HP A5820X & A5800 Switch Series Layer 3 - IP Routing. Configuration Guide. Abstract

Transcription

1 HP A5820X & A5800 Switch Series Layer 3 - IP Routing Configuration Guide Abstract This document describes the software features for the HP A Series products and guides you through the software configuration procedures. These configuration guides also provide configuration examples to help you apply software features to different network scenarios. This documentation is intended for network planners, field technical support and servicing engineers, and network administrators working with the HP A Series products. Part number: Software version: Release 1211 Document version: 5W

2 Legal and notice information Copyright 2011 Hewlett-Packard Development Company, L.P. No part of this documentation may be reproduced or transmitted in any form or by any means without prior written consent of Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. HEWLETT-PACKARD COMPANY MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Hewlett-Packard shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of this material. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.

3 Contents Configuring IP routing 1 Routing table and FIB table 1 Routing table 1 Routing protocol 3 Static routing and dynamic routing 3 Dynamic routing protocol classification 3 Routing protocols and routing preference 3 Route recursion 4 Sharing of routing information 4 Configuring a router ID 4 Displaying and maintaining a routing table 5 Configuring static routing 8 Default route 8 Static route configuration items 8 Configuring a static route 9 Prerequisites 9 Procedure 9 Configuring BFD for static routes 10 BFD control packet mode 10 BFD echo packet mode 10 Configuring static route FRR 11 Displaying and maintaining static routes 12 Static route configuration examples 12 Basic static route configuration example 12 Static route FRR configuration example 14 BFD for static routes configuration example 16 Configuring RIP 19 RIP process 19 RIP routing table 19 RIP timers 20 Preventing routing loops 20 RIP version 20 RIP message format 21 Supported RIP features 22 Protocols and standards 23 Configuring RIP basic functions 23 Prerequisites 23 Procedure 23 Configuring RIP route control 25 Prerequisites 25 Configuring an additional routing metric 25 Configuring RIPv2 route summarization 26 Disabling host route reception 27 Advertising a default route 27 Configuring inbound/outbound route filtering 28 Configuring a priority for RIP 28 Configuring RIP route redistribution 29 iii

4 Tuning and optimizing RIP networks 29 Configuring RIP timers 29 Configuring split horizon and poison reverse 30 Configuring the maximum number of load balanced routes 30 Enabling zero field check on incoming RIPv1 messages 30 Enabling source IP address check on incoming RIP updates 31 Configuring RIPv2 message authentication 32 Specifying a RIP neighbor 32 Configuring RIP-to-MIB binding 33 Configuring the RIP packet sending rate 33 Configuring RIP FRR 33 Configuring BFD for RIP 34 Single-hop detection in BFD echo packet mode 34 Bidirectional detection in BFD control packet mode 35 Displaying and maintaining RIP 35 RIP configuration examples 36 Configuring RIP version 36 Configuring RIP route redistribution 37 Configuring an additional metric for a RIP interface 39 Configuring RIP to advertise a summary route 41 RIP FRR 44 RIP single-hop detection in BFD echo packet mode 45 RIP bidirectional detection in BFD control packet mode 48 Troubleshooting RIP 52 No RIP updates received 52 Route oscillation occurred 52 Configuring OSPF 53 Understanding OSPF 53 Autonomous system 53 OSPF route computation 53 Router ID 54 OSPF packets 54 LSA types 54 Neighbor and Adjacency 55 Area based OSPF network partition 55 Router types 58 Classification of OSPF networks 59 DR and BDR 60 OSPF packet formats 61 Supported OSPF features 70 Protocols and standards 72 Enabling OSPF 72 Prerequisites 72 Procedure 72 Configuring OSPF areas 73 Prerequisites 73 Configuring a stub area 74 Configuring an NSSA area 74 Configuring a virtual link 75 Configuring OSPF network types 75 Prerequisites 76 Configuring the OSPF network type for an interface as broadcast 76 Configuring the OSPF network type for an interface as NBMA 76 iv

5 Configuring the OSPF network type for an interface as P2MP 77 Configuring the OSPF network type for an interface as P2P 78 Configuring OSPF route control 78 Prerequisites 78 Configuring OSPF route summarization 78 Configuring OSPF inbound route filtering 79 Configuring ABR type-3 LSA filtering 80 Configuring an OSPF cost for an interface 80 Configuring the maximum number of OSPF routes 81 Configuring the maximum number of load-balanced routes 81 Configuring a priority for OSPF 81 Configuring OSPF route redistribution 82 Advertising a host route 83 Tuning and optimizing OSPF networks 83 Prerequisites 83 Configuring OSPF packet timers 83 Specifying an LSA transmission delay 84 Specifying SPF calculation interval 85 Specifying the LSA minimum repeat arrival interval 85 Specifying the LSA generation interval 85 Disabling interfaces from sending OSPF packets 86 Configuring stub routers 86 Configuring OSPF authentication 86 Adding the interface MTU into DD packets 87 Configuring the maximum number of external LSAs in LSDB 87 Making external route selection rules defined in RFC 1583 compatible 88 Logging neighbor state changes 88 Configuring OSPF network management 88 Enabling message logging 89 Configuring OSPF to give priority to receiving and processing hello packets 89 Configuring the LSU transmit rate 90 Configuring OSPF FRR 90 Configuring OSPF Graceful Restart 92 Configuring the OSPF GR Restarter 92 Configuring the OSPF GR Helper 93 Triggering OSPF Graceful Restart 94 Configuring BFD for OSPF 94 Configuring control packet bidirectional detection 94 Configuring echo packet single-hop detection 94 Displaying and maintaining OSPF 95 OSPF configuration examples 96 Configuring OSPF basic functions 96 Configuring OSPF route redistribution 99 Configuring OSPF to advertise a summary route 101 Configuring an OSPF stub area 104 Configuring an OSPF NSSA area 106 Configuring OSPF DR election 108 Configuring OSPF virtual links 112 Configuring OSPF graceful restart 114 Configuring route filtering 116 Configuring OSPF FRR 119 Configuring BFD for OSPF 121 Troubleshooting OSPF configuration 125 v

6 No OSPF neighbor relationship established 125 Incorrect routing information 126 IS-IS configuration 127 IS-IS terminology 127 IS-IS address format 127 IS-IS area 129 IS-IS network type 131 IS-IS PDU format 132 Supported IS-IS features 138 Protocols and standards 140 Configuring IS-IS basic functions 141 Prerequisites 141 Enabling IS-IS 141 Configuring the IS level and circuit level 141 Configuring the network type of an interface as P2P 142 Configuring IS-IS routing information control 142 Prerequisites 142 Configuring IS-IS link cost 142 Specifying a priority for IS-IS 144 Configuring the maximum number of equal cost routes 144 Configuring IS-IS route summarization 144 Advertising a default route 145 Configuring IS-IS route redistribution 145 Configuring IS-IS route filtering 146 Configuring IS-IS route leaking 146 Tuning and optimizing IS-IS networks 147 Prerequisites 147 Specifying intervals for sending IS-IS hello and CSNP packets 147 Specifying the IS-IS hello multiplier 147 Configuring a DIS priority for an interface 148 Disabling an interface from sending/receiving IS-IS packets 148 Enabling an interface to send small hello packets 148 Configuring LSP parameters 149 Configuring SPF parameters 152 Setting the LSDB overload bit 152 Configuring system ID to host name mappings 152 Enabling the logging of neighbor state changes 154 Enhancing IS-IS network security 154 Prerequisites 154 Configuring neighbor relationship authentication 154 Configuring area authentication 155 Configuring routing domain authentication 155 Configuring IS-IS GR 155 Configuring IS-IS NSR 156 Configuring IS-IS FRR 156 Enabling IS-IS SNMP trap 158 Binding an IS-IS process with MIBs 158 Configuring BFD for IS-IS 158 Displaying and maintaining IS-IS 159 IS-IS configuration example 160 IS-IS basic configuration 160 DIS election configuration 164 Configuring IS-IS route redistribution 169 vi

7 IS-IS graceful restart configuration example 172 IS-IS NSR configuration example 174 IS-IS FRR configuration example 177 IS-IS authentication configuration example 179 Configuring BFD for IS-IS 181 BGP configuration 185 BGP overview 185 Formats of BGP messages 185 BGP path attributes 188 BGP route selection 192 ibgp and IGP synchronization 194 Settlements for issues in large scale BGP networks 194 BGP GR 197 MP-BGP 198 Protocols and standards 198 Configuring BGP basic functions 199 Prerequisites 199 Creating a BGP connection 199 Specifying the source interface for TCP connections 200 Allowing establishment of ebgp connection to an indirectly connected peer/peer group 200 Controlling route generation 201 Prerequisites 201 Injecting a local network 201 Configuring BGP route redistribution 201 Enabling default route redistribution into BGP 202 Controlling route distribution and reception 202 Prerequisites 202 Configuring BGP route summarization 202 Advertising a default route to a peer or peer group 203 Configuring BGP route distribution/reception filtering policies 203 Enabling BGP and IGP route synchronization 205 Limiting prefixes received from a peer/peer group 205 Configuring BGP route dampening 205 Configuring a shortcut route 206 Configuring BGP route attributes 206 Prerequisites 206 Specifying a preferred value for routes received 206 Configuring preferences for BGP routes 207 Configure the default local preference 207 Configuring the MED attribute 207 Configuring the next hop attribute 209 Configuring the AS-PATH attribute 210 Tuning and optimizing BGP networks 212 Prerequisites 212 Configuring BGP keepalive interval and holdtime 212 Configuring the interval for sending the same update 213 Configuring BGP soft-reset 213 Enabling the BGP ORF capability 214 Enabling quick ebgp session reestablishment 215 Enabling MD5 authentication for TCP connections 215 Configuring BGP load balancing 216 Forbidding session establishment with a peer or peer group 216 Configuring a large scale BGP network 216 vii

8 Prerequisites 216 Configuring BGP peer groups 216 Configuring BGP community 218 Configuring a BGP route reflector 219 Configuring a BGP confederation 219 Configuring BGP GR 220 Enabling trap 221 Enabling logging of peer state changes 221 Configuring BFD for BGP 221 Displaying and maintaining BGP 222 Displaying BGP 222 Resetting BGP connections 223 Clearing BGP information 224 BGP configuration examples 224 BGP basic configuration 224 BGP and IGP synchronization configuration 228 BGP load balancing configuration 231 BGP community configuration 233 BGP route reflector configuration 236 BGP confederation configuration 238 BGP path selection configuration 241 BGP GR configuration 245 Configuring BFD for BGP 246 Troubleshooting BGP 251 No BGP peer relationship established 251 IPv6 static routing configuration 252 Introduction to IPv6 static routing 252 Features of IPv6 static routes 252 Default IPv6 route 252 Configuring an IPv6 static route 252 Prerequisites 252 Procedure 252 Displaying and maintaining IPv6 static routes 253 IPv6 static routing configuration example 253 RIPng configuration 256 Introduction to RIPng 256 RIPng working mechanism 256 RIPng packet format 257 RIPng packet processing procedure 258 Protocols and standards 258 Configuring RIPng basic functions 258 Prerequisites 258 Procedure 258 Configuring RIPng route control 259 Configuring an additional routing metric 259 Configuring RIPng route summarization 259 Advertising a default route 260 Configuring a RIPng route filtering policy 260 Configuring a priority for RIPng 260 Configuring RIPng route redistribution 260 Tuning and optimizing the RIPng network 261 Configuring RIPng timers 261 viii

9 Configuring split horizon and poison reverse 261 Configuring zero field check on RIPng packets 262 Configuring the maximum number of equal cost routes for load balancing 262 Applying IPsec policies for RIPng 262 Displaying and maintaining RIPng 263 RIPng configuration example 264 Configure RIPng basic functions 264 Configuring RIPng route redistribution 266 Configuring RIPng IPsec policies 269 OSPFv3 configuration 272 Introduction to OSPFv3 272 OSPFv3 overview 272 OSPFv3 packets 272 OSPFv3 LSA types 273 Timers of OSPFv3 273 OSPFv3 supported features 274 Protocols and standards 274 Enabling OSPFv3 274 Prerequisites 274 Enabling OSPFv3 274 Configuring OSPFv3 area parameters 275 Prerequisites 275 Configuring an OSPFv3 stub area 275 Configuring an OSPFv3 virtual link 276 Configuring OSPFv3 network types 276 Prerequisites 276 Configuring the OSPFv3 network type for an interface 277 Configuring an NBMA or P2MP neighbor 277 Configuring OSPFv3 routing information control 277 Prerequisites 277 Configuring OSPFv3 route summarization 277 Configuring OSPFv3 inbound route filtering 278 Configuring an OSPFv3 cost for an interface 278 Configuring the maximum number of OSPFv3 load-balanced routes 279 Configuring a priority for OSPFv3 279 Configuring OSPFv3 route redistribution 279 Tuning and optimizing OSPFv3 networks 280 Prerequisites 280 Configuring OSPFv3 timers 280 Configuring a DR priority for an interface 281 Ignoring MTU check for DD packets 281 Disable interfaces from sending OSPFv3 packets 282 Enable the logging neighbor state hangs 282 Configuring OSPFv3 GR 282 Configuring GR Restarter 283 Configuring GR helper 283 Configuring BFD for OSPFv3 283 Applying IPsec policies for OSPFv3 284 Displaying and maintaining OSPFv3 285 OSPFv3 configuration examples 286 Configuring OSPFv3 areas 286 Configuring OSPFv3 DR election 290 Configuring OSPFv3 route redistribution 293 ix

10 Configuring OSPFv3 GR 296 Configuring BFD for OSPFv3 298 Configuring OSPFv3 IPsec policies 301 Troubleshooting OSPFv3 configuration 305 No OSPFv3 neighbor relationship established 305 Incorrect routing information 305 IPv6 IS-IS configuration 307 Introduction to IPv6 IS-IS 307 Configuring IPv6 IS-IS basic functions 307 Prerequisites 307 Procedure 307 Configuring IPv6 IS-IS routing information control 308 Prerequisites 308 Procedure 308 Displaying and maintaining IPv6 IS-IS 309 IPv6 IS-IS configuration examples 310 IPv6 IS-IS basic configuration example 310 IPv6 BGP configuration 313 IPv6 BGP overview 313 Configuring IPv6 BGP basic functions 313 Prerequisites 313 Specifying an IPv6 BGP peer 313 Injecting a local IPv6 route 314 Configuring a preferred value for routes from a peer/peer group 314 Specifying the source interface for establishing TCP connections 314 Allowing the establishment of a non-direct ebgp connection 315 Configuring a description for an IPv6 peer/peer group 315 Disabling session establishment to an IPv6 peer/peer group 316 Logging IPv6 peer/peer group state changes 316 Controlling route distribution and reception 316 Prerequisites 316 Configuring IPv6 BGP route redistribution 316 Configuring IPv6 BGP route summarization 317 Advertising a default route to an IPv6 peer/peer group 317 Configuring outbound route filtering 318 Configuring inbound route filtering 318 Configuring IPv6 BGP and IGP route synchronization 319 Configuring route dampening 319 Configuring IPv6 BGP route attributes 320 Prerequisites 320 Configuring IPv6 BGP preference and default LOCAL_PREF and NEXT_HOP attributes 320 Configuring the MED attribute 321 Configuring the AS_PATH attribute 321 Tuning and optimizing IPv6 BGP networks 322 Prerequisites 322 Configuring IPv6 BGP timers 322 Configuring IPv6 BGP soft reset 323 Enabling the IPv6 BGP ORF capability 324 Configuring the maximum number of load-balanced routes 325 Enabling MD5 authentication for TCP connections 325 Applying an IPsec policy to an IPv6 BGP peer or peer group 325 Configuring a large scale IPv6 BGP network 326 x

11 Prerequisites 326 Configuring IPv6 BGP peer group 327 Configuring IPv6 BGP community 328 Configuring an IPv6 BGP route reflector 328 Displaying and maintaining IPv6 BGP 329 Resetting IPv6 BGP connections 330 Clearing IPv6 BGP information 331 IPv6 BGP configuration examples 331 IPv6 BGP basic configuration 331 IPv6 BGP route reflector configuration 333 IPv6 BGP IPsec policy configuration 334 Configuring BFD for IPv6 BGP 339 Troubleshooting IPv6 BGP configuration 344 No IPv6 BGP peer relationship established 344 Routing policy configuration 345 Introduction to routing policy 345 Routing policy application 345 Routing policy application 345 Routing policy implementation 345 Filters 345 Defining filters 347 Prerequisites 347 Defining an IP-prefix list 347 Defining an AS path list 348 Defining a community list 348 Defining an extended community list 349 Configuring a routing policy 349 Prerequisites 349 Creating a routing policy 349 Defining if-match clauses 350 Defining apply clauses 351 Displaying and maintaining the routing policy 353 Routing policy configuration example 353 Applying a routing policy to IPv4 route redistribution 353 Applying a routing policy to IPv6 route redistribution 356 Applying a routing policy to filter received BGP routes 358 Troubleshooting routing policy configuration 360 IPv4 routing information filtering failure 360 IPv6 routing information filtering failure 361 Policy-based routing configuration 362 Introduction to PBR 362 PBR modes 362 Concepts 362 QoS Mode 363 Configuring PBR (using a PBR policy) 364 Defining a policy 364 Configuring local PBR 365 Configuring interface PBR 365 PBR and track 365 Configuring PBR (using a QoS policy) 366 Configuring a QoS policy 366 Applying the QoS policy 366 xi

12 Displaying and maintaining PBR configuration 367 PBR Configuration (Using a PBR policy) 367 PBR configuration (using a QoS policy) 368 PBR configuration examples 368 Configuring local PBR based on packet type 368 Configuring interface PBR based on packet type 370 IPv4 PBR configuration example (using a QoS policy)example 372 IPv6 PBR configuration example (using a QoS policy) 373 Support and other resources 375 Contacting HP 375 Subscription service 375 Related information 375 Documents 375 Websites 375 Conventions 376 Index 378 xii

13 Configuring IP routing The term router in this document refers to both routers and Layer 3 switches. The interfaces in routing refer to Layer 3 interfaces, including VLAN interfaces and Layer 3 Ethernet interfaces. Layer 3 Ethernet interfaces refer to Ethernet interfaces operating in route mode. For more information about the operating mode of the Ethernet interface, see Layer 2 LAN Switching Configuration Guide. Routers are responsible for forwarding data packets along networks. Upon receiving a packet, a router determines the optimal path based on the destination address and forwards the packet to the next router in the path. When the packet reaches the last router, the router forwards the packet to the intended destination host. Routing provides the path information that guides the forwarded packets. Routing table and FIB table The routing table plays a key role in route selection and the FIB table plays a key role in packet forwarding. Each router maintains a routing table and an FIB table. Routes in a routing table can be divided into the following 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 the physical interface to which a packet should travel, such as the next hop (the next router) or directly to its intended destination. Routing table Each router maintains a local routing table, and each routing protocol maintains a protocol routing table. Local routing table A local routing table stores the routes found by all protocols and delivers the optimal routes to the FIB table to guide packet forwarding. The optimal route selection is based on the routing protocol preferences and route metrics. On a router that supports MPLS L3VPN, each VPN instance maintains a local routing table. Protocol routing table 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 table, and then advertise those routes. Routing table contents A route entry includes the following key items: 1

14 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 up 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 a matching IP packet is to be forwarded. Next hop Specifies the IP address of the next-hop router on the path. If only the outbound interface is specified, its IP address will be the IP address of the next hop. Preference 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 preference (with the smallest metric). Routes can be divided into the following categories by destination: Subnet route The destination is a subnet. Host route The destination is a host. Based on whether the destination is directly connected to the 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, configure a default route. Packets not matching any specific entries in the routing table will be forwarded through the default route. In Figure 1, Router A is connected to three networks. Its routing table is shown under the network topology. Figure 1 Sample routing table Destination Network Nexthop Interface Vlan1 2

15 Vlan Vlan3 Routing protocol 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. Based on dynamic routing protocols, dynamic routing can detect network topology changes and recalculate the routes, making it suitable for large networks. However, dynamic routing is difficult to configure, imposes higher requirements on the system, and consumes more network resources. Dynamic routing protocol classification Operational scope Dynamic routing protocols can be classified based on the following standards: IGPs Work within an autonomous system, including RIP, OSPF, and IS-IS. EGPs Work between autonomous systems. BGP is the most popular. An autonomous system refers to a group of routers that share the same routing policy and work under the same administration. Routing algorithm D-V protocols RIP and BGP. BGP is also considered a path-vector protocol Link-state protocols OSPF and IS-IS These two routing algorithms discover and calculate routes differently. Destination address type IP protocol 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 IP Multicast Configuration Guide. IPv4 routing protocols RIP, OSPF, BGP, and IS-IS IPv6 routing protocols RIPng, OSPFv3, IPv6 BGP, and IPv6 IS-IS Routing protocols and routing preference 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 3

16 routes) is assigned a preference. The routing protocol with the highest preference is preferred for finding the best route. See Table 1. The smaller the preference value, the higher the preference. The preference for a direct route is always 0, which cannot be changed. Any other type of routes can have their priorities manually configured. Each static route can be configured with a different preference. IPv4 and IPv6 routes have their own respective routing tables. Table 1 Routing protocols and default priorities for routes Routing approach Preference DIRECT 0 OSPF 10 IS-IS 15 STATIC 60 RIP 100 OSPF ASE 150 OSPF NSSA 150 IBGP 255 EBGP 255 UNKNOWN 256 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 Different routing protocols use different routing algorithms to calculate and find routes. In a large network with multiple routing protocols, the routing protocols must share routing information. Each routing protocol has its own route redistribution mechanism. Configuring a router ID 1. Enter system view. system-view 2. Configure a router ID. router id router-id Not configured by default. 4

17 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: a. Select the router ID configured with the router id command. b. Select the highest loopback interface IP address as the router ID. c. If no loopback interface IP address is available, the highest physical interface IP address is selected as the router ID (regardless of the interface state). d. 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 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. e. A VPN instance selects a router ID among the IP addresses of interfaces belonging to it according to the preceding procedure. f. When a master/backup switchover occurs, the backup device selects a router ID according to the preceding procedure. g. 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 ip routing-table [ vpn-instance vpn-instance-name ] [ verbose ] [ { begin exclude include } regularexpression ] display ip routing-table ip-address [ mask-length mask ] [ longer-match ] [ verbose ] [ { begin exclude include } regular-expression ] display ip routing-table ip-address1 { mask-length mask } ip-address2 { mask-length mask } [ verbose ] [ { begin exclude include } regularexpression ] display ip routing-table acl acl-number [ verbose ] [ { begin exclude include } regular-expression ] display ip routing-table ip-prefix ipprefix-name [ verbose ] [ { begin exclude include } regular-expression ] display ip routing-table protocol protocol [ inactive verbose ] [ { begin exclude include } regularexpression ] [ { begin exclude include } regular-expression ] [ { begin exclude include } regular-expression ] Available in any view. Available in any view. Available in any view. Available in any view. Available in any view. Available in any view. 5

18 Display statistics about the network routing table or a VPN routing table. Display the router ID. Clear statistics for the routing table or a VPN routing table. Display brief IPv6 routing table information. 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 statistics. Display IPv6 routing information for an IPv6 address range. display ip routing-table [ vpn-instance vpn-instance-name ] statistics [ { begin exclude include } regular-expression ] display router id [ { begin exclude include } regular-expression ] reset ip routing-table statistics protocol [ vpn-instance vpn-instance-name ] { protocol all } display ipv6 routing-table [ vpninstance vpn-instance-name ] [ { begin exclude include } regular-expression ] display ipv6 routing-table [ vpninstance vpn-instance-name ] verbose [ { begin exclude include } regularexpression ] display ipv6 routing-table [ vpninstance vpn-instance-name ] ipv6- address prefix-length [ longer-match ] [ verbose ] [ { begin exclude include } regular-expression ] display ipv6 routing-table [ vpninstance vpn-instance-name ] acl acl6- number [ verbose ] [ { begin exclude include } regular-expression ] display ipv6 routing-table [ vpninstance vpn-instance-name ] ipv6-prefix ipv6-prefix-name [ verbose ] [ { begin exclude include } regular-expression ] display ipv6 routing-table [ vpninstance vpn-instance-name ] protocol protocol [ inactive verbose ] [ { begin exclude include } regularexpression ] display ipv6 routing-table [ vpninstance vpn-instance-name ] statistics [ { begin exclude include } regularexpression ] display ipv6 routing-table [ vpninstance vpn-instance-name ] ipv6- address1 prefix-length1 ipv6-address2 prefix-length2 [ verbose ] [ { begin exclude include } regular-expression ] Available in any view. Available in any view. Available in user 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. Available in any view. Available in any view. 6

19 Clear specified IPv6 routing table statistics. reset ipv6 routing-table statistics protocol [ vpn-instance vpn-instancename ] { protocol all } Available in user view. 7

20 Configuring static routing A static route is manually configured. If a network topology is simple, you only need to configure enough static routes for the network to function. 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 become unreachable and the network breaks. The network administrator has to modify the static routes manually. Default route Without a default route, a packet that does not match any routing entries is discarded and an ICMP destination-unreachable packet is sent to the source. A default route is used to forward packets that do not match any routing entries. It can be configured in either of the following ways: The network administrator can configure a default route with both destination and mask being The router forwards any packet whose destination address fails to match any entry in the routing table to the next hop of the default static route. 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 Before configuring a static route, understand the following concepts: Destination address and mask In the ip route-static command, an IPv4 address is in dotted decimal format and a mask can be either in dotted decimal format or in the form of mask length (the number of consecutive 1s in the mask). Output interface and next hop address When configuring a static route, specify either the output interface or the next hop address, or both depending on the specific occasion. The next hop address cannot be a local interface IP address or the route configuration does 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: If the output interface is a Null 0 interface, there is no need to configure the next hop address. If you specify a broadcast interface (such as VLAN interface) as the output interface, you must specify the corresponding next hop for the output interface. 8

21 Other attributes You can configure different priorities for different static routes so that route management policies can be more flexible. For example, specifying the same priority for different routes to the same destination enables load sharing, but specifying different priorities for these routes enables route backup. Configuring a static route Prerequisites Procedure Before configuring a static route, complete 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 When configuring a static route, the static route does not take effect if you specify the next hop address first and then configure it as the IP address of a local interface, such as VLAN interface. If you do not specify the preference when configuring a static route, the default preference will be used. Reconfiguring the default preference applies only to newly created static routes. 1. Enter system view. system-view 2. Configure a static route. 3. Configure the default preference for static routes. ip route-static dest-address { mask mask-length } { nexthop-address [ track track-entry-number ] interface-type interface-number [ next-hop-address ] vpn-instance d- vpn-instance-name next-hop-address [ track track-entrynumber ] } [ preference preference-value ] [ tag tag-value ] [ permanent ] [ description description-text ] ip route-static vpn-instance s-vpn-instance-name&<1-6> dest-address { mask mask-length } { next-hop-address [ public ] [ track track-entry-number ] interface-type interface-number [ next-hop-address ] vpn-instance d- vpn-instance-name next-hop-address [ track track-entrynumber ] } [ preference preference-value ] [ tag tag-value ] [ permanent ] [ description description-text ] ip route-static default-preference default-preference-value Required. By default, preference for static routes is 60, tag is 0, and no description information is configured. Do not specify the permanent and track keywords simultaneously. If the outgoing interface is down, the permanent static route is still active. 60 by default. 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 the default route. 9

22 For detailed information about track, see High Availability Configuration Guide. Configuring BFD for static routes 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 and MPLS. For more information about BFD, see High Availability Configuration Guide. 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. 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 static route destined to the peer. 1. Enter system view. system-view 2. Enable BFD control packet mode for static routes. ip route-static dest-address { mask mask-length } interfacetype 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> destaddress { mask mask-length } interface-type interface-number next-hop-address bfd control-packet [ preference preferencevalue ] [ 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 them back to test the link. If route flaps occur, enabling BFD could worsen them. 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 the outbound interface and next hop IP address for the route. BFD cannot be used for a static route with the outbound interface having the spoofing attribute. BFD can be used for static routes with direct nexthops rather than non-direct nexthops. 1. Enter system view. system-view 2. Configure the source address of echo packets. bfd echo-source-ip ip-address Required. Not configured by default. 10

23 3. Enable BFD echo packet mode for static routes. ip route-static dest-address { mask mask-length } interfacetype 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> destaddress { mask mask-length } interface-type interface-number next-hop-address bfd echo-packet [ preference preferencevalue ] [ tag tag-value ] [ description description-text ] Use either command. 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 fails, the packets on the path may be discarded, or a routing loop may occur. Then, the traffic will be interrupted. To avoid such issues, you can enable static FRR. Figure 2 Network diagram for static route FRR Prerequisites Procedure As shown in Figure 2, FRR can designate a backup next hop by using a routing policy for routes matching the specified criteria when a network failure is detected so that packets can be directed to the backup next hop for forwarding. This prevents traffic interruption. Configuring static route FRR needs to reference a routing policy. You can specify a backup next hop in a routing policy by using the apply fast-reroute backup-interface command. For more information about the command and routing policy configurations, see Routing policy configuration. 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 route) at the same time. 1. Enter system view. system-view 2. Configure the source address of echo packets. bfd echo-source-ip ip-address Required. Not configured by default. 11

24 3. Configure static route FRR. ip route-static [ vpn-instance vpninstance-name ] fast-reroute routepolicy route-policy-name Required. Not configured by default. Displaying and maintaining static routes The VPN instance support in delete [ vpn-instance vpn-instance-name ] static-routes all depends on the device model. Display information of static routes Delete all the static routes display ip routing-table protocol static [ inactive verbose ] [ { begin exclude include } regularexpression ] delete [ vpn-instance vpn-instance-name ] staticroutes all Available in any view Available in system view For more information about display ip routing-table protocol static [ inactive verbose ] [ { begin exclude include } regular-expression ], see Layer 3 - IP Routing Command Reference. Static route configuration examples Basic static route configuration example Network requirements The IP addresses and masks of the switches and hosts are shown in Figure 3. Static routes are required for interconnection between any two hosts. Figure 3 Network diagram for static route configuration 12

25 Procedure 1. Configure IP addresses for interfaces (omitted) 2. Configure static routes # Configure a default route on Switch A. <SwitchA> system-view [SwitchA] ip route-static # Configure two static routes on Switch B. <SwitchB> system-view [SwitchB] ip route-static [SwitchB] ip route-static # Configure a default route on Switch C <SwitchC> system-view [SwitchC] ip route-static Configure the hosts. The default gateways for hosts A, B and C are , and , respectively. The configuration procedure is omitted. 4. Display the configuration. # Display the IP routing table of Switch A. [SwitchA] display ip routing-table Routing Tables: Public Destinations : 7 Routes : 7 Destination/Mask Proto Pre Cost NextHop Interface /0 Static Vlan /24 Direct Vlan /32 Direct InLoop /30 Direct Vlan /32 Direct InLoop /8 Direct InLoop /32 Direct InLoop0 # Display the IP routing table of Switch B. [SwitchB] display ip routing-table Routing Tables: Public Destinations : 10 Routes : 10 Destination/Mask Proto Pre Cost NextHop Interface /24 Static Vlan /24 Static Vlan /30 Direct Vlan /32 Direct InLoop /30 Direct Vlan600 13

26 /32 Direct InLoop /8 Direct InLoop /32 Direct InLoop /24 Direct Vlan /32 Direct InLoop0 # Use the ping command on Host B to check the reachability of Host A, assuming Windows XP runs on the two hosts. C:\Documents and Settings\Administrator>ping Pinging with 32 bytes of data: Reply from : bytes=32 time=1ms TTL=255 Reply from : bytes=32 time=1ms TTL=255 Reply from : bytes=32 time=1ms TTL=255 Reply from : bytes=32 time=1ms TTL=255 Ping statistics for : Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 1ms, Maximum = 1ms, Average = 1ms # Use the tracert command on Host B to check the reachability of Host A. [HostB] tracert Tracing route to over a maximum of 30 hops 1 <1 ms <1 ms <1 ms <1 ms <1 ms <1 ms ms <1 ms <1 ms Trace complete. Static route FRR configuration example Network requirements Switch S, Switch A, and Switch D are interconnected through static routes, as illustrated in Figure 4. Configure static route FRR so that when the link between Switch S and Switch D fails, traffic can be switched to Link B immediately. 14

27 Figure 4 Network diagram for static route FRR configuration Procedure 1. Configure IP addresses for the interfaces on each switch and configure static routes Follow Figure 4 to configure the IP address and subnet mask of each interface on the switches. The configuration procedure is omitted. Configure static routes on Switch S, Switch A, and Switch D so that Switch S can reach Loopback 0 on Switch D, and Switch D can reach Loopback 0 on Switch S. # Configure a static route on Switch S. <SwitchS> system-view [SwitchS] ip route-static vlan-interface # Configure a static route on Switch D. <SwitchD> system-view [SwitchD] ip route-static vlan-interface # Configure a static route on Switch A. <SwitchA> system-view [SwitchA] ip route-static vlan-interface [SwitchA] ip route-static vlan-interface Configure static route FRR. # Configure Switch S. [SwitchS] bfd echo-source-ip [SwitchS] ip ip-prefix abc index 10 permit [SwitchS] route-policy frr permit node 10 [SwitchS-route-policy] if-match ip-prefix abc [SwitchS-route-policy] apply fast-reroute backup-interface vlan-interface 100 backupnexthop [SwitchS-route-policy] quit [SwitchS] ip route-static fast-reroute route-policy frr # Configure Switch D. [SwitchD] bfd echo-source-ip [SwitchD] ip ip-prefix abc index 10 permit [SwitchD] route-policy frr permit node 10 [SwitchD-route-policy] if-match ip-prefix abc [SwitchD-route-policy] apply fast-reroute backup-interface vlan-interface 101 backupnexthop [SwitchD-route-policy] quit 15

28 [SwitchD] ip route-static fast-reroute route-policy frr 3. Verify the configuration # Display route /32 on Switch S to view the backup next hop information. [SwitchS] display ip routing-table verbose Routing Table : Public Summary Count : 1 Destination: /32 Protocol: Static Process ID: 0 Preference: 60 Cost: 0 NextHop: Interface: vlan 200 BkNextHop: BkInterface: vlan 100 RelyNextHop: Neighbor : Tunnel ID: 0x0 Label: NULL State: Active Adv Age: 00h01m27s Tag: 0 # Display route /32 on Switch D to view the backup next hop information. [SwitchD] display ip routing-table verbose Routing Table : Public Summary Count : 1 Destination: /32 Protocol: Static Process ID: 0 Preference: 60 Cost: 0 NextHop: Interface: vlan 200 BkNextHop: BkInterface: vlan 101 RelyNextHop: Neighbor : Tunnel ID: 0x0 Label: NULL State: Active Adv Age: 00h01m27s Tag: 0 BFD for static routes configuration example Network requirements As shown in Figure 5: Configure a static route to subnet /24 on Switch A and configure a static route to subnet /24 on Switch B. Both routes have BFD enabled. When the link over (which Switch A communicates with Switch B through the Layer 2) switch fails, BFD can detect the failure immediately. Switch A and Switch B then communicate through Switch C. 16

29 Figure 5 Network diagram for configuring BFD for static routes Procedure Device Interface IP address Device Interface IP address Switch A Vlan-int /24 Switch B Vlan-int /24 Vlan-int /24 Vlan-int /24 Switch C Vlan-int /24 Vlan-int /24 1. Configure IP addresses for the interfaces (omitted). 2. Configure BFD # Configure static routes on Switch A and enable BFD control packet mode for the static route through the Layer 2 switch. <SwitchA> system-view [SwitchA] interface vlan-interface10 [SwitchA-vlan-interface10] bfd min-transmit-interval 500 [SwitchA-vlan-interface10] bfd min-receive-interval 500 [SwitchA-vlan-interface10] bfd detect-multiplier 9 [SwitchA-vlan-interface10] quit [SwitchA] ip route-static vlan-interface bfd control-packet [SwitchA] ip route-static vlan-interface preference 65 [SwitchA] quit # Configure static routes on Switch B and enable BFD control packet mode for the static route through the Layer 2 switch. <SwitchB> system-view [SwitchB] interface vlan-interface10 [SwitchB-vlan-interface10] bfd min-transmit-interval 500 [SwitchB-vlan-interface10] bfd min-receive-interval 500 [SwitchB-vlan-interface10] bfd detect-multiplier 9 [SwitchB-vlan-interface10]] quit [SwitchB] ip route-static vlan-interface bfd control-packet [SwitchB] ip route-static vlan-interface preference 65 [SwitchB] quit 3. Verify the configuration. The following operations are performed on Switch A. The operations on Switch B are similar. 17

30 <SwitchA> display bfd session Total Session Num: 1 Init Mode: Active Session Working Under Ctrl Mode: LD/RD SourceAddr DestAddr State Holdtime Interface 4/ Up 2000ms Vlan10 # Display the static route information of Switch A. <SwitchA> display ip routing-table protocol static Public Routing Table : Static Summary Count : 2 Static Routing table Status : < Active> Summary Count : 1 Destination/Mask Proto Pre Cost NextHop Interface /24 Static Vlan10 Direct Routing table Status : <Inactive> Summary Count : 1 Destination/Mask Proto Pre Cost NextHop Interface /24 Static Vlan11 # Enable BFD debugging on Switch A. <SwitchA> debugging bfd event <SwitchA> debugging bfd scm <SwitchA> terminal debugging # When the link between Switch A and Layer 2 switch fails, Switch A can detect the failure. %Jul 27 10:18:18: SwitchA BFD/4/LOG:Sess[ / , Vlan10,Ctrl], Sta: UP->DOWN, Diag: 1 *Jul 27 10:18:18: SwitchA BFD/7/EVENT:Send sess-down Msg, [Src: ,Dst: , Vlan10,Ctrl], instance:0, protocol:static *Jul 27 10:18:19: SwitchA BFD/7/EVENT:Receive Delete-sess, [Src: ,Dst: , Vlan10,Ctrl], Direct, Instance:0x0, Proto:STATIC *Jul 27 10:18:19: SwitchA BFD/7/EVENT:Notify driver to stop receiving bf # Use display ip routing-table protocol static to display the static route information on Switch A. <SwitchA> display ip routing-table protocol static Public Routing Table : Static Summary Count : 2 Static Routing table Status : < Active> Summary Count : 1 Destination/Mask Proto Pre Cost NextHop Interface /24 Static Vlan11 Static Routing table Status : < Inactive> Summary Count : 1 Destination/Mask Proto Pre Cost NextHop Interface /24 Static Vlan10 18