Tip
This is the documentation for the 19.08 version. Looking for the documentation of the latest version? Have a look here.
BGP Router ConfigurationΒΆ
This statement enters BGP Server mode and sets the autonomous system number for
this router to 65002
, and enters config-bgp
mode.
tnsr(config)# route dynamic bgp
tnsr(config-frr-bgp)# server 65002
tnsr(config-bgp)#
BGP mode defines the main behaviors of the BGP daemon, as well as the neighbors and behavior of BGP for different address families, among other possibilities.
From within config-bgp
mode, the following commands are available:
- address-family (ipv4|ipv6) (unicast|multicast)
Enter BGP Address Family Configuration mode.
- always-compare-med
Instructs the BGP daemon to always consult MED values in routes, no matter which AS the routes were received through.
- bestpath as-path (confed|ignore|multipath-relax|as-set|no-as-set)
Controls how the BGP daemon determines the best path to a destination. May be one of:
- confed
Considers the length of confederation path sets and sequences.
- ignore
Ignores AS path lengths when computing the route to a destination.
- multipath-relax
Consider paths of equal length when choosing between multiple paths to a destination, rather than looking for an exact match. This allows load sharing across different AS paths, so long as they are of equal length.
- as-set
For use with
multipath-relax
, it adds AS set information for aggregate routes.- no-as-set
For use with
multipath-relax
, it prevents AS set generation.
- bestpath compare-routerid
Uses the router ID of peers (or originator ID, if present) to break ties when computing paths to a destination based on other information. A lower router ID will win in a tie.
- bestpath med confed
Compare confederation path MEDs
- bestpath med missing-as-worst
If a route is missing MED information, it will be considered least preferred.
- client-to-client reflection
Enables reflection of routes from one client to another client.
- cluster-id (<ipv4>|<value>)
Configures the BGP daemon to participate in route reflection with the given cluster ID. The ID may be given in IP address (dotted quad) notation or as an unsigned 32-bit integer (
1-4294967295
).- coalesce-time <value>
Configures the Subgroup coalesce timer, in milliseconds (
1-4294967295
).- confederation identifier <ASN>
Configures an AS number for the entire group of IBGP routers participating in confederation.
- confederation peer <ASN>
Configures the sub-AS number for the subset of peers inside a group of IBGP routers participating in confederation.
- dampening [penalty <val> [reuse <val> [suppress <val> [maximum <max>]]]]
This command enables BGP route flap dampening (RFC 2439) to prevent unstable routers from adversely affecting routing behavior.
- penalty <penalty-val>
The time duration during which the stability value will be reduced by half if the route is unreachable.
- reuse <reuse-val>
Stability threshold that must be crossed for a route to be reused.
- suppress <suppress-val>
Stability threshold that, when crossed, a route will be suppressed.
- maximum <suppress-max>
Maximum time to suppress a route considered stable.
- deterministic-med
Determine route selection locally, even when MED values are present. Picks the best MED path from neighbor advertisements.
- disable-ebgp-connected-route-check
Disable checking if nexthop is an eBGP session.
- enforce-first-as
When set, enforces the first AS for eBGP routes.
- listen limit <value>
Maximum number of dynamic neighbors from
1-5000
.- listen range (<ip4-prefix>|<ip6-prefix>) peer-group <peer-group-name>
Listen range for dynamic neighbors.
- max-med administrative [<med>]
Sends the defined MED value, or
4294967294
when unset, at all times.- max-med on-startup period <seconds> [<med>]
Sends the defined MED value, or
4294967294
when unset, only at startup for the defined period in seconds, from5-86400
.- neighbor <peer>
Enter BGP Neighbor Configuration mode.
- network import-check
Checks if a BGP network route exists in IGP before creating BGP table entries.
- route-reflector allow-outbound-policy
Allows attributes modified by route maps to be reflected.
- router-id <A.B.C.D>
Sets the router ID for the BGP daemon. This is typically set to an IP address unique to this router, and commonly is set to a local private address.
- timers keep-alive <interval> hold-time <hold-time>
Configures the intervals between keep alive messages and how long to wait for a response before considering the peer unreachable.
- update-delay <delay>
Keeps BGP in a read-only mode for the specified time after the daemon restarts or peers are cleared.
- write-quanta <packets>
Controls the size of peer update transmissions.