Viewing Information and LDP-Signaled LSPs in the Routing Tables
Problem
After you have configured MPLS and LDP on your router, you want to look at the information in the routers routing tables.
Solution
Look in the inet.3 routing table to view the LDP routes:
aviva@RouterG> show route table inet.3 inet.3: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 192.168.16.1/32 *[LDP/9] 1d 23:02:21, metric 1 > via t1-4/0/0.0, Push 100000 192.168.17.1/32 *[LDP/9] 1d 23:02:21, metric 1 > via t1-4/0/0.0
Look in the mpls.0 table to see the routers label information:
aviva@RouterG> show route table mpls.0 mpls.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 0 *[MPLS/0] 2d 01:59:47, metric 1 Receive 1 *[MPLS/0] 2d 01:59:47, metric 1 Receive 2 *[MPLS/0] 2d 01:59:47, metric 1 Receive 100064 *[ LDP/9] 1d 23:02:36, metric 1 > via t1-4/0/0.0, Pop 100064(S=0) *[LDP/9] 1d 23:02:36, metric 1 > via t1-4/0/0.0, Pop 100080 *[LDP/9] 1d 23:02:36, metric 1 > via t1-4/0/0.0, Swap 100000
Discussion
After configuring MPLS and LDP, if you look in the default JUNOS routing table, inet.0, you don see any of the MPLS or LSP routes and you don see any routers learned from LDP:
aviva@RouterG> show route table inet.0 inet.0: 12 destinations, 13 routes (12 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 0.0.0.0/0 *[Static/5] 2d 19:44:09 > to 172.19.121.1 via fe-0/0/0.0 10.0.0.0/24 *[Direct/0] 1d 23:01:58 > via t1-4/0/0.0 [OSPF/10] 1d 23:01:57, metric 65 > via t1-4/0/0.0 10.0.0.1/32 *[Local/0] 3d 02:43:04 Local via t1-4/0/0.0 10.0.8.0/24 *[OSPF/10] 1d 23:01:49, metric 66 > via t1-4/0/0.0 10.0.13.0/24 *[OSPF/10] 1d 23:01:49, metric 131 > via t1-4/0/0.0 172.19.121.0/24 *[Direct/0] 1w3d 21:48:23 > via fe-0/0/0.0 172.19.121.119/32 *[Local/0] 1w3d 21:48:26 Local via fe-0/0/0.0 192.168.15.1/32 *[OSPF/10] 1d 23:01:49, metric 131 > via t1-4/0/0.0 192.168.16.1/32 *[OSPF/10] 1d 23:01:49, metric 66 > via t1-4/0/0.0 192.168.17.1/32 *[OSPF/10] 1d 23:01:49, metric 65 > via t1-4/0/0.0 192.168.19.1/32 *[Direct/0] 3d 02:18:53 > via lo0.0 224.0.0.5/32 *[OSPF/10] 2d 02:31:29, metric 1 MultiRecv
This routing table shows only the unicast routes, listing the routes learned from OSPF, which is the IGP we configured in the previous recipe, and the directly connected routes. In the JUNOS software, MPLS and LDP store their routing and forwarding information in two other routing tables, inet.3 and mpls.0. The inet.3 table contains the LDP FECs:
aviva@RouterG> show route table inet.3 inet.3: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 192.168.16.1/32 *[LDP/9] 5d 00:51:17, metric 1 > via t1-4/0/0.0, Push 100000 192.168.17.1/32 *[ LDP/9] 5d 00:51:17, metric 1 > via t1-4/0/0.0
This output shows two LDP FECs (routes) to the two LDP neighbors. The first FEC is to the LSPs egress router, 192.168.16.1/32 (RouterF), and the second is to the transit router. Both FECs have a route preference of 9 and a metric of 1, which are the default JUNOS values for LDP. Both routes use the t1-4/0/0 interface, which is what you expect. The end of the second line of the FEC for 192.168.16.1/32 shows a push operation and a label value. When forwarding packets, LDP pushes a label of 100000 onto the packet. LDP stores all the labels being used in LDP-signaled LSPs, which you can display with the following command:
aviva@RouterF> show ldp database Input label database, 192.168.16.1:0--192.168.17.1:0 Label Prefix 100000 192.168.16.1/32 3 192.168.17.1/32 100032 192.168.19.1/32 Output label database, 192.168.16.1:0--192.168.17.1:0 Label Prefix 3 192.168.16.1/32 100000 192.168.17.1/32 100032 192.168.19.1/32
The inet.3 table on RouterF shows similar FECs:
aviva@RouterF> show route table inet.3 inet.3: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 192.168.17.1/32 *[LDP/9] 5d 03:33:23, metric 1 > to 10.0.8.1 via fe-0/0/1.0 192.168.19.1/32 *[LDP/9] 5d 00:57:15, metric 1 > to 10.0.8.1 via fe-0/0/1.0, Push 100032
When the router is forwarding packets on this LSP, LDP pushes a label value, this time 100032, onto all packets entering the LSP.
The second JUNOS routing table, mpls.0, stores label values for MPLS and for LDP. Heres the mpls.0 table on RouterG:
aviva@RouterG> show route table mpls.0 mpls.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 0 *[MPLS/0] 5d 03:58:02, metric 1 Receive 1 *[MPLS/0] 5d 03:58:02, metric 1 Receive 2 *[MPLS/0] 5d 03:58:02, metric 1 Receive 100064 *[ LDP/9] 5d 01:00:51, metric 1 > via t1-4/0/0.0, Pop 100064(S=0) *[LDP/9] 5d 01:00:51, metric 1 > via t1-4/0/0.0, Pop 100080 *[LDP/9] 5d 01:00:51, metric 1 > via t1-4/0/0.0, Swap 100000
This table is the MPLS label-swapping table and is actually a switching table rather than a routing table. Instead of a prefix in the first column, you see a label value. In this output, the first three entries correspond to reserved labels, defined in RFC 3032. These three entries are learned from MPLS (as indicated by [MPLS/0] in the second column) and are always in the mpls.0 routing table. The remaining three entries are for incoming labels that MPLS assigns to each upstream neighbor. Label 100064 has two entries because the stack value in the MPLS header can be different in different packets. In the first entry label, 100064, the S (stack) bit is 1, so this label matches packets that have only one label on their stacks. The second entry, 100064(S=0), has the stack bit set to 0 and is used when the stack depth is not 1. That is, it is used when the packet is carrying more than one label. For both labels, the operation pops the top label off the stack. The third label, 100080, has a swap operation associated with it.
You can quickly check all the routes learned from LDP with the show route protocol ldp command:
aviva@RouterG> show route protocol ldp inet.0: 12 destinations, 13 routes (12 active, 0 holddown, 0 hidden) inet.3: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 192.168.16.1/32 *[LDP/9] 1d 23:03:35, metric 1 > via t1-4/0/0.0, Push 100000 192.168.17.1/32 *[LDP/9] 1d 23:03:35, metric 1 > via t1-4/0/0.0 __juniper_private1__.inet.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden) mpls.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 100064 *[LDP/9] 1d 23:03:35, metric 1 > via t1-4/0/0.0, Pop 100064(S=0) *[LDP/9] 1d 23:03:35, metric 1 > via t1-4/0/0.0, Pop 100080 *[LDP/9] 1d 23:03:35, metric 1 > via t1-4/0/0.0, Swap 100000
This output displays the routes for the LDP FECs, stored in inet.3, and the labelswitching state stored in mpls.0.
Use the show route forwarding-table mpls command to see the active MPLS routes in the Routing Engines forwarding table:
aviva@RouterG> show route forwarding-table family mpls Routing table: mpls MPLS: Destination Type RtRef Next hop Type Index NhRef Netif default perm 0 dscd 28 1 0 user 0 recv 27 3 1 user 0 recv 27 3 2 user 0 recv 27 3 100064 user 0 Pop t1-4/0/0.0 100064(S=0) user 0 Pop t1-4/0/0.0 100080 user 0 Swap 100000 t1-4/0/0.0
The Destination column lists labels that the router is using to forward traffic, and the last column, Netif, shows the interfaces that are being used to send the labeled traffic. For the nonreserved labels, the second Type column shows the operation performed on matching packets. For packets with label 100064, the label is popped, and packets with label 100080 have their label swapped for 100000.
To see the forwarding entries used by the Packet Forwarding Engine to forward MPLS packets, use the following version of the show pfe route command:
aviva@RouterG> show pfe route mpls MPLS Route Table 0, MPLS.0, 0x0: Destination Type ID NhRef ----------------------- -------- ----- ----- default Discard 28 1 0 Receive 27 3 1 Receive 27 3 2 Receive 27 3 100064 Unicast 330 1 t1-4/0/0.0 100064(S=0) Unicast 332 1 t1-4/0/0.0 100080 Unicast 333 1 t1-4/0/0.0
Looking at this output, you can see that it shows pretty much the same information as the Routing Engines forwarding table.
See Also
Recipe 8.1
Router Configuration and File Management
- Introduction
- Configuring the Router for the First Time
- Configuring the Router from the CLI
- Getting Exclusive Access to Configure the Router
- Displaying the Commands to Recreate a Configuration
- Including Comments in the Configuration
- Checking the Syntax of the Configuration
- Activating the Router Configuration
- Debugging a Failed Commit
- Exiting Configuration Mode
- Keeping a Record of Configuration Changes
- Determining What Changes You Have Made to the Configuration
- Configuring the Router by Copying a File from a Server
- Configuring the Router by Copying Text from a Terminal Window
- Backing Up the Routers Configuration
- Scheduling the Activation of a Configuration
- Provisionally Activating a Configuration
- Loading a Previous Router Configuration
- Creating an Emergency Rescue Configuration
- Backing Up Filesystems on M-Series and T-Series Routers
- Backing Up Filesystems on J-Series Routers
- Restoring a Backed-Up Filesystem
- Installing a Different Software Release on M-Series and T-Series Routers
- Installing a Different Software Release on J-Series Routers
- Creating an Emergency Boot Disk
- Gathering Software Version Information
- Gathering Hardware Inventory Information
- Finding Out How Long the Router Has Been Up
- Gathering Information Before Contacting Support
- Managing Routers with Similar Configurations
- Managing Redundant Routing Engines
- Using the Second Routing Engine to Upgrade to a New Software Version
Basic Router Security and Access Control
- Basic Router Security and Access Control
- Introduction
- Allowing Access to the Router
- Controlling Root Authentication
- Logging In to the Routers Console
- Setting the Login Authentication Methods
- Setting Up Login Accounts on the Router
- Changing the Format of Plain-Text Passwords
- Changing the Plain-Text Password Encryption Method
- Creating a Login Account for Remote Authentication
- Creating a Group Login Account
- Customizing Account Privileges
- Creating a Privilege Class that Hides Encrypted Passwords
- Setting Up RADIUS User Authentication
- Setting Up TACACS+ User Authentication
- Restricting Inbound SSH and Telnet Access
- Setting the Source Address for Telnet Connections
- Creating a Login Banner
- Finding Out Who Is Logged In to the Router
- Logging Out of the Router
- Forcibly Logging a User Out
IPSec
- IPSec
- Introduction
- Configuring IPSec
- Configuring IPSec Dynamic SAs
- Creating IPSec Dynamic SAs on J-Series Routers or Routers with AS PICs
- Using Digital Certificates to Create Dynamic IPSec SAs
SNMP
- SNMP
- Introduction
- Configuring SNMP
- Setting Router Information for the MIB-II System Group
- Setting Up SNMP Traps
- Controlling SNMP Access to the Router
- Using a Firewall Filter to Protect SNMP Access
- Controlling Access to Router MIBs
- Extracting Software Inventory Information with SNMP
- Extracting Hardware Inventory Information with SNMP
- Collecting Router Operational Information with SNMP
- Logging SNMP Access to the Router
- Logging Enterprise-Specific Traps
- Using RMON Traps to Monitor the Routers Temperature
- Configuring SNMPv3
- Tracking Router Configuration Changes
- Setting Up SNMPv3 Traps
Logging
- Logging
- Introduction
- Turning On Logging
- Limiting the Messages Collected
- Including the Facility and Severity in Messages
- Changing the Size of a Logging File
- Clearing the Routers Logfiles
- Sending Log Messages to Your Screen
- Sending Logging Messages to a Log Server
- Saving Logging Messages to the Other Routing Engine
- Turning Off Logging
- Turning On Basic Tracing
- Monitoring Interface Traffic
NTP
- NTP
- Introduction
- Setting the Date and Time on the Router Manually
- Setting the Time Zone
- Synchronizing Time When the Router Boots
- Synchronizing Time Periodically
- Authenticating NTP
- Checking NTP Status
Router Interfaces
- Router Interfaces
- Introduction
- Viewing Interface Status
- Viewing Traffic Statistics on an Interface
- Setting an IP Address for the Router
- Setting the Routers Source Address
- Configuring an IPv4 Address on an Interface
- Configuring an IPv6 Address on an Interface
- Configuring an ISO Address on an Interface
- Creating an MPLS Protocol Family on a Logical Interface
- Configuring an Interface Description
- Choosing Primary and Preferred Interface Addresses
- Using the Management Interface
- Finding Out What IP Addresses Are Used on the Router
- Configuring Ethernet Interfaces
- Using VRRP on Ethernet Interfaces
- Connecting to an Ethernet Switch
- Configuring T1 Interfaces
- Performing a Loopback Test on a T1 Interface
- Setting Up a BERT Test on a T1 Interface
- Configuring Frame Relay on a T1 Interface
- Configuring a SONET Interface
- Using APS to Protect Against SONET Circuit Failures
- Configuring an ATM Interface
- Dealing with Nonconfigurable Interfaces
- Configuring Interfaces Before the PICs Are Installed
IP Routing
- IP Routing
- Introduction
- Viewing the Routes in the Routing Table
- Viewing Routes to a Particular Prefix
- Viewing Routes Learned from a Specific Protocol
- Displaying the Routes in the Forwarding Table
- Creating Static Routes
- Blackholing Routes
- Filtering Traffic Using Unicast Reverse-Path Forwarding
- Aggregating Routes
- Load-Balancing Traffic Flows
- Adding Martian Addresses
- Changing Route Preferences to Migrate to Another IGP
- Configuring Routing Protocols to Restart Without Losing Adjacencies
Routing Policy and Firewall Filters
- Routing Policy and Firewall Filters
- Introduction
- Creating a Simple Routing Policy
- Changing a Routes Routing Information
- Filtering Routes by IP Address
- Filtering Long Prefixes
- Filtering Unallocated Prefix Blocks
- Creating a Chain of Routing Policies
- Making Sure a Routing Policy Is Functioning Properly
- Creating a Simple Firewall Filter that Matches Packet Contents
- Creating a Firewall Filter that Negates a Match
- Reordering Firewall Terms
- Filtering Traffic Transiting the Router
- Using a Firewall Filter to Count Traffic on an Interface
- Logging the Traffic on an Interface
- Limiting Traffic on an Interface
- Protecting the Local Routing Engine
- Rate-Limiting Traffic Flow to the Routing Engine
- Using Counters to Determine Whether a Router Is Under Attack
RIP
- RIP
- Introduction
- Configuring RIP
- Having RIP Advertise Its Routes
- Configuring RIP for IPv6
- Enabling RIP Authentication
- Routing RIP Traffic over Faster Interfaces
- Sending Version 1 Update Messages
- Tracing RIP Protocol Traffic
IS-IS
- IS-IS
- Introduction
- Configuring IS-IS
- Viewing the IS-IS Link-State Database
- Viewing Routes Learned by IS-IS
- Configuring IS-IS for IPv6
- Configuring a Level 1Only Router
- Controlling DIS Election
- Enabling IS-IS Authentication
- Redistributing Static Routes into IS-IS
- Leaking IS-IS Level 2 Routes into Level 1
- Adjusting IS-IS Link Costs
- Improving IS-IS Convergence Times
- Moving IS-IS Traffic off a Router
- Disabling IS-IS on an Interface
- Tracing IS-IS Protocol Traffic
OSPF
- Introduction
- Configuring OSPF
- Viewing Routes Learned by OSPF
- Viewing the OSPF Link-State Database
- Configuring OSPF for IPv6
- Configuring a Multiarea OSPF Network
- Setting Up Stub Areas
- Creating a Not-So-Stubby Area
- Summarizing Routes in OSPF
- Enabling OSPF Authentication
- Redistributing Static Routes into OSPF
- Adjusting OSPF Link Costs
- Improving OSPF Convergence Times
- Moving OSPF Traffic off a Router
- Disabling OSPF on an Interface
- Tracing OSPF Protocol Traffic
BGP
- Introduction
- Configuring a BGP Session Between Routers in Two ASs
- Configuring BGP on Routers Within an AS
- Diagnosing TCP Session Problems
- Adjusting the Next-Hop Attribute
- Adjusting Local Preference Values
- Removing Private AS Numbers from the AS Path
- Prepending AS Numbers to the AS Path
- Filtering BGP Routes Based on AS Paths
- Restricting the Number of Routes Advertised to a BGP Peer
- Authenticating BGP Peers
- Setting Up Route Reflectors
- Mitigating Route Instabilities with Route Flap Damping
- Adding a BGP Community to Routes
- Load-Balancing BGP Traffic
- Tracing BGP Protocol Traffic
MPLS
- Introduction
- Configuring LSPs Using LDP as the Signaling Protocol
- Viewing Information and LDP-Signaled LSPs in the Routing Tables
- Verifying that an LDP-Signaled LSP Is Carrying Traffic
- Enabling LDP Authentication
- Tracing LDP Operations
- Setting Up RSVP-Signaled LSPs
- Viewing Information About RSVP-Signaled LSPs in the Routing Tables
- Verifying Packet Labels
- Verifying that the RSVP-Signaled LSP Is Carrying Traffic
- Configuring RSVP Authentication
- Protecting an LSPs Path
- Using Fast Reroute to Reduce Packet Loss Following a Link Failure
- Automatically Allocating Bandwidth
- Prioritizing LSPs
- Allowing IGP Traffic to Use an LSP
- Installing LSPs into the Unicast Routing Table
- Tracing RSVP Operations
VPNs
- Introduction
- Setting Up a Simple Layer 3 VPN
- Viewing the VPN Routing Tables
- Adding a VPN for a Second Customer
IP Multicast
- Introduction
- Configuring PIM-SM
- Manually Establishing a PIM-SM RP
- Using Auto-RP to Dynamically Map RPs
- Setting Up a PIM-SM Bootstrap Router
- Filtering PIM-SM Bootstrap Messages
- Configuring Multiple RPs in a PIM-SM Domain with Anycast RP
- Configuring Multiple RPs in a PIM-SM Domain Anycast PIM
- Limiting the Group Ranges an RP Services
- Viewing Multicast Routes
- Checking the Groups for Which a PIM-SM Router Maintains Join State
- Manually Configuring IGMP
- Using SSM
- Connecting PIM-SM Domains Using MSDP and MBGP
- Configuring PIM-DM
- Tracing PIM Packets
EAN: 2147483647
Pages: 290
