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 voic –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 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 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 Cisco Catalyst 6509 MDF 2 x 1000Base-LX 1000Base-SX downlinks 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

Contact Info Carl Harris