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Table of Contents
- play_arrow Overview
- play_arrow Introduction to IS-IS
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- play_arrow Configuring IS-IS
- play_arrow Configuring a Basic IS-IS Network
- Understanding IS-IS Configuration
- Example: Configuring IS-IS
- Understanding IS-IS Areas to Divide an Autonomous System into Smaller Groups
- Example: Configuring a Multi-Level IS-IS Topology to Control Interarea Flooding
- Understanding IS-IS Designated Routers
- Configuring Designated Router Election Priority for IS-IS
- Configuring an ISO System Identifier for the Router
- Understanding Default Routes
- How to Configure Multiple Independent IGP Instances of IS-IS
- play_arrow Configuring IS-IS Authentication and Checksums
- Configuring IS-IS Authentication
- Configuring IS-IS Authentication Without Network-Wide Deployment
- Understanding Hitless Authentication Key Rollover for IS-IS
- Example: Configuring Hitless Authentication Key Rollover for IS-IS
- Understanding Checksums on IS-IS Interfaces for Error Checking
- Example: Enabling Packet Checksums on IS-IS Interfaces for Error Checking
- play_arrow Configuring IS-IS Routing Policy and Route Redistribution
- Understanding Routing Policies
- Understanding Backup Selection Policy for IS-IS Protocol
- Example: Configuring Backup Selection Policy for IS-IS Protocol
- Configuring Backup Selection Policy for the IS-IS Protocol
- Example: Redistributing OSPF Routes into IS-IS
- Example: Configuring IS-IS Route Leaking from a Level 2 Area to a Level 1 Area
- Handling of the IS-IS Binding SID S Flag and RFC 7794 Prefix Attribute Flags
- Understanding BGP Communities, Extended Communities, and Large Communities as Routing Policy Match Conditions
- Example: Configuring a Routing Policy to Redistribute BGP Routes with a Specific Community Tag into IS-IS
- IS-IS Extensions to Support Route Tagging
- Example: Configuring a Routing Policy to Prioritize IS-IS Routes
- Configuring Overloading of Stub Networks
- play_arrow Configuring IS-IS Bidirectional Forwarding Detection
- play_arrow Configuring IS-IS Flood Groups
- play_arrow Configuring IS-IS Multitopology Routing and IPv6 Support
- IS-IS Multicast Topologies Overview
- Example: Configuring IS-IS Multicast Topology
- Understanding Dual Stacking of IPv4 and IPv6 Unicast Addresses
- Example: Configuring IS-IS Dual Stacking of IPv4 and IPv6 Unicast Addresses
- Understanding IS-IS IPv4 and IPv6 Unicast Topologies
- Example: Configuring IS-IS IPv4 and IPv6 Unicast Topologies
- play_arrow Configuring IS-IS Link and Node Link Protection
- Understanding Loop-Free Alternate Routes for IS-IS
- Example: Configuring Node-Link Protection for IS-IS Routes in a Layer 3 VPN
- Understanding Remote LFA over LDP Tunnels in IS-IS Networks
- Configuring Remote LFA Backup over LDP Tunnels in an IS-IS Network
- Example: Configuring Remote LFA over LDP Tunnels in IS-IS Networks
- Understanding Weighted ECMP Traffic Distribution on One-Hop IS-IS Neighbors
- Example: Weighted ECMP Traffic Distribution on One-Hop IS-IS Neighbors
- play_arrow Configuring IS-IS Traffic Engineering
- IS-IS Extensions to Support Traffic Engineering
- Using Labeled-Switched Paths to Augment SPF to Compute IGP Shortcuts
- Example: Enabling IS-IS Traffic Engineering Support
- Understanding Forwarding Adjacencies
- Example: Advertising Label-Switched Paths into IS-IS
- Understanding Wide IS-IS Metrics for Traffic Engineering
- Example: Enabling Wide IS-IS Metrics for Traffic Engineering
- Understanding LDP-IGP Synchronization
- Example: Configuring Synchronization Between IS-IS and LDP
- Layer 2 Mapping for IS-IS
- Example: Configuring Layer 2 Mapping for IS-IS
- Understanding Source Packet Routing in Networking (SPRING)
- Understanding Adjacency Segments, Anycast Segments, and Configurable SRGB in SPRING
- Example: Configuring SRGB in Segment Routing for IS-IS
- Example: Configuring Anycast and Prefix Segments in SPRING for IS-IS to Increase Network Speed
- Configuring Segment Routing Global Blocks Label Ranges in SPRING for IS-IS Protocol
- Configuring Anycast and Prefix segments in SPRING for IS-IS Protocol
- Flexible Algorithms in IS-IS for Segment Routing Traffic Engineering
- Configuring Flexible Algorithm for Segment Routing Traffic Engineering
- Understanding Topology-Independent Loop-Free Alternate with Segment Routing for IS-IS
- Configuring Topology-Independent Loop-Free Alternate with Segment Routing for IS-IS
- Example: Configuring Topology Independent Loop-Free Alternate with Segment Routing for IS-IS
- Static Adjacency Segment Identifier for ISIS
- Understanding Segment Routing over RSVP Forwarding Adjacency in IS-IS
- Understanding IS-IS Microloop Avoidance
- How to Enable SRv6 Network Programming in IS-IS Networks
- Example: Configuring SRv6 Network Programming in IS-IS Networks
- How to Enable Link Delay Measurement and Advertising in IS-IS
- How to Enable Strict SPF SIDs and IGP Shortcut
- play_arrow Configuring IS-IS Scaling and Throttling
- Understanding Link-State PDU Throttling for IS-IS Interfaces
- Example: Configuring the Transmission Frequency for Link-State PDUs on IS-IS Interfaces
- Understanding the Transmission Frequency for CSNPs on IS-IS Interfaces
- Example: Configuring the Transmission Frequency for CSNP Packets on IS-IS Interfaces
- Understanding IS-IS Mesh Groups
- Example: Configuring Mesh Groups of IS-IS Interfaces
- play_arrow Configuring IS-IS CLNS
- play_arrow Configuring IS-IS on Logical Systems
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- play_arrow Configuration Statements and Operational Commands
list Table of Contents
Isolating a Broken Network Connection
date_range
26-Jan-21
By applying the standard four-step process illustrated in Figure 1, you can isolate a failed node in the network. Note that the functionality described in this section is not supported in versions 15.1X49, 15.1X49-D30, or 15.1X49-D40.
Figure 1: Process for Diagnosing Problems in
Your Network
Before you embark on the four-step process, however, it is important that you are prepared for the inevitable problems that occur on all networks. While you might find a solution to a problem by simply trying a variety of actions, you can reach an appropriate solution more quickly if you are systematic in your approach to the maintenance and monitoring of your network. To prepare for problems on your network, understand how the network functions under normal conditions, have records of baseline network activity, and carefully observe the behavior of your network during a problem situation.
Figure 2 shows the network topology used in this topic to illustrate the process of diagnosing problems in a network.
Figure 2: Network with a Problem
The network in Figure 2 consists of
two autonomous systems (ASs). AS 65001 includes two routers, and AS
65002 includes three routers. The border router (R1) in
AS 65001 announces aggregated prefixes 100.100/24 to the
AS 65002 network. The problem in this network is that R6 does not have access to R5 because of a loop between R2 and R6.
To isolate a failed connection in your network, follow the steps in these topics:
