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Technical white paper

HPN SDN Controller Link

Discovery

Understanding and configuring controlled networks for link discovery

Table of contents

How OpenFlow Link Discovery works ................................................................................................................................. 2

Keys to Correct Link Discovery ............................................................................................................................................ 3

Known issues ......................................................................................................................................................................... 3

Discovery packet injection................................................................................................................................................ 4

Discovery packet reception .............................................................................................................................................. 4

Non-conforming configuration example ........................................................................................................................... 4

Device-specific recommendations ...................................................................................................................................... 5

ProVision: Virtualization Mode ......................................................................................................................................... 5

Comware: PVID in OpenFlow instance ............................................................................................................................ 5

Previous discovery methods ............................................................................................................................................... 1

LLDP Ethertype .................................................................................................................................................................. 1

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Summary of content (7 pages)

PAGE 1
Technical white paper HPN SDN Controller Link Discovery Understanding and configuring controlled networks for link discovery Table of contents How OpenFlow Link Discovery works .................................................................................................................................2 Keys to Correct Link Discovery ............................................................................................................................................3 Known issues ................
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Technical white paper | HPN SDN Controller Link Discovery HPN SDN Controller Link Discovery This document is intended for sales support and networking professionals who wish to configure their networks for successful HPN SDN Controller link discovery. This document will give a deeper understanding of how link discovery is performed and some recommended configurations.
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Technical white paper | HPN SDN Controller Link Discovery When the controller is configured for hybrid.mode=true, the controller installs a flow rule on every OpenFlow instance to steal these packets: Packets which match this flow rule are forwarded to the controller from the OpenFlow instance and port where they were received.
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Technical white paper | HPN SDN Controller Link Discovery Please see the tables below for details about whether your network configuration will meet either of the above conditions: Discovery packet injection Product Tagging of Controller-Injected Packets ProVision In aggregation mode, the switch Openflow agent does not apply a tag to injected link discovery packets.
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Technical white paper | HPN SDN Controller Link Discovery Using the example topology above, we will illustrate a few of the issues that may arise with link discovery. Assume that switches A, B, C OpenFlow instances are configured to connect to the same controller and that each inter-switch physical connection is tagged with the vlans shown. The notation “OF Inst” indicates an OpenFlow instance running on the given switch.
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Previous discovery methods LLDP Ethertype Rather than using an Ethernet type of 0x8999, previous versions of the controller injected packets with an Ethernet type of LLDP (0x88cc). By using this Ethernet type for direct link discovery packets, all direct links would be correctly discovered because LLDP is defined as being below the 802.1Q vlan tagging layer. This approach is no longer considered an option because LLDP is also used by end-hosts for other purposes, such as PoE.