Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 1 Diffserv deployment in the wide area: network design and testing Tiziana Ferrari Italian National Institute for Nuclear Physics [email protected]TF-TANT task force http://www.dante.net/tf-tant/
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Tiziana Ferrari Diffserv deployment in the wide area: network design and testing1 Diffserv deployment in the wide area: network design and testing Tiziana.
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Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 1
Diffserv deployment in the wide area: network design and testing
Tiziana FerrariItalian National Institute for Nuclear Physics
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 2
Overview
• Why diffserv?
• Test programme
• testbed
• interim results:
– classification and marking
– policing
– scheduling
• QoS measurement
• services:
– VLL
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 3
Motivation
• Why diffserv?– independent of layer 2 technologies– interoperability:
> diffserv domains National Research Networks (NRN)
> diffserv region: NRN + 1 diffserv core domain> independent diffserv implementation in each
diffserv domain – traffic aggregation– scalability– transparency to the application
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 4
Motivation (cont)
– (some) benefits:> network layer:
• VLL service, a potential replacement of ATM permanent connections
• resource allocation on congested links • QoS support in/to NRN which are not ATM
based> application layer:
• QoS support for mission critical applications (RSVP - diffserv)
e.g.: good QoS support to client-server distributed applications thanks to traffic aggregation
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 5
Diffserv and the European network model
DS domain
DS domain
DS domainDS domain
Non DS capabledomain
MPLS
NRN
NRN
TEN-155
(marking)
Markingpolicing scheduling
shaping
DS domain
NRN
NRN
NRN
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 6
Overview of test programme
• Diffserv – DSCP: class selectors, EF, AF– test of basic QoS features in diffserv platforms– parameter tuning– interoperability– services: definition, implementation, validation through test
applications (video streaming, IP telephony, distributed applications)
• diffserv and intserv (end-to-end QoS)• diffserv and MPLS • QoS measurement • Policy management
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 7
Work accomplished (June 99-Oct 99)
• network configuration
• baseline performance testing
• marking
• policing:
– functionality, token bucket parameter tuning (normal and exceed burst size) with TCP traffic
– CB-WFQ (Class Based WFQ): traffic isolation
• scheduling:
– CB-WFQ: traffic isolation, VLL service in the wide area
– SCFQ (Self Clocked Fair Queuing): EF, AF and best-effort
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 8
Work accomplished (cont)
• QoS measurement (ongoing):
– parameters: one-way delay and one-way delay variation
> LAN and WAN (VLL service implementation and validation)
– traffic generators with GPS antennas
– NTP
• definition of test services:
– point to point virtual leased line
– one-to-many virtual leased line
– resource allocation on congested links
– better than best-effort
– services for remote instrumentation control (AF)
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 9
Diffserv test network
EPFL
CSELT
Uni. Bologna
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 10
LAN layout (example)
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 11
Equipment
• Test workstations (ATM, Ethernet, Fast Ethernet, Giga Ethernet interfaces)
Table 5: throughput of 5 TCP connections for increasing values of the normal and exceed burst size
• CISCO platforms• Target rate: 1.25 Mbps
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 17
Policing: TCP burst tolerance (cont)
• IBM platforms (IBM 2212)• Small TCP burst tolerance in a policer can completely starve a TCP stream. Token bucket depth is function of the rate at which traffic is policed tuning needed
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 18
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 21
Scheduling: CB-WFQ
Scheduling implementation to provide minimum bandwidth
guarantees to classes
• tested on CISCO platforms - C7200, IOS 12.0(5)T -• class definition: based on class selectors for aggregation OK
• bandwidth allocation: no starvation, dynamic allocation in case of classes which are not fully deploying the capacity guaranteed to them OK
• traffic isolation between EF BA and best-effort: – several combinations of TCP and UDP traffic
– variable number of TCP streams (different aggregation degrees)
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 22
CB-WFQ: set-up
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 23
CB-WFQ: traffic isolation, 1 TCP stream
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
• different ATM burst tolerances on the WAN connections seem seem to be the cause traffic isolation on WAN connections can be an issue
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 24
CB-WFQ: traffic isolation, multiple TCP streams
Throughput of multiple high priority TCP connections:CB-WFQ rate = 1300 Kbps, UDP background traffic at 2 Mbps
Source site Destination site Number ofTCP streams
Aggregate applicationTCP throughput (Kbps)
1 1003 130
10 221
INFN CERN
20 6801 7003 1000
10 1180
GRNET CERN
20 1270
• Overall TCP performance of the behaviour aggregate improves when the aggregation degree increases• TCP performance of a single connection still low problem under investigation
Tiziana Ferrari Diffserv deployment in the wide area: network design and testing 25
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