CONTENTS Title Page Copyright Page How to Use This Manual 1 How to Begin Problem Solving 1.1 Isolating the Problem 1.2 Which Manual? 1.3 How to Work Through This Manual 1.4 Tools Required for Problem Solving 1.4.1 NCL 1.4.2 Event Logging 1.4.3 Common Trace Facility 1.4.4 Loopback Tests 1.5 Information Required for Problem Solving 1.5.1 Constructing a Tower Set 1.6 Problem Solving Procedures 1.6.1 The Start 2 DECNIS Unreachable 2.1 Problems Loading the DECNIS 2.1.1 DECNIS Nonvolatile Memory (Flash) Loading Problems 2.1.2 MOP Loading Problems 2.1.3 BOOTP Loading Problems 2.2 DECNIS Dumps or Reloads 2.2.1 DECNIS Dumps or Reloads: MOP Load Hosts 2.2.2 DECNIS Dumps or Reloads: BOOTP Load Hosts 2.3 DECNIS Has Loaded but Will Not Respond 2.3.1 Routing Vector Algorithm 2.3.2 Link State Routing Algorithm 3 DECNIS Reachable 3.1 Packet Prioritization 3.1.1 Problems Setting Up PACKET and PATTERN Entities 3.1.2 Prioritized Packets Are Not Reaching The Remote Node 3.1.2.1 NIC Has Used Up All Its Transmit Buffering 3.1.2.2 MAXIMUM QUEUE LENGTH Has Been Exceeded 3.1.3 Packets are Assigned to the Wrong Priority Queue 4 Checking Circuits 4.1 CSMA/CD Circuits 4.2 FDDI Circuits 4.3 HDLC Circuits 4.3.1 Checking Device Availability on HDLC Circuits 4.4 DDCMP Circuits 4.4.1 Checking Device Availability on DDCMP Circuits 4.5 PPP Circuits 4.5.1 Checking Device Availability on PPP Circuits 4.5.2 Using a Loopback Path to Check PPP Links 4.6 CHDLC Circuits 4.6.1 Checking Device Availability on CHDLC Circuits 4.6.2 Using a Loopback Path to Check CHDLC Links 4.7 SMDS Circuits 4.7.1 Using Loopback to Check SMDS Circuits 4.8 Tunnel Circuits 4.8.1 Tunnel Point-To-Point Circuits 4.8.2 Tunnel Broadcast Circuits 4.9 X.25 Static Circuits 4.10 X.25 Permanent Circuits 4.11 Dynamically Assigned X.25 Circuits 5 Proxy Loading Problems 6 DECnet/OSI Routing Problems 7 X.25 Problems 7.1 Incoming Calls Failing 7.1.1 Incoming Calls on the DECNIS 7.1.2 Incoming Calls on X.25 Client Systems 7.2 Outgoing Calls Failing 7.2.1 Outgoing Calls from the DECNIS 7.2.2 Outgoing Calls from a Client System 7.3 Local DTE Fails 7.3.1 ENABLE X25 PROTOCOL DTE Exceptions 7.3.2 DTE Restart Failure 7.3.3 Link Set Up Failure 7.3.4 LLC2 Link Inoperative 7.3.5 Line Set Up Failure on LAPB Links 7.4 X.25 Relay 7.4.1 Checking Relay SVCs 7.4.2 ENABLE X25 Relay Client Exceptions 7.4.3 Checking Relay PVCs 8 Internet Protocol (IP) Problems 8.1 Generating ICMP Echo Requests 8.2 Diagnosing IP Router Path Problems 8.3 Local OSPF Fails 9 Bridging Problems 10 AppleTalk Problems 11 NetWare IPX Problems 12 Loopback Testing 12.1 Testing HDLC, DDCMP and LAPB Data Links 12.1.1 Setting Up the Test 12.1.2 Performing the Loopback Test 12.2 Testing CSMA/CD and FDDI Circuits 12.3 Testing Logical Links Between Nodes 12.3.1 Checking the Local Nodes 12.3.2 Checking Remote Nodes 13 Event Logging 13.1 Checking that Event Logging Is Working Correctly 13.2 Faulty Event Logging 14 Reporting Problems to Digital 14.1 Details of the Software 14.2 Details of the Problem Glossary of Event Messages Access Control Violation . . . Alignment Error Attempt to Exceed Maximum Sequence Number . . . Carrier Check Failure Change Confidence . . . Connection State Transition Control Protocol Reject Message Received . . . Destination Address Error Packet Discard Device Failure . . . DXI Protocol State Transition EGP Message Discard . . . Fragmentation Failure Discard Frame Check Error . . . Initialization Failure Inlink Change . . . IP Adjacency State Change IP Destination Address Error Packet Discard . . . LCP Initialization Failure LCP State Change . . . Link Resetting Link Running . . . LSP L2 Database Overload Management Protocol Transition . . . Outgoing Call Blocked Outgoing Call Configuration Error . . . Port State Change Port Terminated . . . Reject Packet Received Reject Received . . . Ring Initialization Received Ring Purge Error . . . Shutdown Source Address Error Packet Discard . . . Successful Load SVC Failed . . . Unknown Community Name PDU Discard Unknown PDU Type Discard . . . Verification Reject EXAMPLES 12-1 MOP Circuit with Assistant Name 12-2 MOP Client with Assistant Name 12-3 MOP Client with Assistant Address FIGURES 1-1 Problem Solving Documentation TABLES 2-1 BOOTP Load Files 2-2 MS-DOS Load files 2-3 BOOTP Load Files 2-4 MS-DOS Load files 12-1 STARTLOOP MODEM CONNECT LINE Modes 12-2 LOOP MOP COUNT, LENGTH, and FORMAT Arguments 12-3 LOOP MOP Arguments for Loopback Through Assistant Systems 12-4 LOOP LOOPBACK APPLICATION Arguments