H3C S5820X&S5800 Series Ethernet Switches

Transcription

1 H3C S5820X&S5800 Series Ethernet Switches Layer 3 - IP Routing Configuration Guide Hangzhou H3C Technologies Co., Ltd. Document Version: 6W Product Version: Release 1110

2 Copyright , Hangzhou H3C Technologies Co., Ltd. and its licensors All Rights Reserved No part of this manual may be reproduced or transmitted in any form or by any means without prior written consent of Hangzhou H3C Technologies Co., Ltd. Trademarks H3C,, Aolynk,, H 3 Care,, TOP G,, IRF, NetPilot, Neocean, NeoVTL, SecPro, SecPoint, SecEngine, SecPath, Comware, Secware, Storware, NQA, VVG, V 2 G, V n G, PSPT, XGbus, N-Bus, TiGem, InnoVision and HUASAN are trademarks of Hangzhou H3C Technologies Co., Ltd. All other trademarks that may be mentioned in this manual are the property of their respective owners. Notice The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations in this document do not constitute the warranty of any kind, express or implied.

3 Preface The H3C S5800&S5820X documentation set includes 11 configuration guides, which describe the software features for the S5800&S5820X Series Ethernet Switches and guide you through the software configuration procedures. These configuration guides also provide configuration examples to help you apply software features to different network scenarios. The Layer 3 IP Routing Configuration Guide describes routing fundamentals and configuration. It covers the mainstream routing protocols for IPv4 and IPv6 networks, and describes how to use policies to filter routes and affect routing decisions. This preface includes: Audience Document Organization Conventions About the H3C S5800&S5820X Documentation Set Obtaining Documentation Documentation Feedback Audience This documentation set is intended for: Network planners Field technical support and servicing engineers Network administrators working with the S5800 and S5820X series Document Organization The Layer 3 IP Routing Configuration Guide comprises these parts: IP Routing Basics Configuration Static Routing Configuration RIP Configuration OSPF Configuration IS-IS Configuration BGP Configuration IPv6 Static Routing Configuration RIPng Configuration OSPFv3 Configuration IPv6 IS-IS Configuration IPv6 BGP Configuration Route Policy Configuration Policy Routing Configuration MCE Configuration Conventions This section describes the conventions used in this documentation set. Command conventions Boldface Convention Description Bold text represents commands and keywords that you enter literally as shown.

4 Convention Description italic [ ] { x y... } [ x y... ] { x y... } * [ x y... ] * &<1-n> Italic text represents arguments that you replace with actual values. Square brackets enclose syntax choices (keywords or arguments) that are optional. Braces enclose a set of required syntax choices separated by vertical bars, from which you select one. Square brackets enclose a set of optional syntax choices separated by vertical bars, from which you select one or none. Asterisk marked braces enclose a set of required syntax choices separated by vertical bars, from which you select at least one. Asterisk marked square brackets enclose optional syntax choices separated by vertical bars, from which you may select multiple choices or none. The argument or keyword and argument combination before the ampersand (&) sign can be entered 1 to n times. # A line that starts with a pound (#) sign is comments. GUI conventions Boldface > Convention Description Window names, button names, field names, and menu items are in Boldface. For example, the New User window appears; click OK. Multi-level menus are separated by angle brackets. For example, File > Create > Folder. Symbols Convention Description Means reader be extremely careful. Improper operation may cause bodily injury. Means reader be careful. Improper operation may cause data loss or damage to equipment. Means a complementary description. About the H3C S5800&S5820X Documentation Set The H3C S5800&S5820X documentation set also includes: Category Documents Purposes Product description and specifications Pluggable module description Marketing brochures Technology white papers PSR150-A [ PSR150-D ] Power Modules User Manual Describe product specifications and benefits. Provide an in-depth description of software features and technologies. Describes the appearances, features, specifications, installation, and removal of the pluggable 150W power modules available for the products.

5 Category Documents Purposes Power configuration Hardware installation PSR300-12A [ PSR300-12D1 ] Power Modules User Manual PSR750-A [ PSR750-D ] Power Modules User Manual RPS User Manual LSW1FAN and LSW1BFAN Installation Manual LSW148POEM Module User Manual S5820X [ S5800 ] Series Ethernet Switches Interface Cards User Manual H3C OAP Cards User Manual H3C Low End Series Ethernet Switches Pluggable Modules Manual S C-PWR Ethernet Switch Hot Swappable Power Module Ordering Guide RPS Ordering Information for H3C Low-End Ethernet Switches S5800 Series Ethernet Switches Quick Start S5820X Series Ethernet Switches Quick Start S5800 Series Ethernet Switches CE DOC S5820X Series Ethernet Switches CE DOC S5800 Series Ethernet Switches Quick Start S5820X Series Ethernet Switches Quick Start Describes the appearances, features, specifications, installation, and removal of the pluggable 300W power modules available for the products. Describes the appearances, features, specifications, installation, and removal of the pluggable 750W power modules available for the products. Describes the appearances, features, and specifications of the RPS units available for the products. Describes the appearances, specifications, installation, and removal of the pluggable fan modules available for the products. Describes the appearance, features, installation, and removal of the pluggable PoE module available for the products. Describes the models, hardware specifications, installation, and removal of the interface cards available for the products. Describes the benefits, features, hardware specifications, installation, and removal of the OAP cards available for the products. Describes the models, appearances, and specifications of the pluggable modules available for the products. Guides you through ordering the hot-swappable power modules available for the S C-PWR switches in different cases. Provides the RPS and switch compatibility matrix and RPS cable specifications. Provides regulatory information and the safety instructions that must be followed during installation. Guides you through initial installation and setup procedures to help you quickly set up and use your device with the minimum configuration.

6 Category Documents Purposes Software configuration Operations and maintenance S5800 Series Ethernet Switches Installation Manual S5820X Series Ethernet Switches Installation Manual Pluggable SFP[SFP+][XFP] Transceiver Modules Installation Guide S C-PWR Switch Video Installation Guide S5820X-28C Switch Video Installation Guide Configuration guide Command reference H3C Series Ethernet Switches Login Password Recovery Manual Release notes Provides a complete guide to hardware installation and hardware specifications. Guides you through installing SFP/SFP+/XFP transceiver modules. Shows how to install the H3C S C-PWR and H3C S5820X-28C Ethernet switches. Describe software features and configuration procedures. Provide a quick reference to all available commands. Tells how to find the lost password or recover the password when the login password is lost. Provide information about the product release, including the version history, hardware and software compatibility matrix, version upgrade information, technical support information, and software upgrading. Obtaining Documentation You can access the most up-to-date H3C product documentation on the World Wide Web at Click the links on the top navigation bar to obtain different categories of product documentation: [Technical Support & Documents > Technical Documents] Provides hardware installation, software upgrading, and software feature configuration and maintenance documentation. [Products & Solutions] Provides information about products and technologies, as well as solutions. [Technical Support & Documents > Software Download] Provides the documentation released with the software version. Documentation Feedback You can your comments about product documentation to info@h3c.com. We appreciate your comments.

7 Table of Contents 1 IP Routing Basics Configuration 1-1 Routing 1-1 Routing Table and FIB Table 1-1 Routing Protocol Overview 1-3 Static Routing and Dynamic Routing 1-3 Classification of Dynamic Routing Protocols 1-3 Routing Protocols and Routing Priority 1-4 Load Balancing and Route Backup 1-5 Route Recursion 1-6 Sharing of Routing Information 1-6 Configuring a Router ID 1-6 Displaying and Maintaining a Routing Table Static Routing Configuration 2-1 Introduction 2-1 Static Route 2-1 Default Route 2-1 Static Route Configuration Items 2-1 Configuring a Static Route 2-2 Configuration Prerequisites 2-2 Configuration Procedure 2-2 Configuring BFD for Static Routes 2-3 BFD Control Packet Mode 2-4 BFD Echo Packet Mode 2-4 Configuring Static Route FRR 2-5 Displaying and Maintaining Static Routes 2-6 Static Route Configuration Example 2-7 Basic Static Route Configuration Example 2-7 Static Route BFD Configuration Example 2-9 Static Route FRR Configuration Example RIP Configuration 3-1 RIP Overview 3-1 Operation of RIP 3-1 Operation of RIP 3-2 RIP Version 3-3 RIP Message Format 3-3 Supported RIP Features 3-5 Protocols and Standards 3-5 RIP Configuration Task List 3-6 Configuring RIP Basic Functions 3-7 Configuration Prerequisites 3-7 i

8 Configuration Procedure 3-7 Configuring RIP Route Control 3-9 Configuring an Additional Routing Metric 3-10 Configuring RIPv2 Route Summarization 3-10 Disabling Host Route Reception 3-11 Advertising a Default Route 3-12 Configuring Inbound/Outbound Route Filtering 3-13 Configuring a Preference for RIP 3-14 Configuring RIP Route Redistribution 3-14 Configuring RIP Network Optimization 3-15 Configuring RIP Timers 3-15 Configuring Split Horizon and Poison Reverse 3-15 Configuring the Maximum Number of Load Balanced Routes 3-16 Enabling Zero Field Check on Incoming RIPv1 Messages 3-16 Enabling Source IP Address Check on Incoming RIP Updates 3-17 Configuring RIPv2 Message Authentication 3-17 Specifying a RIP Neighbor 3-18 Configuring RIP-to-MIB Binding 3-19 Configuring the RIP Packet Sending Rate 3-19 Configuring RIP FRR 3-19 Configuring BFD for RIP 3-20 Single-Hop Detection in BFD Echo Packet Mode 3-21 Bidirectional Detection in BFD Control Packet Mode 3-21 Displaying and Maintaining RIP 3-22 RIP Configuration Examples 3-22 Configuring RIP Version 3-22 Configuring RIP Route Redistribution 3-24 Configuring an Additional Metric for a RIP Interface 3-26 Configuring RIP to Advertise a Summary Route 3-28 RIP FRR Configuration Example 3-30 Configuring BFD for RIP (Single-Hop Detection in BFD Echo Packet Mode) 3-31 Configuring BFD for RIP (Bidirectional Detection in BFD Control Packet Mode) 3-34 Troubleshooting RIP 3-38 No RIP Updates Received 3-38 Route Oscillation Occurred OSPF Configuration 4-1 Introduction to OSPF 4-1 Basic Concepts 4-2 OSPF Area Partition 4-3 Router Types 4-7 Classification of OSPF Networks 4-8 DR and BDR 4-9 OSPF Packet Formats 4-10 Supported OSPF Features 4-18 Protocols and Standards 4-19 ii

9 OSPF Configuration Task List 4-19 Enabling OSPF 4-21 Prerequisites 4-21 Configuration Procedure 4-21 Configuring OSPF Areas 4-22 Prerequisites 4-23 Configuring a Stub Area 4-23 Configuring an NSSA Area 4-24 Configuring a Virtual Link 4-24 Configuring OSPF Network Types 4-25 Prerequisites 4-25 Configuring the OSPF Network Type for an Interface as Broadcast 4-26 Configuring the OSPF Network Type for an Interface as NBMA 4-26 Configuring the OSPF Network Type for an Interface as P2MP 4-27 Configuring the OSPF Network Type for an Interface as P2P 4-28 Configuring OSPF Route Control 4-28 Prerequisites 4-28 Configuring OSPF Route Summarization 4-28 Configuring OSPF Inbound Route Filtering 4-30 Configuring ABR Type-3 LSA Filtering 4-31 Configuring an OSPF Cost for an Interface 4-31 Configuring the Maximum Number of OSPF Routes 4-32 Configuring the Maximum Number of Load-balanced Routes 4-32 Configuring a Preference for OSPF 4-33 Configuring OSPF Route Redistribution 4-33 Advertising a Host Route 4-35 Configuring OSPF Network Optimization 4-35 Prerequisites 4-35 Configuring OSPF Packet Timers 4-36 Specifying an LSA Transmission Delay 4-37 Specifying SPF Calculation Interval 4-37 Specifying the LSA Minimum Repeat Arrival Interval 4-38 Specifying the LSA Generation Interval 4-38 Disabling Interfaces from Sending OSPF Packets 4-39 Configuring Stub Routers 4-40 Configuring OSPF Authentication 4-40 Adding the Interface MTU into DD Packets 4-41 Configuring the Maximum Number of External LSAs in LSDB 4-41 Making External Route Selection Rules Defined in RFC 1583 Compatible 4-42 Logging Neighbor State Changes 4-42 Configuring OSPF Network Management 4-43 Enabling Message Logging 4-43 Enabling the Advertisement and Reception of Opaque LSAs 4-44 Configuring OSPF to Give Priority to Receiving and Processing Hello Packets 4-44 Configuring the LSU Transmit Rate 4-44 Configuring OSPF FRR 4-45 iii

10 Configuring OSPF Graceful Restart 4-46 Configuring the OSPF GR Restarter 4-47 Configuring the OSPF GR Helper 4-48 Triggering OSPF Graceful Restart 4-49 Configuring BFD for OSPF 4-49 Configuring Control Packet Bidirectional Detection 4-49 Configuring Echo Packet Single-Hop Detection 4-50 Displaying and Maintaining OSPF 4-51 OSPF Configuration Examples 4-52 Configuring OSPF Basic Functions 4-52 Configuring OSPF Route Redistribution 4-55 Configuring OSPF to Advertise a Summary Route 4-56 Configuring an OSPF Stub Area 4-59 Configuring an OSPF NSSA Area 4-62 Configuring OSPF DR Election 4-64 Configuring OSPF Virtual Links 4-68 Configuring OSPF Graceful Restart 4-70 Configuring Route Filtering 4-72 Configuring OSPF FRR 4-74 Configuring BFD for OSPF 4-76 Troubleshooting OSPF Configuration 4-79 No OSPF Neighbor Relationship Established 4-79 Incorrect Routing Information IS-IS Configuration 5-1 IS-IS Overview 5-1 Basic Concepts 5-2 IS-IS Area 5-3 IS-IS Network Type 5-6 IS-IS PDU Format 5-7 Supported IS-IS Features 5-13 Protocols and Standards 5-16 IS-IS Configuration Task List 5-16 Configuring IS-IS Basic Functions 5-17 Configuration Prerequisites 5-17 Enabling IS-IS 5-18 Configuring the IS Level and Circuit Level 5-18 Configuring the Network Type of an Interface as P2P 5-19 Configuring IS-IS Routing Information Control 5-19 Configuration Prerequisites 5-19 Configuring IS-IS Link Cost 5-20 Specifying a Preference for IS-IS 5-21 Configuring the Maximum Number of Equal Cost Routes 5-22 Configuring IS-IS Route Summarization 5-22 Advertising a Default Route 5-23 Configuring IS-IS Route Redistribution 5-23 iv

11 Configuring IS-IS Route Filtering 5-24 Configuring IS-IS Route Leaking 5-25 Tuning and Optimizing IS-IS Networks 5-25 Configuration Prerequisites 5-25 Specifying Intervals for Sending IS-IS Hello and CSNP Packets 5-26 Specifying the IS-IS Hello Multiplier 5-26 Configuring a DIS Priority for an Interface 5-27 Disabling an Interface from Sending/Receiving IS-IS Packets 5-27 Enabling an Interface to Send Small Hello Packets 5-28 Configuring LSP Parameters 5-28 Configuring SPF Parameters 5-32 Setting the LSDB Overload Bit 5-32 Configuring IS-IS Authentication 5-33 Configuration Prerequisites 5-33 Configuring Neighbor Relationship Authentication 5-33 Configuring Area Authentication 5-34 Configuring Routing Domain Authentication 5-34 Configuring System ID to Host Name Mappings 5-35 Configuring a Static System ID to Host Name Mapping 5-35 Configuring Dynamic System ID to Host Name Mapping 5-35 Configuring IS-IS GR 5-36 Configuring IS-IS FRR 5-37 Enabling the Logging of Neighbor State Changes 5-38 Enabling IS-IS SNMP Trap 5-39 Binding an IS-IS Process with MIBs 5-39 Configuring BFD for IS-IS 5-39 Displaying and Maintaining IS-IS 5-40 IS-IS Configuration Example 5-41 IS-IS Basic Configuration 5-41 DIS Election Configuration 5-45 Configuring IS-IS Route Redistribution 5-49 IS-IS Graceful Restart Configuration Example 5-53 IS-IS FRR Configuration Example 5-54 IS-IS Authentication Configuration Example 5-56 Configuring BFD for IS-IS BGP Configuration 6-1 BGP Overview 6-1 Formats of BGP Messages 6-2 BGP Path Attributes 6-5 BGP Route Selection 6-9 ibgp and IGP Synchronization 6-11 Settlements for Problems in Large Scale BGP Networks 6-11 BGP GR 6-15 MP-BGP 6-15 Protocols and Standards 6-16 v

12 BGP Configuration Task List 6-17 Configuring BGP Basic Functions 6-18 Prerequisites 6-18 Creating a BGP Connection 6-18 Specifying the Source Interface for TCP Connections 6-19 Allowing Establishment of ebgp Connection to a Non Directly Connected Peer/Peer Group 6-20 Controlling Route Generation 6-21 Prerequisites 6-21 Injecting a Local Network 6-21 Configuring BGP Route Redistribution 6-21 Enabling Default Route Redistribution into BGP 6-22 Controlling Route Distribution and Reception 6-22 Prerequisites 6-22 Configuring BGP Route Summarization 6-23 Advertising a Default Route to a Peer or Peer Group 6-23 Configuring BGP Route Distribution/Reception Filtering Policies 6-24 Enabling BGP and IGP Route Synchronization 6-25 Limiting Prefixes Received from a Peer/Peer Group 6-26 Configuring BGP Route Dampening 6-27 Configuring a Shortcut Route 6-27 Configuring BGP Route Attributes 6-27 Prerequisites 6-27 Specifying a Preferred Value for Routes Received 6-27 Configuring Preferences for BGP Routes 6-28 Configure the Default Local Preference 6-28 Configuring the MED Attribute 6-29 Configuring the Next Hop Attribute 6-31 Configuring the AS-PATH Attribute 6-32 Tuning and Optimizing BGP Networks 6-34 Prerequisites 6-34 Configuring BGP Keepalive Interval and Holdtime 6-34 Configuring the Interval for Sending the Same Update 6-35 Configuring BGP Soft-Reset 6-36 Enabling the BGP ORF Capability 6-37 Enabling Quick ebgp Session Reestablishment 6-38 Enabling MD5 Authentication for TCP Connections 6-38 Configuring BGP Load Balancing 6-39 Forbiding Session Establishment with a Peer or Peer Group 6-39 Configuring a Large Scale BGP Network 6-39 Configuration Prerequisites 6-40 Configuring BGP Peer Groups 6-40 Configuring BGP Community 6-42 Configuring a BGP Route Reflector 6-43 Configuring a BGP Confederation 6-44 Configuring BGP GR 6-45 Enabling Trap 6-46 vi

13 Enabling Logging of Peer State Changes 6-46 Configuring BFD for BGP 6-46 Displaying and Maintaining BGP 6-47 Displaying BGP 6-47 Resetting BGP Connections 6-48 Clearing BGP Information 6-49 BGP Configuration Examples 6-49 BGP Basic Configuration 6-49 BGP and IGP Synchronization Configuration 6-52 BGP Load Balancing Configuration 6-55 BGP Community Configuration 6-57 BGP Route Reflector Configuration 6-59 BGP Confederation Configuration 6-61 BGP Path Selection Configuration 6-65 Configuring BFD for BGP 6-68 BGP GR Configuration 6-72 Troubleshooting BGP 6-73 No BGP Peer Relationship Established IPv6 Static Routing Configuration 7-1 Introduction to IPv6 Static Routing 7-1 Features of IPv6 Static Routes 7-1 Default IPv6 Route 7-1 Configuring IPv6 Static Routes 7-1 Configuration prerequisites 7-1 Configuration procedure 7-2 Displaying and Maintaining IPv6 Static Routes 7-2 IPv6 Static Routing Configuration Example RIPng Configuration 8-1 Introduction to RIPng 8-1 RIPng Working Mechanism 8-1 RIPng Packet Format 8-2 RIPng Packet Processing Procedure 8-3 Protocols and Standards 8-3 Configuring RIPng Basic Functions 8-3 Configuration Prerequisites 8-4 Configuration Procedure 8-4 Configuring RIPng Route Control 8-4 Configuring an Additional Routing Metric 8-5 Configuring RIPng Route Summarization 8-5 Advertising a Default Route 8-5 Configuring a RIPng Route Filtering Policy 8-6 Configuring a Preference for RIPng 8-6 Configuring RIPng Route Redistribution 8-7 Tuning and Optimizing the RIPng Network 8-7 Configuring RIPng Timers 8-7 vii

14 Configuring Split Horizon and Poison Reverse 8-8 Configuring Zero Field Check on RIPng Packets 8-9 Configuring the Maximum Number of Equal Cost Routes for Load Balancing 8-9 Displaying and Maintaining RIPng 8-10 RIPng Configuration Example 8-10 Configure RIPng Basic Functions 8-10 Configuring RIPng Route Redistribution OSPFv3 Configuration 9-1 Introduction to OSPFv3 9-1 OSPFv3 Overview 9-1 OSPFv3 Packets 9-2 OSPFv3 LSA Types 9-2 Timers of OSPFv3 9-3 OSPFv3 Features Supported 9-3 Protocols and Standards 9-4 IPv6 OSPFv3 Configuration Task List 9-4 Enabling OSPFv3 9-5 Prerequisites 9-5 Enabling OSPFv3 9-5 Configuring OSPFv3 Area Parameters 9-5 Prerequisites 9-6 Configuring an OSPFv3 Stub Area 9-6 Configuring an OSPFv3 Virtual Link 9-6 Configuring OSPFv3 Network Types 9-7 Prerequisites 9-7 Configuring the OSPFv3 Network Type for an Interface 9-7 Configuring an NBMA or P2MP Neighbor 9-8 Configuring OSPFv3 Routing Information Control 9-8 Prerequisites 9-8 Configuring OSPFv3 Route Summarization 9-8 Configuring OSPFv3 Inbound Route Filtering 9-9 Configuring an OSPFv3 Cost for an Interface 9-9 Configuring the Maximum Number of OSPFv3 Load-balanced Routes 9-10 Configuring a Preference for OSPFv Configuring OSPFv3 Route Redistribution 9-11 Tuning and Optimizing OSPFv3 Networks 9-12 Prerequisites 9-12 Configuring OSPFv3 Timers 9-12 Configuring a DR Priority for an Interface 9-13 Ignoring MTU Check for DD Packets 9-14 Disable Interfaces from Sending OSPFv3 Packets 9-14 Enable the Logging of Neighbor State Changes 9-15 Configuring OSPFv3 GR 9-15 Configuring GR Restarter 9-15 Configuring GR Helper 9-16 viii

15 Displaying and Maintaining OSPFv OSPFv3 Configuration Examples 9-17 Configuring OSPFv3 Areas 9-17 Configuring OSPFv3 DR Election 9-21 Configuring OSPFv3 Route Redistribution 9-24 Configuring OSPFv3 GR 9-26 Troubleshooting OSPFv3 Configuration 9-28 No OSPFv3 Neighbor Relationship Established 9-28 Incorrect Routing Information IPv6 IS-IS Configuration 10-1 Introduction to IPv6 IS-IS 10-1 Configuring IPv6 IS-IS Basic Functions 10-2 Configuration Prerequisites 10-2 Configuration Procedure 10-2 Configuring IPv6 IS-IS Routing Information Control 10-2 Configuration Prerequisites 10-2 Configuration Procedure 10-3 Displaying and Maintaining IPv6 IS-IS 10-4 IPv6 IS-IS Configuration Example IPv6 BGP Configuration 11-1 IPv6 BGP Overview 11-1 Configuration Task List 11-2 Configuring IPv6 BGP Basic Functions 11-3 Prerequisites 11-3 Specifying an IPv6 BGP Peer 11-3 Injecting a Local IPv6 Route 11-4 Configuring a Preferred Value for Routes from a Peer/Peer Group 11-4 Specifying the Source Interface for Establishing TCP Connections 11-5 Allowing the Establishment of a Non-Direct ebgp connection 11-5 Configuring a Description for an IPv6 Peer/Peer Group 11-6 Disabling Session Establishment to an IPv6 Peer/Peer Group 11-6 Logging IPv6 Peer/Peer Group State Changes 11-6 Controlling Route Distribution and Reception 11-7 Prerequisites 11-7 Configuring IPv6 BGP Route Redistribution 11-7 Configuring IPv6 BGP Route Summarization 11-8 Advertising a Default Route to an IPv6 Peer/Peer Group 11-8 Configuring Outbound Route Filtering 11-9 Configuring Inbound Route Filtering Configuring IPv6 BGP and IGP Route Synchronization Configuring Route Dampening Configuring IPv6 BGP Route Attributes Prerequisites Configuring IPv6 BGP Preference and Default LOCAL_PREF and NEXT_HOP Attributes Configuring the MED Attribute ix

16 Configuring the AS_PATH Attribute Tuning and Optimizing IPv6 BGP Networks Prerequisites Configuring IPv6 BGP Timers Configuring IPv6 BGP Soft Reset Enabling the IPv6 BGP ORF Capability Configuring the Maximum Number of Load-Balanced Routes Configuring a Large Scale IPv6 BGP Network Prerequisites Configuring IPv6 BGP Peer Group Configuring IPv6 BGP Community Configuring an IPv6 BGP Route Reflector Displaying and Maintaining IPv6 BGP Displaying BGP Resetting IPv6 BGP Connections Clearing IPv6 BGP Information IPv6 BGP Configuration Examples IPv6 BGP Basic Configuration IPv6 BGP Route Reflector Configuration Troubleshooting IPv6 BGP Configuration No IPv6 BGP Peer Relationship Established Route Policy Configuration 12-1 Introduction to Route Policy 12-1 Introduction to Route Policy 12-1 Route Policy Application 12-1 Route Policy Implementation 12-1 Filters 12-2 Route Policy Application 12-3 Route Policy Configuration Task List 12-3 Defining Filters 12-3 Prerequisites 12-3 Defining an IP-prefix List 12-3 Defining an AS Path List 12-5 Defining a Community List 12-5 Defining an Extended Community List 12-6 Configuring a Route Policy 12-6 Prerequisites 12-6 Creating a Route Policy 12-6 Defining if-match Clauses 12-7 Defining apply Clauses 12-9 Displaying and Maintaining the Route Policy Route Policy Configuration Examples Applying a Route Policy to IPv4 Route Redistribution Applying a Route Policy to IPv6 Route Redistribution Applying a Route Policy to Filter Received BGP Routes x

17 Troubleshooting Route Policy Configuration IPv4 Routing Information Filtering Failure IPv6 Routing Information Filtering Failure Policy Routing Configuration 13-1 Policy Routing Overview 13-1 Configuring Policy Routing 13-1 Configuring a QoS Policy 13-1 Applying the QoS Policy 13-2 Displaying and Maintaining QoS Policies 13-3 Policy Routing Configuration Examples 13-4 IPv4 Policy Routing Configuration Example 13-4 IPv6 Policy Routing Configuration Example MCE Configuration 14-1 MCE Overview 14-1 Introduction to MPLS L3VPN 14-1 MPLS L3VPN Concepts 14-2 Multi-VPN-Instance CE 14-4 How MCE works 14-5 Using MCE in Tunneling Applications 14-5 Routing Information Exchange for MCE 14-6 Route Exchange between an MCE and the Private Network 14-6 Route Exchange between MCE and PE 14-9 Configuring Multi-VPN-Instance CE 14-9 Configuring VPN Instances 14-9 Configuring Route Exchange for MCE Displaying and Maintaining MCE Resetting BGP Connections Displaying and Maintaining MCE MCE Configuration Examples Using OSPF to Redistribute VPN Routes Between an MCE and PE Using BGP to Redistribute VPN Routes Between an MCE and PE Using MCE to Advertise VPN Routes Through Tunnels Index 15-1 xi

18 1 IP Routing Basics Configuration This chapter includes these sections: Routing Routing Protocol Overview Configuring a Router ID Displaying and Maintaining a Routing Table The term router in this document refers to both routers and Layer 3 switches. Routing Routing in the Internet is achieved through routers. Upon receiving a packet, a router finds an optimal route based on the destination address and forwards the packet to the next router in the path until the packet reaches the last router, which forwards the packet to the intended destination host. Routing provides the path information that guides the forwarding of packets. Routing Table and FIB Table Routing tables play a key role in route selection and forwarding information bases (FIBs) play a key role in packet forwarding. Each router maintains a routing table and a FIB table at least. Routes in a routing table can be divided into three categories by origin: Direct routes: Routes discovered by data link protocols, also known as interface routes. Static routes: Routes that are manually configured. Dynamic routes: Routes that are discovered dynamically by routing protocols. Each entry in the FIB table specifies which physical interface a packet destined for a certain destination should go out to reach the next hop (the next router) or the directly connected destination. Introduction to routing table Each router maintains a local routing table. Each routing protocol also maintains a protocol routing table. Routing table of a protocol A protocol routing table stores routes discovered by the routing protocol. A routing protocol can redistribute and advertise routes generated by other protocols. For example, OSPF can redistribute direct routes, static routes, and IS-IS routes to the OSPF routing domain. Local routing table 1-1

19 A local routing table stores the routes found by all protocols and determines the optimal routes that the router will deliver to the FIB table to guide packet forwarding. The selection of an optimal route is based on the preferences of routing protocols and metrics of routes. Contents of a routing table A routing table includes the following key items: Destination address: Destination IP address or destination network. Network mask: Specifies, in company with the destination address, the address of the destination network. A logical AND operation between the destination address and the network mask yields the address of the destination network. For example, if the destination address is and the mask , the address of the destination network is A network mask is made of a certain number of consecutive 1s. It can be expressed in dotted decimal format or by the number of the 1s. Outbound interface: Specifies the interface through which the IP packets are to be forwarded. IP address of the next hop: Specifies the address of the next router on the path. If only the outbound interface is configured, its address will be the IP address of the next hop. Priority for the route. Routes to the same destination but having different nexthops may have different priorities and be found by various routing protocols or manually configured. The optimal route is the one with the highest priority (with the smallest metric). Routes can be divided into two categories by destination: Subnet routes: The destination is a subnet. Host routes: The destination is a host. Based on whether the destination is directly connected to a given router, routes can be divided into: Direct routes: The destination is directly connected to the router. Indirect routes: The destination is not directly connected to the router. To prevent the routing table from getting too large, you can configure a default route. All packets without matching any entry in the routing table will be forwarded through the default route. In Figure 1-1, the IP address on each cloud represents the address of the network. Router G is connected to three networks and therefore has three IP addresses for its three physical interfaces. Its routing table is shown under the network topology. 1-2

20 Figure 1-1 A sample routing table Router A Router F Router D Router B Router G Router E Router C Router H Destination Network Nexthop Interface Routing Protocol Overview Static Routing and Dynamic Routing Static routing is easy to configure and requires less system resources. It works well in small, stable networks with simple topologies. Its major drawback is that you must perform routing configuration again whenever the network topology changes; it cannot adjust to network changes by itself. Dynamic routing is based on dynamic routing protocols, which can detect network topology changes and recalculate the routes accordingly. Therefore, dynamic routing is suitable for large networks. Its disadvantages are that it is difficult to configure, and that it not only imposes higher requirements on the system, but also consumes a certain amount of network resources. Classification of Dynamic Routing Protocols Dynamic routing protocols can be classified based on the following standards: Operational scope Interior gateway protocols (IGPs): Work within an autonomous system, including RIP, OSPF, and IS-IS. 1-3

21 Exterior gateway protocols (EGPs): Work between autonomous systems. The most popular one is BGP. An autonomous system refers to a group of routers that share the same routing policy and work under the same administration. Routing algorithm Distance-vector protocols: RIP and BGP. BGP is also considered a path-vector protocol. Link-state protocols: OSPF and IS-IS. The main differences between the above two types of routing algorithms lie in the way routes are discovered and calculated. Type of the destination address Unicast routing protocols: RIP, OSPF, BGP, and IS-IS. Multicast routing protocols: PIM-SM and PIM-DM. This chapter focuses on unicast routing protocols. For information on multicast routing protocols, see the IP Multicast Configuration Guide. Version of IP protocol IPv4 routing protocols: RIP, OSPFv2, BGP4, and IS-IS. IPv6 routing protocols: RIPng, OSPFv3, BGP4+, and IPv6 IS-IS. Routing Protocols and Routing Priority Different routing protocols may find different routes to the same destination. However, not all of those routes are optimal. In fact, at a particular moment, only one protocol can uniquely determine the current optimal route to the destination. For the purpose of route selection, each routing protocol (including static routes) is assigned a priority. The route found by the routing protocol with the highest priority is preferred. The following table lists some routing protocols and the default priorities for routes found by them: Routing approach Priority DIRECT 0 OSPF 10 IS-IS 15 STATIC 60 RIP 100 OSPF ASE 150 OSPF NSSA

22 Routing approach Priority IBGP 255 EBGP 255 UNKNOWN 256 The smaller the priority value, the higher the priority. The priority for a direct route is always 0, which you cannot change. Any other type of routes can have their priorities manually configured. Each static route can be configured with a different priority. IPv4 and IPv6 routes have their own respective routing tables. Load Balancing and Route Backup Load Balancing In multi-route mode, a routing protocol can be configured with multiple equal-cost routes to the same destination. These routes have the same priority and will all be used to accomplish load balancing if there is no route with a higher priority available. A given routing protocol may find several routes with the same metric to the same destination, and if this protocol has the highest priority among all the active protocols, these routes will be considered valid routes for load balancing. The number of routes for load balancing is 8. In current implementations, routing protocols supporting load balancing are static routing, RIP, OSPF, BGP, and IS-IS. Route backup Route backup can help improve network reliability. With route backup, you can configure multiple routes to the same destination, expecting the one with the highest priority to be the main route and all the rest backup routes. Under normal circumstances, packets are forwarded through the main route. When the main route goes down, the route with the highest priority among the backup routes is selected to forward packets. When the main route recovers, the route selection process is performed again and the main route is selected again to forward packets. 1-5

23 Route Recursion The nexthops of some BGP routes (except ebgp routes) and static routes configured with nexthops may not be directly connected. To forward the packets, the outgoing interface to reach the nexthop must be available. Route recursion is used to find the outgoing interface based on the nexthop information of the route. Link-state routing protocols, such as OSPF and IS-IS, do not need route recursion because they obtain nexthop information through route calculation. Sharing of Routing Information As different routing protocols use different routing algorithms to calculate routes, they may find different routes. In a large network with multiple routing protocols, it is required for routing protocols to share their routing information. Each routing protocol has its own route redistribution mechanism. For detailed information, see the Layer 3 - IP Routing Configuration Guide. Configuring a Router ID Some routing protocols use a router ID to identify a device. You can configure a global router ID for a device. If no router ID is configured for a protocol, the global router ID is used. Enter system view system-view Configure a router ID router id router-id Not configured by default. Some routing protocols use a router ID to identify a device. You can configure a global router ID for a device. If no router ID is configured for a protocol, the global router ID is used. A route ID is selected in the following sequence: 1-6

24 Select the router ID configured with the router id command; Select the highest IP address among the IP addresses of loopback interfaces as the router ID: If no loopback interface IP address is available, the highest IP address among the IP addresses of physical interfaces is selected as the router ID (regardless of the interface state). If the interface whose IP address is the router ID is removed or modified, a new router ID is selected. Other events, (the interface goes down; after a physical interface s IP address is selected as the router ID, an IP address is configured for a loopback interface; a higher interface IP address is configured) will not trigger router ID re-selection. A VPN instance selects a router ID among the IP addresses of interfaces belonging to it according to the preceding procedure. When a master/backup switchover occurs, the backup device selects a router ID according to the preceding procedure. After a router ID is changed, you need to use the reset command to make it effective. Displaying and Maintaining a Routing Table Display brief information about the active routes in the routing table Display information about routes to the specified destination Display information about routes with destination addresses in the specified range Display information about routes permitted by an IPv4 basic ACL Display routing information permitted by an IPv4 prefix list Display routes of a routing protocol Display statistics about the network routing table or a VPN routing table display ip routing-table [ vpn-instance vpn-instance-name ] [ verbose { begin exclude include } regular-expression ] display ip routing-table ip-address [ mask-length mask ] [ longer-match ] [ verbose ] display ip routing-table ip-address1 { mask-length mask } ip-address2 { mask-length mask } [ verbose ] display ip routing-table acl acl-number [ verbose ] display ip routing-table ip-prefix ip-prefix-name [ verbose ] display ip routing-table protocol protocol [ inactive verbose ] display ip routing-table [ vpn-instance vpn-instance-name ] statistics Available in any view Available in any view Available in any view Available in any view Available in any view Available in any view Available in any view Display the router ID display router id Available in any view 1-7

25 Clear statistics for the routing table or a VPN routing table reset ip routing-table statistics protocol [ vpn-instance vpn-instance-name ] { all protocol } Available in user view Display brief IPv6 routing table information display ipv6 routing-table Available in any view Display verbose IPv6 routing table information Display routing information for a specified destination IPv6 address Display routing information permitted by an IPv6 ACL Display routing information permitted by an IPv6 prefix list Display IPv6 routing information of a routing protocol display ipv6 routing-table verbose display ipv6 routing-table ipv6-address prefix-length [ longer-match ] [ verbose ] display ipv6 routing-table acl acl6-number [ verbose ] display ipv6 routing-table ipv6-prefix ipv6-prefix-name [ verbose ] display ipv6 routing-table protocol protocol [ inactive verbose ] Available in any view Available in any view Available in any view Available in any view Available in any view Display IPv6 routing statistics display ipv6 routing-table statistics Available in any view Display IPv6 routing information for an IPv6 address range Clear specified IPv6 routing table statistics display ipv6 routing-table ipv6-address1 prefix-length1 ipv6-address2 prefix-length2 [ verbose ] reset ipv6 routing-table statistics protocol { all protocol } Available in any view Available in user view 1-8

26 2 Static Routing Configuration This chapter includes these sections: Introduction Configuring a Static Route Configuring BFD for Static Routes Static Route Configuration Example The term router in this document refers to both routers and Layer 3 switches. Introduction Static Route A static route is a manually configured route. If a network s topology is simple, you only need to configure static routes for the network to work normally. The proper configuration and usage of static routes can improve network performance and ensure bandwidth for important network applications. The disadvantage of using static routes is that they cannot adapt to network topology changes. If a fault or a topological change occurs in the network, the routes will be unreachable and the network breaks. In this case, the network administrator has to modify the static routes manually. Default Route A default route is used to forward packets that match no specific entry in the routing table. Without a default route, a packet matching no routing entry is discarded and an ICMP destination-unreachable packet is sent to the source. Default routes can be configured in two ways: The network administrator can configure a default route with both destination and mask being Some dynamic routing protocols, such as OSPF, RIP and IS-IS, can also generate a default route. For example, an upstream router running OSPF can generate a default route and advertise it to other routers, which install the default route with the next hop being the upstream router. Static Route Configuration Items 1) Destination address and mask 2-1

27 In the ip route-static command, a specified IPv4 address is in dotted decimal format and a specified mask can be either in dotted decimal format or in the form of mask length (the number of consecutive 1s in the mask). 2) Output interface and next hop While configuring a static route, you can specify the output interface and/or the next hop address depending on the specific occasion. The next hop address cannot be a local interface IP address; otherwise, the route configuration will not take effect. In fact, each route lookup operation has to find the next hop to resolve the destination link layer address. When specifying the output interface, note that: If the output interface is a Null 0 interface, there is no need to configure the next hop address. If the output interface is a broadcast interface (such as a VLAN interface), you must specify the corresponding next hop. 3) Other attributes You can configure different preferences for different static routes so that route management policies can be applied more flexibly. For example, specifying the same preference for different routes to the same destination enables load sharing, while specifying different preferences for these routes enables route backup. Configuring a Static Route Configuration Prerequisites Before configuring a static route, you need to finish the following tasks: Configure the physical parameters for related interfaces Configure the link-layer attributes for related interfaces Configure the IP addresses for related interfaces Configuration Procedure Follow these steps to configure a static route: Enter system view system-view 2-2

28 Configure a static route ip route-static dest-address { mask mask-length } { next-hop-address interface-type interface-number [ next-hop-address ] vpn-instance d-vpn-instance-name next-hop-address } track track-entry-number [ preference preference-value ] [ tag tag-value ] [ description description-text ] ip route-static vpn-instance s-vpn-instance-name&<1-6> dest-address { mask mask-length } { next-hop-address track track-entry-number [ public ] interface-type interface-number [ next-hop-address ] vpn-instance d-vpn-instance-name next-hop-address track track-entry-number } [ preference preference-value ] [ tag tag-value ] [ description description-text ] Required By default, preference for static routes is 60, tag is 0, and no description information is configured. Configure the default preference for static routes ip route-static default-preference default-preference-value 60 by default The static route does not take effect if you specify the next hop address first and then configure the next hop address as the IP address of a local interface, such as a VLAN interface. If you do not specify the preference when configuring a static route, the default preference is used. Reconfiguring the default preference applies only to subsequently created static routes. You can flexibly control static routes by configuring tag values and using the tag values in the routing policy. If the destination IP address and mask are both configured as with the ip route-static command, the route is a default route. For detailed information about track, see Track Configuration in the High Availability Configuration Guide. Configuring BFD for Static Routes Bidirectional forwarding detection (BFD) provides a general-purpose, standard, medium- and protocol-independent fast failure detection mechanism. It can uniformly and quickly detect the failures of the bidirectional forwarding paths between two routers for protocols, such as routing protocols. For details about BFD, see BFD Configuration in the High Availability Configuration Guide. 2-3

29 A dynamic routing protocol notifies BFD of its neighbor information. BFD uses such information to establish sessions with neighbors by sending BFD control packets. Static routing, which has no neighbor discovery mechanism, implements BFD as follows: BFD Control Packet Mode To use BFD control packets for bidirectional detection between two devices, you need to enable BFD control packet mode for each device s static route destined to the peer. Follow these steps to configure BFD control packet mode for static routes: Enter system view system-view Enable BFD control packet mode for static routes ip route-static dest-address { mask mask-length } interface-type interface-number next-hop-address bfd control-packet [ preference preference-value ] [ tag tag-value ] [ description description-text ] ip route-static vpn-instance s-vpn-instance-name&<1-6> dest-address { mask mask-length } interface-type interface-number next-hop-address bfd control-packet [ preference preference-value ] [ tag tag-value ] [ description description-text ] Use either command BFD Echo Packet Mode With BFD echo packet mode enabled for a static route, the local device sends BFD echo packets to the peer, which loops it back to test the link in between. Follow these steps to configure BFD echo packet mode for static routes: Enter system view system-view Configure the source address of echo packets bfd echo-source-ip ip-address Required Not configured by default 2-4

30 Enable BFD echo packet mode for static routes ip route-static dest-address { mask mask-length } interface-type interface-number next-hop-address bfd echo-packet [ preference preference-value ] [ tag tag-value ] [ description description-text ] ip route-static vpn-instance s-vpn-instance-name&<1-6> dest-address { mask mask-length } interface-type interface-number next-hop-address bfd echo-packet [ preference preference-value ] [ tag tag-value ] [ description description-text ] Use either command If route flaps occur, enabling BFD may worsen the route flaps. Therefore, enable BFD with care in such cases. The source address of echo packets must be configured if the BFD session operates in the echo mode. If you configure BFD for a static route, you need to specify both the outbound interface and next hop IP address for the route. BFD cannot be used for a static route whose outbound interface has the spoofing attribute. BFD can be used for static routes with direct next hops rather than non-direct next hops. In the draft, the BFD echo function is revised to specify that a BFD session is established at only one end when the echo mode is used. Configuring Static Route FRR When the link in the network below fails, the packets on the path may be discarded, or a routing loop may occur. Then, the traffic will be interrupted. To avoid such problems, you can enable static route fast reroute (FRR). Figure 2-1 Network diagram for static route FRR As shown in Figure 2-1, FRR can designate a backup next hop by using a route policy, and packets are forwarded to the backup next hop, thus to avoid traffic interruption. 2-5

31 Configuration prerequisites Configuring static route FRR needs to reference a route policy. You can specify a backup next hop in a route policy by using the apply fast-reroute backup-interface command. For details about the command and routing policy configurations, see Route Policy Configuration in the Layer 3 - IP Routing Configuration Guide. Configuration procedure Follow these steps to configure static route FRR: Enter system view system-view Configure the source address of echo packets bfd echo-source-ip ip-address Required Not configured by default. Configure static route FRR ip route-static [ vpn-instance vpn-instance-name ] fast-reroute route-policy route-policy-name Required Not configured by default. Static route FRR takes effect only for static routes that have both the outbound interface and next hop specified. Do not use static route FRR and BFD for static routing at the same time. Displaying and Maintaining Static Routes Display the current configuration information display current-configuration Display the brief information of the IP routing table Display the detailed information of the IP routing table display ip routing-table display ip routing-table verbose Available in any view Display static route information Delete all the static routes display ip routing-table protocol static [ inactive verbose ] delete [ vpn-instance vpn-instance-name ] static-routes all Available In system view 2-6