Campus Network Wired connection Troubleshooting

Campus Network Wired connection Troubleshooting

This KB describes the process used to do initial troubleshooting and information gathering when a wired network issue is reported. This assumes that device troubleshooting has been done, and this article is written primarily for IT staff (CSS-IT).  

Information collection

• Cable ID:  Identify wall jack Cable ID (marked next to jack, usually ends in "-D", usually does not include building which needs to be looked up, see below KB link) and verify cable ID via telcat (copy/paste from telcat avoids typos or incomplete IDs) This is the single most important piece of information.  (See self service lookups for cable is telcat here)  If multiple connections are affected, include a sample of affected cable IDs.  
• See cable lookup in Telcat to determine if Cable (Wall Jack) is active or not (searching by building and station room is helpful) and also to validate the cable ID as correct.  If the cable is inactive, submit a work order via the telecom catalog in telcat to have the cable activated (no charge).  
• Location - Where is the problem specifically, what building/room.  If a *full* cable ID is available (e.g. BUILDING-123-456-001-D), this can be skipped, otherwise this becomes critical.
• Note IP address (or lack therof) and MAC address of device's wired interface (not the wireless, make sure you have the right one)
• Ask if there is a Firewall on the subnet, and who administers it.  (Have rules checked by FW admin before escalating to network group).  

Diagnostic procedures

• Remove any user installed network equipment if present (switches, routers etc between the device and the wall jack) and see if direct to the jack works. (Network supports to the jack only)
• Note if IP Address is obtained, and if it matches expected subnet? (See cable lookups)
• Check Wired interface MAC address to see if it's registered to campus (often wireless mac is done by mistake) https://netreg.berkeley.edu/ (get device registered if need be, unregister wireless interface if it was registered, WiFi is authenticated via other means)
• Check IP and MAC address block lists at security to determine if it's a security block- https://security.berkeley.edu/resources/block-lists (Pursue with security if blocked with related ticket # in subject line of email to security@berkeley.edu)
• Connect known good patch cable and device to jack, See if layer 2 link is established (link light on), note speed and duplex, any IP address obtained and if connectivity exists. If the connection functions, the issue lies with the user device and the incident should not be escalated to the network group.
• Please note that locating hosts for security tickets is not available anymore due to staff reduction, if necessary have security block the host to flush out the user.  

Escalation to NOS

Put the following collected field information into the incident comments prior to escalating to the network team:

• Full Cable ID(s):
• Host wired interface MAC Address:
• IP Address of host (NA if unable to obtain):
• Location of problem (Building/room): 
• Firewall presence and admin phone, email:

Assign ticket:

• Assignment Group: "IST - Data Network Support"
• Assigned To: BLANK (it is assigned by NOS internally)
• Status: New

Building lookup procedure