Spotlight On Backbone Technologies Shawn Stevens Technical Lead, Data Center Technologies CCIE #4618 shawn.stevens@cdw.com CDW.com/network 800.800.4239
Agenda Overview of Software-Defined Networking (SDN) SDN use-cases Next-Gen Network Virtualization Next-Gen WAN Summary
Key features of Software Defined Networking (SDN) Separation of control and data planes A centralized controller Programmability of the network
Competing definitions of SDN Cisco advocates a broader view of SDN multiple models for network programmability Network virtualization provides hardware independence by completely decoupling networking components from underlying physical network infrastructure. SDN allows network administrators to manage network services through abstraction of lower level functionality separate networking software into four layers (planes): Management, Services, Control, and Forwarding Centralize the appropriate aspects of the Management, Services and Control planes
What is in a networking device?
Data Plane Forward packets Enforce L4 security policies Honor Quality-of-Service (QoS) policies Do it really fast!
Control Plane Background chatter Routing protocols Spanning-Tree Link Negotiation Multicast Join ARP ICMP
Management Plane Configure the device and its control plane Interactive: CLI, GUI Scripts: TCL, Python, Bash, EEM Network Management: SNMP, XML switch1#config term Enter configuration commands, one per line. End with CNTL/Z. switch1(config)#int po57 switch1(config-if)#switchport trunk allowed vlan add 35 switch1(config-if)#end switch1#copy run start Building configuration... [OK]
OpenFlow Nearly all OpenFlow switches today support version 1.0. HP has a single OF 1.3 capable switch and other vendors are increasing adoption (some software switches are available as well). OpenFlow version support is largely at the mercy of Intel and Broadcom, who make the Ethernet chips that everyone uses.
How does pure OpenFlow really work? Packet processing in an OpenFlow switch environment Controller Controller must be down very = close Network to devices down How many flows are on your network?
99% of OpenFlow use cases will be hybrid The network is designed, configured and operated almost exactly like today. The controller collects network information The SDN app can alter the normal behavior Controller Make flow use path A SDN App
Cisco s Application Centric Infrastructure (ACI) NetFlow and SNMP traps Cisco OnePK API JSON API SNMP SDN App Cisco Enterprise APIC CLI OpenFlow Controller (Open Daylight/XNC) OpenFlow
By many definitions, SDN is already among us Wireless LAN Controllers SNMP/RMON Cisco UCS RADIUS authentication Network Access Control (NAC) HP VirtualConnect Guest portals Distributed Virtual Switch and Nexus 1000v
Use case: per-flow path selection A flow is defined by source and destination (among other things ) Bike Route (Path 1) Highway (Path 2)
Network Virtualization with Overlays Rest of the network
vlan 20 vlan 30 vlan 40 Network Virtualization for Security App1 Load-balancer Firewall Internet App2 App4 App5 App3 App3 App6
vlan 40 Network Virtualization for Security App1 LB FW App4 App2 FW Internet LB FW App5 App3 LB FW App6
Network Virtualization Concerns Visibility into overlay traffic IPS, firewalls, and many network monitoring packages do not support overlay traffic. Overlay traffic doesn t respond to congestion It s a proverbial fire hose! Network design Large MTU needed Overlays should not be allowed into the routed network Virtualization engineers need more networking skills Routing protocols Proxy Servers, NAT, Firewall, Load-balancers
SDN for Wide Area Networking (WAN) Benefits Centralized routing and QoS policies Multiple WAN paths VPN backup Cloud management Controller We can do this NOW!!
In Summary.. SDN = programmable networks Still waiting for a killer app. It s worth evaluating some of the WAN router management options out there. Put telnet/ssh out to pasture It s time to pivot away from MPLS WAN. Plan a strategy with WAN contracts in mind. Branch Internet Edge is inevitable. Do your own cost analysis ASAP!
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