Title
Copyright
Preface
1. Introduction to X.25 and Packet Switching
1.1 Packet Switching Data Networks
1.1.1 Major Components of a PSDN
1.1.2 Packet Flow Through a PSDN
1.1.3 Physical Connections
1.1.4 Logical Channels and Logical Channel Numbers
1.1.5 Virtual Circuits
1.2 X.25 Protocol Levels
1.2.1 Data Flow Through the Protocol Levels
1.2.2 Packet Level
1.2.3 Frame Level
1.2.4 Physical Level
1.3 Types of X.25 Addresses
1.3.1 DTE Addresses
1.3.2 Network Service Access Points (NSAPs)
1.3.2.1 IDP
1.3.2.2 DSP
1.4 Optional Facilities of Public and Private PSDNs
1.4.1 General Optional User Facilities
1.4.2 Closed User Groups
1.4.3 Bilateral Closed User Groups
1.4.4 System Parameters
1.5 PSDN Support
2. Designing Your X.25 System
2.1 The X.25 Management Model
2.1.1 How an X.25 System Handles Calls
2.1.1.1 Making a Call
2.1.1.2 Receiving a Call
2.2 Designing X.25 Modules For Your System
2.2.1 Designing DTEs
2.2.1.1 Using Local DTE Classes
2.2.2 Designing Groups
2.2.3 Designing LAPB Links
2.2.4 Designing Line Control and Monitoring
2.2.5 Designing Templates
2.2.5.1 Call Setup
2.2.5.2 Special Features
2.2.5.3 Additional Information for Filtering
2.3 Designing Filters
3. Managing Your X.25 System
3.1 Introduction
3.2 Tasks
3.2.1 Add a Local DTE Using NCL
3.2.2 Modify a Local DTE Using NCL
3.2.3 Delete a Local DTE Using NCL
3.2.4 Add a Local DTE Class
3.2.5 Add a Group
3.2.6 Modify a Group
3.2.7 Delete a Group
3.2.8 Add Members to a Group
3.2.9 Remove Members from a Group
3.2.10 Add a Template
3.2.11 Modify a Template
3.2.12 Delete a Template
3.2.13 Add a Filter
3.2.14 Modify a Filter
3.2.15 Delete a Filter
3.2.16 Add an X.25 Dynamically Assigned Router Circuit
3.2.17 Add a Reachable Address
3.2.18 Add an IP Reachable Address
4. Managing X.25 Security
4.1 Introduction
4.2 Introduction to the X.25 Security Model
4.2.1 Setting Up Filter Security
4.2.2 Setting Up SECURITY DTE CLASS
4.2.3 Controlling Access to Bilateral Closed User Groups
4.3 X.25 Security Protection Mechanisms
4.3.1 Rights Identifiers
4.3.2 Access Control
4.3.3 X.25 Security Specific Identifiers
4.4 How the X.25 Security Model Operates
4.4.1 How X.25 Security Checks Incoming Calls
4.4.2 How X.25 Security Selects a Remote DTE
4.4.3 How X.25 Security Uses Access Control Lists
4.4.3.1 Null ACLs
4.4.3.2 Null Rights Identifiers
4.4.3.3 The Order of ACL Entries
4.5 Managing X.25 Security
4.5.1 Planning Security for Your System
4.5.1.1 Planning Filter Security
4.5.1.2 Planning REMOTE DTE CLASS
4.5.1.3 Planning Group Security
4.5.2 Displaying a Group
4.5.3 Setting Up an Open System
4.6 Monitoring X.25 Security
4.6.1 Security Events
4.6.2 Security Counters
4.6.3 Monitoring Events and Counters
4.6.4 Monitoring the Status of Security Entities
4.6.5 Monitoring Match all Security
5. X.25 Problem Solving
5.1 Introduction
5.2 Steps in Locating and Correcting X.25 Problems
5.3 Using Event Messages for Problem Solving
5.3.1 Local DTE Fails
5.3.1.1 DTE Restart Failure
5.3.1.2 LAPB Link Setup Failure
5.3.1.3 Modem Connect Line Setup Failure
5.3.2 Incoming Calls Cannot be Received
5.3.3 Outgoing Calls Cannot be Made
5.3.4 Virtual Circuit Fails
A. General Optional PSDN Facilities Supported by DEC WANrouter X.25
B. Optional Facilities of CUGs and BCUGs
C. DTE System Parameters
D. X.25 Security Checking Procedure
D.1 Checking Incoming Calls That Do Not Use BCUGs
D.1.1 Finding the Security DTE Class
D.1.2 Matching the Calling DTE Address Against Remote DTE Entities
D.1.3 Finding the Rights Identifiers for the Selected Remote DTE
D.1.4 Finding the Filter that Matches the Call
D.1.5 Finding the Security Filter
D.1.6 Checking the Access Level
D.1.7 What Happens if X.25 Security Blocks Access?
D.2 Checking Incoming Calls That Use BCUGs
D.2.1 Finding the Group Entity
D.2.2 Finding the Rights Identifiers
D.2.3 Finding the Filter that Matches the Call
D.2.4 Finding the Security Filter
D.2.5 Checking the Access Level to the Filter
D.2.6 What Happens if X.25 Security Blocks Access?
E. X.25 Security Events
List of Figures
Figure 11 Major Components of a PSDN
Figure 12 X.25 Protocol Levels
Figure 13 Format of a DTE Address
Figure 14 The Format of an NSAP
Figure 21 X.25 Modules and Entities
Figure 41 Entities Used by X.25 Security
Figure 42 SECURITY FILTER Entities
Figure 43 SECURITY DTE CLASS Entity
Figure 44 X25 PROTOCOL GROUP Entity
Figure 45 Example Incoming Call
Figure 46 Local DTE Security
Figure 47 Remote DTEs with Valid RAPs
Figure 48 The Ordering of ACL Entries
Figure D1 How X.25 Security Checks Incoming Calls
List of Tables
Table 21 X.25 Module Description
Table 22 X.25 Modules and Entities
Table 23 Characteristic Attributes of an X25 PROTOCOL DTE Entity
Table 24 Characteristics of an X25 PROTOCOL GROUP Entity
Table 25 Characteristics of an LAPB LINK Entity
Table 26 Characteristics of a MODEM CONNECT LINE Entity
Table 27 Characteristics of an X25 ACCESS TEMPLATE Entity
Table 28 Characteristics of an X25 ACCESS FILTER Entity
Table 31 Management Tasks Using NCL
Table 41 X.25 Security Access Levels
Table 42 ACL Matching
Table 43 X.25 Access Module Security Counters
Table 44 Entity Specific Security Counters
Table 45 Status Attributes
Table 51 Event Messages
Table A1 Optional Facilities Supported by PSDNs
Table B1 Optional Facilities Related to CUGs
Table B2 Optional Facilities Related to BCUGs
Table C1 Packet Control Parameters
Table C2 Frame Control Parameters
Table E1 INCOMING CALL BLOCKED Arguments