Transcript Lecture Slides - Virginia Tech

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.
Type III Building Network
Catalyst 1924
Catalyst 1924
100Base-FX downlinks
Catalyst 1924
Catalyst 1924
Catalyst 1924
Cisco
Catalyst
5000
• 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.
10Base-T
to wall portal
ATM OC3c
FORE
ASX-1000
Cisco
7507
MDF
VT ATM Backbone (since 1996)
BUR
Catalyst
5500
OC12c ATM (622 Mbit/s)
OC3c ATM (155 Mbit/s)
HIL
Catalyst
5000
Modem
Pool
ISB
Cisco
7507
ISB
Cisco
7507
ISB
Cisco
7507
SHA
Cisco
7507
SHA
FORE
ASX-1000
OWE
Catalyst
5000
ISB
Catalyst
5500
OWE
FORE
ASX-1000
ISB
FORE
ASX-1000
OWE
Cisco
7507
LMDS
Internet
N.W.V
Internet2
HIL
Cisco
7507
HIL
FORE
ASX-1000
BUR
FORE
ASX-1000
SHA
Catalyst
5500
BUR
Cisco
7507
CAS
FORE
ASX-1000
CAS
Catalyst
5000
CAS
Cisco
7507
xDSL
T1/FR
MSAP
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).
Type IV Building Network
Catalyst 1924
Catalyst 1924
100Base-FX downlinks
Catalyst 1924
• 2 x 100Base-FX building feed,
no more ATM
• Simpler model.
• Low cost conversion
• Scalable building feed
Catalyst 1924
Catalyst 1924
Cisco
Catalyst
5000
10Base-T
to wall portal
2 x 100Base-FX
Cisco
Catalyst
6509
MDF
Type V Building Network
Catalyst 3524
Catalyst 3524
Catalyst 3524
Catalyst 3524
Catalyst 3524
1000Base-T4
interswitch links
• 10/100 to the desktop
• High capacity building
concentrator switch.
• Scalable Gigabit Ethernet building
backbone.
• Deployed in ACITC
Catalyst 3524
Catalyst 3524
10/100Base-TX
to wall portal
Catalyst 3524
Cisco
Catalyst
6509
2 x 1000Base-LX
Cisco
Catalyst
6509
MDF
VT Gigabit Backbone (Fall 2000)
2 x 1000Base-LX
1 x 1000Base-LX
1 x 1000Base-SX
1 x 100Base-FX/TX
ATM OC3c
Future POS/DPT/ATM OC12c
or 1000Base-ZX
BUR
Catalyst
6509
HIL
Catalyst
6509
SHA
Catalyst
6509
ISB
Catalyst
6509
OWE
Catalyst
6509
ISB
Catalyst
6006
Modem
Pool
ISB
Cisco
7507
Internet
N.W.V
Internet2
ISB
Cisco
7507
VT
ATM
Backbone
CAS
Catalyst
6509
CAS
Cisco
7507
MSAP
xDSL
T1/FR
LMDS
VT ATM Backbone (Fall 2000)
ATM OC3c multi-mode
ATM OC3c single-mode
1000Base-SX
BUR
ASX-200BX
SHA
ASX-200WG
HIL
ASX-200BX
OWE
ASX-200WG
ISB
ASX-1000
CAS
ASX-200BX
ISB
Cisco
7507
N.W.V
Internet
Internet2
ISB
Cisco
7507
VT
Gigabit
Backbone
CAS
Cisco
7507
Net.Work.Virginia
• Provides ATM services throughout Virginia to K12 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
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•
•
•
rdweb.cns.vt.edu
www.networkvirginia.net
www.internet2.edu
www.abilene.iu.edu
Contact Info
Carl Harris
[email protected]