1 / 10

AP/AR Discovery

This document discusses the requirements and potential solutions for AP/AR discovery in a scalable network with minimal administration. It explores the use of SLP-based and DHCP-based discovery methods, their advantages, disadvantages, and necessary next steps.

asley
Download Presentation

AP/AR Discovery

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. AP/AR Discovery CAPWAP BOF IETF-57, Vienna Inderpreet Singh isingh@chantrynetworks.com

  2. Discovery Requirements • Scalability • 100’s of AP’s per AR • Multiple AR’s • Minimal administration • Speed • msecs per discovery? • Minimize code size of protocol/mechanism • Work in general topologies • on-subnet (switches) • off-subnet (multiple router hops) • Service Availability (robustness)

  3. Discovery Steps • Discovery • AR IP address • Capabilities (protocols supported, link speed, etc) • Bootup discovery • Dynamic discovery • Service Availability • Fault tolerance

  4. Potential Solutions • SLP based discovery • Service Location Protocol • RFC 2608 • RFC 2609 • RFC 2610 • DHCP based discovery • New vendor specific option • Static Config • No brainer • Scalability issues

  5. SLP Based discovery (Unicast) DHCP server DA AR network AP • AR/SA registers service with DA • Looks up location of DA with DHCP Option 78/79 • Statically configured DA location • AP/UA looks up location of service with DHCP Option 78/79 • Needs to get IP address anyway from DHCP • AP/UA contacts DA with service-type = [WLAN] • AP attempts to connect to AR for WLAN services (continues with discovery/join process)

  6. SLP Based Discovery (Multicast/B’cast w/ no DA) AP multicast multicast unicast AR L2 switch AP unicast multicast • AP (or UA) issues multicast svr. request • AR (or SA) issues unicast svr. response • AP continues with discovery/join process

  7. SLP based discovery • Advantages • Works with “on” or “off” subnet topologies • AR addition to network is also automatic (registers with DA) • Disadvantages • SLP deployment in existing networks • AP assignment to AR’s is not automatic – may require admin intervention

  8. DHCP options for AP/AR Discovery DHCP server AR network AP • AP sends DHCP-inform for WLAN AR option • DHCP server responds with IP address of AR • AP proceeds with discovery/join process

  9. DHCP based discovery • Advantages • AP already has DHCP code (maybe?), needs to just be changed with DHCP options • Works in L2 and L3 (need DHCP relay) • Disadvantage • Admin overhead for adding AR’s to system • Admin overhead to assign specific AP’s to specific AR’s

  10. Next steps • Other requirements • I-D for Discovery • If SLP based – then best practices draft? • If DHCP based – then option draft • If other – then other draft

More Related