Allied Telesis X8100, x908 manual set community community-values additive

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BGP: Configuring Route Maps

Community Community set clauses give you a lot of control over the community values in updates.

You can:

Replace the set of community values in an update, by using the command: set community <community-values>

Add more communities to the set of community values in an update, by using the command:

set community <community-values> additive

Remove the community attribute from an update, by using the command: set community none

Remove communities from the set of community values in an update, by creating a community list (see "Configuring a match clause" on page 27) and then applying it in a set clause. Use the command:

set comm-list <list-id>

Localpref This specifies a value to set as the Localpref attribute in the update message.

Use the command:

set local-preference <0-4294967295>

Metric (MED) This specifies a value to set as the MED attribute in the update message. You can:

Set the MED in an update, by using the command: set metric <0-4294967295>

Increase or decrease the MED in an update by a specified amount, by using one of the commands:

set metric +<amount> set metric -<amount>

For example, to increase the MED by 2, use the command:

set metric +2

Origin This specifies a value to set as the Origin attribute in the update message.

Use the command:

set origin {igpegpincomplete}

Aggregator This specifies the update’s aggregator attribute. The aggregator attribute specifies the AS and IP address of the device that performed the aggregation.

Use the command:

set aggregator <asn> <ipadd>

Use Route Maps and Other Filters to Filter and Alter BGP and OSPF Routes Page 31

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Contents Technical Guide IntroductionBGP Applying Route Maps to Imported Routes ContentsIntroduction Which products and software version does it apply to?Which products and software version does it apply to? Related How To NotesBGP Concepts and Terminology BGP updatesBGP peers Next-hop Update attributesOrigin AS-pathDistribute filters Access Control List ACL filtersBGP Overview of the Available Filter Types Filter typesDifference and Relationship in BGP Examples for filtering BGP Update messages Example AS path filters on page  Example Prefix filters on page Hierarchy of the Different FiltersBGP Example  Example Distribute filters on pageBasic configuration AlliedWare switch Confirming the neighbor relationshipawplus#show ip route About ACLs BGP Configuring Distribute FiltersExample Distribute filters Using ACLs as filtersFilter out one particular route from a neighbor Filter out a range of prefix lengths 3. Check that the IP route table now includes all the routes awplusconfig# neighbor 45.45.45.46 distribute-list list2 in6. Shut down the neighbor, and then bring it up again Use a numbered ACL instead of a named ACL 4. Check that the IP route table no longer includes 52.0.0.0/8 AS path lists BGP Configuring AS Path FiltersExample AS path filters Using AS path lists as path filtersDiscard or allow routes from a neighbor a neighbor 4. Shut down the neighbor, and then bring it up again7. Shut down the neighbor, and then bring it up again An outgoing filter that uses an AS-path list Another exampleBGP Configuring AS Path Filters About prefix lists BGP Configuring Prefix FiltersMask length awplusconfig-router# neighbor neighbor prefix-list list-name out Using prefix lists as prefix filtersExample Prefix filters awplusconfig-router# neighbor neighbor prefix-list list-name inFilter out a range of different prefix lengths awplusconfig-router# do show ip route Structure of a route map BGP Configuring Route MapsClauses Configuring a match clauseAn AS path list Case A community listOne or more prefixes, by using an ACL One or more prefixes, by using a prefix listA metric the MED attribute Configuring a set clauseA next hop address An originset community community-values additive set ip next-hop ipadd set weightset atomic-aggregate set extcommunity rtsoo ext-comm-numberA match clause and one or more set clauses The effect of different combinations of clausesOne match clause with an action No match clause and one or more set clausesRouter AS Update from PeerUpdate 1 to Peer Update 2 to PeerFirst, enter BGP router mode for the AS. The prompt should look like awplusconfig-route-map#set metric ExamplesExample B Match on a prefix-list that denies an entry awplusconfig#ip prefix-list test1 permit 52.0.0.0/84. Apply this route map as the in route map on the neighbor awplusconfig-route-map#router bgp Example D Matching on a next-hop prefix-listExample E Prepending AS numbers awplusconfig-route-map#match ip addressset bgp peer=45.45.45.45 outroutemap=com sendcommunity=yes 1. Configure the AW peer to send out a community numberThe routes coming from that peer has community add ip routem=com entry=1 set commmun=8989BGP#show ip route set bgp peer=45.45.45.45 outroutemap=mixed sendcommunity=yes 8. Add that ACL as a distribute-list in-filter on the neighbor route-map marker permit Examples Route maps ACLs Path filters Prefix filtersSyntax BGP Applying Route Maps to Imported Routesnetwork neighbor default-originateOther Uses of Route Maps neighbor unsuppress-mapRoute map configuration BGP configurationBGP Route Map Filtering Example set local-preference route-map outdef permit Metric OSPF Configuring Route Maps for Filtering and Modifying OSPF RoutesInterface A prefix, by using an ACL A prefix, by using a prefix listExternal route type  Set the metric, by using the command set metric OSPF Applying Route Maps
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