Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force)1 Diffserv testing in the wide area TF-TANT task force Tiziana Ferrari Italian National

Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 1

Diffserv testing in the wide area

TF-TANT task force

Tiziana FerrariItalian National Institute for Nuclear Physics

[email protected]


European research network model according to diffserv

(marking)

DS domainDS domain

DS domain

DS domainDS domain

Non DS capabledomain

MPLS

NRN

NRN

TEN-155Markingpolicing scheduling

shapingNRN

NRN

NRN

diffserv domain National Research Network (NRN)

diffserv region NRNs diffserv core domain


Diffserv test network (Nov `99)

EPFL

CSELT

Uni. Bologna

GRNET (GR)

Uni Utrecht (NL)

Uni Twente (NL)

EPFL (CH)SWITCH (CH)

RedIRIS (SP)

DANTE (Frankfurt PoP)

Uni Stuttgart (DE)CSELT (IT)

INFN/GARR (IT)

Uni Bologna (IT)

CERN (CH)

Cabletron Ethernet swCisco C7200, C7500IBM 2212, IBM 2216LinuxSmartBits 200 (Netcom)


Work accomplished (June 99-Oct 99)

• network configuration, baseline performance testing

• -1- marking

• -2- policing: functionality, token bucket tuning

• -3- scheduling:

– CB-WFQ

– SCFQ (Self Clocked Fair Queuing)

• -4- QoS measurement (ongoing):– goal: validation of EF PHB

– parameters: one-way delay and one-way delay variation

– LAN and WAN

• -5- definition, implementation and validation of test services:

– point to point virtual leased line VLL

– one-to-many virtual leased lines mVLL


Policing

• -1- two-parameter token bucket:

– burst size tuning according to different policing rates

• -2- multi-parameter token bucket:

– normal and exceed burst (TCP)

• -3- policing and scheduling:

– token bucket size and premium queue size


Policing, two-parameter TB:optimum burst size for different traffic rates

•Small TCP burst tolerance: it can completely starve a TCP stream•optimum token bucket size: function of the policing rate

IBM2212


Policing, multi-parameter TB: normal and exceed burst size tuning

Throughput of 1 TCP connection (Mbps)Exceed (bytes)Normal

(bytes) 32000 48000 64000 96000 12800032000 0.98 1.23 1.23 1.25 1.2548000 1.09 1.21 1.25 12564000 1.18 1.24 1.2596000 1.24 1.25128000 1.25

Table 4: throughput of 1 TCP connection for increasing values of the normal and exceed burst size

Aggregate throughput of 5 concurrent TCP connection (Mbps)Exceed (bytes)Normal

(bytes) 32000 48000 64000 96000 12800032000 1.26 1.26 1.25 1.26 1.2548000 1.25 1.26 1.25 12664000 1.25 1.27 1.2596000 1.26 1.26128000 1.25

Table 5: throughput of 5 TCP connections for increasing values of the normal and exceed burst size

CISCO C7200

(Target rate: 1.25 Mbps)

rule: exceed burst = 2 * normal independently of the platform normal burst = 0.5 sec * R


Scheduling and policing:two-parameter TB and premium buffer size

Recommendation: token bucket size < premium buffer size(for low packet loss probability)


Scheduling: WFQ

• CB-WFQ (cisco) and SCFQ (IBM)

• traffic isolation between EF BA, AF BA and best-effort traffic: – combinations of TCP and UDP traffic

– different aggregation degrees (variable number of TCP streams)

• class selectors, EF and AF

• bandwidth allocation: – no starvation

– dynamic allocation among lightly loaded and overloaded classes


Scheduling:CB-WFQ and traffic isolation - WAN -

Throughput of a single TCP high priority connection:CB-WFQ rate = 1300 Kbps

Test site (tx) Neighbour (rx) Throughput (Kbps)GRNET 1250CERN

INFN 1210CERN 700GRNET

Uni. of Utrecht 710CERN 100

Uni. of Stuttgart 100INFN

Uni. of Utrecht 100SWITCH NA

Uni. of Stuttgart 880Uni of Twente

Uni. of Utrecht 880GRNET 1110

INFN 1160Uni of Utrecht

Uni. of Twente 1180Table 6: results of CAR and WFQ tests with 1 TCP high priority stream and UDP background traffic• Inconsistent results, for some sites TCP throughput < 1.25 Mbps (target rate)

• different ATM burst tolerances • tuning of configuration at layer 2 needed • shaping

•overall TCP performance improves with larger aggregation degrees

traffic isolation on WAN connections can be an issue


Scheduling: Self Clocked Fair Queuing - LAN -

• IBM 2212

• Policy = (traffic profile, validity period, diffserv action)

• Diffserv action = (type of marking, queue type, bandwidth)

• optimum traffic isolation (UDP)

Premium TCP traffic throughput, target rate: 163 KbpsTest

numberStreams BE

throughput(Kbps)

AssuredThroughput

(Kbps)

Premiumthroughput

(Kbps)

Total throughput(Kbps)

1 BE 1967.7 / / 1967.72 A / 1968.0 / 1968.03 P / / 159.8 159.84 BE + A 649.8 1367.0 / 2016.85 BE + P 1852.5 / 159.8 2012.36 A + P / 1852.0 159.8 2011.87 BE + A + P 617.8 1236.9 159.8 2014.6

Premium: 163.8 Kbps guaranteed (8% PPP link bw)Assured: 819.2 Kbps (40% PPP bw)


Services

• Virtual leased line:

– replacement of ATM permanent connections, support to managed bandwidth service

– QoS support in/to NRN which are not ATM based

> point to point VLL

> one to many mVLL

• capacity allocation on congested links (e.g. US links)

• better-than-best-effort (qualitative definition)


Services:mVLL


Services:mVLL implementation


QoS measurement: 1-way delay and instantaneous delay variation (LAN)

SmartBitstx rx

Goal : VLL service implementation and validationMetric: Type-P-One-way-Delay (RFC 2679), type-P-one-way-ipdv Variables:

• WFQ/SCFQ EF queue depth• packet size• EF queue “weight” • traffic volume


One-way delay: average vs packet size

Latency vs. Packet Size

0,0

2000,0

4000,0

6000,0

8000,0

10000,0

12000,0

Packet Size (bytes)

La

ten

cy

(m

icro

se

co

nd

s)

Without Best Effort Traffic

With Best Effort Traffic

64 by 128 by256 by

512 by

1024 by

1518 by

1280 by

1248 RFC


Latency in time

Latency vs. timeBandwith=300 Kbps, Buffer Size=1500 bytes

WITHOUT BEST EFFORT TRAFFIC

0,0

1000,0

2000,0

3000,0

4000,0

5000,0

6000,0

7000,0

8000,0

9000,0

50 57 64 71 78 85 92 99 106

113

120

127

134

141

148

155

162

169

176

183

190

197

204

211

218

225

time (ms)

Lat

ency

(m

icro

seco

nd

s)

Packet Size=64 bytes

Pac. Size=128 bytes

Pac. Size=256 bytes

Pac. Size=512 bytes

Pac. Size=1024 bytes




ipdv (*without* best-effort)

Delay Variation vs. timeBandwith=300 Kbps, Buffer Size=1500 bytes

WITHOUT BEST EFFORT TRAFFIC

-300,0

200,0

700,0

1200,0

1700,0

2200,0

2 10 18 26 34 42 50 58 66 74 82 90 98 106

114

122

130

138

146

154

162

170

178

186

194

202

210

218

226

234

242

250

time (ms)

De

lay

Var

iati

on

(m

icro

seco

nd

s)





ipdv (*with* best-effort)

Delay Variation vs. timeBandwith=300 Kbps, Buffer Size=1500 bytes

WITH BEST EFFORT TRAFFIC

0,0

1000,0

2000,0

3000,0

4000,0

5000,0

6000,0

7000,0

8000,0

9000,0

10000,0

2 11 20 29 38 47 56 65 74 83 92 101

110

119

128

137

146

155

164

173

182

191

200

209

218

227

236

245

time (ms)

Del

ay V

aria

tio

n (

mic

rose

con

ds)




Future work

• Weighted Random Early Discard (WRED)

• interoperability testing (possible addition of new platforms)

• study of aggregation effects

• study of TCP related issues: ACK colouring, TCP and UDP aggregations with AF

• service implementation and validation

• diffserv and MPLS

• diffserv and intserv

• policy management and bandwidth brokerage


To know more

• Interim report:http://www.cnaf.infn.it/~ferrari/tfng/ds/rep1-del.doc

• Diffserv test programme and interim test results:http://www.cnaf.infn.it/~ferrari/tfng/ds

• QoS measurement test programme:http://www.cnaf.infn.it/~ferrari/tfng/qosmon

• Activities of the TF-TANT task force:http://www.dante.net/tf-tant

• [email protected]

Documents

Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force)1 Diffserv testing in the wide area TF-TANT task force Tiziana Ferrari Italian National