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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 the Causes of a Network Problem
date_range
17-Feb-21
Problem
Description
A particular symptom can be the result of one or more causes. Narrow down the focus of your search to find each individual cause of the unwanted behavior.
Solution
To isolate the cause of a particular problem, enter one or all of the following Junos OS CLI operational mode command:
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user@host> show < configuration | bgp | interfaces | isis | ospf | route >
Your particular problem may require the use of more than just the commands listed above. See the appropriate command reference for a more exhaustive list of commonly used operational mode commands.
Sample Output
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user@R6> show interfaces terse
Interface Admin Link Proto Local Remote
so-0/0/0 up up
so-0/0/0.0 up up inet 10.1.56.2/30
iso
so-0/0/2 up up
so-0/0/2.0 up up inet 10.1.26.2/30
iso
so-0/0/3 up up
so-0/0/3.0 up up inet 10.1.36.2/30
iso
[...Output truncated...]
The following sample output is from R2:
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user@R2> show route 10.0.0.5
inet.0: 22 destinations, 25 routes (22 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
10.0.0.5/32 *[Static/5] 00:16:21
> to 10.1.26.2 via so-0/0/2.0
[BGP/170] 3d 20:23:35, MED 5, localpref 100
AS path: 65001 I
> to 10.1.12.1 via so-0/0/0.0
Meaning
The sample output shows that all interfaces on R6 are up. The output from R2 shows that a static route
[Static/5] configured on R2 points to R6 (10.1.26.2) and is the preferred route to R5 because of its low preference value. However, the route is looping
from R2 to R6, as indicated by the missing reference
to R5 (10.1.15.2).
