Allied Telesis x908 BGP Overview of the Available Filter Types, Filter types, Distribute filters

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BGP: Overview of the Available Filter Types

BGP: Overview of the Available Filter Types

The following sections describe the various types of filters that can be applied to BGP updates and the hierarchy of the filters.

Filter types

There are a number of filter types that can be applied to the BGP updates being exchanged between BGP peers:

Distribute filters

Distribute list can filter the routing information between the routing protocol (RIP, RIPng, OSPF, OSPFv3 or BGP) and its IP route table (routing information base - RIB). It has to make the use of ACL, prefix list, or route map depending on which routing protocol it is configured for. For BGP, it can only use ACL to match prefix (ip address).

These use ACLs and look at the individual prefixes within an update message. If a prefix within the update message matches the filter criteria then that individual prefix is filtered out or accepted depending on what action the filter entry has been configured to carry out. Note that you cannot combine distribute filters and prefix filters.

AS Path filters

These look at the AS-Path attribute in update messages. If the AS-Path attribute in the update matches the filter criteria then the whole update message is filtered out or accepted, depending on what action the filter entry has been configured to carry out.

Prefix filters

These use prefix lists and look at the individual prefixes within an update message. If a prefix within the update message matches the filter criteria then that individual prefix is filtered out or accepted depending on what action the filter entry has been configured to carry out.

Note that you cannot combine distribute filters and prefix filters.

Route maps

These are a structured combination of match criteria and actions. They can be used to filter out routes and also to alter the attributes in update messages.

Access Control List (ACL) filters

ACL is mainly use to limit the network traffic. It can be used by distribute list and route map to filter the routing updates. ACLs (Access Control Lists) can be used to do a number of different things on your network, from controlling what type of traffic passes through your devices to deciding on what routing protocols you wish to be advertised out of your routers.

Page 6 Use Route Maps and Other Filters to Filter and Alter BGP and OSPF Routes

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Contents Introduction Technical GuideWhich products and software version does it apply to? ContentsIntroduction BGP Applying Route Maps to Imported RoutesRelated How To Notes Which products and software version does it apply to?BGP updates BGP Concepts and TerminologyBGP peers AS-path Update attributesOrigin Next-hopFilter types Access Control List ACL filtersBGP Overview of the Available Filter Types Distribute filtersExamples for filtering BGP Update messages Difference and Relationship in BGP Example Distribute filters on page Hierarchy of the Different FiltersBGP Example  Example AS path filters on page  Example Prefix filters on pageBasic configuration Confirming the neighbor relationship AlliedWare switchawplus#show ip route BGP Configuring Distribute Filters About ACLsUsing ACLs as filters Example Distribute filtersFilter out one particular route from a neighbor Filter out a range of prefix lengths awplusconfig# neighbor 45.45.45.46 distribute-list list2 in 3. Check that the IP route table now includes all the routes6. Shut down the neighbor, and then bring it up again Use a numbered ACL instead of a named ACL awplusconfig-router# do show ip route BGP Configuring AS Path Filters AS path listsUsing AS path lists as path filters Example AS path filtersDiscard or allow routes from a neighbor 4. Shut down the neighbor, and then bring it up again a neighbor7. Shut down the neighbor, and then bring it up again Another example An outgoing filter that uses an AS-path listBGP Configuring AS Path Filters BGP Configuring Prefix Filters About prefix listsMask length awplusconfig-router# neighbor neighbor prefix-list list-name in Using prefix lists as prefix filtersExample Prefix filters awplusconfig-router# neighbor neighbor prefix-list list-name outFilter out a range of different prefix lengths BGP Configuring Prefix Filters BGP Configuring Route Maps Structure of a route mapConfiguring a match clause ClausesAn AS path list A community list CaseOne or more prefixes, by using a prefix list One or more prefixes, by using an ACLAn origin Configuring a set clauseA next hop address A metric the MED attributeset community community-values additive set extcommunity rtsoo ext-comm-number set weightset atomic-aggregate set ip next-hop ipaddNo match clause and one or more set clauses The effect of different combinations of clausesOne match clause with an action A match clause and one or more set clausesUpdate 2 to Peer Update from PeerUpdate 1 to Peer Router ASFirst, enter BGP router mode for the AS. The prompt should look like awplusconfig#ip prefix-list test1 permit 52.0.0.0/8 ExamplesExample B Match on a prefix-list that denies an entry awplusconfig-route-map#set metric4. Apply this route map as the in route map on the neighbor awplusconfig-route-map#match ip address Example D Matching on a next-hop prefix-listExample E Prepending AS numbers awplusconfig-route-map#router bgpadd ip routem=com entry=1 set commmun=8989 1. Configure the AW peer to send out a community numberThe routes coming from that peer has community set bgp peer=45.45.45.45 outroutemap=com sendcommunity=yesBGP#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 ACLs Path filters Prefix filters Route mapsBGP Applying Route Maps to Imported Routes Syntaxneighbor unsuppress-map neighbor default-originateOther Uses of Route Maps networkBGP configuration Route map configurationBGP Route Map Filtering Example set local-preference route-map outdef permit OSPF Configuring Route Maps for Filtering and Modifying OSPF Routes MetricInterface A prefix, by using a prefix list A prefix, by using an ACLExternal route type OSPF Applying Route Maps  Set the metric, by using the command set metric
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X8100, x908 specifications

The Allied Telesis x908 and the SwitchBlade x900 series of network switches are cutting-edge solutions designed to address the demands of modern networking environments. These switches are known for their high performance, reliability, and robust feature sets, making them ideal for enterprise and service provider networks.

The Allied Telesis x908 series consists of modular and chassis-based systems that can accommodate a variety of network configurations. One of the main features of the x908 series is its ability to offer high scalability with support for a large number of ports. This makes it suitable for data centers and large enterprise networks where space and bandwidth optimization are critical.

In addition to scalability, the x908 series supports advanced Layer 2 and Layer 3 switching capabilities. This allows for efficient traffic management and routing, ensuring that data is delivered swiftly and reliably. The x908 also incorporates intelligent features such as Quality of Service (QoS), which prioritizes critical network traffic, ensuring that time-sensitive data—like voice and video—maintains its quality during transmission.

The SwitchBlade x900 series takes this functionality further with its innovative modular architecture. This allows organizations to configure their networks to meet specific needs by choosing from a variety of interface cards and service modules. The SwitchBlade x900 also supports advanced security features such as Access Control Lists (ACLs) and VLAN segmentation, which provide enhanced protection against unauthorized access and network threats.

Another hallmark of the x908 and SwitchBlade series is their support for high-speed Ethernet technologies, including 10G and 40G Ethernet. This enables organizations to keep pace with the increasing bandwidth demands of applications and services, particularly in cloud computing and data-intensive workloads.

Both the x908 and the SwitchBlade x900 series are designed with energy efficiency in mind, featuring power-saving technologies that reduce overall operational costs. Coupled with Allied Telesis' management tools, which provide detailed analytics and monitoring, network administrators can optimize performance and energy consumption simultaneously.

In summary, the Allied Telesis x908 and SwitchBlade x900 series offer a comprehensive suite of features, high performance, scalability, and advanced networking technologies. They represent a strategic investment for organizations looking to build resilient, efficient, and future-proof network infrastructures.
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