Software Defined Networking (SDN) for ISP Networks01...Software Defined Networking (SDN) for ISP...
Transcript of Software Defined Networking (SDN) for ISP Networks01...Software Defined Networking (SDN) for ISP...
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
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)
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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
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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
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RouteFlow Behavior
Topology independent test cases
Control traffic handling
Data traffic handling
Failure handling
RouteFlow specific
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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
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ARP Packet Flow
No ARP processing in OF switches
Reactive flow installation for the host
Unicast ARP queries during running IP flows
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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
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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
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Analysis…(2)
Avoid unicast ARP packets between transit
routers
ICMP packets for specific router sent to controller
Similar modification is useful for BGP packets
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Conclusion…(2)
RouteFlow is not a very good SDN solution
Require changes in RouteFlow implementation
Integration with other SDN solutions
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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
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Questions
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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.