Network Essentials INetwork Essentials I
Technical Support Advisory ConsortiumScott Genung, TNSS
04/09/232
AgendaAgenda
IntroductionISUnet Design OverviewForms of AccessConnectivityTroubleshooting
04/09/233
Introduction Introduction describe the ISUnet network model in
understandable terms
describe the different types of access users have to electronic resources on ISUnet
describe some basic IP definitions for connectivity to ISUnet
describe some basic network tools to aid in problem reporting or troubleshooting
ISUnet Design OverviewISUnet Design Overview
04/09/235
ISUnet Design OverviewISUnet Design Overview
LAN (Local Area Network)CAN (Campus Area Network)WAN (Wide Area Network)RAS (Remote Access Services)
04/09/236
ISUnet Design OverviewISUnet Design OverviewLAN (Local Area Network)
– for ISUnet, a LAN is defined as a network environment that provides direct connectivity for the end user
– 300+ access switches throughout ISUnet provide 13,000+ devices with ethernet connectivity
– includes connectivity for desktop computers, laptops, notebooks, servers (of all sizes), PDAs, peripherals, etc
04/09/237
04/09/238
ISUnet Design OverviewISUnet Design Overview CAN (Campus Area Network)
– also known as the network backbone or core– a CAN is defined as a network environment that
provides high performance interconnectivity for local area networks
– 20+ group switches are used to connect multiple access switches within a building (unless there’s a distribution switch)
– 15 distribution switches provide connectivity for multiple access or group switches and are attached to multiple core switches
04/09/239
ISUnet Design OverviewISUnet Design Overview
CAN (continued)– 4 core switches are interconnected in a complete mesh
for scalability and survivability
– provides routing for IP, AppleTalk, and IPX
04/09/2310
04/09/2311
ISUnet Design OverviewISUnet Design Overview
WAN (Wide Area Network)– an environment that provides inter-connectivity
between networks using a 3rd party service provider– includes access to and from the public Internet,
residential broadband, peering connectivity, and access to remote affiliated networks
– routers used to direct traffic from CAN to public Internet or private WAN circuits
04/09/2312
ISUnet Design OverviewISUnet Design Overview
WAN (continued)– NAT (Network Address Translation) engines to
provide translation between private and public IP address space
– QoS (Quality of Service) appliances to provide bandwidth reservation, shaping, and priority policies
04/09/2313
04/09/2314
ISUnet Design OverviewISUnet Design OverviewRAS (Remote Access Services)
– provides access to a data network through the public or campus telephone network
– user must authenticate to directory using PAP– authenticated user is served IP address over
PPP– pools
30 minute (438-8200 or 8-8200)6 hour (438-8210 or 8-8210)
04/09/2315
04/09/2316
Forms of AccessForms of Access
04/09/2317
Forms of AccessForms of Access
private access networkpublic access networkresidential broadbandResNetwirelessdialupapartment complex networksfrom the Internet
04/09/2318
Forms of AccessForms of Access
private access network– provide access for stationary network devices such as
desktop computers, servers, printers, etc
– provide enhanced access for servers
– physical security
– static public IP address, static private IP address, or served private IP address through DHCP (Dynamic Host Configuration Protocol)
04/09/2319
Forms of AccessForms of Access public access network
– provide access for mobile network devices such as laptop and notebook computers, PDAs (Personal Digital Assistant), etc
– not for servers– user authentication (must be affiliated with the
University)– served private IP address through DHCP (Dynamic
Host Configuration Protocol)– technologies such as switched ethernet and wireless
ethernet– locations include Bone, Milner, and all dining centers
04/09/2320
Forms of AccessForms of Access
residential broadband– provide dedicated (always on) access to local or
Internet services to users affiliated with the University from their residence
– technologies include ADSL (Asymmetric Digital Subscriber Line) service, cable, wireless Internet, and satellite
– basis for telecommuting access– dependence upon a 3rd party access provider (DHCP
with private IP addressing)– University as an ISP or 3rd party ISP (with VPN)
04/09/2321
Forms of AccessForms of Access
ResNet– port per pillow– registration model– DHCP with private IP addressing– 5,000+ wired jacks in select residence halls by
spring 2002– 7,300+ wired jacks by spring 2003
04/09/2322
Forms of AccessForms of Access
wireless– provide mobile access to campus
or Internet based services
– pilot expected to last into fall semester
– (LEAP or TLS) authentication and (dWEP) encryption
04/09/2323
04/09/2324
Forms of AccessForms of Access
dialup– provides access to the campus
network and the public Internet through the campus or public telephone system
– narrowband (53Kb/s or less using V.90)
04/09/2325
Forms of AccessForms of Access
apartment complex networks– networks developed and maintained by management
companies– use of 3rd party ISPs (such as A5 networks)– peering circuit for dedicated connectivity– VPN client for secure access
04/09/2326
Forms of AccessForms of Access
from the Internet– accessing campus resources
from a 3rd party ISP or external enterprise network
– access public services such as campus public web sites
– use VPN client to access restricted resources on campus including Windows and Novell domains
04/09/2327
ConnectivityConnectivity
04/09/2328
ConnectivityConnectivity physical connectivity obtaining an ethernet link state statically defining IP properties learning IP properties through DHCP blocking DDNS registering Internet host names with DNS registering NetBIOS names with WINS
04/09/2329
ConnectivityConnectivity physical connectivity
– RJ-45 jacks can be ordered or activated from TNSS
– RJ45 jack needs UTP-5e (category 5 enhanced) patch cable (or better)
– UDC jack needs a 10BaseT balun and UTP-5e patch cable (or better)
– UTP cables and baluns can be ordered from STSS
04/09/2330
ConnectivityConnectivity
obtaining an ethernet link state– polarity
– duplex auto for clients full duplex for servers
– link speed
– check troubleshooting documentation on TNSS web site for help
04/09/2331
ConnectivityConnectivity statically defining IP properties
– for NT, 2K, XP
04/09/2332
ConnectivityConnectivity
learning IP properties through DHCP – for NT, 2K, XP
– IP address
– gateway
– subnet mask
– DNS servers
– WINS servers
04/09/2333
04/09/2334
ConnectivityConnectivity
blocking DDNS– Internet name space is
managed
– uncheck Register this connection’s address in DNS
– register address as a static host name if needed
04/09/2335
ConnectivityConnectivity registering Internet host names
04/09/2336
ConnectivityConnectivity
registering with WINS– NetBIOS name and IP address are registered with
primary WINS server
– peering WINS servers will replicate address pair
04/09/2337
04/09/2338
TroubleshootingTroubleshooting
04/09/2339
TroubleshootingTroubleshooting
ipconfig, winipcfg, ifconfigping traceroutenbtstat
04/09/2340
TroubleshootingTroubleshooting ipconfig
– describes addressing for interface served or defined address gateway and mask DNS and WINS servers
– Windows 98, NT, 2K, XP winipcfg
– Windows 95, ME open transport
– MacOS ifconfig
– Linux
04/09/2341
04/09/2342
TroubleshootingTroubleshooting
what are we looking for with ipconfig?– what is the media state? (connected or
disconnected)– are the IP address, mask, or gateway valid?– are the DNS or WINS server address valid?– if using DHCP, is the lease period valid?– is the name valid?
04/09/2343
TroubleshootingTroubleshooting ping
– used to determine the reachability of a destination IP address and the responsiveness of the path
– is not a reliable tool for measuring performance because of QoS policies that many organizations have for ICMP
– should see between 1 and 30ms on campus depending upon load using 32 byte packets
– should see between 20 and 80ms from ADSL using 32 byte packets
– can see response times exceed 300ms over the public Internet using 32 byte packets
– response times will dramatically increase for much larger packet sizes
04/09/2344
04/09/2345
(this ping was run from an ADSL circuit)
04/09/2346
TroubleshootingTroubleshooting
what are we looking for with ping?– is the destination host, network, or protocol
reachable?
– is there evidence of packet loss or delay (subjective)?
– is the packet loss or delay variable or consistent?
– are other devices experiencing the same problem?
– testing gateway, on-campus, and off-campus access
04/09/2347
TroubleshootingTroubleshooting traceroute
– used to trace record the route between source and destination IP addresses
– provides a sample of response times between the source and each hop
– can tell you when a host, network, or protocol is unreachable (ie: !H, !N, or !P)
– tracert under Windows 95, 98, NT, 2K, ME, XP
– traceroute under all flavors of Unix
04/09/2348
04/09/2349www.samspade.org
04/09/2350
TroubleshootingTroubleshooting
what are we looking for with traceroute?– is the destination host, network, or protocol
reachable?
– is there evidence of packet loss or delay (subjective) at any hop between source and destination?
– is the packet loss or delay variable or consistent?
– are other devices experiencing the same problem?
– testing gateway, on-campus, and off-campus access
– testing connectivity from off-campus to campus
04/09/2351
TroubleshootingTroubleshooting
nbtstat– used to troubleshoot NetBIOS/IP connectivity
from a Windows OS
04/09/2352
04/09/2353
04/09/2354
04/09/2355
04/09/2356
TroubleshootingTroubleshooting
what are we looking for with nbtstat?– is the NetBIOS name of the local device
registered with WINS?– are we able to resolve multiple NetBIOS
names from WINS?
04/09/2357
ConclusionConclusion
04/09/2358
ConclusionConclusion
many resources available for assistance– Outages and Alerts– isunet-l listserv– TSAC public website– TNSS public website
04/09/2359
04/09/2360
04/09/2361
04/09/2362
ConclusionsConclusions
what other type of information would be of value?
other questions?
Top Related