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Transcript of Virginia Tech Campus Network Overview Internet2 Campus Focused Workshop On Advanced Networks Clark...
Virginia Tech Campus Network Overview
Internet2 Campus Focused WorkshopOn Advanced Networks
Clark GaylordVirginia Tech
[email protected]://rdweb.cns.vt.edu/
30 May 2001
30 May 2001 Gaylord: Virginia Tech Campus Overview
2
Basic Services• Basic Ethernet portal service (~25,000 ports)
– Switched 10Base-T (10 Mbit/s)– Some switched 100Base-TX (100 Mbit/s)
• Dial-in modem pool with ~1,200 56k modems• Wireless LAN (currently in pilot phase,
beginning second round deployment)• ATM portal service (25 or 155 Mbps), mostly
for specialized applications (e.g. distance learning programs)
• Local network access point provides campus backbone access to local ISPs. Ethernet in apartment complexes
• Telephone (~13,000 phones) and cable television (~5,000 connections)
30 May 2001 Gaylord: Virginia Tech Campus Overview
3
Some Network Management Tools
• Largely home-grown– ARP/Forwarding table/Cable plant databases (HC++ ™)– Device status reports– TACACS+ database query tool– nemisys - Network Engineering Management Information
SYStem ™– Various ad hoc tools– People
• Commercial– Smarts InCharge– Concord Network Health– InterMapper, What’s Up “inventory” tools (“Your switch is
still alive.”)
• Freeware, etc– Usual suspects: MRTG, Big Brother, Netsaint
30 May 2001 Gaylord: Virginia Tech Campus Overview
7
End-to-End Management
• Largely ad hoc, informal measurements• ttcp, netperf, treno, Ganymede• nlanr AMP project • How to you obtain measurements from the far
end?• Usual SNMP tools cannot/do not address
burstiness• Configuration management/production quality
30 May 2001 Gaylord: Virginia Tech Campus Overview
10
• Switched 10 Mbps to the desktop.
• Switched 100 Mbps where desired.
• Switched 100 Mbps building backbone.
• N x 100 Mbps scalable building feed.
• Simple model• ISL virtual LAN capability
Standard Building Network
Catalyst 1900/1924Catalyst
1900/1924
Core
n x 100Base-FX
10
0B
ase
-FX
do
wn
links
10Base-Tto wall portal
CiscoCatalyst
5000
CiscoCatalyst
6500
Catalyst 1900/1924
Catalyst 1900/1924Catalyst
1900/1924
30 May 2001 Gaylord: Virginia Tech Campus Overview
11
CiscoCatalyst
6500
• 10/100 available to the desktop• Scalable Gigabit Ethernet building
backbone and building feed• 802.1Q/ISL virtual LAN capability• 802.1p packet prioritization
capability• 802.11b Wireless LAN• Deployed in Torgersen Hall
Advanced Building Network
CiscoCatalyst
6500
Catalyst 3500
Catalyst 3500
Catalyst 3500
Catalyst 3500
Catalyst 3500
Catalyst 3500
Catalyst 3500
Catalyst 3500
Coren x 1000Base-LX
10
00
Ba
se-S
X d
ow
nli n
ks
1000Base-TX inter-switch links
10/100Base-TXto wall portal
Wireless LANAccess point
30 May 2001 Gaylord: Virginia Tech Campus Overview
12
Wireless LAN Deployment Plan (2001-2002)
• Current/pilot:– Torgersen (ACITC)– Information
Systems• Summer 2001:
– Library (partial)– Student Centers
(partial)– Randolph
(Engineering)– Pamplin (Business)
• 2001-2002:– Veterinary
Medicine– Seitz (Agriculture)– McBryde (Math,
CS)
30 May 2001 Gaylord: Virginia Tech Campus Overview
13
Wireless LAN Deployment• Two-three year deployment schedule
– Instructional space– Student centers– Other space as needed
• Facilities to support portable computing• Based on 802.11b
– Economics of 802.11a dubious
• Keep it “standards” based• Large perimeter
– WEP/ESSID not supportable, negligible benefit
• 802.1X/EAP– a definite maybe
• Airspace internal policy• Custom antenna design?
30 May 2001 Gaylord: Virginia Tech Campus Overview
14
MSAP
DSL
T1/FR
LMDS
ModemPool
VT ATM
Backbone
N.W.V
1 x 1000Base-SX
1 x 1000Base-LX
2 x 1000Base-LX
ATM OC3c
1 x 100Base-FX/TX
SHACatalyst
6500
OWECatalyst
6500
HILCatalyst
6500
ISBCisco 7500
Internet
Internet2
ISBCatalyst
6500
BURCatalyst
6500
CASCatalyst
6500
ISBCatalyst
6000
ISBCisco 7500
CASCisco 7500
Future POS/DPT/ATM OC12cor 1000Base-ZX
VT Gigabit Backbone
30 May 2001 Gaylord: Virginia Tech Campus Overview
15
ATM Architecture
• ATM provides key benefits, not yet feasible or cost-effective using other technologies– Integrated, multi-service WAN access
• Voice transport (toll-bypass)• Videoconferencing (distance learning)• IP data transport
– Layer 2 virtual private networks with explicit resource provisioning; vital to network layer research.
• Also provides last-resort backup for the gigabit backbone.– When all else fails, we haul it over ATM.
30 May 2001 Gaylord: Virginia Tech Campus Overview
16
N.W.V VTGigabit
Backbone
ATM OC3c multi-mode
ATM OC3c single-mode
1000Base-SX
Internet
Internet2
SHAASX-200WG
OWEASX-200WG
BURASX-200BX
CASASX-200BX
ISBASX-1000
HILASX-200BX
CASCisco 7507
ISBCisco 7507
ISBCisco 7507
VT ATM Backbone
30 May 2001 Gaylord: Virginia Tech Campus Overview
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Net.Work.Virginia
• Provides ATM services throughout Virginia to K-12 schools, institutions of higher education, and state agencies
• Low cost access with level pricing statewide– OC3c (155 Mbit/s), ~ $134,000/annum– DS3 (45 Mbit/s), ~$53,000/annum– DS1 (1.5 Mbit/s), ~$12,000/annum
• Provides Internet access services, as well as supporting a wealth of ATM-based services (intranet, videoconferencing, PSTN toll bypass, etc)
• Provides access to research backbones (e.g. Abilene)
• Currently 595 sites
30 May 2001 Gaylord: Virginia Tech Campus Overview
18
Net.Work.Virginia
SprintLink(Internet)
Abilene(Internet2)
SprintPublic ATM ESnet
RegionalLEC ATM
RegionalLEC ATM
OC-12c ATMOC-12c POSOC-12c POS
N x OC-3c/DS-3 ATM WTNASX-1000
ROAASX-1000
RICASX-1000
ROAGSR
12016
RICGSR
12016
WTNGSR
12016
WTNGSR
12016
RegionalLEC ATM
RegionalLEC ATM
RegionalLEC ATM
RegionalLEC ATM
RegionalLEC ATM
RegionalLEC ATM
30 May 2001 Gaylord: Virginia Tech Campus Overview
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Quality of Service
• Traffic Classification• Congestion Avoidance
– Policing– WRED
• Congestion Management– CBWFQ– Shaping/Conditioning
30 May 2001 Gaylord: Virginia Tech Campus Overview
20
Traffic Classification
• DSCP/IP Precedence marking• Classify different classes of “Best Effort”
to protect each from each other• Classes can be based on users or
applications• Use netflow to determine major
applications• Use business rules to determine major
user bases
30 May 2001 Gaylord: Virginia Tech Campus Overview
21
Traffic Classification
• Only bits 0-2 are used (DiffServLite?)– Control Plane (DSCP=56(?) set by routers)– IP Telephony (DSCP=40(?) set by end-station)– On-campus any-to-any (DSCP=24)[Following are destined off-campus]– Non-residential (aaanet) TCP (DSCP=16)– Residential (resnet) TCP (DSCP=8)– Other residential and non-residential (notTCP)
(DSCP=0)– Should these be xxxx11?
• Except for IP Telephony and control plane, classification is done at entry to core (DSCP is only trusted in one edge VLAN, viz. telephony)
• No use of 802.1p (outside of telephony LAN)
30 May 2001 Gaylord: Virginia Tech Campus Overview
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Traffic Shaping
• Outgoing only (ATM OC-3 … nominally 100Mbps)– aaanet 40Mbps– resnet 40Mbps– notTCP 10Mbps– CBWFQ– No priority queuing (at this time)
• No shaping for on-campus traffic
30 May 2001 Gaylord: Virginia Tech Campus Overview
23
Traffic Policing
• On-campus– No policing– All best-effort– Lots of excess capacity
• Incoming to campus– Same as on-campus
• Outbound– Police resnet to 60Mbps (nominal 60% of
Internet pipe) at entry to border area– Formerly specifically policed “application of
special interest”
30 May 2001 Gaylord: Virginia Tech Campus Overview
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CiscoCatalyst
5000
Path of a packet
CiscoCatalyst
6500
Catalyst 1900/1924Catalyst
1900/1924
Catalyst 1900/1924
Catalyst 1900/1924Catalyst
1900/1924
Core
n x 100Base-FX
10
0B
ase
-FX
do
wn
links
DSCP marking happens here
30 May 2001 Gaylord: Virginia Tech Campus Overview
25
Path of a packet
MSAP
DSL
T1/FR
LMDS
ModemPool
N.W.V
SHACatalyst
6500
OWECatalyst
6500
HILCatalyst
6500
ISBCisco 7500
Internet
Internet2
ISBCatalyst
6500
BURCatalyst
6500
CASCatalyst
6500
ISBCatalyst
6000
CASCisco 7500
From building network DSCP marking happens here
Policing happens here
Conditioning happens here
VT ATM
Backbone
ISBCisco 7500
30 May 2001 Gaylord: Virginia Tech Campus Overview
26
What we have learned
• Outbound congestion creates poor inbound TCP performance
• Conditioning alone does not work well when offered load is high
• Leave room for bursts (set sum of committed traffic to 90% of link?)
• Policing alone works for isolated traffic classes
• Doing anything is better than doing nothing - even for voice
• Divide and conquer
30 May 2001 Gaylord: Virginia Tech Campus Overview
27
Futures
• Priority queuing for voice• Traffic classes for distance learning
(DLoIP ™), Research Computing, et al.• Per-user classification and user-class
policing• Netflow data gathering and traffic
classification• Remote monitoring of end-to-end
performance• How do we measure bursts?