Transcript Document 750650

Campus Networks, Various Topics
Eric Brown, Network Architect, VT
Agenda
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Network Cardinality
Switching versus Routing
Network Topology
Wireless Coverage, Use, Engineering
Internet Connectivity
Electronic Message Boards
Copyright Complaints
Network Security
Network Documentation
TCP
Future
Network Cardinality
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35,000 users
6 primary switching centers
120 buildings
415 equipment rooms
100,000 horizontal links
27,000 active wired Ethernet connections
1500 access switches
450 distribution switches
50 routers (core, IPv6, data-center, WAN, border)
13,000 phones (5000 that never get used)
5000 cable television connections
200 modem pool connections
Switching versus Routing
• How has routing/switching tradeoff changed over
time
• One large bridged LAN (c. 1985)
• Routed IP + Appletalk + IPX, FDDI ring core, Other protocols
bridged (c. 1992)
• ATM + Emulated LAN: Ouch! (c. 1995)
• Gigabit Ethernet core, Ethernet to Ethernet routing (c. 1999)
• Increasing reach of routing: to some buildings (c. 2006)
Switching versus Routing
• Liabilities of switching:
• Generally no visibility into switched network unless you are
on it
• No support for multiple valid paths,
• ARP is hearsay and potentially dangerous
• Both IP and Ethernet have a notion of mutlicast
• Implementing multicast requires some mapping between layers
• High risk of soft failures (a misplaced root in a large network
can lead to very inefficient operation)
• No real support for default gateway redundancy, we have to
fake it through VRRP or HSRP
• No TTL, i.e. no stop gap way to remove old frames from the
network
Switching versus Routing
• Benefits of switching
• Network Address use efficiency, too small of subnets leads
to inefficient use of IP addresses
• Address portability
• Simple network configuration
• Subnets create convenient boundary for implementing policy
“Soft Failure” in the LAN
Primary
Backup
ROOT
“Soft Failure” in the LAN
Primary
ROOT ?!
Backup
SPANNING KUDZU!
Diameter = 8?!
Core Topology
BUR Core
Switch/Router
Remote
Access
ISB Data
Center
SHA Core
Switch/Router
ISB Core
Switch/Router
OWE Core
Switch/Router
HIL Core
Switch/Router
ISB Border
Switch/Router
MSAP
ISB
Border
Router
ISB
Border
Router
Internet
Internet2
McLean
NLR
Ashurn
CAS Core
Switch/Router
Remote offices
DSL/T-1
Wireless Coverage
Wireless Utilization
Current Wireless Deployment
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Over 20,000 Registered Users
Over 6,000 Simultaneous Users, Daily
1,726 Light-weight Wireless Access Points
24 Cisco wireless controllers
2 Stand-alone Application Services
Appliances providing NAT
• 6 RADIUS Servers
• 1 Very Tired Spectrum Analyzer
Wireless RF planning
Equinix
MBC 10GE
Cassell
National Lambda Rail
MAX / Internet2
Level3
Cogent
Equinix Exchange
Hurricane Electric
Cogent
TransitRail
Future Internet Connectivity
MBC 10GE
McLean
Verizon 10 GE
ISB
Network Metrics
Internet – 10G Ethernet – Daily
Internet – 10G Ethernet – Monthly
Classroom Emergency
Notification
Openfire
INS
Alert Agent
Jabber/XMPP
OAMP
Sign
Controller
Diagnostic Agent
Sign
Controller
SSH
sign
sign
sign
Sign Agents
and Adapters
Sign
Controller