Internet2 QoS:
Overview and Early Experiences
Ben Teitelbaum <ben@internet2.edu>
November 15, 2000
Purdue University
Talk Overview
Internet2 Overview
(10 min)
Internet2 QoS &
QBone (10 min)
Abilene Premium
Service (25 min)
Questions (10 min)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
2
Executive Overview
Elevator Explanation
• The Internet2 mission is to develop and deploy advanced
network applications and technologies, accelerating the
creation of tomorrow’s Internet
Goals
• Enable new generation of advanced applications
• Re-create leading edge R&E network capability
• Transfer capability to global production internet
Activity Areas
• Advanced Applications
• Advanced Network Infrastructure
• Middleware
• Partnerships (Government, Industry, International)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
3
Internet Development Spiral
Commercialization
Privatization
Internet1
Research and
Development
Source: Ivan Moura Campos
Internet2
Partnerships
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Virtual Laboratories
Real-time access to
remote instruments
3-D Brain Mapping
(Pitt, PSC)
Distributed nanoManipulator
(UNC-CH)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Tele-immersion
Shared virtual
reality
University of Illinois
at Chicago
Virtual
Temporal
Bone
Images courtesy
Univ. of IllinoisChicago
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Tele-cubicles and the CAVE
Source: University of Illinois-Chicago
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Distributed Computation
Large-scale
computation
University
Corporation for
Atmospheric
Research
Image courtesy of UCAR
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Internet2 Universities
179 Universities as of June 2000
+ over 30 affiliate members
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Internet2 Corporate Partners
3Com
Advanced Network &
Services
Alcatel
Ameritech
AT&T
Cabletron Systems
Cisco Systems
IBM
ITC^Deltacom
Lucent Technologies
Marconi
MCI Worldcom
Microsoft
Newbridge Networks
Netcom Systems
Nortel Networks
Qwest Communications
WCI Cable
+ over 70 corporate members
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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International MoU Partners
32 as of June 2000
AAIREP (Australia)
APAN (Asia-Pacific)
APAN-KR (Korea)
ARNES (Slovenia)
BELNET (Belgium)
CANARIE (Canada)
CESnet (Czech Republic)
CERNET, CSTNET, NSFC (China)
CUDI (Mexico)
DANTE (Europe)
DFN-Verein (Germany)
Fundacion Internet 2 Argentina
(Argentina)
GIP RENATER (France)
GRNET (Greece)
HEAnet (Ireland)
HUNGARNET (Hungary)
INFN-GARR (Italy)
Israel-IUCC (Israel)
JAIRC (Japan)
NORDUnet (Nordic countries)
POL-34 (Poland)
RCCN (Portugal)
RedIRIS (Spain)
RESTENA (Luxembourg)
REUNA (Chile)
RNP2 (Brazil)
SingAREN (Singapore)
Stichting SURF (Netherlands)
SWITCH (Switzerland)
TAnet2 (Taiwan)
TERENA (Europe)
JISC/UKERNA (UK)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
11
Abilene Topology
October, 2000
178 Participants, 46 connectors + 3 NGIXs + STARTAP
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Developing International Peering
STARTAP Abilene
vBNS
ESnet
DREN
NREN
NISN
SEATTLE
Abilene
ESnet
CA*net3
AARnet
CERNET
IUCC
GEMNET
APAN
Renater
CERN
SINET
Singaren
Tanet
NYC
(Telehouse
25 Broadway)
NYC
(60 Hudson)
Abilene
ESnet
vBNS
LA
Abilene
Singaren
CA*net3
SURFnet
MIRnet
NORDUnet
REUNA
CUDI
HARNET
SINET
Courtesy: Linda Winkler, STAR TAP
Miami
DFN
INFN
DANTE
CA*net3
CERN
SINET
JAnet
SURFnet
NORDUnet
Argentina
Brazil
Chile
Columbia
Brazil
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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New Network Capabilities
Quality of Service
• http://www.internet2.edu/qos/
Multicast
• http://www.internet2.edu/multicast/
IPv6
• http://www.internet2.edu/ipv6/
Distributed Storage: I2-DSI
• http://dsi.internet2.edu/
Middleware
• www.internet2.edu/middleware/
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Internet2 QoS & QBone...
Internet2 QoS &
QBone (10 min)
Abilene Premium
Service (25 min)
Questions (10 min)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
15
How We Got Here (short version)
• Began chanting:
“enable advanced applications,…”
• Assessed requirements
• Recommended DiffServ
• Selected “Premium” service to meet
demands of loss/jitter sensitive apps
• Charted QBone initiative
• Specified QBone architecture
• Now proceeding to implement it and
tweak the architecture
architecture
deployment
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Internet2 QoS Milestones1/2
Jun 1997
Jan 1998
Bay Workshop
QoS WG DiffServ
Recommendation
Early Internet2 QoS
requirements gathering
Jun 1998
Jan 1999
QBone CFP
QIG opened
RTP QIG
Evanston QIG
QBone initiative launched
Jun 1999
Jan 2000
BBop
QCon
QBone architecture draft (v1.0)
QUALIT
Houston I2/DOE
QBone Workshop
QBone architecture “last call”
Pittsburgh
QBone
BOF
QPS demonstrated
(nM demo)
Las Cruces QIG
APS Test
Program
launched
QBone Forum
launched
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Internet2 QoS Milestones2/2
Jun 2000
Jan 2001
Toronto
QoS BOF
WG re-chartering
You are here!
SC2K QBone demo
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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IntServ/RSVP vs DiffServ
IntServ/RSVP
•Per-flow service state at every hop
•Scalability problems
•Focus on multipoint multicast
BB
BB
DiffServ
•Abstract/manage each cloud’s resources (BBs)
•Packets colored to indicate forwarding “behavior”
•Focus on aggregates not individual flows
•Policing at edge
to get services
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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DiffServ Overview
Applications contract for specific QoS profiles
• Policing at network periphery
• “Color” packets with a few simple, differentiated per-hop
forwarding behaviors (PHBs)
– Indicated in packet header
– Applied to PHB traffic aggregates
• PHBs + policing rules = range of services
DS domains contract with each other for
aggregate QoS traffic profiles
• Policing at cloud-cloud boundary
• Supports simple, bilateral business agreements
Exploits edge/core distinction for scalability
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Example Service #1: Premium
Assurance: like a leased line
PHB: Expedited Forwarding (RFC 2598)
• EF in separate queue configured with minimum
departure rate
• Example mechanisms: strict priority, MDRR, WFQ
Policing: police to a specified peak rate
and drop out-of-profile packets; effectively
a leaky bucket with depth 1 MTU
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Example Service #2:
Controlled Load
Assurance: network looks “lightly-loaded”
for conforming traffic
PHB: Assured Forwarding (RFC 2597)
• 4 independent AF classes
• 3 drop preference levels within each class
• Example mechanisms: WRED, WFQ
Policing: police to specified rate and burst
profile, remarking out-of-profile packets to
have higher drop probability
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Example Service #3: CoS
Assurance: “better than Joe”
PHB: “drop the lower classes first ” (AF or
class selector PHBs)
Policing: could be based on anything
(e.g. higher priority for the CEO)
A.K.A.“Olympic” classes of BE service
(e.g. Gold, Silver, Bronze)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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QBone Architecture
A Service: QBone Premium Service
• Built on Expedited Forwarding (EF) (RFC 2598)
• Assurance: near-zero loss & low, bounded jitter for
marked traffic conforming to a specified peak rate
– a.k.a. “virtual leased line”, “virtual wire”
Reservation Setup Protocol
• Now: long-lived, manual setup
• Proposed: SIBBS protocol between QBone domains;
RSVP end-to-end between hosts
QBone Measurement Architecture
• Uniform collection of QoS metrics
• Uniform dissemination interface
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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QBone Measurement Architecture1/2
Collection
Active
Measurements
•  metrics, EF and BE...
• Active metrics (paths)
AM node
– One-way delay-variation
– One-way loss
– Traceroutes
– e.g. IPPM Surveyors
MIB-based
statistics
Boundary
Router
Intra-Domain
Premium Path
• Passive metrics (interfaces)
– Load
– EF reservation load
– Discards (suggested)
– Link bandwidths (suggested)
– e.g. OCxMon, RTFM, MIBs
Inter-Domain
Premium Path
PM node
PM node
Passive
Measurements
Passive
Measurements
QBone
Domain2
QBone
Domain1
QBone
Domain3
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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QBone Measurement Architecture2/2
Dissemination
• Standard URL query syntax:
label ::= <alphanum> { <alphanum> }
router ::= label"-ROUTER”
probe ::= label"-PROBE”
sniffer ::= label "-SNIFFER”
host ::= router | probe | sniffer
path ::= host "/" host
PHB ::= "BE" | "EF”
metric ::= "LOSS" | "ONEWAY" | "PING" | "IPDV" | "LOAD" | "TRACEROUTE" |
"COMMITMENT" | "RESERVATION"
year ::= digit digit digit digit
month ::= "01" | "02" | ... | "12”
day ::= "01" | "02" | ... | "31”
YYYYMMDD ::= year month day
aggregation ::= <unsigned_integer>
prefix ::= “http” | “ftp” | <other>
query ::= prefix ”://" path "/" PHB "/" metric "/” YYYYMMDD "/" metric "/" aggregation
• whois server to learn canonical names for QBone
domains, routers, sniffers, etc
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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QBone E2E Picture
Campus
A
GigaPoP
A
Campus
B
Backbone
Campus
C
Key
X Kbps of QPS from
hither to………..yon
GigaPoP
B
Campus
D
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Abilene Premium Service...
Internet2 QoS &
QBone (10 min)
Abilene Premium
Service (25 min)
Questions (10 min)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
28
Overview
APS motivation and background
Initial engineering plan
Limitations and modifications to the plan
Future directions
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Abilene Premium Service (APS)
Goal:
• Make APS a reference implementation of the QBone
architecture
Why?
• Catalyst: Enable wide-area QoS experimentation and
propagate Abilene’s experiences to larger community
• Safety Belt: Congestion is only one success
catastrophe away!
The Team:
• Cisco
• UCAID
• Qwest
• Indiana University
• I-TECs (NCNI, OARnet) • Nortel
• NLANR/NCNE
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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APS Participation
Participation Criteria
• Abilene connector status necessary but not sufficient
• QBone participation
• Capability of access router / Abilene edge card
Current Participants
• MAGPI (U. Penn)
• iCAIR
• PSC (Penn State)
• OARNet (Ohio State)
• ANL
• UIUC
• DOE Science GRID (peering
transit network)
Others in the wings
• NASA EOS
• Various international
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Initial Engineering Plan (obsolete)
Sweetwater Midland
Odessa
Pecos
Measurement (Surveyor + SNMP + HTTP)
Edge Policing (“Firehose” CAR)
Manual Setup (Whiteboard + CLI)
EF Core Forwarding (MDRR)
EF Edge Forwarding (MDRR)
Automated Setup (BB)
Shaping (GTS)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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APS Phase 1: “Sweetwater”
First, crawl…
• Ingress policing
• Measurement feedback
• Limited technical support
• No priority queuing yet, but still get benefit of Abilene’s
over-provisioning!
Goals
• Begin to establish operational practices for responding
to admissions requests
• Provide participants with the experience of sitting behind
a policer
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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APS Measurements
Goal: implement QBone measurement
architecture (collection + dissemination) for a
single QBone domain
Hoped-for Side Effects:
• Tools to ease implementation for others
• Adjustments to QMA based on implementation
experiences
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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APS Measurement Collection
Status:
• Currently collecting SNMP stats of EF/BE loads and
CAR profiling
• Abilene Surveyors OC-3 connected and operational
Near Future:
• IPDV along edge-to-edge QBone paths
• Abilene Surveyor timing improvements
– Better external stratum 1 NTP servers
– Improved NTP on Surveyors
– CDMA timing signal (under consideration)
• Collection of AS-level traffic matrices
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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APS Measurement Dissemination
Ohio I-TEC hosting APS measurement server
Status:
• EF/BE loads and CAR stats served through web server
(raw data and plots available)
• Implementation of WHOIS server to learn canonical
names (QBone domains, routers, active and passive
measurement devices)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Committed Access Rate (CAR)
Classifies traffic based on certain matching
criteria (interface, DSCP, or ACL) and meters
it to a leaky bucket traffic profile
Depending on metering result, different
actions applied (drop, transmit, set DSCP,…)
Syntax:
rate-limit {input | output} [access-group [rate-limit]
acl-index] bps burst-normal burst-max conform-action
action exceed-action action
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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CAR Experience
For the most part, CAR is exactly what the
DiffServ doctor ordered
However, there are some limitations…
• Performance
• Token bucket depth
• Classification of DiffServ aggregates
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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CAR Limitation 1: Performance
On E0 edge cards, no ASIC support for CAR
 there is a performance hit
pps @ 256 bytes
250000
200000
150000
no CAR
100000
CAR
50000
0
OC-12 POS
OC-3 POS
OC-12 ATM
qOC-3 ATM
* Preliminary E0 CAR performance figures under retest by ITEC-NC
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Addressing CAR Performance
Out of our hands
The Plan:
• Load on access interfaces is still light, so performance
not really an issue for now
• Wait for E3 edge cards, which will have CAR in
hardware
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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CAR Limitation 2:
Policing Granularity
Cisco CAR Doc:
• “burst-normal Normal burst size in bytes. The
minimum value is bps divided by 2000”
burst-normal  max (mtu, bps/2000)
But, Premium service demands token
bucket depth of 1 MTU…
 bps  3Mbps
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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“Continuous State”
Leaky Bucket Algorithm
rate  <configured value>
burst  <configured value>
deficit  0
last_time  time()
while true do
packet  next_packet_in_incoming_queue()
current_time  time()
size  size(packet)
new_deficit  deficit - rate*(current_time - last_time)
if new_deficit < 0 then
new_deficit  0
eligible_for_drop  false
else
eligible_for_drop  true
fi
if eligible_for_drop and new_deficit + size > burst then
exceed_action(packet)
else
deficit  new_deficit + size
last_time  current_time
conform_action(packet)
fi
elihw
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Addressing CAR Policing
Granularity
Again, out of our hands
The Plan: Have raised issue with Cisco
and are hoping E3 cards will address the
limitation
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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CAR Limitation 3: Classification
CAR can classify by:
• DSCP, ACL
Current SLA
• Profile applied to all injected EF traffic up to agreedupon peak-rate
• “firehose” classification
But, we need {inputIF, outputIF, DSCP}
classification
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Virtual Trunk vs.“Firehose”
Classification
What we want...
What we have now...
The good news: CAR can also classify by:
• qos-group (Cisco proprietary concept)
• With packets assigned to QoS groups through QoS
Policy Propagation via BGP (QPPB)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Addressing CAR Classification
The Plan: use QPPB and encourage broader
Cisco support for the feature
QoS Policy Propagation via BGP (QPPB)
• BGP used to propagate QoS policies to all border routers
• Each BGP community associated with a qos-group
• qos-group field added to forwarding table (FIB)
• Using CAR, packets may then be classified at ingress
according to their egress point from the cloud (next AS)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Abilene Architecture Limitation:
“Porous” Edge Problem
QoS theft problem with current architecture
MDRR (EF forwarding) on interior interfaces
easily subverted by unpoliced connectors
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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How to “Crisp” the Edge?
EF traffic injected by all Abilene connectors
must be policed
Some possible solutions:
• Detection:
Might detect illegal EF traffic with NetFlow and/or
passive monitoring; gigaPoP would be asked to police
• Prevention with performance hit:
CAR + load monitoring for E0 connectors
• Prevention without performance hit:
Re-write DSCP with PIRC for E2 connectors (Dunn
hack)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Looking Forward: Resource
Accounting and Admissions
Problem: how to account for link EF capacity
and commitment in routed network?
Potential solution: DiffServ-Aware MPLS-TE
• Basic idea:
– Edge-to-edge MPLS tunnels;
– LSP setup constrained by available EF bandwidths;
– OSPF augmented to carry QoS link state attributes;
– see draft-lefaucheur-diff-te-reqts-00.txt
• “Solves” DiffServ admission control problem
• Does not solve general DiffServ provisioning problem
• Status: evaluating Cisco implementation of this idea
(DBP-TE) in EFT
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Current Engineering Plan
Sweetwater Midland
Odessa
Pecos
Measurement (Surveyor + SNMP + HTTP + WHOIS + traffic matrices)
Edge Policing (CAR + QPPB + PIRC filtering?)
Manual Setup (Whiteboard + CLI)
EF Core Forwarding (MDRR)
EF Edge Forwarding (MDRR)
Automated Setup (DBP-TE? + BB)
Shaping (GTS)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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SC2000 Interdomain QoS Demo
November 6-9, 2000
Premium service over two wide-area paths
• LBNL-ESnet-Abilene-SCinet-Internet2 booth
• Stanford-CalREN2-Abilene-SCinet-Internet2 booth
Congestion induced at multiple points
CD-quality interactive audio application
shown with/without QoS
ESnet and Abilene QoS capabilities will form
nucleus of QBone
SC2000 Network Challenge Winner: "Most
Captivating and Best Tuned Award"
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Interdomain Quality of Service Demo
Extreme
Summit1i
ALS
GE
Device
control Extreme
Summit1i
LBL-TB1
ANL-TB1
IPLS-QOS
Cisco 7505
Cisco 7505
Cisco 7505
OC-12
GE
10 Mbps
ESNet/DOE Science Grid
stan.calren2
OC-48 POS
Abilene Core
qsv.calren2
OC-12
LBNL
OC-3
Cisco 12008
CalREN2
OC-12
Cisco
12008
Abilene
OC-48
OC-12
I2-GW
Cisco 12008
CCRMA
OC-3
Audio
SND-GW
CCRMA
Audio
Access
Edge
Cisco 7505
Cisco 7505
Q-GW
OC-3
core-conf
Cisco
12008
SCinet
SmartBits
NetCom
Cisco 7505
Cisco 7505
Traffic Generators
SmartBits 200
X-Port
Crystallography
Network
Monitoring
GARA
Internet2 SC2000 Booth
Stanford University
= congestion + QoS control
* All links 100Mbps fast Ethernet (FE) unless otherwise noted
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Deployment
Good News:
• DiffServ functionality in most modern routers
• Many hosts support QoS signaling
• Lots of isolated testbed trials
• Some partial backbone implementations
Bad News:
• Weak demand
• Turnkey solutions are a long way off
• Vendor implementations don’t always live up to hype
• HR scarcity
Bottom line:
• Progress can be made, but it takes a lot of people, time,
and effort
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Going Forward
Need increased focus on low-hanging fruit
• Less than Best-Efforts (LBE)
• Ad-hoc CoS at congestion points
Basic LBE idea
• Low-priority traffic class
• Agree on an Internet2 LBE code point
• Benefits
– Traffic management
– License to hog (some users are self-policing)
– New advanced applications (e.g. large scale distributed
computation)
– It’s easy!
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Class-Selector PHBs
IP precedence subsumed into new class
selector field (RFC2474 )
Class Selector PHB Requirements
• 8 DSCPs = xxx000
• PHB selected by CSx SHOULD have a probability of
“timely forwarding”  those selected by CSy, where x > y
• CS PHB “SHOULD be independently forwarded”
• “A discarded packet is considered to be an extreme
case of untimely forwarding”
• PHBs selected '11x000' MUST be given better than BE
treatment (DSCP='000000’)
• “PHBs mapped to by these codepoints MAY have a
more detailed list of specifications”
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Specifying an LBE PHB
Extend a CS PHB to break the “SHOULD”
relating numerical DSCP value to preference
• Agree on an LBE DS codepoint (e.g. 001000)
• Select a CS PHB to be given a probability of timely
forwarding  BE (000000)
Possible implementations
• Just forward as BE
• WRED, PQ hierarchy, CBQ, WFQ, WRR
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Starvation: Making LBE Stronger
Define “starvation class selector” (SCS)
• An SCS packet MUST never consume a network
resource desired by a non-SCS packet
• Corollary 1: there must not be a configured minimum
departure rate for SCS traffic
• Corollary 2: all queued SCS packets must be evicted
before a forwarding element can drop a non-SCS
packet (probably difficult to implement)
Result: it’s the dual of EF!
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Any Questions?
Internet2 QoS &
QBone (10 min)
Abilene Premium
Service (25 min)
Questions (10 min)
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
58
For more information...
Internet2 Home:
• http://www.internet2.edu/
Internet2 QoS Working Group Home:
• http://www.internet2.edu/wg/qos/
QBone Home:
• http://qbone.internet2.edu/
Abilene Premium Service Home:
• http://www.internet2.edu/abilene/qos/
Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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Internet2 QoS: Overview and Experiences—Purdue University (November 15, 2000)
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