QoS in PPPoE. Quality of Service in the Point-to-Point Protocol over Ethernet. Master s Thesis. Patrik Lahti KTH, Telia Research AB

Transcription

1 QoS in PPPoE Quality of Service in the Point-to-Point Protocol over Ethernet Master s Thesis Patrik Lahti KTH, Telia Research AB

2 Outline Introduction Problem Definition Background and Model Point-to-Point Protocol over Ethernet QoS in the PPPoE-based Broadband IP Access. Stability and Performance of PPPoE Summary & Questions QoS in PPPoE 2

3 Problem Definition With what methods can QoS be support be introduced in PPPoE? Can services with different QoS requirements be multiplexed in one PPPoE session? Does PPP/PPPoE cope with loss, delay, reordering, and duplication? How is performance affected by PPP/PPPoE? What issues have to be addressed in the IP access? QoS in PPPoE 3

4 Background IP PPP IP PPP IP? PPPoE Sw Sw PPPoE Ethernet Ethernet Ethernet Ethernet Ethernet Ethernet & Model Physical Physical Physical Physical Physical Physical Customer Equipment Ethernet Switch Ethernet Switch IP-access Node CPN VLAN STB PC IPT 10Mbps Ethernet Ethernet Sw 100Mbps Ethernet IP Access Node New Services => QoS NSP selection Ethernet Sw Ethernet Sw 1Gbps Ethernet IP-access Node AAA IP Network Protocols ATM DSLAM STB IPT 10Mbps Ethernet PC ADSL. ADSL QoS in PPPoE 4

5 Point-to-Point Protocol over Ethernet Client AC Purpose To setup Client to Access Concentrator relationship Encapsulate PPP Operation Simple Active discovery Mulitcast PADI, w Service-Name Unicast PADO, w Service-Name(s) & AC-Name Unicast PADO, w Service-Name(s) & AC-Name *) Unicast PADR, w Service-Name Unicast PADS, w Service-Name & Session ID PPP session Stage Unicast PADT, w Session ID **) Session t *) There may be multiple ACs answering with a PADO **) May be sent by either side QoS in PPPoE 5

6 Why PPP/PPPoE? + NSP selection + IP address allocation + Reuse of Legacy Equipment + Unified Model (Bridged ADSL) + Familiar to users + Per user access control and billing - Overhead and Connection delay(?) - Software update for Clients - QoS issues unresolved (?) QoS in PPPoE 6

7 Problem Definition With what methods can QoS be support be introduced in PPPoE? Can services with different QoS requirements be multiplexed in one PPPoE session? Does PPP/PPPoE cope with loss, delay, reordering, and duplication? How is performance affected by PPP/PPPoE? What issues have to be addressed in the IP access? QoS in PPPoE 7

8 QoS in the PPPoE-based Broadband IP Access. IP Differentiated Services Guaranteed Service Low Delay Low Loss Best Effort Ethernet User Priorities, 802.1p 7 Traffic types: NC, Voice, Video, Controlled Load, Excellent Effort, BE, Background PPP/PPPoE? QoS in PPPoE 8

9 QoS PPPoE PPP Service Name Tag, request certain DS or Service. Allows CAC Integrate with/similar to SBM? One session/service or DSCP DiffServ SLA negotiation Allows CAC Fragmentation (slow link) QoS in PPPoE 9

10 QoS QoS scope QoS in PPPoE 10

11 QoS Mapping DS to 802.1p Static Hint in DS field SBM Recommendation: Static Proposed mapping No change to PPP/PPPoE Ethernet Traffic Class Service Class 7 Network Control Guaranteed Service 6 Voice Low Delay (-jitter) 5 Video 4 Controlled Load Low Loss 3 Excellent Effort 0 Best Effort Best Effort 1 Background QoS in PPPoE 11

12 Multiplexing QoS Alternatives One PPPoE session/nsp One PPPoE session/ds class One PPP session/ds class QoS in PPPoE 12

13 Stability and Performance of PPPoE Stability Loss Delay Reorder Duplication Performance Connection delay Maximum throughput QoS in PPPoE 13

14 Stability Lab QoS in PPPoE 14

15 Stability Result PADS, PAP Authentication sensitive to loss Old LCP, IPCP packet Ids not ignored TCP segment size smaller than necessary Termination and Link maintenance Delays < 3s QoS in PPPoE 15

16 Performance Lab 10Mbps FD 1Mbps HD 9 Mbps Load w/wo VLAN Connection Delay QoS in PPPoE 16

17 Performance Results No significant difference Except on 1Mbps HD Throughput [kbps] Time [s] Throughput [kbps] (variance) IP PPPoE Difference 10Mbps Full-Duplex 7955 (208) 7520 (242) -5.5% Serie1 Connection Delay ~7s Can be optimised to ~1s 1Mbps Bottleneck 853 (60.0) 767 (170) -10.1% 9 Mbps Load 4760 (12.3) 4644 (14.4) -2.4% 9 Mbps Load VLAN sep (18.3) 4646 (16.1) -2.4% QoS in PPPoE 17

18 Summary QoS can be incorporated in the PPPoE architecture without changes to protocol standards. PPPoE implementation to set Ethernet user priorities according to IP DS. Simple multiplexing should be used, one PPPoE session/nsp. PPP/PPPoE is reasonably stable and performs well. Some issues to be further investigated and improved. QoS in PPPoE 18

19 Questions? QoS in PPPoE 19

20 Thank you! Tack till Fredrik Roos, Stefan Sandell Alla på Bredbandsnät Telia Research AB QoS in PPPoE 20