Cisco IOS XR IP Addresses and Services Configuration Guide for the Cisco XR 12000 Series Router, Release 4.3.x
Configuring Transports
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Configuring Transports

Configuring Transports

This module provides information about Nonstop Routing (NSR), Stream Control Transmission Protocol (SCTP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP ), and RAW Transports.

If you have specific requirements and need to adjust the NSR, SCTP, TCP, UDP, or RAW values, refer to the Transport Stack Commands on Cisco IOS XR IP Addresses and Services Command Reference for the Cisco XR 12000 Series Router.

Feature History for Configuring NSR, SCTP, TCP, UDP, and UDP RAW Transports on the Cisco IOS XR Software

Release

Modification

Release 3.6.0

The following features were introduced:

  • Nonstop Routing (NSR)
  • Stream Control Transmission Protocol (SCTP)

Prerequisites for Configuring NSR, SCTP, TCP, UDP ,and RAW Transports

The following prerequisites are required to implement NSR, SCTP, TCP, UDP ,and RAW Transports:

You must be in a user group associated with a task group that includes the proper task IDs. The command reference guides include the task IDs required for each command. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Information About Configuring NSR, SCTP, TCP, UDP, and RAW Transports

To configure NSR, SCTP, TCP, UDP, and RAW transports, you must understand the following concepts:

NSR Overview

Nonstop Routing (NSR) is provided for Open Shortest Path First (OSPF) and Label Distribution Protocol (LDP) protocols for the following events:

  • Route Processor (RP) or Distributed Route Processor (DRP) failover
  • Process restart for either OSPF, LDP, or TCP
  • Minimum Disruption Restart (MDR)

In the case of the RP failover, NSR is achieved by for both TCP and the applications (OSPF or LDP).

NSR is a method to achieve High Availability (HA) of the routing protocols. TCP connections and the routing protocol sessions are migrated from the active RP to standby RP after the RP failover without letting the peers know about the failover. Currently, the sessions terminate and the protocols running on the standby RP reestablish the sessions after the standby RP goes active. Graceful Restart (GR) extensions are used in place of NSR to prevent traffic loss during an RP failover but GR has several drawbacks.

You can use the nsr process-failures switchover command to let the RP failover be used as a recovery action when the active TCP or active LDP restarts. When standby TCP or LDP restarts, only the NSR capability is lost till the standby instances come up and the sessions are resynchronized but the sessions do not go down. In the case of the process failure of an active OSPF, a fault-management policy is used. For more information, refer to Implementing OSPF on Cisco IOS XR Routing Configuration Guide for the Cisco XR 12000 Series Router.

SCTP Overview

Stream Control Transmission Protocol (SCTP) is a reliable transport protocol that provides multihoming, stream support, and partial reliability. Multihoming occurs when one (or both) endpoints of a connection can consist of more than one IP address, which enables transparent failover between redundant network paths. SCTP can transport multiple message-streams.

TCP Overview

TCP is a connection-oriented protocol that specifies the format of data and acknowledgments that two computer systems exchange to transfer data. TCP also specifies the procedures the computers use to ensure that the data arrives correctly. TCP allows multiple applications on a system to communicate concurrently, because it handles all demultiplexing of the incoming traffic among the application programs.

UDP Overview

The User Datagram Protocol (UDP) is a connectionless transport-layer protocol that belongs to the IP family. UDP is the transport protocol for several well-known application-layer protocols, including Network File System (NFS), Simple Network Management Protocol (SNMP), Domain Name System (DNS), and TFTP.

Any IP protocol other than TCP, UDP, or SCTP is known as a RAW protocol.

For most sites, the default settings for the TCP, UDP, and RAW transports need not be changed.

How to Configure Failover as a Recovery Action for NSR

This section contains the following procedure:

Configuring Failover as a Recovery Action for NSR

This task allows you to configure failover as a recovery action to process failures of active instances.

When the active TCP or the NSR client of the active TCP terminates or restarts, the TCP sessions go down. To continue to provide NSR, failover is configured as a recovery action. If failover is configured, a switchover is initiated if the active TCP or an active application (for example, LDP, OSPF, and so forth) restarts or terminates.

For information on how to configure MPLS Label Distribution Protocol (LDP) for NSR, refer to the Cisco IOS XR MPLS Configuration Guide for the Cisco XR 12000 Series Router.

For information on how to configure NSR on a per-process level for each Open Shortest Path First (OSPF) process, refer to the Cisco IOS XR Routing Configuration Guide for the Cisco XR 12000 Series Router.

SUMMARY STEPS

    1.    configure

    2.    nsr process-failures switchover

    3.    Use the commit or end command.


DETAILED STEPS
     Command or ActionPurpose
    Step 1 configure


    Example:
    RP/0/0/CPU0:router# configure
     

    Enters global configuration mode.

     
    Step 2 nsr process-failures switchover


    Example:
    
    RP/0/0/CPU0:router(config)# nsr process-failures switchover
    
    
    
     

    Configures failover as a recovery action for active instances to switch over to a standby route processor (RP) or a distributed route processor (DRP) to maintain nonstop routing (NSR).

     
    Step 3 Use the commit or end command.  

    commit—Saves the configuration changes, and remains within the configuration session.

    end—Prompts user to take one of these actions:
    • Yes— Saves configuration changes and exits the configuration session.
    • No—Exits the configuration session without committing the configuration changes.
    • Cancel—Remains in the configuration mode, without committing the configuration changes.
     

    Additional References

    The following sections provide references related to configuring NSR, SCTP, TCP, UDP, and RAW transports.

    Related Documents

    Related Topic

    Document Title

    the Cisco IOS XR Software Transport Stack commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

    Transport Stack Commands in the Cisco IOS XR IP Addresses and Services Command Reference for the Cisco XR 12000 Series Router

    the Cisco IOS XR Software MPLS LDP commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

    MPLS Label Distribution Protocol Commands in the Cisco IOS XR MPLS Command Reference for the Cisco XR 12000 Series Router

    the Cisco IOS XR Software OSPF commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

    OSPF Commands in the Cisco IOS XR Routing Command Reference for the Cisco XR 12000 Series Router

    MPLS Label Distribution Protocol feature information

    Implementing MPLS Label Distribution Protocol in the Cisco IOS XR MPLS Configuration Guide for the Cisco XR 12000 Series Router

    OSPF feature information

    Implementing OSPF in the Cisco IOS XR Routing Configuration Guide for the Cisco XR 12000 Series Router

    Standards

    Standards

    Title

    No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

    MIBs

    MIBs

    MIBs Link

    To locate and download MIBs, use the Cisco MIB Locator found at the following URL and choose a platform under the Cisco Access Products menu: http:/​/​cisco.com/​public/​sw-center/​netmgmt/​cmtk/​mibs.shtml

    RFCs

    RFCs

    Title

    No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

    Technical Assistance

    Description

    Link

    The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

    http:/​/​www.cisco.com/​techsupport