Contents

Configuring routing policies· 1

About routing policies· 1

Implementation of a routing policy· 1

Filters· 1

Routing policy tasks at a glance· 2

Configuring an IPv4 prefix list 2

Configuring an IPv6 prefix list 3

Configuring an AS path list 3

Configuring a community list 3

Configuring an extended community list 4

Configuring a tag list 4

Configuring a routing policy· 4

Creating a routing policy· 4

Configuring if-match clauses· 5

Configuring apply clauses· 6

Configuring the continue clause· 8

Display and maintenance commands for routing policies· 8

 

Configuring routing policies

About routing policies

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.

Implementation of a routing policy

To configure a routing policy:

1.     Configure filters based on route attributes.

2.     Create a routing policy and apply filters to the routing policy.

Filters

Routing policies can use the following filters to match routes.

ACL

An ACL can match the destination or next hop of routes.

For more information about ACLs, see ACL and QoS Configuration Guide.

IP prefix list

An IP prefix list matches the destination address of routes.

An IP prefix list can contain multiple items that specify prefix ranges. Each destination IP address prefix of a route is compared with these items in ascending order of their index numbers. A prefix matches the IP prefix list if it matches one item in the list.

AS path list

An AS path list matches the AS_PATH attribute of BGP routes. The AS_PATH attribute identifies the ASs through which a route has passed.

For more information about AS path lists, see "Configuring BGP."

Community list

A community list matches the COMMUNITY attribute of BGP routes. The COMMUNITY attribute identifies the community of BGP routes.

For more information about community lists, see "Configuring BGP."

Extended community list

An extended community list matches the extended community attribute (Route-Target for VPN and Site of Origin) of BGP routes.

Tag list

A tag list matches the tag of IGP routes.

Routing policy

A routing policy can contain multiple nodes, which are in a logical OR relationship. A node with a smaller number is matched first. A route matches the routing policy if it matches one node (except the node configured with the continue clause) in the routing policy.

Each node has a match mode of permit or deny.

·     permit—Specifies the permit match mode for a routing policy node. If a route meets all the if-match clauses of the node, it is handled by the apply clauses of the node. The route is not compared with the next node unless the continue clause is configured. If a route does not meet all the if-match clauses of the node, it is compared with the next node.

·     deny—Specifies the deny match mode for a routing policy node. The apply and continue clauses of a deny node are never executed. If a route meets all the if-match clauses of the node, it is denied without being compared with the next node. If a route does not meet all the if-match clauses of the node, it is compared with the next node.

A node can contain a set of if-match, apply, and continue clauses.

·     if-match clauses—Specify the match criteria that match the attributes of routes. The if-match clauses are in a logical AND relationship. A route must meet all the if-match clauses to match the node.

·     apply clauses—Specify the actions to be taken on permitted routes, such as modifying a route attribute.

·     continue clause—Specifies the next node. A route that matches the current node (permit node) must match the specified next node in the same routing policy. The continue clause combines the if-match and apply clauses of the two nodes to improve flexibility of the routing policy.

Follow these guidelines when you configure if-match, apply, and continue clauses:

·     If you only want to filter routes, do not configure apply clauses.

·     If you do not configure any if-match clauses for a permit node, the node will permit all routes.

·     Configure a permit node containing no if-match or apply clauses following multiple deny nodes to allow unmatched routes to pass.

Routing policy tasks at a glance

To configure a routing policy, perform the following tasks:

1.     (Optional.) Configure filters:

?     Configuring an IPv4 prefix list

?     Configuring an IPv6 prefix list

?     Configuring an AS path list

?     Configuring a community list

?     Configuring an extended community list

?     Configuring a tag list

2.     Configuring a routing policy

a.     Creating a routing policy

b.     Configuring if-match clauses

c.     Configuring apply clauses

d.     Configuring the continue clause

Configuring an IPv4 prefix list

Restrictions and guidelines

If all the items are set to deny mode, no routes can pass the IPv4 prefix list. To permit unmatched IPv4 routes, you must configure the permit 0.0.0.0 0 less-equal 32 item following multiple deny items.

Procedure

1.     Enter system view.

system-view

2.     Configure an IPv4 prefix list.

ip prefix-list prefix-list-name [ index index-number ] { deny | permit } ip-address mask-length [ greater-equal min-mask-length ] [ less-equal max-mask-length ]

Configuring an IPv6 prefix list

Restrictions and guidelines

If all items are set to deny mode, no routes can pass the IPv6 prefix list. To permit unmatched IPv6 routes, you must configure the permit :: 0 less-equal 128 item following multiple deny items.

Procedure

1.     Enter system view.

system-view

2.     Configure an IPv6 prefix list.

ipv6 prefix-list prefix-list-name [ index index-number ] { deny | permit } ipv6-address { inverse inverse-prefix-length | prefix-length [ greater-equal min-prefix-length ] [ less-equal max-prefix-length ] }

Configuring an AS path list

About this task

You can configure multiple items for an AS path list that is identified by a number. The relationship between the items is logical OR. A route matches the AS path list if it matches one item in the list.

Procedure

1.     Enter system view.

system-view

2.     Configure an AS path list.

ip as-path as-path-number { deny | permit } regular-expression

Configuring a community list

About this task

You can configure multiple items for a community list that is identified by a number. The relationship between the items is logical OR. A route matches the community list if it matches one item in the list.

Procedure

1.     Enter system view.

system-view

2.     Configure a community list.

?     Configure a basic community list.

ip community-list { basic-comm-list-num | basic basic-comm-list-name } { deny | permit } [ community-number&<1-32> | aa:nn&<1-32> ] [ internet | no-advertise | no-export | no-export-subconfed ] *

?     Configure an advanced community list.

ip community-list { adv-comm-list-num | advanced adv-comm-list-name } { deny | permit } regular-expression

Configuring an extended community list

About this task

You can configure multiple items for an extended community list that is identified by a number. The relationship between the items is logical OR. A route matches the extended community list if it matches one item in the list.

Procedure

1.     Enter system view.

system-view

2.     Configure an extended community list.

ip extcommunity-list ext-comm-list-number [ index index-number ] { deny | permit } { rt route-target | soo site-of-origin }&<1-32>

Configuring a tag list

About this task

You can configure multiple items for a tag list. The relationship between the items is logical OR. A route matches the tag list if it matches one item in the list.

Procedure

1.     Enter system view.

system-view

2.     Configure a tag list.

route tag-list tag-list-number [ index index-number ] { deny | permit } tag-value&<1-32>

Configuring a routing policy

Creating a routing policy

About this task

A routing policy must have a minimum of one permit node. If all the nodes are in deny mode, no routes can pass the routing policy.

Procedure

1.     Enter system view.

system-view

2.     Create a routing policy and a node, and enter routing policy node view.

route-policy route-policy-name { deny | permit } node node-number

3.     (Optional.) Configure a description for the routing policy node.

description text

Configuring if-match clauses

About this task

You can either specify no if-match clauses or multiple if-match clauses for a routing policy node. If no if-match clause is specified for a permit node, all routes can pass the node. If no if-match clause is specified for a deny node, no routes can pass the node.

Restrictions and guidelines

When you configure if-match clauses, follow these restrictions and guidelines:

·     The if-match clauses of a routing policy node have a logical AND relationship. A route must meet all if-match clauses before it can be executed by the apply clauses of the node. If an if-match command exceeds the maximum length, multiple if-match clauses of the same type are generated. These clauses have a logical OR relationship. A route only needs to meet one of them.

·     All IPv4 routes match a node if the if-match clauses of the node use only IPv6 ACLs. All IPv6 routes match a node if the if-match clauses of the node use only IPv4 ACLs.

·     If the ACL used by an if-match clause does not exist, the clause is always matched. If no rules of the specified ACL are matched or the match rules are inactive, the clause is not matched.

·     If the prefix list, community list, or extended community list used by an if-match clause does not exist, the clause is always matched. If no rules of the specified prefix list, community list, or extended community list are matched, the clause is not matched.

Procedure

1.     Enter system view.

system-view

2.     Enter routing policy node view.

route-policy route-policy-name { deny | permit } node node-number

3.     Match routes whose destination, next hop, or source address matches an ACL or prefix list.

IPv4:

if-match ip { address | next-hop | route-source } { acl { ipv4-acl-number | name ipv4-acl-name } | prefix-list prefix-list-name }

IPv6:

if-match ipv6 { address | next-hop | route-source } { acl { ipv6-acl-number | name ipv6-acl-name } | prefix-list prefix-list-name }

By default, no ACL or prefix list match criterion is configured.

The ACL specified in an if-match clause must be a non-VPN ACL.

4.     Configure BGP route match criteria.

?     Match BGP routes whose AS_PATH attribute matches a specified AS path list.

if-match as-path as-path-number&<1-32>

?     Match BGP routes whose COMMUNITY attribute matches a specified community list.

if-match community { { basic-community-list-number | name comm-list-name } [ whole-match ] | adv-community-list-number }&<1-32>

?     Match BGP routes whose extended community attribute matches a specified extended community list.

if-match extcommunity ext-comm-list-number&<1-32>

?     Match BGP routes having the specified local preference.

if-match local-preference preference

By default, no BGP route match criteria are configured.

5.     Configure route match criteria.

?     Match routes having the specified cost.

if-match cost cost-value

?     Match routes having the specified output interface.

if-match interface { interface-type interface-number }&<1-16>

This command is not supported by BGP.

?     Match routes having the specified route type.

if-match route-type { bgp-evpn-imet | bgp-evpn-ip-prefix | bgp-evpn-mac-ip | ?external-type1 | external-type1or2 | external-type2 | internal | is-is-level-1 | is-is-level-2 | nssa-external-type1 | nssa-external-type1or2 | nssa-external-type2 } *

?     Match IGP routes having the specified tag value.

if-match tag tag-value

?     Match IGP routes whose tag matches the specified tag list.

if-match tag-list tag-list-number

By default, no route match criteria are configured.

Configuring apply clauses

1.     Enter system view.

system-view

2.     Enter routing policy node view.

route-policy route-policy-name { deny | permit } node node-number

3.     Configure BGP route attributes.

?     Set the AS_PATH attribute for BGP routes.

apply as-path as-number&<1-32> [ replace ]

?     Delete the specified COMMUNITY attribute for BGP routes.

apply comm-list { comm-list-number | comm-list-name } delete

By default, no COMMUNITY attribute is deleted for BGP routes.

?     Set the specified COMMUNITY attribute for BGP routes.

apply community { none | additive | { community-number&<1-32> | aa:nn&<1-32> | internet | no-advertise | no-export | no-export-subconfed } * [ additive ] }

?     Set the extended community attribute for BGP routes.

apply extcommunity { rt route-target }&<1-32> [ additive ]

?     Set a local preference for BGP routes.

apply local-preference preference

?     Set the ORIGIN attribute for BGP routes.

apply origin { egp as-number | igp | incomplete }

?     Set a preferred value for BGP routes.

apply preferred-value preferred-value

?     Set a traffic index for BGP routes.

apply traffic-index { value | clear }

By default, no BGP route attributes are configured.

4.     Configure the route cost and cost type.

?     Set a cost for routes.

apply cost [ + | - ] cost-value

By default, no cost is set for routes.

?     Set a cost type for routes.

apply cost-type ?{ external | internal | type-1 | type-2 }

By default, no cost type is set for routes.

5.     Set the next hop for routes.

IPv4:

apply ip-address next-hop ip-address [ public | vpn-instance vpn-instance-name ]

IPv6:

apply ipv6 next-hop ipv6-address

By default, no next hop is set for routes.

The configuration does not apply to redistributed routes.

6.     Configure route priorities.

?     Set an IP precedence for matching routes.

apply ip-precedence { value | clear }

By default, no IP precedence is set.

?     Set a preference.

apply preference preference

By default, no preference is set.

?     Set a prefix priority.

apply prefix-priority { critical | high | medium }

By default, the prefix priority is low.

7.     Redistribute routes to the specified IS-IS level.

apply isis { level-1 | level-1-2 | level-2 }

By default, routes are not redistributed into the specified IS-IS level.

8.     Set a local QoS ID for matching routes.

apply qos-local-id { local-id-value | clear }

By default, no local QoS ID is set.

9.     Set a tag value for IGP routes.

apply tag tag-value

By default, no tag value is set for IGP routes.

10.     Set a backup link for fast reroute (FRR).

IPv4:

apply fast-reroute { backup-interface interface-type interface-number [ backup-nexthop ip-address ] | backup-nexthop ip-address }

IPv6:

apply ipv6 fast-reroute { backup-interface interface-type interface-number [ backup-nexthop ipv6-address ] | backup-nexthop ipv6-address }

By default, no backup link is set for FRR.

Configuring the continue clause

Restrictions and guidelines

When you configure the continue clause to combine multiple nodes, follow these restrictions and guidelines:

·     If you configure an apply clause that sets different attribute values on all the nodes, the apply clause of the node configured most recently takes effect.

·     If you configure the following apply clauses on all the nodes, the apply clause of each node takes effect:

?     apply as-path without the replace keyword.

?     apply cost with the + or – keyword.

?     apply community with the additive keyword.

?     apply extcommunity with the additive keyword.

·     The apply comm-list delete clause configured on the current node cannot delete the community attributes set by the apply community clauses of the preceding nodes.

Procedure

1.     Enter system view.

system-view

2.     Enter routing policy node view.

route-policy route-policy-name { deny | permit } node node-number

3.     Specify the next node to be matched.

continue [ node-number ]

By default, no continue clause is configured.

The specified next node must have a larger number than the current node.

Display and maintenance commands for routing policies

Execute display commands in any view and reset commands in user view.

 

Task	Command
Display BGP AS path list information.	display ip as-path [ as-path-number ]
Display BGP community list information.	display ip community-list [ basic-community-list-number | adv-community-list-number | name comm-list-name ]
Display BGP extended community list information.	display ip extcommunity-list [ ext-comm-list-number ]
Display IPv4 prefix list statistics.	display ip prefix-list [ name prefix-list-name ]
Display IPv6 prefix list statistics.	display ipv6 prefix-list [ name prefix-list-name ]
Display tag list information.	display route tag-list [ tag-list-number ]
Display routing policy information.	display route-policy [ name route-policy-name ]
Clear IPv4 prefix list statistics.	reset ip prefix-list [ prefix-list-name ]
Clear IPv6 prefix list statistics.	reset ipv6 prefix-list [ prefix-list-name ]

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