifier and Traffic Conditioner

18. Terminology Classifier Traffic Profile Specifies the temporal properties of a traffic stream selected by a classifier. It provides rules for determining whether a particular packet is in- profile or out-of-profile BA Classifier MF Classifier

19. Terminology Traffic Conditioner Meter Marker Shaper Dropper Host Marking Router Marking

20. Service Taxonomy Quantitative Service Qualitative Service Relative Quantification Service Traffic offered at service level A will be delivered with low latency 90% of in profile traffic delivered at service level B will experience of no more than 50 msec latency Traffic with drop precedence AF12 has a higher probability of delivery than traffic with drop precedence AF13

21. Assured Forwarding (AF) Class As long as aggregate traffic from some sites connecting to internet does not exceed the subscribed information rate, forward packets with high probability AF PHB group - Forwarding of IP packets in N independent AF classes. Within each class, an IP packet is assigned M different levels of drop precedence Queuing and discard behavior

22. Expedited Forwarding (EF) Class Providing low loss, low latency, low jitter, assured bandwidth, end-to-end service through DS domains EF PHB A router uses policing and shaping mechanism to ensure that the maximum arrival rate of a traffic aggregate is less than its minimum departure rate

23. Working within a Domain

24. Step 1 Source sends request message to first hop router Step 2 First hop router sends request to BB, which sends back either a accept or reject Step 3 If accept, either source or first hop router will mark DSCP and start sending packets

25. Working within a Domain Step 4 Edge router checks compliance with SLA and does policing. Excess packets are either discarded or marked as low priority to comply with the SLA Step 5 Core routers will just look at DSCP and decide PHB

26. Intra-Domain Resource Allocation Architecture

27. Edge Router-BB Communication BB contains the flow database containing information regarding flows requesting increased level of service. It contains ingress/egress interface, resources requested, start/finish time BB sends the TCA to the domain’s edge routers

28. Edge Router-BB Communication COPS is used for this. BB’s COPS server TCA to COPS client residing at edge router COPS client translates these commands to parameters understood by forwarding path via the Forwarding path driver(FPD)

29. Interdomain Communication

30. Functions of BB Negotiation of SLAs with BBs of neighboring domains Translation of SLAs into one or several TCAs for edge devices Delivery of the TCAs to the edge routers of the administered domain, using one of many proposed protocols

31. Steps in Interdomain Communication Assumption Needs of domain 1 towards domain 3 are satisfied by a 64kb/s flow of premium traffic Step 1 BB1 learns internally that a 64kb/s SLA is needed Step2 BB1 requests the SLA from BB2, BB2 performs admission control

32. Steps in Interdomain Communication Step 3 If the request is admitted, BB2 sends a TCA derived from the SLA requested to R2( it’s administered edge router) Step 4 BB2 responds positively to BB1. This TCA models the traffic to be transferred from domain1 via R2

33. Steps in Interdomain Communication Step 5 A similar TCA is sent by BB1 to it’s administered edge router R1 instructing it to allow the given traffic to flow out to domain 2 Step 6 BB2 may request more premium resources from BB3 to aggregate the new premium traffic demand to the existing SLA between BB2 and BB3

34. Multicasting in DS Domain Neglected Reservation Subtree Problem (NRS) Heterogeneous Multicasting Groups Dynamic of Arbitrary Sender Change

35. NRS Multicast packet replication in a DS router

36. NRS cont.

38. Heterogeneous Multicasting Groups Participants requesting a best effort quality only should also be able to participate in a group communication which otherwise utilises a better service class Support heterogeneous groups with different service classes in a consistent way

39. Dynamics of Arbitrary Sender Change A sender resource must be reserved seperately if simultaneous sending delivery trees are used

40. Security Consideration Theft of service Denial of service

41. 2 Bit Differentiated Services Architecture for the Internet Premium service Premium service levels are specified as a desired peak bit rate for a specific flow Assured service Best-effort service

42. Block Diagram of First Hop Router Input Functionality

43. Markers to Implement the 2 Different Services

44. Border Router Input Interface Profile Meters

45. Router Output Interface for 2-bit Architecture

46. Statically Configured Example with no BB Messages Exchanged All allocations are statically preallocated through purely bilateral agreements between users. This negotiation is done by human repreentatives of each domain BBs perform function to allocate profile within their local domain

47. End-to-End Example with Static Allocation

48. End-to-End Static Allocation eg. with no Remaining Allocation

49. First Step in End-to-End Dynamic Allocation Example

50. Second Step in End-to-End Dynamic Allocation Example

51. Third Step in End-to-End Dynamic Allocation Example

52. Fourth Step in End-to-End Dynamic Allocation Example

53. Final Step in End-to-End Dynamic Allocation Example

54. Intserv Operation over Diffserv

55. Selecting an appropriate PHB for the requested service Performing appropriate policing at the edges of Diffserv region Exporting Intserv parameters from the Diffserv region Performing admission control on the Intserv requests

56. Statically Provisioned Diffserv Network Region RSVP messages carried transparently through the Diffserv network region The corresponding service level is determined by the Intserv to Diffserv mapping discussed previously

57. RSVP -Aware Diffserv Network Region Signaling between the Diffserv network region and network elements outside it

58. Comparison of Intserv & Diffserv Architectures