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diff --git a/docs/configuration/protocols/bfd.md b/docs/configuration/protocols/bfd.md new file mode 100644 index 00000000..13623e03 --- /dev/null +++ b/docs/configuration/protocols/bfd.md @@ -0,0 +1,205 @@ +--- +lastproofread: '2023-01-27' +--- + +```{include} /_include/need_improvement.txt +``` + +(routing-bfd)= + +# BFD + +{abbr}`BFD (Bidirectional Forwarding Detection)` is described and extended by +the following RFCs: {rfc}`5880`, {rfc}`5881` and {rfc}`5883`. + +In the age of very fast networks, a second of unreachability may equal millions of lost packets. +The idea behind BFD is to detect very quickly when a peer is down and take action extremely fast. + +BFD sends lots of small UDP packets very quickly to ensures that the peer is still alive. + +This allows avoiding the timers defined in BGP and OSPF protocol to expires. + +## Configure BFD + +```{cfgcmd} set protocols bfd peer \<address\> + +Set BFD peer IPv4 address or IPv6 address +``` + +```{cfgcmd} set protocols bfd peer \<address\> echo-mode + +Enables the echo transmission mode +``` + +```{cfgcmd} set protocols bfd peer \<address\> multihop + +Allow this BFD peer to not be directly connected +``` + +```{cfgcmd} set protocols bfd peer \<address\> source [address \<address\> | interface \<interface\>] + +Bind listener to specific interface/address, mandatory for IPv6 +``` + +```{cfgcmd} set protocols bfd peer \<address\> interval echo-interval \<10-60000\> + +The minimal echo receive transmission interval that this system is +capable of handling +``` + +```{cfgcmd} set protocols bfd peer \<address\> interval multiplier \<2-255\> + +Remote transmission interval will be multiplied by this value +``` + +```{cfgcmd} set protocols bfd peer \<address\> interval [receive | transmit] \<10-60000\> + +Interval in milliseconds +``` + +```{cfgcmd} set protocols bfd peer \<address\> shutdown + +Disable a BFD peer +``` + +```{cfgcmd} set protocols bfd peer \<address\> minimum-ttl \<1-254\> + +For multi hop sessions only. Configure the minimum expected TTL for an +incoming BFD control packet. + +This feature serves the purpose of thightening the packet validation +requirements to avoid receiving BFD control packets from other sessions. +``` + +### Enable BFD in BGP + +```{cfgcmd} set protocols bgp neighbor \<neighbor\> bfd + +Enable BFD on a single BGP neighbor +``` + +```{cfgcmd} set protocols bgp peer-group \<neighbor\> bfd + +Enable BFD on a BGP peer group +``` + +### Enable BFD in OSPF + +```{cfgcmd} set protocols ospf interface \<interface\> bfd + + Enable BFD for OSPF on an interface + +``` + +```{cfgcmd} set protocols ospfv3 interface \<interface\> bfd + +Enable BFD for OSPFv3 on an interface +``` + +### Enable BFD in ISIS + +```{cfgcmd} set protocols isis \<name\> interface \<interface\> bfd + +Enable BFD for ISIS on an interface + +``` + +## Operational Commands + +```{opcmd} show bfd peers + + Show all BFD peers + + :::{code-block} none + BFD Peers: + peer 198.51.100.33 vrf default interface eth4.100 + ID: 4182341893 + Remote ID: 12678929647 + Status: up + Uptime: 1 month(s), 16 hour(s), 29 minute(s), 38 second(s) + Diagnostics: ok + Remote diagnostics: ok + Local timers: + Receive interval: 300ms + Transmission interval: 300ms + Echo transmission interval: 50ms + Remote timers: + Receive interval: 300ms + Transmission interval: 300ms + Echo transmission interval: 0ms + + peer 198.51.100.55 vrf default interface eth4.101 + ID: 4618932327 + Remote ID: 3312345688 + Status: up + Uptime: 20 hour(s), 16 minute(s), 19 second(s) + Diagnostics: ok + Remote diagnostics: ok + Local timers: + Receive interval: 300ms + Transmission interval: 300ms + Echo transmission interval: 50ms + Remote timers: + Receive interval: 300ms + Transmission interval: 300ms + Echo transmission interval: 0ms + ::: +``` + +## BFD Static Route Monitoring + + +A monitored static route conditions the installation to the RIB on the BFD +session running state: when BFD session is up the route is installed to RIB, +but when the BFD session is down it is removed from the RIB. + + +### Configuration + +```{cfgcmd} set protocols static route \<subnet\> next-hop \<address\> bfd profile \<profile\> + +Configure a static route for \<subnet\> using gateway \<address\> +and use the gateway address as BFD peer destination address. +``` + +```{cfgcmd} set protocols static route \<subnet\> next-hop \<address\> bfd multi-hop source \<address\> profile \<profile\> + +Configure a static route for \<subnet\> using gateway \<address\>, +use source address to identify the peer when is multi-hop session +and the gateway address as BFD peer destination address. +``` + +```{cfgcmd} set protocols static route6 \<subnet\> next-hop \<address\> bfd profile \<profile\> + +Configure a static route for \<subnet\> using gateway \<address\> +and use the gateway address as BFD peer destination address. +``` + +```{cfgcmd} set protocols static route6 \<subnet\> next-hop \<address\> bfd multi-hop source \<address\> profile \<profile\> + +Configure a static route for \<subnet\> using gateway \<address\>, +use source address to identify the peer when is multi-hop session +and the gateway address as BFD peer destination address. +``` + +(bfd-operational-commands)= + +## Operational Commands + +```{opcmd} show bfd static routes + +Showing BFD monitored static routes + +:::{code-block} none +Showing BFD monitored static routes: + + Next hops: + VRF default IPv4 Unicast: + 10.10.13.3/32 peer 192.168.2.3 (status: installed) + 172.16.10.3/32 peer 192.168.10.1 (status: uninstalled) + + VRF default IPv4 Multicast: + + VRF default IPv6 Unicast: +::: +```
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