Cisco Systems 12.4 manual How to Configure Mpls LDP, Enabling Directly Connected LDP Sessions

Page 11

MPLS Label Distribution Protocol (LDP)

How to Configure MPLS LDP

•Platform-wide--An LDP platform supports a single platform-wide label space for use by interfaces that can share the same labels. For Cisco platforms, all interface types, except LC-ATM, use the platform- wide label space.

LDP uses a 6-byte quantity called an LDP Identifier (or LDP ID) to name label spaces. The LDP ID is made up of the following components:

•The first four bytes, called the LPD router ID, identify the LSR that owns the label space.

•The last two bytes, called the local label space ID, identify the label space within the LSR. For the platform-wide label space, the last two bytes of the LDP ID are always both 0.

The LDP ID takes the following form: <LDP router ID> : <local label space ID> The following are examples of LPD IDs:

•172.16.0.0:0

•192.168.0.0:3

The router determines the LDP router ID as follows, if the mpls ldp router-idcommand is not executed,

1The router examines the IP addresses of all operational interfaces.

2If these IP addresses include loopback interface addresses, the router selects the largest loopback address as the LDP router ID.

3Otherwise, the router selects the largest IP address pertaining to an operational interface as the LDP router ID.

The normal (default) method for determining the LDP router ID may result in a router ID that is not usable in certain situations. For example, the router might select an IP address as the LDP router ID that the routing protocol cannot advertise to a neighboring router. The mpls ldp router-idcommand allows you to specify the IP address of an interface as the LDP router ID. Make sure the specified interface is operational so that its IP address can be used as the LDP router ID.

When you issue the mpls ldp router-idcommand without the force keyword, the router select selects the IP address of the specified interface (provided that the interface is operational) the next time it is necessary to select an LDP router ID, which is typically the next time the interface is shut down or the address is configured.

When you issue the mpls ldp router-idcommand with the force keyword, the effect of the mpls ldp router-idcommand depends on the current state of the specified interface:

•If the interface is up (operational) and if its IP address is not currently the LDP router ID, the LDP router ID changes to the IP address of the interface. This forced change in the LDP router ID tears down any existing LDP sessions, releases label bindings learned via the LDP sessions, and interrupts MPLS forwarding activity associated with the bindings.

•If the interface is down (not operational) when the mpls ldp router-idinterfaceforce command is issued, when the interface transitions to up, the LDP router ID changes to the IP address of the interface. This forced change in the LDP router ID tears down any existing LDP sessions, releases label bindings learned via the LDP sessions, and interrupts MPLS forwarding activity associated with the bindings.

How to Configure MPLS LDP

•Enabling Directly Connected LDP Sessions, page 6

MPLS LDP Configuration Guide, Cisco IOS Release 12.4

5

Page 10 Page 12
Image 11
Page 10 Page 12
Contents Mpls LDP Configuration Guide, Cisco IOS Release Page N T E N T S Mpls LDP Inbound Label Binding Filtering Mpls LDP Graceful Restart Contents Mpls LDP Configuration Guide, Cisco IOS Release Information About Mpls LDP Finding Feature InformationPrerequisites for Mpls LDP Train and Release Introduction to Mpls LDPMpls LDP Functional Overview LDP and TDP SupportTrain and Release LDP/TDP Support Introduction to LDP SessionsNondirectly Connected Mpls LDP Sessions Enabling Directly Connected LDP Sessions, How to Configure Mpls LDPExample Step Command or Action PurposeEnabling Directly Connected LDP Sessions Step Command or Action PurposeExamples Step Command or ActionEstablishing Nondirectly Connected Mpls LDP Sessions Mpls label protocol ldp tdp both Interface tunnelnumber Tunnel destination ip-address Saving Configurations Mpls Tag Switching Commands Specifying the LDP Router ID Routerconfig# mpls ldp Router-id pos2/0/0 Following example displays the LDP router ID Preserving QoS Settings with Mpls LDP Explicit NullInterface type number Command or Action Purpose Local Outgoing Prefix Protecting Data Between LDP Peers with MD5 Authentication Summary Steps Mpls ldp neighbor vrf vpn-nameip Configuring Directly Connected Mpls LDP Sessions Example Mpls LDP Configuration ExamplesRouter 3 Configuration Router 1 ConfigurationRouter 2 Configuration Establishing Nondirectly Connected Mpls LDP Sessions Example Router 6 Configuration Router 4 ConfigurationRouter 5 Configuration Additional References Technical Assistance Description Link Feature Information for Mpls Label Distribution ProtocolRouter-id Releases Feature InformationFeature Name Releases Feature Name Releases Feature Information Page Information About Mpls LDP Session Protection Restrictions for Mpls LDP Session ProtectionMpls LDP Session Protection Customizations Enabling Mpls LDP Session Protection How to Configure Mpls LDP Session ProtectionRouterconfig-if#mpls label protocol ldp Verifying Mpls LDP Session Protection Router# show mpls ldp neighbor detail Troubleshooting TipsIp classless Redundancy Full-duplex Interface Ethernet5/0/2 RFCs Title MIBs MIBs LinkCommand Reference Restrictions Mpls LDP Inbound Label Binding FilteringConfiguring Mpls LDP Inbound Label Binding Filtering How to Configure Mpls LDP Inbound Label Binding FilteringIp access-list standard access-list-number Router# show mpls ldp neighbor 10.12.12.12 detail Verifying that Mpls LDP Inbound Label Bindings are FilteredAccess-list-number Access-list-name LDP Specification, draft-ietf-mpls-ldp-08.txt Technical Assistance Description Link Glossary Releases Feature InformationMpls LDP Inbound Label Binding Filtering Page Restrictions for Mpls LDP Autoconfiguration Mpls LDP AutoconfigurationConfiguring Mpls LDP Autoconfiguration with Ospf Interfaces Information About Mpls LDP AutoconfigurationHow to Configure Mpls LDP Autoconfiguration Mpls LDP Autoconfiguration on Ospf and IS-IS InterfacesGlobally enables hop-by-hop forwarding Router ospf process-id Verifying Mpls LDP Autoconfiguration with Ospf Router# show mpls interfaces Serial 2/0 detail Command or Action Purpose Step Configuring Mpls LDP Autoconfiguration with IS-IS InterfacesEnables IS-IS for IP on the interface Enables the LDP for interfaces that belong to an IS-IS Router# show isis mpls ldp Verifying Mpls LDP Autoconfiguration with IS-ISTroubleshooting Tips Mpls LDP Autoconfiguration with Ospf ExampleCommand Reference Mpls LDP Autoconfiguration with IS-IS ExamplesFeature Information for Mpls LDP Autoconfiguration Feature Information for Mpls LDP Autoconfiguration Mpls LDP Graceful Restart How Mpls LDP Graceful Restart Works Information About Mpls LDP Graceful RestartConfiguring Mpls LDP Graceful Restart How to Configure Mpls LDP Graceful RestartMpls ip Mpls label protocol ldptdpboth Verifying the Configuration Configuration Example for Mpls LDP Graceful RestartRouter 2 configured with LDP SSO/NSF Router 1 configured with LDP GRMpls label protocol ldp mpls traffic-eng tunnels mpls ip Router 3 configured with LDP SSO/NSFMpls Label Distribution Protocol Feature Information for Mpls LDP Graceful Restart Feature Information for Mpls LDP Graceful Restart

12.4 specifications

Cisco Systems has consistently been at the forefront of networking technology, and one of its notable software releases is IOS version 12.4. This version introduced significant enhancements and features that continue to influence networking practices. IOS 12.4 was specifically designed to accommodate the growing demands of network reliability, scalability, and advanced functionalities.

One of the primary characteristics of IOS 12.4 is its enhanced security features. The version integrates advanced security protocols, including improvements in IPsec, which allows for secure communication across potentially insecure networks. Additionally, it supports firewall technologies and access control lists (ACLs), ensuring that organizations can implement stringent security measures tailored to their traffic requirements.

Another defining feature of IOS 12.4 is its support for IPv6. As the internet continued to grow, the need for expanded address space became critical. With IOS 12.4, Cisco provided robust capabilities for transitioning from IPv4 to IPv6, ensuring that network managers could adopt the newer standard without sacrificing performance or reliability. This included support for routing protocols and other networking functions that were essential in an IPv6 environment.

Performance improvements were also a key aspect of IOS 12.4. The release optimized routing protocols, including Enhanced Interior Gateway Routing Protocol (EIGRP) and Open Shortest Path First (OSPF), to enhance convergence times and reduce latency. This effectively contributed to improved network efficiency and uptime.

Cisco also included advanced Quality of Service (QoS) capabilities in IOS 12.4, allowing organizations to prioritize critical traffic. Features such as class-based weighted fair queuing and low-latency queuing became invaluable for organizations requiring seamless voice and video communications over IP networks. This focus on QoS demonstrated Cisco's understanding of the growing importance of multimedia applications in modern business environments.

With a set of stable and scalable routing features, IOS 12.4 supports a variety of platforms, enabling businesses to deploy it across different networking hardware to suit their needs. The modularity of this IOS version makes it flexible for various applications, from small business networks to large enterprise systems.

In summary, Cisco Systems' IOS 12.4 brought forth a wealth of features aimed at enhancing security, performance, and flexibility. Through improved routing capabilities, strong IPv6 support, and advanced QoS features, this version laid the foundation for many of the networking principles that organizations still utilize today.
Top Page Image Contents