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Software Defined Networking (SDN) for ISP Networks01...Software Defined Networking (SDN) for ISP...

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Network Architectures and Services, Georg Carle Faculty of Informatics Technische Universität München, Germany Software Defined Networking (SDN) for ISP Networks Syed Naveed Abbas Rizvi Supervisors: Prof. Georg Carle M.Sc. Florian Wohlfart M.Sc. Daniel Raumer
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  • Network Architectures and Services, Georg Carle

    Faculty of Informatics

    Technische Universitt Mnchen, Germany

    Software Defined Networking

    (SDN) for ISP Networks

    Syed Naveed Abbas Rizvi

    Supervisors:

    Prof. Georg Carle

    M.Sc. Florian Wohlfart

    M.Sc. Daniel Raumer

  • Software Defined Networking (SDN) for ISP Networks 2

    Agenda

    Introduction

    ISP Networks

    Software Defined Networking

    Introduction to RouteFlow

    Behavior of RouteFlow

    Conclusion

  • Software Defined Networking (SDN) for ISP Networks 3

    Introduction

    Evaluation of SDN for ISPs

    Focus is on datacenter networks

    Fewer efforts for ISP networks

    RouteFlow used as a SDN solution

    Test cases for characterization

  • Software Defined Networking (SDN) for ISP Networks 4

    ISP Networks

    ISPs provide network based services. Internet access, VPN, VPLS etc.

    ISPs implement internal functions. Routing, traffic engineering, monitoring, failure

    recovery, billing etc.

    Interacts with customers and other ISPs

    Core-edge arrangement

    Geographically distributed network

    Vertically integrated devices

  • Software Defined Networking (SDN) for ISP Networks 5

    Challenges for ISPs

    Demand for swift service deployment

    Dependence on vendor development lifecycle

    Slow and manual device configurations

    Difficulty in customization for diverse customers

  • Software Defined Networking (SDN) for ISP Networks 6

    Software Defined Networking (SDN)

    A new concept proposed by Open Networking

    Foundation (ONF)

    Separation of the control and the data planes

    Centralized controller with global network view

    Programmable control of network

    Feature Feature

    Operating System

    Specialized Packet Forwarding Hardware

    Feature Feature

    Operating System

    Specialized Packet Forwarding Hardware

    Feature Feature

    NetworkOperatingSystem

    PacketForwardingHardware

    PacketForwardingHardware

  • Software Defined Networking (SDN) for ISP Networks 7

    SDN Components

    Physical or virtual switches/datapaths

    OpenFlow protocol

    Messages, flow tables, match fields, actions, counters

    Network Operating System(NOS)

    Control processes & network view

    Network Applications

    VPN, VPLS, BWoD, managed routers, MPLS tunnel creation, traffic engineering etc.

  • Software Defined Networking (SDN) for ISP Networks 8

    RouteFlow

    Enables legacy routing in OpenFlow networks.

    Utilizes distributed virtual control plane.

    Enables transparent operation with non OpenFlow networks.

  • Software Defined Networking (SDN) for ISP Networks 9

    RouteFlow Configuration

    Static and manual configuration

    Runtime changes in network are not supported

    Two step configuration process

    Router virtual machine (VM) creation

    Router virtual machines to OpenFlow switch

    mappings

  • Software Defined Networking (SDN) for ISP Networks 10

    RouteFlow Operation

    Multiple mapping modes

    Logical split (1:1)

    Router multiplexation (1:n)

    Router aggregation (m:1)

  • Software Defined Networking (SDN) for ISP Networks 11

    RouteFlow Flow Table Installation

    Types of flows Fixed Flows (FF)

    Variable Flows (VF)

    Total Flows (TF) = FF + VF

    VF depends on Number of ports (NP)

    Directly (DC) & indirectly connected (IC) network destinations

    VF = (NP - 1) x (DC + IC)

    Flow Type Fixed Flows (FF) Variable Flows (VF)

    Installation Proactive Proactive & reactive

    Priority 32800 Depends on prefix length

    Number 10 variable

    Packet Types BGP, OSPF, ICMP, ARP etc. IPv4

  • Software Defined Networking (SDN) for ISP Networks 12

    Relation between Routing & Flow Tables

    One to many relation between routing and flow table entries

    Each routing table entry cause (NP-1) flow table entries

    Total BGP prefixes = 0.5 million

    OpenFlow table size required ~ 5 million for a 10 port switch

    Wildcard Input port match field or use FIBIUM like approach

  • Software Defined Networking (SDN) for ISP Networks 13

    RouteFlow Behavior

    Topology independent test cases

    Control traffic handling

    Data traffic handling

    Failure handling

    RouteFlow specific

  • Software Defined Networking (SDN) for ISP Networks 14

    Control Traffic Handling in RouteFlow

    ARP packet flow

    b1

    RFClient

    Veth Tunnels

    OF Packet Out

    tcp: controller ip:port=6633

    tcp: controller ip:port=6633

    e2 B e1

    e1 e2

    e0

    a1 a2

    Router B

    RFClient

    lxcbr0

    Veth Tunnels

    RFServer

    Mininet

    ICMP Request

    OF Packet In

    Starting Point

    e2 e1

    e0

    b2

    a0

    e1 A e2H1 e1 e1 H2

    RFVS (dp0)

    POXRFProxy

    Router A

    b0

    Mongo DB

    ICMP Reply

  • Software Defined Networking (SDN) for ISP Networks 15

    ARP Packet Flow

    No ARP processing in OF switches

    Reactive flow installation for the host

    Unicast ARP queries during running IP flows

  • Software Defined Networking (SDN) for ISP Networks 16

    Control Traffic Handling in RouteFlow

    High priority ICMP, BGP etc. flow table entries

    b1

    RFClient

    Veth Tunnels

    OF Packet Out

    tcp: controller ip:port=6633

    tcp: controller ip:port=6633

    e2 B e1

    e1 e2

    e0

    a1 a2

    Router B

    RFClient

    lxcbr0

    Veth Tunnels

    RFServer

    Mininet

    ICMP Request

    OF Packet In

    Starting Point

    e2 e1

    e0

    b2

    a0

    e1 A e2H1 e1 e1 H2

    RFVS (dp0)

    POXRFProxy

    Router A

    b0

    Mongo DB

    Requires Modification in RouteFlow

  • Software Defined Networking (SDN) for ISP Networks 17

    Analysis

    Control packets sent to routers at each hop

    Fine for OSPF, RIP, ARP packets but adds extra

    delay for ICMP, BGP packets

    Adds extra traffic on RFVS & OF Controller link

    Decrease the priority for ICMP, BGP control flows

    Increase flow table lookup delays inside switch

  • Software Defined Networking (SDN) for ISP Networks 18

    Analysis(2)

    Avoid unicast ARP packets between transit

    routers

    ICMP packets for specific router sent to controller

    Similar modification is useful for BGP packets

  • Software Defined Networking (SDN) for ISP Networks 19

    Traceroute in RouteFlow

    Tool for route and transit delay discovery

    ICMP & UDP probe packets

    ICMP probe yields two different results High priority flow >>> 4 hops

    Low priority flow >>> 1 hop

    No TTL decrement in OpenFlow 1.0

    UDP probe detects only 1 hop

    Legacy networks connected via RouteFlow network

    Number of hops remain unknown

    Host1Switch

    AHost2

    Switch

    C

    Switch

    B

    Requires newer OpenFlow version

  • Software Defined Networking (SDN) for ISP Networks 20

    Host1Switch

    AHost2

    Switch

    C

    Switch

    B

    Port & Link Failure in RouteFlow

    Port failure cause port status modification

    messages

    Link failure is simulated to avoid status change

    messages

    Host1Switch

    AHost2

    Switch

    C

    Switch

    BHub

  • Software Defined Networking (SDN) for ISP Networks 21

    Port & Link Failure...(2)

    No response to status modification messages

    Relies on OSPF dead interval for recovery

    Slow recovery process approx. 10sec for 4 sec

    OSPF dead interval

    MPLS FRR ~ 50 ms recovery time

    Requires Modification in RouteFlow

  • Software Defined Networking (SDN) for ISP Networks 22

    UDP/TCP Packet Flow

    Similar forwarding response

    Both UDP/TCP Packet drops at egress switch B

    No flow entry for Host 2

    No ICMP error report to source Host 1

    Require a generic IPv4 flow entry in edge switches

    Host1Switch

    AHost2

    Switch

    C

    Switch

    B

    RouteFlow Problem

  • Software Defined Networking (SDN) for ISP Networks 23

    Link Failure between Controller & Switches

    SDN/OF specific failure

    Two scenarios tested Link failure with complete network

    Link failure with few switches

    UDP, TCP and ICMP flows used

    Switches retained flow tables for complete failure

    Switches with link to controller received flow modifications

    Host1Switch

    ASwitch

    B

    Host3

    SwitchC

    SwitchD

    Host2

    Host4

    Complete

    Failure

    Partial Failure

  • Software Defined Networking (SDN) for ISP Networks 24

    Link Failure between Controller & Switches(2)

    Running flow in both scenarios stopped after some

    random time

    No backup controller in OF 1.0

    Main cause of flow disruption is unsuccessful ARP

    queries

    Impossible to start new flows using affected switches

    Flow recovery in second scenario if alternative path

    available

    SDN & OpenFlow

    Problem

  • Software Defined Networking (SDN) for ISP Networks 25

    Router VM State Modification

    Specific to RouteFlow

    Unexpected failure or planned state modification

    Recover from planned state modification

    Unable to recover from VM failures

    Manual effort required to recover from VM failure

    Host1Switch

    ASwitch

    B

    Host3

    SwitchC

    SwitchD

    Host2

    Host4

    VM freezes

    VM fails

    Requires Modification in RouteFlow

  • Software Defined Networking (SDN) for ISP Networks 26

    Router Multiplexation Mode

    Logically isolated network segments

    Isolation not achieved in OF network

    Flows for all ingress ports

    Require modification in RouteFlow

    Somewhat similar to virtual routing & forwarding (VRF)

    Host2Host1

    Switch

    A

    Host4

    Switch

    B

    Host3

    Requires Modification in RouteFlow

  • Software Defined Networking (SDN) for ISP Networks 27

    Router Aggregation

    Single router for multiple switches

    Linear and full mesh topologies

    Requires configuration of inter switch links

    No flow entries for switch C except fixed flows

    Switch A and B have flow entries for directly connected host

    Linear topology do not utilize ISL for data packets

    Host1Switch

    AHost2

    Switch

    C

    Switch

    B

    Requires Modification in RouteFlow

  • Software Defined Networking (SDN) for ISP Networks 28

    Router Aggregation(2)

    All ISLs are used for data packets

    All switches have host specific flow entries for all hosts

    Requires full mesh topology for proper aggregation

    Useful for isolation between intra and inter domain routing

    Host1Switch

    AHost2

    Switch

    C

    Switch

    B

    Host3

  • Software Defined Networking (SDN) for ISP Networks 29

    BGP Router Aggregation

    EBGP speakers aggregated for a domain

    Routers in AS100 for switch 102 & 103

    No IBGP session required between switch 102 &103

    Easy to manage single router

    Host2

    Host1

    Switch102

    Host3

    Switch103

    Switch101

    Switch201

    AS100

    AS200

  • Software Defined Networking (SDN) for ISP Networks 30

    Miscellaneous Test cases

    DHCP server in RouteFlow routers

    Interfacing with customer routers

    Some interesting future scenarios

    Multipath routing

    Multicast routing

    MPLS switching

    QoS related tests

  • Software Defined Networking (SDN) for ISP Networks 31

    Conclusion

    RouteFlow as a SDN solution

    Separation of the control and data plane

    Centralized controller

    Distributed routing

    No abstraction for network applications

    Other SDN solutions

    OPEN : MPLS TE, VPN

    Mutilflow : Multicast routing

    Inter AS routing component

    ONIX : Distributed controller paltform

  • Software Defined Networking (SDN) for ISP Networks 32

    Conclusion(2)

    RouteFlow is not a very good SDN solution

    Require changes in RouteFlow implementation

    Integration with other SDN solutions

  • Software Defined Networking (SDN) for ISP Networks 33

    Future Work

    Isolation between Inter & intra domain routing

    Centralized routing for intra domain destinations

    Integration with other SDN solutions

    Provision of APIs for network applications

  • Software Defined Networking (SDN) for ISP Networks 34

    Questions

  • Software Defined Networking (SDN) for ISP Networks 35

    RouteFlow Components

    RFServer

    RFClient

    RFProxy

    RFProtocol

    RouteFlow virtual switch (RFVS)

    Management Switch

    Inter-process communication (IPC) Database

    OpenFlowPhysicalNetwork

    Switch1

    OpenFlowController

    ManagementNetwork

    ManagementSwitch

    RFServer

    IPCDBVirtualControl

    Plane

    Router1VM

    RouterNVM

    RFProxy

    RFV

    S

    IPC

    IPC

    VethTunnels

    SwitchN

  • Software Defined Networking (SDN) for ISP Networks 36

    RouteFlow Operation

    Management switch & IPC database is initialized

    Router VMs & OpenFlow controller is started

    RFServer with configured mappings is started

    RFVS is connected to OF controller and router

    VMs

    OpenFlow switches are added to the network

  • Software Defined Networking (SDN) for ISP Networks 37

    RouteFlow Operation

    Routing tables are built

    Proactive and reactive flow table entries are

    installed in switches

  • Software Defined Networking (SDN) for ISP Networks 38

    RouteFlow Flow Table Installation(2)

    Directly and indirectly connected network destinations for A.

    Directly connected (DC) destinations for A = N + 2

    Indirectly connected (IC) subnets for A = 1

    VF = (NP - 1) x (DC + IC)

    IC flows are subnet specific & DC flows are network address specific

    Host1

    Host2

    HostN

    L2SwitchSwitch

    A

    SwitchC

    SwitchB

  • Software Defined Networking (SDN) for ISP Networks 39

    Control Traffic Handling in RouteFlow

    High priority flow table entries

    b1

    RFClient

    Veth Tunnels

    OF Packet Out

    tcp: controller ip:port=6633

    tcp: controller ip:port=6633

    e2 B e1

    e1 e2

    e0

    a1 a2

    Router B

    RFClient

    lxcbr0

    Veth Tunnels

    RFServer

    Mininet

    ICMP Request

    OF Packet In

    Starting Point

    e2 e1

    e0

    b2

    a0

    e1 A e2H1 e1 e1 H2

    RFVS (dp0)

    POXRFProxy

    Router A

    b0

    Mongo DB

  • Software Defined Networking (SDN) for ISP Networks 40

    Control Traffic Handling in RouteFlow

    High priority flow table entries

    b1

    RFClient

    Veth Tunnels

    OF Packet Out

    tcp: controller ip:port=6633

    tcp: controller ip:port=6633

    e2 B e1

    e1 e2

    e0

    a1 a2

    Router B

    RFClient

    lxcbr0

    Veth Tunnels

    RFServer

    Mininet

    ICMP Reply

    OF Packet In

    Starting Point

    e2 e1

    e0

    b2

    a0

    e1 A e2H1 e1 e1 H2

    RFVS (dp0)

    POXRFProxy

    Router A

    b0

    Mongo DB

  • Software Defined Networking (SDN) for ISP Networks 41

    Network Architecture

    The design and framework of a network, including the characteristics of individual

    hardware, software, and transmission system components and how they interact in

    order to ensure the reliable transfer of information. Prior to the development of such

    architectures, interoperability between the various systems of a single manufacturer

    was unusual, and it certainly did not exist between the products of multiple

    manufacturers. IBM's Systems Network Architecture (SNA) and the Digital Equipment

    Corporation's (DEC's) Digital Network Architecture (DNA), aka DECnet, corrected these

    shortcomings within the IBM and DEC domains, but they still did not interoperate. Truly

    open systems architectures still remain in the distant future, although great strides have

    been made in this regard through the Open Systems Interconnection (OSI) model

    fostered by the International Organization for Standardization (ISO). Network

    architectures tend to be layered, which serves to enhance their development and

    management. While they primarily address issues of data communications, they also

    include some data processing activities at the upper layers. These upper layers

    address application software processes, presentation format, and the establishment of

    user sessions. Each independent layer, or level, of a network architecture addresses

    different functions and responsibilities. The layers work together, as a whole, to

    maximize the performance of the process. See also ISO, OSI Reference Model, and

    SNA

    Webster's New World Telecom Dictionary Copyright 2010 by Wiley Publishing, Inc.,

    Indianapolis, Indiana.


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