Internetworking and QoS Classical IP

Internetworking and applications QoS ATM’s first use was: high-speed backbone for data traffic –Architectures which allow existing data networks, internetworking devices and end systems, to connect to an ATM network Data architectures –Create a Layer 3 overlay across the ATM network –Integrate the ATM layer with Layer 3 Classical IP over ATM –ATM as a link-layer –Gains: support of greater bandwidth, QoS for a connection Bridged environment over the ATM (LAN Emulation) –Provides the link-layer connectivity for Multi-Protocol over ATM (MPOA) Peer Model –Peer the internetwork address with ATM addressing –Traditional routing protocols control the ATM forwarding path

Internetworking and applications QoS LightWeight subnet – minimize the amount of IP header overhead transported across the ATM network once a binding has been established via signaling mechanisms –TCP and UDP aver Lightweight IP (TULIP) AAL5 will ensure that packets are not fragmented or misordered, and will also indicate the packet size –TCP and UDP over a Non-existed IP Connection (TUNIC) No layer 3 information is carried across the ATM network Applications will communicate via a dedicated VC utilizing TCP or UDP directly over AAL5

Internetworking User Applications IP, IPX, etc OSPF, NLSP, etc ATM Signaling And Routing ATM Physical User Applications IP, IPX, etc OSPF, NLSP, etc ATM Signaling And Routing ATM Physical ATM Signaling And Routing ATM ATM Signaling And Routing ATM Edge Device (a) IP(a), ATM(a) Edge Device (b) IP(b), ATM(b) Switch (c) ATM(c) Switch (d) ATM(d) Layer 3 Routing IP(b) via ATM(b) ATM overlay model (Source: Cisco Systems)

Internetworking Network layer –Responsible for end-to-end connectivity –Based on logical and topological addressing –Addressing at Layer 3 is protocol dependent Routing –Routing protocols: protocol specific or suitable for two or more internetwork protocols (IP, IPX, …)

Application QoS and resource reservation Integrated Services Internet model Resource Reservation Protocol (RSVP) IP Precedence

The Integrated Services (IS) Internet model Real-Time (RT) QoS with control over end-to-end delay Support for multicasting Ability to assign percentages of a physical link bandwidth to different traffic classes Real-TimeElastic IntolerantTolerant Interactive Burst Interactive Bulk Asynchronous Bulk GuaranteedControlled LoadBest Effort Traffic Classes

The integrated Services (IS) Internet model Support of different QoS for real-time applications in addition to the traditional Best Effort service Traffic control –Packet scheduler – determines which packets will be transferred to the physical medium and in what order –Classifier – maps incoming packets into a given class for equal treatment by the packet scheduler –Admission control – determines whether or not a new flow may be established without affecting existing sessions –The ability to mark some packets as eligible for discard under network congestion

Resource ReSerVation Protocol (RSVP) RSVP reservation –Flow spec – application QoS requirements (bandwidth, delay) –Filter spec – determines to witch packets the flow spec will apply The protocol operates in simplex mode RSVP-enabled network –Sources characterize their flows by generating PATH (TSPEC) messages, transmitted downstream (source to receivers) along the data packet route as determined by the unicast or multicast routing protocol –A receiver will generate an RESV (RSPEC) message, that is sent hop- by-hop upstream to the unicast address of the previous RSVP hop –The RESV message is used by the sender to set first hop traffic parameters

IP precedence IP header contains IP precedence bits This field has existed since the first deployment of IP Represents different levels of priority for user traffic (IP Class of Service) –i.e. 2 - standard traffic, 4 - premium traffic

IP QoS to ATM QoS interworking Layer 3 Peer 1 Layer 3 Peer 2 ATM One VC – maximum service guarantee Layer 3 Peer 1 Layer 3 Peer 2 ATM One VC for each priority -One VP at maximum QoS -Two VPs -one for real-time traffic - one for best-effort -Weighted Fair Queuing (WFQ) on the packet side of the ATM interface

IP QoS to ATM QoS interworking Integrated service specification GuaranteedControlled loadBest effort End-to-End behavior Guaranteed max delay Best-effort on unloaded net Best-effort only Intended applications Real-timeSensitive to congestion Legacy Control mechanism Leaky bucket, Reserved rate and WFQ Leaky bucketNone ATM mappingCBR, rt-VBRnrt-VBR, ABR w/ MCR UBR, ABR Integrated Service Specifications Applicable to RSVP Applicable to IP Precedence by choosing proper values

Deploying QoS and the ATM Programming Interface API – map application QoS requirements to ATM Virtual Channel Connection (VCC) parameters Applications RSVPPIMFlow SpecsFlow IDs Packet Scheduling ATM Signaling VC Routing Traffic Contract VPI / VCI Traffic Mgmt GuaranteesRequests API Integrated Services Internet ATM

WinSock 2 Independent of a specific Layer 3 protocol or any Layer 2 network Supports QoS, allows applications to utilize both pt-pt and pt-mpt VCCs, and uses ATM addressing QoS support within WinSock 2 is based on the flow specification –Source traffic description (token bucket size and token rate) –Latency (time elapsed between a bit sent by the sender and arrival at the destination), delay variation (the difference between the minimum and maximum latency)

WinSock 2 PC Windows implementation Application WinSock 2 IPXSNANetBeuiTCP/IP Direct AAL access Direct Protocol Access Eth./TRN ATM Adaptation Layer (AAL) ATM Layer Physical Layer 155 Mbps ATM | 25.6 ATM Ethernet & Token Ring Mac Driver Eth. / TRN Adapter MMF (fiber)UTPSTP LAN Emul. Clas. IP Signaling

Classical IP and ARP over ATM ATM network acting as a replacement for existing Layer 2 ATM cloud treated as a single or as multiple Logical IP Subnets (LISs) Classical IP and ARP over ATM (Classical model) –Routers to connect members of different LISs –Address resolution over the ATM network (ATMARP) and Inverse ATM Address resolution protocol (InATMARP) – for only a single LIS Classical IP and ARP WAN over ATM –ATM as a core network (subnetwork) –Users, each on separate IP networks, will interconnect via the ATM network

Multicasting and broadcasting Differences between internetwork and ATM multicast Internetwork multicastingATM multicasting BidirectionalUnidirectional Multipoint-to-MultipointPoint-to-Multipoint Receiver-initiated joinSender-initiated join (UNI 3.0/3.1) Leaf-initiated join (UNI 4.0) ConnectionlessConnection oriented Open-group (non-members may send)No multicast ‘group’ concept at present

Multicasting and broadcasting Two new entities within an ATM network –Multicast Address Resolution Server (MARS) –Multicast Server (MCS) (optional) – used for mpt-mpt sessions Broadcasting –A special case of multicasting –A group containing all hosts –The MARS maintain the registry of all group members, in this case all end systems within the LIS

Optimizing routing Next Hop Resolution Protocol (NHRP) –Extension of the Classical model and the Non-Broadcast Multi-Access (NBMA) Address Resolution Protocol (NARP) –An IP source station will use NHRP to determine the best IP and link layer (NBMA) address to use to reach a destination station Next Hop Servers NS1 NS2NS3 NS4 NH-Requests Source (S) Destination (D) NH-Reply Direct Connection Single VCC LIS1LIS2LIS3LIS4 ATMARP LIS1LIS2LIS3LIS4 4 VCCs

IPv6 IP Version 6 Header: VersionFlow Label Payload LengthTypeHops Source Address (16 Octets) Destination Address (16 Octets) Options Requirements: Real Time support Hierarchical Addressing and IPv4 Compatibility; Autoconfiguration Source Routing, Authentication, Encryption, etc Unicast, Multicast and Broadcast support