LDP Configuration Application

Transcription

1 CHAPTER 17 The contains the following tabs and subtabs. Interfaces Tab, page General Tab, page Neighbors Tab, page Operations Tab, page The LDP Configuration application allows you to configure Label Distribution Protocol (LDP) to perform label distribution in Multiprotocol Label Switching (MPLS) environments. LDP performs hop-by-hop or dynamic path setup, but does not provide end-to-end switching services. LDP also provides constraint-based routing, using LDP extensions for traffic engineering. LDP provides the means for label switching routers (LSRs) to request, distribute, and release label prefix binding information to peer routers in a network. LDP enables LSRs to discover potential peers and establish LDP sessions with those peers to exchange label binding information. LDP is deployed in the core of the router and is one of the key protocols used in Layer 2 virtual private networks (VPNs). LDP assigns labels to routes using the underlying Interior Gateway Protocol (IGP) routing. See Figure 17-1 for an example of the LDP Configuration application. See the Cisco Craft Works Interface User Interface Guide for information on the common window elements and procedures for common activities in the LDP Configuration application

2 Interfaces Tab Chapter 17 Figure 17-1 LDP Application Interfaces Tab The Interfaces tab allows you to perform the following tasks: Specify the LDP interface name. Configure the discovery transportation address. See Figure 17-1 for an example of the Interfaces tab. Table 17-1 describes the Interfaces tab fields. Table 17-1 Interfaces Tab Basics Area Name Name field Name Discovery Transportation Address Area Default radio This interface s IP radio Allows you to choose the interface name. Allows you to enter a name. Allows you to choose a name from the Select Interfaces dialog box. Allows you to specify that LDP 1 use the router ID as its source address for TCP 2 connection setup with its peer. Hello messages include this address in transport address TLV 3 objects. Allows you to specify that the alternative address for a TCP connection is the interface IP address. Hello messages include this address in transport address TLV objects

3 Chapter 17 General Tab Table 17-1 Interfaces Tab (continued) Specific IP Specific IP radio Specific IP field Allows you to provide an alternative address for a TCP connection. Hello messages include this address in transport address TLV objects. Allows you to enable an alternative address for a TCP connection. Allows you to enter an address. 1. LDP = Label Distribution Protocol 2. TCP = Transmission Control Protocol 3. TLV = type, length, and value General Tab The General tab allows you to perform the following tasks: Configure the router ID. Set the linked and targeted hello hold time and interval. Set the session hold time. Enable advertising Explicit Null labels. Configure backoff time parameters. Configure graceful restart parameters. Enable logging neighbor changes. See Figure 17-2 for an example of the General tab. Table 17-2 describes the General tab fields

4 General Tab Chapter 17 Figure 17-2 General Tab Table 17-2 General Tab Router ID Area Default radio Use Loopback Interface Use Loopback Interface radio Use Loopback Interface field Use Loopback Interface Use IP Address Allows you to specify that LDP 1 obtains its router ID from the router-wide router ID configuration, if available. Allows you to provide a loopback interface name for the router ID. Allows you to enable using the loopback interface name for the router ID. Allows you to enter a loopback interface name. This field is enabled when the Use Loopback Interface radio is activated. (See Use Loopback Interface radio.) Allows you to choose a loopback interface name from the Select Interfaces dialog box. This field is enabled when the Use Loopback Interface radio is activated. (See Use Loopback Interface radio.) Allows you to provide a routable IP address for the router ID

5 Chapter 17 General Tab Table 17-2 General Tab (continued) Use IP Address Allows you to enable using the IP Address for the router ID. radio Use IP Address field Allows you to enter an IP address. This field is enabled when the Use IP Address radio is activated. (See Use IP Address radio.) Discovery Area Linked Hello Hold time (sec) field Linked Hello Interval (sec) field Targeted Hello Hold time (sec) field Targeted Hello Interval (sec) field Accept Targeted Hellos check box Session Area Allows you to configure the linked hello hold time. This is the hold time for a discovered LDP neighbor. This field specifies the length of time that a discovered neighbor is assumed to be present in the absence of discovery messages. Allows you to configure the linked hello interval. This is the interval between transmission of consecutive LDP discovery messages. Allows you to configure the targeted hello hold time. This is the hold time for targeted neighbors. This field specifies the length of time that a targeted neighbor is assumed to be present in the absence of discovery messages. Allows you to configure the targeted hello interval. This is the interval between transmission of consecutive LDP discovery messages. Allows you to accept from and respond to targeted hellos from the interfaces. Hold time (sec) field Allows you to specify the time for which an LDP session is maintained in the absence of LDP messages from the session peer. Label Advertisement Area Advertise Explicit Null labels check box Allows you to cause a router to advertise an Explicit Null label in situations where it would normally advertise an Implicit Null label. Normally, LDP advertises an Implicit Null label for directly connected routes. The Implicit Null label causes the previous hop (penultimate) router to do penultimate hop popping. Situations exist in which it might be desirable to prevent the penultimate router from performing penultimate hop popping and to force it to replace the incoming label with the Explicit Null label. Backoff Time Area Hold time (sec) field Allows you to specify the initial session time for LDP backoff. The LDP backoff mechanism prevents two incompatibly configured LSR 2 s from engaging in an unthrottled sequence of session setup failures. If a session setup attempt fails due to such incompatibility, each LSR delays its next attempt (backs off), increasing the delay exponentially with each successive failure, until the maximum backoff delay is reached. Maximum (sec) field Allows you to specify the maximum session time for LDP backoff. The LDP backoff mechanism prevents two incompatibly configured LSRs from engaging in an unthrottled sequence of session setup failures. If a session setup attempt fails due to such incompatibility, each LSR delays its next attempt (backs off), increasing the delay exponentially with each successive failure, until the maximum backoff delay is reached

6 Neighbors Tab Chapter 17 Table 17-2 General Tab (continued) Logging Area Log Neighbor Changes check box Graceful Restart Area Enable check box Forwarding State Holdtime (sec) field Reconnection timeout (sec) field Allows you to enable the logging of neighbor session changes. You receive a message when a neighbor goes up or down. Allows you to enable the graceful restart capability. You must restart the LDP process to have the graceful restart configuration take effect. Allows you to specify the length of time that the peer label mapping entries are kept and can be reclaimed. The Forwarding State hold time value is the time for which the restarting LSR intends to keep its forwarding state stale entries after restart. After restart and recovering its preserved forwarding entries, LSR starts a Forwarding State hold timer and waits for peers to resynchronize with the LSR. The recovery time value in the FT 3 session TLV (INIT message) to another peer after a restart or reconnect computes to be the value of the timer at the time of the INIT message. Allows you to specify the time given to the peer to reestablish the connection before it is considered a neighbor that is disconnected indefinitely. The Reconnection timeout value is the reconnect timeout that will be sent in the FT Session TLV (INIT message) to another peer. 1. LDP = Label Distribution Protocol 2. LSR = label switching router 3. FT = fault-tolerant Neighbors Tab The Neighbors tab allows you to perform the following tasks: Provide the IP address of an LDP neighbor whose password and encryption type you want to set. Set the password and password encryption type for the LDP neighbor. See Figure 17-3 for an example of the Neighbors tab. Table 17-3 describes the Neighbors tab fields

7 Chapter 17 Neighbors Tab Figure 17-3 Neighbors Tab Table 17-3 Neighbors Tab Neighbor IP Address field Password field Encryption Type list Allows you to enter the LDP 1 neighbor IP address. Allows you to enter a password so that a session establishment attempt between two LDP peers is allowed only when a password match has been configured. The passwords for the peers must be configured so that the passwords for both peers match. Allows you to choose the password encryption type. The following options are listed: None Cisco Proprietary 1. LDP = Label Distribution Protocol

8 Operations Tab Chapter 17 Operations Tab The Operations tab allows you to perform the following tasks: Clear all message counters or a counter for a specific neighbor IP address. Restart all LDP sessions or a specific neighbor session. Note Restarting a session could impact forwarding in nongraceful restart mode. See Figure 17-4 for an example of the Operations tab. Table 17-4 describes the Operations tab fields. Figure 17-4 Operations Tab

9 Chapter 17 Operations Tab Table 17-4 Operations Tab Clear Counters Area All Message Counters radio Specify Neighbor IP Address Specify Neighbor IP Address radio Specify Neighbor IP Address field Clear Counters Restart Sessions Area Restart all LDP Sessions radio By Neighbor Session IP Address By Neighbor Session IP Address radio By Neighbor Session IP Address field Restart Sessions 1. LDP = Label Distribution Protocol Allows you to clear the statistics message counters for all neighbors. Allows you to clear the statistics message counters for a specific neighbor. This sets the clear counters feature to clear counters only for the specified neighbor. Allows you to enable clearing statistics message counters for a specific neighbor. Allows you to enter a neighbor IP address. This field is enabled when the Specify Neighbor IP Address radio is activated. (See Specify Neighbor IP Address radio.) Runs the clear counters operation based on the criteria configured in the Clear Counters area. When the is clicked, a Confirm dialog box appears. Click Yes to proceed with the clear operation or click No to cancel the operation. Allows you to restart all LDP 1 sessions without restarting LDP itself. Allows you to restart a single LDP session without restarting LDP itself Allows you to enable a single LDP session without restarting LDP itself. Allows you to enter an IP address. Runs the restart sessions operation based on the criteria configured in the Restart Sessions area (restart one or all LDP sessions). When the is clicked, a Confirm dialog box appears. Click Yes to proceed with the operation or click No to cancel the operation

10 Operations Tab Chapter