Routing policies control routing paths by filtering and modifying routing information. Routing policies can filter advertised, received, and redistributed routes, and modify attributes for specific routes.

Prerequisites

This document is not restricted to specific software or hardware versions.

The configuration examples in this document were created and verified in a lab environment, and all the devices were started with the factory default configuration. When you are working on a live network, make sure you understand the potential impact of every command on your network.

This document assumes that you have basic knowledge of routing polices.

Example: Configuring routing polices

Network configuration

As shown in Figure 1, a company's two departments reside in different ASs. Device A and Device F are the egress devices of the two departments. OSPF is the IGP protocol in AS 100.

· Configure BGP to make the two departments reachable to each other.

· Configure routing polices to specify the link Device B<—>Device C<—>Device D as the primary link to forward traffic between Device A and Device F. When the primary link fails, the link Device B<—>Device E<—>Device D forwards the traffic.

Figure 1 Network diagram

Table 1 Interface and IP address assignment

Device	Interface	IP address	Device	Interface	IP address
Device A	Vlan-int100	120.1.0.1/24	Device D	Vlan-int20	10.2.0.101/24
Device B	Vlan-int10	10.1.0.101/24		Vlan-int40	13.1.1.101/24
	Vlan-int30	192.168.0.101/24		Vlan-int100	120.2.0.2/24
	Vlan-int100	120.1.0.2/24	Device E	Vlan-int30	192.168.0.102/24
Device C	Vlan-int10	10.1.0.102/24		Vlan-int40	13.1.1.102/24
	Vlan-int20	10.2.0.102/24	Device F	Vlan-int100	120.2.0.1/24

Analysis

To meet the network requirements, you must perform the following tasks:

· Configure the link Device B<—>Device C<—>Device D as the primary link:

¡ On Device B, set the local preference to 200 for the path Device D—>Device C—>Device B. The path Device D—>Device E—>Device B uses the default local preference 100.

¡ On Device D, set the local preference to 200 for the path Device B—>Device C—>Device D. The path Device B—>Device E—>Device D uses the default local preference 100.

· Set a higher preference for IBGP routes to ensure that IBGP routes rather than OSPF external routes are used in AS 100.

Applicable hardware and software versions

The following matrix shows the hardware and software versions to which this configuration example is applicable:

Hardware	Software version
S6520XE-HI switch series	Supported in Release 11xx
S5560X-EI switch series	Supported in Release 111x
S5500V2-EI switch series	Supported in Release 111x
MS4520V2-30F switch	Supported in Release 111x
S5560S-EI switch series S5560S-SI switch series	Supported in Release 612x
S5130S-HI switch series S5130S-EI switch series S3100V3-EI switch series S5110V2 switch series	Not supported
S5130S-SI switch series S5130S-LI switch series S5120V2-SI switch series S5120V2-LI switch series S3100V3-SI switch series	Not supported
S5110V2-SI switch series S5000V3-EI switch series S5000E-X switch series	Not supported
WAS6000 switch series	Not supported
E128C switch E152C switch E500C switch series E500D switch series	Not supported
MS4520V2 switch series (except the MS4520V2-30F switch)	Supported in Release 612x
MS4320V2 switch series MS4300V2 switch series MS4320 switch series MS4200 switch series	Not supported
WS5850-WiNet switch series	Supported in Release 612x
WS5820-WiNet switch series WS5810-WiNet switch series	Not supported

Procedures

Configuring IP addresses

# Configure an IP address for VLAN-interface 100.

<DeviceA> system-view

[DeviceA] interface vlan-interface100

[DeviceA-Vlan-interface100] ip address 120.1.0.1 24

[DeviceA-Vlan-interface100] quit

# Configure IP addresses for other interfaces, as shown in Figure 1. (Details not shown.)

Configuring OSPF

Configuring Device B

<DeviceB> system-view

[DeviceB] ospf

[DeviceB-ospf-1] import-route direct

[DeviceB-ospf-1] area 0

[DeviceB-ospf-1-area-0.0.0.0] network 10.1.0.0 0.0.0.255

[DeviceB-ospf-1-area-0.0.0.0] network 192.168.0.0 0.0.0.255

[DeviceB-ospf-1-area-0.0.0.0] quit

[DeviceB-ospf-1] quit

Configuring Device C

<DeviceC> system-view

[DeviceC] ospf

[DeviceC-ospf-1] area 0

[DeviceC-ospf-1-area-0.0.0.0] network 10.1.0.0 0.0.0.255

[DeviceC-ospf-1-area-0.0.0.0] network 10.2.0.0 0.0.0.255

[DeviceC-ospf-1-area-0.0.0.0] quit

[DeviceC-ospf-1] quit

Configuring Device D

<DeviceD> system-view

[DeviceD] ospf

[DeviceD-ospf-1] import-route direct

[DeviceD-ospf-1] area 0

[DeviceD-ospf-1-area-0.0.0.0] network 10.2.0.0 0.0.0.255

[DeviceD-ospf-1-area-0.0.0.0] network 13.1.1.0 0.0.0.255

[DeviceD-ospf-1-area-0.0.0.0] quit

[DeviceD-ospf-1] quit

Configuring Device E

<DeviceE> system-view

[DeviceE] ospf

[DeviceE-ospf-1] area 0

[DeviceE-ospf-1-area-0.0.0.0] network 13.1.1.0 0.0.0.255

[DeviceE-ospf-1-area-0.0.0.0] network 192.168.0.0 0.0.0.255

[DeviceE-ospf-1-area-0.0.0.0] quit

[DeviceE-ospf-1] quit

Configuring BGP

Configuring Device A

# Enable BGP, set the local AS number to 200, and configure the router ID for BGP as 1.1.1.1.

<DeviceA> system-view

[DeviceA] bgp 200

[DeviceA-bgp-default] router-id 1.1.1.1

# Establish an EBGP connection with Device B.

[DeviceA-bgp-default] peer 120.1.0.2 as-number 100

# Create the BGP IPv4 unicast address family and enter its view.

[DeviceA-bgp-default] address-family ipv4 unicast

# Enable Device A to exchange IPv4 unicast routing information with peer 120.1.0.2.

[DeviceA-bgp-default-ipv4] peer 120.1.0.2 enable

# Inject network 120.1.0.0/24 to the BGP routing table.

[DeviceA-bgp-default-ipv4] network 120.1.0.0 255.255.255.0

[DeviceA-bgp-default-ipv4] quit

Configuring Device B

# Enable BGP, set the local AS number to 100, and configure the router ID for BGP as 2.2.2.2.

<DeviceB> system-view

[DeviceB] bgp 100

[DeviceB-bgp-default] router-id 2.2.2.2

# Establish an EBGP connection with Device A.

[DeviceB-bgp-default] peer 120.1.0.1 as-number 200

# Establish IBGP connections with Device D.

[DeviceB-bgp-default] peer 10.2.0.101 as-number 100

[DeviceB-bgp-default] peer 13.1.1.101 as-number 100

# Create the BGP IPv4 unicast address family and enter its view.

[DeviceB-bgp-default] address-family ipv4 unicast

# Enable Device B to exchange IPv4 unicast routing information with peer 10.2.0.101.

[DeviceB-bgp-default-ipv4] peer 10.2.0.101 enable

# Specify Device B as the next hop for routes sent to peer 10.2.0.101.

[DeviceB-bgp-default-ipv4] peer 10.2.0.101 next-hop-local

# Enable Device B to exchange IPv4 unicast routing information with peer 13.1.1.101.

[DeviceB-bgp-default-ipv4] peer 13.1.1.101 enable

# Specify Device B as the next hop for routes sent to peer 13.1.1.101.

[DeviceB-bgp-default-ipv4] peer 13.1.1.101 next-hop-local

# Enable Device B to exchange IPv4 unicast routing information with peer 120.1.0.1.

[DeviceB-bgp-default-ipv4] peer 120.1.0.1 enable

[DeviceB-bgp-default-ipv4] quit

Configuring Device D

# Enable BGP, set the local AS number to 100, and configure the router ID for BGP as 4.4.4.4.

<DeviceD> system-view

[DeviceD] bgp 100

[DeviceD-bgp-default] router-id 4.4.4.4

# Establish IBGP connections with Device B.

[DeviceD-bgp-default] peer 10.1.0.101 as-number 100

[DeviceD-bgp-default] peer 192.168.0.101 as-number 100

# Establish an EBGP connection with Device F.

[DeviceD-bgp-default] peer 120.2.0.1 as-number 300

# Create the BGP IPv4 unicast address family and enter its view.

[DeviceD-bgp-default] address-family ipv4 unicast

# Enable Device D to exchange IPv4 unicast routing information with peer 10.1.0.101.

[DeviceD-bgp-default-ipv4] peer 10.1.0.101 enable

# Specify Device D as the next hop for routes sent to peer 10.1.0.101.

[DeviceD-bgp-default-ipv4] peer 10.1.0.101 next-hop-local

# Enable Device D to exchange IPv4 unicast routing information with peer 192.168.0.101.

[DeviceD-bgp-default-ipv4] peer 192.168.0.101 enable

# Specify Device D as the next hop for routes sent to peer 192.168.0.101.

[DeviceD-bgp-default-ipv4] peer 192.168.0.101 next-hop-local

# Enable Device D to exchange IPv4 unicast routing information with peer 120.2.0.1.

[DeviceD-bgp-default-ipv4] peer 120.2.0.1 enable

[DeviceD-bgp-default-ipv4] quit

Configuring Device F

# Enable BGP, set the local AS number to 300, and configure the router ID for BGP as 6.6.6.6.

<DeviceF> system-view

[DeviceF] bgp 300

[DeviceF-bgp-default] router-id 6.6.6.6

# Establish an EBGP connection with Device D.

[DeviceF-bgp-default] peer 120.2.0.2 as-number 100

# Create the BGP IPv4 unicast address family and enter its view.

[DeviceF-bgp-default] address-family ipv4 unicast

# Inject network 120.2.0.0/24 to the BGP routing table.

[DeviceF-bgp-default-ipv4] network 120.2.0.0 255.255.255.0

# Enable Device F to exchange IPv4 unicast routing information with peer 120.2.0.2.

[DeviceF-bgp-default-ipv4] peer 120.2.0.2 enable

[DeviceF-bgp-default-ipv4] quit

# Verify BGP peer information on Device B.

[DeviceB] display bgp peer ipv4

BGP local router ID: 2.2.2.2

Local AS number: 100

Total number of peers: 3 Peers in established state: 3

* - Dynamically created peer

Peer AS MsgRcvd MsgSent OutQ PrefRcv Up/Down State

10.2.0.101 100 6 4 0 1 00:00:56 Established

13.1.1.101 100 6 5 0 1 00:00:56 Established

120.1.0.1 200 6 5 0 1 00:00:56 Established

The output shows that Device B has established two IBGP connections with Device D, and an EBGP connection with Device A. The connections are all in Established state.

# Test the network connectivity between Device A and Device F.

[DeviceA] ping 120.2.0.1

Ping 120.2.0.1 (120.2.0.1): 56 data bytes, press CTRL_C to break

56 bytes from 120.2.0.1: icmp_seq=0 ttl=252 time=1.189 ms

56 bytes from 120.2.0.1: icmp_seq=1 ttl=252 time=1.095 ms

56 bytes from 120.2.0.1: icmp_seq=2 ttl=252 time=1.086 ms

56 bytes from 120.2.0.1: icmp_seq=3 ttl=252 time=1.097 ms

56 bytes from 120.2.0.1: icmp_seq=4 ttl=252 time=1.089 ms

--- Ping statistics for 120.2.0.1 ---

5 packet(s) transmitted, 5 packet(s) received, 0.0% packet loss

round-trip min/avg/max/std-dev = 1.086/1.111/1.189/0.039 ms

The output shows that Device A and Device F can reach each other.

Configuring routing polices

Configuring Device B

# Configure ACL 2000 to permit route 120.1.0.0/24.

[DeviceB] acl basic 2000

[DeviceB-acl-ipv4-basic-2000] rule permit source 120.1.0.0 0.0.0.255

[DeviceB-acl-ipv4-basic-2000] quit

# Configure routing policy local-pre to set the local preference to 200 for route 120.1.0.0/24.

[DeviceB] route-policy local-pre permit node 10

[DeviceB-route-policy-local-pre-10] if-match ip address acl 2000

[DeviceB-route-policy-local-pre-10] apply local-preference 200

[DeviceB-route-policy-local-pre-10] quit

# Apply routing policy local-pre to routes outgoing to peer 10.2.0.101.

[DeviceB] bgp 100

[DeviceB-bgp-default] address-family ipv4 unicast

[DeviceB-bgp-default-ipv4] peer 10.2.0.101 route-policy local-pre export

# Set the preference for IBGP routes to 100 (higher than the default preference of OSPF external routes 150).

[DeviceB-bgp-default-ipv4] preference 255 100 130

[DeviceB-bgp-default-ipv4] quit

Configuring Device D

# Configure ACL 2000 to permit route 120.2.0.0/24.

[DeviceD] acl basic 2000

[DeviceD-acl-ipv4-basic-2000] rule permit source 120.2.0.0 0.0.0.255

[DeviceD-acl-ipv4-basic-2000] quit

# Configure routing policy local-pre to set the local preference to 200 for route 120.2.0.0/24.

[DeviceD] route-policy local-pre permit node 10

[DeviceD-route-policy-local-pre-10] if-match ip address acl 2000

[DeviceD-route-policy-local-pre-10] apply local-preference 200

[DeviceD-route-policy-local-pre-10] quit

# Apply routing policy local-pre to routes outgoing to peer 10.1.0.101.

[DeviceD] bgp 100

[DeviceD-bgp-default] address-family ipv4 unicast

[DeviceD-bgp-default-ipv4] peer 10.1.0.101 route-policy local-pre export

# Set the preference for IBGP routes to 100 (higher than the default preference of OSPF external routes 150).

[DeviceD-bgp-default-ipv4] preference 255 100 130

[DeviceD-bgp-default-ipv4] quit

Verifying the configuration

# On Device B, display the BGP routing table.

[DeviceB] display bgp routing-table ipv4

Total number of routes: 3

BGP local router ID is 2.2.2.2

Status codes: * - valid, > - best, d - dampened, h - history

s - suppressed, S - stale, i - internal, e – external

a - additional-path

Origin: i - IGP, e - EGP, ? - incomplete

Network NextHop MED LocPrf PrefVal Path/Ogn

* >e 120.1.0.0/24 120.1.0.1 0 0 200i

* >i 120.2.0.0/24 10.2.0.101 0 200 0 300i

* i 13.1.1.101 0 100 0 300i

The output shows that Device B has two routes to 120.2.0.0/24 with local preferences 100 and 200.

# Trace the path that traffic traverses from Device A to Device F.

[DeviceA] tracert 120.2.0.1

traceroute to 120.2.0.1 (120.2.0.1), 30 hops at most, 52 bytes each packet, press CTRL_C to break

1 120.1.0.2 (120.1.0.2) 2.208 ms 1.119 ms 1.085 ms

2 10.1.0.102 (10.1.0.102) 1.083 ms 1.100 ms 1.085 ms

3 10.2.0.101 (10.2.0.101) 2.364 ms 1.099 ms 1.086 ms

4 120.2.0.1 (120.2.0.1) 3.825 ms 3.693 ms 4.008 ms

The output shows that traffic is forwarded along the path Device A—>Device B—>Device C—>Device D—>Device F.

# When the primary link fails, display the BGP routing table on Device B.

[DeviceB] display bgp routing-table ipv4

Total number of routes: 2

BGP local router ID is 2.2.2.2

Status codes: * - valid, > - best, d - dampened, h - history

s - suppressed, S - stale, i - internal, e – external

a - additional-path

Origin: i - IGP, e - EGP, ? - incomplete

Network NextHop MED LocPrf PrefVal Path/Ogn

* >e 120.1.0.0/24 120.1.0.1 0 0 200i

* >i 120.2.0.0/24 13.1.1.101 0 100 0 300i

The output shows that Device B has one route to 120.2.0.0/24.

# Trace the path that traffic traverses from Device A to Device F.

[DeviceA] tracert 120.2.0.1

traceroute to 120.2.0.1 (120.2.0.1), 30 hops at most, 52 bytes each packet, press CTRL_C to break

1 120.1.0.2 (120.1.0.2) 2.308 ms 1.127 ms 1.091 ms

2 192.168.0.102 (192.168.0.102) 1.086 ms 1.102 ms 1.096 ms

3 13.1.1.101 (13.1.1.101) 2.451 ms 2.087 ms 1.092 ms

4 120.2.0.1 (120.2.0.1) 3.533 ms 3.818 ms 4.002 ms

The output shows that traffic is forwarded along the path Device A—>Device B—>Device E—>Device D—>Device F.

Configuration files

· Device A:

vlan 100

interface Vlan-interface100

ip address 120.1.0.1 255.255.255.0

bgp 200

router-id 1.1.1.1

peer 120.1.0.2 as-number 100

address-family ipv4 unicast

network 120.1.0.0 255.255.255.0

peer 120.1.0.2 enable

· Device B:

ospf 1

import-route direct

area 0.0.0.0

network 10.1.0.0 0.0.0.255

network 192.168.0.0 0.0.0.255

vlan 10

vlan 30

vlan 100

interface Vlan-interface10

ip address 10.1.0.101 255.255.255.0

interface Vlan-interface30

ip address 192.168.0.101 255.255.255.0

interface Vlan-interface100

ip address 120.1.0.2 255.255.255.0

bgp 100

router-id 2.2.2.2

peer 10.2.0.101 as-number 100

peer 13.1.1.101 as-number 100

peer 120.1.0.1 as-number 200

address-family ipv4 unicast

preference 255 100 130

peer 10.2.0.101 enable

peer 10.2.0.101 next-hop-local

peer 10.2.0.101 route-policy local-pre export

peer 13.1.1.101 enable

peer 13.1.1.101 next-hop-local

peer 120.1.0.1 enable

route-policy local-pre permit node 10

if-match ip address acl 2000

apply local-preference 200

acl number 2000

rule 0 permit source 120.1.0.0 0.0.0.255

· Device C:

ospf 1

area 0.0.0.0

network 10.1.0.0 0.0.0.255

network 10.2.0.0 0.0.0.255

vlan 10

vlan 20

interface Vlan-interface10

ip address 10.1.0.102 255.255.255.0

interface Vlan-interface20

ip address 10.2.0.102 255.255.255.0

· Device D:

ospf 1

import-route direct

area 0.0.0.0

network 10.2.0.0 0.0.0.255

network 13.1.1.0 0.0.0.255

vlan 20

vlan 40

vlan 100

interface Vlan-interface20

ip address 10.2.0.101 255.255.255.0

interface Vlan-interface40

ip address 13.1.1.101 255.255.255.0

interface Vlan-interface100

ip address 120.2.0.2 255.255.255.0

bgp 100

router-id 4.4.4.4

peer 10.1.0.101 as-number 100

peer 120.2.0.1 as-number 300

peer 192.168.0.101 as-number 100

address-family ipv4 unicast

preference 255 100 130

peer 10.1.0.101 enable

peer 10.1.0.101 next-hop-local

peer 10.1.0.101 route-policy local-pre export

peer 192.168.0.101 enable

peer 192.168.0.101 next-hop-local

peer 120.2.0.1 enable

route-policy local-pre permit node 10

if-match ip address acl 2000

apply local-preference 200

acl number 2000

rule 0 permit source 120.2.0.0 0.0.0.255

· Device E:

ospf 1

area 0.0.0.0

network 13.1.1.0 0.0.0.255

network 192.168.0.0 0.0.0.255

vlan 30

vlan 40

interface Vlan-interface30

ip address 192.168.0.102 255.255.255.0

interface Vlan-interface40

ip address 13.1.1.102 255.255.255.0

· Device F:

vlan 100

interface Vlan-interface100

ip address 120.2.0.1 255.255.255.0

bgp 300

router-id 6.6.6.6

peer 120.2.0.2 as-number 100

address-family ipv4 unicast

network 120.2.0.0 255.255.255.0

peer 120.2.0.2 enable

H3C Fixed Port Campus Switches Configuration Examples-B70D022-6W100

Configuring Device B

Configuring Device C

Configuring Device D

Configuring Device E

Configuring Device A

Configuring Device B

Configuring Device D

Configuring Device F

Configuring Device B

Configuring Device D

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