Transcript QoS in PPPoE

QoS in PPPoE
Quality of Service in the Point-to-Point Protocol over Ethernet
Master’s Thesis
Patrik Lahti
KTH, Telia Research AB
Outline
• Introduction
– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband
IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
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Quality of Service
• Enhance the network
with the intelligence to
treat traffic according
to application
requirements.
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• IP
– Differentiated Services
– Integrated Services
• Ethernet
Delay
Delay variation
Loss
Others...
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QoS in PPPoE
– Priorities (802.1p)
– Subnet Bandwidth
Manager
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Point-to-Point Protocol over Ethernet
• Purpose
– To set up Client to Access Concentrator relationship
– Encapsulate PPP, and multiplex multiple PPPoE
sessions
• Operation
– Simple Active discovery
– Session
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Mulitcast PADI, w Service-Name
Client
Unicast PADO, w Service-Name(s)
& AC-Name
AC
PPP/PPPoE
Unicast PADO, w Service-Name(s)
& AC-Name *)
Client
AC
LCP
Unicast PADR, w Service-Name
Auth
Unicast PADS, w Service-Name
& Session ID
IPCP
PPP session Stage
Unicast PADT, w Session ID **)
IP data
t
*) There may be multiple ACs answering with a PADO
**) May be sent by either side
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Outline
• Introduction
– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband
IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
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Background
& Model
IP
IP
PPP
PPP
?
PPPoE
Sw
Sw
PPPoE
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Physical
Physical
Physical
Physical
Physical
Physical
Customer
Equipment
STB
CPN
VLAN
IP Access Node
New Services => QoS
NSP selection
Protocols
Ethernet
Switch
IPT
Ethernet
Switch
Ethernet Sw
PC
IP-access
Node
10Mbps Ethernet
100Mbps Ethernet
Ethernet Sw
1Gbps Ethernet
Ethernet Sw
IP-access
Node
IP Network
AAA
DSLAM
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•
•
•
•
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IP
STB
IPT
ATM
10Mbps Ethernet
ADSL
mod.
PC
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ADSL
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Why PPP/PPPoE?
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+
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+
+
+
NSP selection
IP address allocation
Reuse of Legacy Equipment
Unified Model (Bridged ADSL)
Familiar to users
Per user access control and
billing
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Overhead and Connection
delay(?)
Software update for Clients
QoS issues unresolved (?)
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Outline
• Introduction
– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband
IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
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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?
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Outline
• Introduction
– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband
IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
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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?
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QoS
• PPPoE
– Service Name Tag, request certain DS or Service.
• Allows CAC
• Integrate with/similar to SBM?
• One session/service or DSCP
• PPP
– DiffServ SLA negotiation
• Allows CAC
– Fragmentation (slow link)
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QoS
• QoS scope
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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
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Multiplexing QoS
• Alternatives
– One PPPoE session/NSP
– One PPPoE session/DS class
– One PPP session/DS class
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Outline
• Introduction
– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband
IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
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Stability and Performance of PPPoE
• Stability
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Loss
Delay
Reorder
Duplication
• Performance
– Connection delay
– Maximum throughput
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Stability
• Lab
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Stability
• Result
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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
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Performance
• Lab
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10Mbps FD
1Mbps HD
9 Mbps Load w/wo VLAN
Connection Delay
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1000
900
600
500
Serie1
400
300
200
100
65
61
57
53
49
45
41
Time [s]
Throughput [kbps] (variance) IP
PPPoE
Difference
10Mbps Full-Duplex
7955 (208)
7520 (242)
-5.5%
1Mbps Bottleneck
853 (60.0)
767 (170)
-10.1%
4760 (12.3)
4644 (14.4)
-2.4%
4759 (18.3)
4646 (16.1)
-2.4%
9 Mbps Load
– Connection
9 Mbps Load VLAN sep.
Delay ~7s
– Can be optimised to ~1s
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33
29
25
21
17
13
9
0
5
– No significant
difference
– Except on
1Mbps HD
700
1
• Results
Throughput [kbps]
Performance
800
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Outline
• Introduction
– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband
IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
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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.
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Opposition
• ...
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Questions
• ?
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Thank you!
• Tack till Fredrik Roos, Stefan Sandell
• Alla på Bredbandsnät, Telia Research AB
• Tack till Björn Pehrson och Mikael Lind
• Tack till alla som kom.
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Information
• http://www.e.kth.se/~e95_pla/exjobb
• Still have my opposition to do.
• I am currently working at Nortel Networks’
Routing Architecture Lab:
[email protected]
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