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