Title: Tiziana Ferrari Diffserv testing in the wide area TFTANT task force
1Diffserv testing in the wide area
- TF-TANT task force
- Tiziana Ferrari
- Italian National Institute for Nuclear Physics
- ferrari_at_cnaf.infn.it
2European research network model according to
diffserv
diffserv domain ? National Research Network
(NRN) diffserv region ? NRNs ? diffserv
core domain
(marking)
3Diffserv test network (Nov 99)
Cabletron Ethernet sw Cisco C7200, C7500 IBM
2212, IBM 2216 Linux SmartBits 200 (Netcom)
4Work 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
5Policing
- -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
6Policing, two-parameter TBoptimum burst size
for different traffic rates
IBM 2212
- Small TCP burst tolerance it can completely
starve a TCP stream - optimum token bucket size function of the
policing rate
7Policing, multi-parameter TB normal and exceed
burst size tuning
(Target rate 1.25 Mbps)
CISCO C7200
rule exceed burst 2 normal independently
of the platform normal burst 0.5 sec R
8Scheduling and policingtwo-parameter TB and
premium buffer size
Recommendation token bucket size lt premium
buffer size (for low packet loss probability)
9Scheduling 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
10SchedulingCB-WFQ and traffic isolation - WAN -
- Inconsistent results, for some sites TCP
throughput lt 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
11Scheduling 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 163.8 Kbps guaranteed (8 PPP link
bw) Assured 819.2 Kbps (40 PPP bw)
12Services
- 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)
13ServicesmVLL
14ServicesmVLL implementation
15QoS measurement 1-way delay and instantaneous
delay variation (LAN)
Goal VLL service implementation and
validation Metric 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
16One-way delay average vs packet size
1518 by
1280 by
1024 by
512 by
256 by
128 by
64 by
1248 RFC
17Latency in time
18ipdv (without best-effort)
19ipdv (with best-effort)
20Future 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
21To 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
- tiziana.ferrari_at_cnaf.infn.it