Ethanol Software Defined Networking for 802 11 Wireless

Ethanol: Software Defined Networking for 802. 11 Wireless Networks Henrique Moura, Gabriel V. C. Bessa, Marcos A. M. Vieira, Daniel F. Macedo E-mails: henriquemoura, gabrielvcbessa, mmvieira, damacedo@dcc. ufmg. br Slide 1

Software-Defined Networking • Separation of control and data planes – the controller contains all the logic on how the forwarding table is updated – the network device executes the forwarding rules programmed by the controller • Simple network devices, intelligence at the controller • State of the art: Open. Flow – Controls only wired networks Slide 2

Software-Defined Wireless Networks • Programmability of network control • Abstraction of the underlying infrastructure from the wireless applications • Issues: – Supporting a large number of subscribers, frequent station mobility, fine-grained measurement and control, and real-time adaptation Slide 3

Current challenges for SDWN I. III. IV. V. VI. Variable link characteristics Node mobility Quality of service Virtualization Security User Location Slide 4

SDWN Challenges – Variable links • Wireless networks have different error and data rates, that may vary for every packet transmitted – Transmission quality is greatly affected by congestion and interferences I. III. IV. V. VI. • IEEE 802. 11 k (Radio Resource Measurement of Wireless LANs) provides mechanisms for access points and stations to dynamically measure and report available radio resources. Variable link characteristics Node mobility Quality of service Virtualization Security User Location Future work Slide 5

SDWN Challenges – Node mobility • SDWN should: – Manage node mobility, controlling which users should associate to a certain access point, and – Identify when a handoff to another AP is about to take place I. III. IV. V. VI. Slide 6 Variable link characteristics Node mobility Quality of service Virtualization Security User Location

SDWN Challenges – Node mobility • IEEE standards addressing mobility – 802. 11 f • Enforcement of unique association throughout an ESS • Secure exchange of station’s security context between current and new AP during handoff I. III. IV. V. VI. – IEEE 802. 21 • Handovers between heterogeneous wireless networks – IEEE 802. 11 r • Fast BSS Transitions with security key negotiation Slide 7 Variable link characteristics Node mobility Quality of service Virtualization Security User Location

SDWN Challenges – Qo. S • Openflow has basic Qo. S support – Set a flow to a queue – Setting “meters” (optional feature) • So Openflow as it is does not ensure a minimum Qo. E to the user • It is important to integrate 802. 11 e feature with DSCP for packet classification purposes I. III. IV. V. VI. – SDWN provides global knowledge of flows to and from wireless medium Slide 8 Variable link characteristics Node mobility Quality of service Virtualization Security User Location

SDWN Challenges – Qo. S • IEEE 802. 11 e – Service differentiation – Error-correcting mechanisms for delay sensitive applications – Only handles Qo. S parameters inside a BSS I. III. IV. V. VI. • The controller should be able to configure the Qo. S parameters in a condinated way of wired and wireless flows Slide 9 Variable link characteristics Node mobility Quality of service Virtualization Security User Location

SDWN Challenges – Virtualization • Flow. Visor achieves network segmentation, slicing five dimensions: bandwidth, topology, traffic, device CPU and forwarding tables • Wireless networks imposes some restriction to virtualization: I. III. IV. V. VI. Variable link characteristics Node mobility Quality of service Virtualization Security User Location – Wifi APs do not have forwarding tables – Wifi router has a limited number of physical radios, tipically one or two Future work Slide 10

SDWN Challenges – Security • Open. Flow does not emphasize security • Security is an important topic in a wireless environment: I. III. IV. V. VI. Variable link characteristics Node mobility Quality of service Virtualization Security User Location – Eavesdropping or disruption • SDWN could facilitate monitoring – Allows a clear vision of the network – Supplies means to detect intruders – Detect abnormal activities/Rogue APs Future work Slide 11

SDWN Challenges – User location • Location is important for: I. III. IV. V. VI. Variable link characteristics Node mobility Quality of service Virtualization Security User Location – Location-aware services – Handoff decisions – Network security Future work Slide 12

Ethanol – SDN for IEEE 802. 11 Networks Slide 13

Ethanol Architecture Two types of devices: • Controller • Ethanol-enabled APs Does not require changes on the terminals Ø Data collected from clients relies on 802. 11 standards Slide 14

Architecture - Design goals • Supports IEEE 802. 11 as well as Ethernet NICs; • No changes on the terminals – 802. 11 standards • Provides APIs for node mobility, AP virtualization, WLAN security, and Qo. S (on Wi. Fi and Ethernet) Slide 15

Class Model Slide 16

Implementation • Ethanol prototype – Ethanol controller • Linux computer using POX/Openflow • handles the Ethanol messages encoded with XML-RPC over HTTPS – Ethanol-enabled APs • Linux computer with Ubuntu LTS 14. 04. 2 and Atheros AR 9170 802. 11 n wireless card, with Openvswitch and hostapd • Broadcom WRT 54 GL router running Open. WRT and Openvswitch No modification required on client software. Decision is made on AP side through the Ethanol controller. Slide 17

Experiments Slide 18

Load-aware association Connection established Check association Association granted Ethanol controller Connection established Clients should associate with the APs that have the smallest number of clients Slide 19

Experiments Load-Aware Client Association Ethanol enables load-aware client association Slide 20

Quality of Service 1. When a user´s flow starts, the Ethanol router sends a packet_in event to the controller 2. The controller matches some packet parameter (eg. Source IP address) to a preconfigured table 3. This flow is enqueued to a predefined queue Algorithm 2 sets a bandwidth limit for each flow Slide 21

Quality of Service 1 st setup 2 nd setup Ethanol router Qo. S = 6 ps b 10 M Qo. S = 3 Ethanol controller Qo. S = 1 Slide 22

Quality of Service 6/9 3/9 6/10 3/10 1 st round 2 nd round Ethanol enables Qo. S traffic Slide 23

ARP Filtering • Cheng et. analyzed traces of a Wi. Fi campus network – concluded that ARP packets consume almost 10% of the air time of wireless links Slide 24

ARP Filtering Setup Ethanol router ARP traffic: only to/from client Ethanol controller st round: 2 nd 1 round: without arp control arp activated control Slide 25

ARP Overhead Experiments With ARP control activated, we only notice ARP requests from the wireless client and ARP replies to it Ethanol reduces ARP traffic Slide 26

Conclusions • Ethanol extends the SDN concept to allow the programmability of wireless APs • It provides an API for the control of AP events, allowing new applications in – – – Qo. S Mobility control Security Virtualization etc Slide 27

Future Work • Implement a larger subset of the functions • Use cases on security and virtualization • Evaluate our prototype on larger networks with more APs, clients, and traffic • Implement new management algorithms for wireless networks Slide 28

SDNs don´t solve it all ! Slide 29

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