Campus Network Overview
Carl Harris
Associate Director, Research and Development
Communications Network Services
Virginia Tech
What is CNS?
•
Communications
Network
Services provides the
following services to Virginia Tech faculty, staff,
and students
–
traditional telephone and voice
-
mail
–
cable television (mostly residence halls)
–
IP/IPX/AppleTalk
network layer
and below
•
Exception: DNS and DHCP
•
Provide services on Blacksburg campus and at
graduate centers around the state.
Basic Link Layer Services
•
Basic Ethernet portal service
–
Switched 10Base
-
T (10 Mbit/s)
–
Some switched 100Base
-
TX (100 Mbit/s), but very
expensive.
•
Dial
-
in modem pool with ~1,200 56K modems.
•
MSAP provides campus backbone access to local
ISPs.
–
Ethernet in apartment complexes
•
ATM portal service for specialized applications
(e.g. videoconferencing used in distance learning
programs)
Network Layer Architecture
•
IP routing
–
Within our autonomous system (AS):
•
OSPF plus some static routes
–
Extending beyond our (AS):
•
BGP4+ (
a.k.a.
MBGP) plus some static routes
•
In the modem pool:
EIGRP (Cisco proprietary): fast convergence, low overhead,
few knobs. Low CPU cost despite lots of link state changes.
–
Coming soon:
•
Multiprotocol Label Switching (MPLS,
a.k.a.
tag switching) to
support certain kinds of policy routing
•
Packet prioritization and custom queuing disciplines to support
apps with strict latency and loss requirements.
Network Layer Architecture
•
IP multicast routing
–
Within our AS:
•
Protocol Independent Multicast, Sparse Mode (PIM
-
SM)
between routers.
•
Internet Group Management Protocol (IGMPv2) manages
multicast group membership to control distribution to hosts.
–
Extending beyond our AS:
•
PIM
-
SM
•
MBGP (multiprotocol,
not
multicast)
•
Multicast Source Discovery Protocol (MSDP)
•
A few legacy DVMRP tunnels
Network Layer Architecture
•
IPX routing: IPX RIP, NLSP (similar to OSPF)
•
AppleTalk routing:
who cares
?
Layer 1 and 2 Architecture
•
Primary switching facilities are located in:
–
Andrews Information Systems Building
–
Cassell Coliseum
–
Burruss Hall
–
Hillcrest Hall
–
Owens Hall
–
Shanks Hall
•
Use fiber
-
optics to interconnect switching
facilities and to fan out to building backbones.
Layer 1 and 2 Architecture
•
ATM backbone used as a “substrate” on which to
build network layer services.
–
LAN Emulation (LANE)
•
Routers connect to ATM backbone and use LANE
to establish virtual connections to each building
subnet. LANE also used to interconnect the
routers to form a network layer backbone.
•
Ethernet switches with LANE capability used in
building backbones, ATM connection to campus
backbone.
100Base
-
FX downlinks
Cisco
Catalyst
5000
Catalyst 1924
Catalyst 1924
Catalyst 1924
Catalyst 1924
Catalyst 1924
MDF
ATM OC3c
FORE
ASX
-
1000
Cisco
7507
•
Ethernet edge switches go in
wiring closets located throughout
the building
•
LANE connects the router (Cisco
7507) to the primary building
switch (Catalyst 5000) via the
ATM backbone switch.
Type III Building Network
10Base
-
T
to wall portal
MSAP
xDSL
T1/FR
LMDS
Modem
Pool
N.W.V
VT ATM Backbone (since 1996)
OC3c ATM (155 Mbit/s)
OC12c ATM (622 Mbit/s)
SHA
FORE
ASX
-
1000
OWE
FORE
ASX
-
1000
HIL
FORE
ASX
-
1000
ISB
Cisco
7507
Internet
Internet2
ISB
FORE
ASX
-
1000
BUR
FORE
ASX
-
1000
CAS
FORE
ASX
-
1000
ISB
Cisco
7507
CAS
Cisco
7507
OWE
Cisco
7507
SHA
Cisco
7507
BUR
Cisco
7507
HIL
Cisco
7507
ISB
Cisco
7507
ISB
Catalyst
5500
HIL
Catalyst
5000
BUR
Catalyst
5500
SHA
Catalyst
5500
OWE
Catalyst
5000
CAS
Catalyst
5000
What Now?
•
Need low cost 10/100Base
-
TX portal service
•
Need to provide greater resiliency, lower latency,
more bandwidth, and packet switching with
differentiated QoS for next
-
generation
applications
–
university administrators using desktop
videoconferencing over IP
–
telephone services (voice
-
over
-
IP)
–
bandwidth killer applications (e.g.
Napster
)
•
Need architecture consist with high
-
bit
-
rate
multicast (e.g. streaming HDTV via multicast).
•
2 x 100Base
-
FX building feed,
no more ATM
•
Simpler model.
•
Low cost conversion
•
Scalable building feed
Cisco
Catalyst
5000
Type IV Building Network
Cisco
Catalyst
6509
Catalyst 1924
Catalyst 1924
Catalyst 1924
Catalyst 1924
Catalyst 1924
MDF
2 x 100Base
-
FX
100Base
-
FX downlinks
10Base
-
T
to wall portal
•
10/100 to the desktop
•
High capacity building
concentrator switch
.
•
Scalable Gigabit Ethernet building
backbone.
•
Deployed in ACITC
Type V Building Network
Cisco
Catalyst
6509
Catalyst 3524
Catalyst 3524
Catalyst 3524
Catalyst 3524
Catalyst 3524
Catalyst 3524
Catalyst 3524
Catalyst 3524
Cisco
Catalyst
6509
MDF
2 x 1000Base
-
LX
1000Base
-
T4
interswitch links
10/100Base
-
TX
to wall portal
MSAP
xDSL
T1/FR
LMDS
Modem
Pool
VT
ATM
Backbone
N.W.V
VT Gigabit Backbone (Fall 2000)
1 x 1000Base
-
SX
1 x 1000Base
-
LX
2 x 1000Base
-
LX
ATM OC3c
1 x 100Base
-
FX/TX
SHA
Catalyst
6509
OWE
Catalyst
6509
HIL
Catalyst
6509
ISB
Cisco
7507
Internet
Internet2
ISB
Catalyst
6509
BUR
Catalyst
6509
CAS
Catalyst
6509
ISB
Catalyst
6006
ISB
Cisco
7507
CAS
Cisco
7507
Future POS/DPT/ATM OC12c
or 1000Base
-
ZX
VT ATM Backbone (Fall 2000)
N.W.V
VT
Gigabit
Backbone
ATM OC3c multi
-
mode
ATM OC3c single
-
mode
1000Base
-
SX
Internet
Internet2
SHA
ASX
-
200WG
OWE
ASX
-
200WG
BUR
ASX
-
200BX
CAS
ASX
-
200BX
ISB
ASX
-
1000
HIL
ASX
-
200BX
CAS
Cisco
7507
ISB
Cisco
7507
ISB
Cisco
7507
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), ~ $150,000/annum
•
DS3 (45 Mbit/s), ~$60,000/annum
•
DS1 (1.5 Mbit/s), ~12,000/annum
–
provides Internet access services, as well as supporting
a wealth of ATM
-
based services (intranet,
videoconferening, PSTN toll bypass, etc).
–
provides access to Internet2 backbones (Abilene,
vBNS)
For More Information
•
rdweb.cns.vt.edu
•
www.networkvirginia.net
•
www.internet2.edu
•
www.abilene.iu.edu
Contact Info
Carl Harris
ceharris@vt.edu
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