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

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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)


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


4

ARP/MAC mappings 1


5

ARP/MAC mappings 2


6

Roll your own


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


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ISM


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AMP


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• 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


1900/1924


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


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)


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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?


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


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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.


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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


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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


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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


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Quality of Service

• Traffic Classification• Congestion Avoidance

– Policing– WRED

• Congestion Management– CBWFQ– Shaping/Conditioning


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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


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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)


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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


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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”


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CiscoCatalyst

5000

Path of a packet

CiscoCatalyst

6500


1900/1924

Catalyst 1900/1924


1900/1924

Core

n x 100Base-FX

10

0B

ase

-FX

do

wn

links

DSCP marking happens here


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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


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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


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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?


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For More Information

• http://rdweb.cns.vt.edu/• http://www.networkvirginia.net/

Virginia Tech Campus Network Overview Internet2 Campus Focused Workshop On Advanced Networks Clark...

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