protocols bgp <asn> neighbor <id> address-family ipv4-unicast allowas-in number <number>
Allows or disallows receiving BGP advertisements containing the AS path of the local router.
Readvertisement is disabled.
- asn
- The number for the AS in which this router resides. The number ranges from 1 through 4294967295.
- id
- The IPv4 or IPv6 address of a BGP neighbor.
- number
- Specifies the number of times to accept an AS path containing the readvertisement of the ASN of the local router. The numbers range from 1 through 10. The default is 3.
Configuration mode
protocols {
bgp asn {
neighbor id {
address-family {
ipv4-unicast {
allowas-in {
number number
}
}
}
}
}
}
Use the set form of this command to allow the router to accept BGP AS paths advertising the AS number of the router.
This situation could indicate a routing loop, and by default such an update is dropped. However, you can use this command to direct the router to accept updates readvertising its AS number for a specified number of times.
Use the delete form of this command to disallow readvertisement of the AS path of the router.
Use the show form of this command to view BGP neighbor configuration settings.
When you configure this command and do a soft reset in the peer, the BGP table should flush out the prefixes that have an as-path length that is more than the configured allowas-in value.
When soft-reconfiguration is enabled irrespective of the configured allowas-in value, all the received prefixes should be stored in Adj-Rib-In, and then allowas-in should be applied and prefixes with an as-path length more than the configured value should be flushed out of the BGP table. For more information on soft-reconfiguration, see protocols bgp <asn> neighbor <id> address-family ipv4-unicast soft-reconfiguration inbound.