Network Essentials I Technical Support Advisory Consortium

Network Essentials INetwork Essentials I

Technical Support Advisory ConsortiumScott Genung, TNSS

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AgendaAgenda

IntroductionISUnet Design OverviewForms of AccessConnectivityTroubleshooting

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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

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LAN (Local Area Network)CAN (Campus Area Network)WAN (Wide Area Network)RAS (Remote Access Services)

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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

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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

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CAN (continued)– 4 core switches are interconnected in a complete mesh

for scalability and survivability

– provides routing for IP, AppleTalk, and IPX

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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

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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

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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)

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Forms of AccessForms of Access

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private access networkpublic access networkresidential broadbandResNetwirelessdialupapartment complex networksfrom the Internet

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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)

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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

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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)

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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

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wireless– provide mobile access to campus

or Internet based services

– pilot expected to last into fall semester

– (LEAP or TLS) authentication and (dWEP) encryption

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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)

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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

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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

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ConnectivityConnectivity

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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

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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

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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

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ConnectivityConnectivity statically defining IP properties

– for NT, 2K, XP

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learning IP properties through DHCP – for NT, 2K, XP

– IP address

– gateway

– subnet mask

– DNS servers

– WINS servers

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blocking DDNS– Internet name space is

managed

– uncheck Register this connection’s address in DNS

– register address as a static host name if needed

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ConnectivityConnectivity registering Internet host names

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registering with WINS– NetBIOS name and IP address are registered with

primary WINS server

– peering WINS servers will replicate address pair

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TroubleshootingTroubleshooting

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ipconfig, winipcfg, ifconfigping traceroutenbtstat

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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

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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?

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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

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(this ping was run from an ADSL circuit)

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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

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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

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04/09/2349www.samspade.org

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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

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nbtstat– used to troubleshoot NetBIOS/IP connectivity

from a Windows OS

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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?

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ConclusionConclusion

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ConclusionConclusion

many resources available for assistance– Outages and Alerts– isunet-l listserv– TSAC public website– TNSS public website

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ConclusionsConclusions

what other type of information would be of value?

other questions?

Network Essentials I Technical Support Advisory Consortium

Documents

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