Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force)1 Diffserv testing in the wide...
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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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 2
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 3
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)
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 4
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 5
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 6
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 7
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 8
Scheduling and policing:two-parameter TB and premium buffer size
Recommendation: token bucket size < premium buffer size(for low packet loss probability)
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 9
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 10
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 11
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)
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 12
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)
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 14
Services:mVLL implementation
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 15
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 16
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 17
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
Pac. Size=1280 bytes
Pac. Size=1518 bytes
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 18
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)
Packet Size=64 bytes
Packet Size=128 bytes
Packet Size=256 bytes
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 19
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)
Packet Size=64 bytes
Packet Size=128 bytes
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 20
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
Tiziana Ferrari Diffserv testing in the wide area (TF-TANT task force) 21
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