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vyos-documentation/docs/configuration/protocols/ospf.rst
Leonid Voronkin 188cf66956
ospf: update routing protocol command definitions
2021-01-08 18:39:29 +01:00

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.. include:: /_include/need_improvement.txt
.. _routing-ospf:
####
OSPF
####
:abbr:`OSPF (Open Shortest Path First)` is a routing protocol for Internet
Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls
into the group of interior gateway protocols (IGPs), operating within a single
autonomous system (AS). It is defined as OSPF Version 2 in :rfc:`2328` (1998)
for IPv4. Updates for IPv6 are specified as OSPF Version 3 in :rfc:`5340`
(2008). OSPF supports the :abbr:`CIDR (Classless Inter-Domain Routing)`
addressing model.
OSPF is a widely used IGP in large enterprise networks.
OSPFv2 (IPv4)
#############
General configuration
---------------------
.. cfgcmd:: set protocols ospf area <number>
This command is udes to enable the OSPF process. The area number can be
specified in decimal notation in the range from 0 to 4294967295. Or it
can be specified in dotted decimal notation similar to ip address.
.. cfgcmd:: set protocols ospf area <number> network <A.B.C.D/M>
This command specifies the OSPF enabled interface(s). If the interface has
an address from defined range then the command enables OSPF on this
interface so router can provide network information to the other ospf
routers via this interface.
.. cfgcmd:: set protocols ospf auto-cost reference-bandwidth <number>
This command sets the reference bandwidth for cost calculations, where
bandwidth can be in range from 1 to 4294967, specified in Mbits/s. The
default is 100Mbit/s (i.e. a link of bandwidth 100Mbit/s or higher will
have a cost of 1. Cost of lower bandwidth links will be scaled with
reference to this cost).
.. cfgcmd:: set protocols ospf default-information originate [always] [metric <number>] [metric-type <1|2>] [route-map <name>]
Originate an AS-External (type-5) LSA describing a default route into all
external-routing capable areas, of the specified metric and metric type.
If the :cfgcmd:`always` keyword is given then the default is always advertised,
even when there is no default present in the routing table. The argument
:cfgcmd:`route-map` specifies to advertise the default route if the route map
is satisfied.
.. cfgcmd:: set protocols ospf distance global <distance>
This command change distance value of OSPF. The distance range is 1 to 255.
.. cfgcmd:: set protocols ospf distance ospf <external|inter-area|intra-area> <distance>
This command change distance value of OSPF. The arguments are the distance
values for external routes, inter-area routes and intra-area routes
respectively. The distance range is 1 to 255.
.. note:: Routes with a distance of 255 are effectively disabled and not
installed into the kernel.
.. cfgcmd:: set protocols ospf parameters router-id <rid>
This command sets the router-ID of the OSPF process. The router-ID may be an
IP address of the router, but need not be – it can be any arbitrary 32bit number.
However it MUST be unique within the entire OSPF domain to the OSPF speaker – bad
things will happen if multiple OSPF speakers are configured with the same router-ID!
.. cfgcmd:: set protocols ospf parameters abr-type <cisco|ibm|shortcut|standard>
This command selects ABR model. OSPF router supports four ABR models:
"cisco" – a router will be considered as ABR if it has several configured links to
the networks in different areas one of which is a backbone area. Moreover, the link
to the backbone area should be active (working).
"ibm" – identical to "cisco" model but in this case a backbone area link may not be active.
"standard" – router has several active links to different areas.
"shortcut" – identical to "standard" but in this model a router is allowed to use a
connected areas topology without involving a backbone area for inter-area connections.
Detailed information about "cisco" and "ibm" models differences can be found in :rfc:`3509`.
A "shortcut" model allows ABR to create routes between areas based on the topology of the
areas connected to this router but not using a backbone area in case if non-backbone route
will be cheaper. For more information about "shortcut" model, see :t:`ospf-shortcut-abr-02.txt`
.. cfgcmd:: set protocols ospf parameters rfc1583-compatibility
:rfc:`2328`, the successor to :rfc:`1583`, suggests according to section G.2 (changes)
in section 16.4.1 a change to the path preference algorithm that prevents possible
routing loops that were possible in the old version of OSPFv2. More specifically it
demands that inter-area paths and intra-area backbone path are now of equal preference
but still both preferred to external paths.
This command should NOT be set normally.
.. cfgcmd:: set protocols ospf passive-interface <interface>
This command specifies interface as passive. Passive interface advertises its address,
but does not run the OSPF protocol (adjacencies are not formed and hello packets are
not generated).
.. cfgcmd:: set protocols ospf passive-interface default
This command specifies all interfaces as passive by default. Because this command changes
the configuration logic to a default passive; therefore, interfaces where router adjacencies
are expected need to be configured with the :cfgcmd:`passive-interface-exclude` command.
.. cfgcmd:: set protocols ospf passive-interface-exclude <interface>
This command allows exclude interface from passive state. This command is used if the
command :cfgcmd:`passive-interface default` was configured.
.. cfgcmd:: set protocols ospf refresh timers <seconds>
The router automatically updates link-state information with its neighbors. Only an obsolete
information is updated which age has exceeded a specific threshold. This parameter changes
a threshold value, which by default is 1800 seconds (half an hour). The value is applied
to the whole OSPF router. The timer range is 10 to 1800.
Areas configuration
-------------------
.. cfgcmd:: set protocols ospf area <number> area-type stub
This command specifies the area to be a Stub Area. That is, an area where no router
originates routes external to OSPF and hence an area where all external routes are
via the ABR(s). Hence, ABRs for such an area do not need to pass AS-External LSAs
(type-5) or ASBR-Summary LSAs (type-4) into the area. They need only pass
Network-Summary (type-3) LSAs into such an area, along with a default-route summary.
.. cfgcmd:: set protocols ospf area <number> area-type stub no-summary
This command specifies the area to be a Totally Stub Area. In addition to stub area
limitations this area type prevents an ABR from injecting Network-Summary (type-3)
LSAs into the specified stub area. Only default summary route is allowed.
.. cfgcmd:: set protocols ospf area <number> area-type stub default-cost <number>
This command sets the cost of default-summary LSAs announced to stubby areas.
The cost range is 0 to 16777215.
.. cfgcmd:: set protocols ospf area <number> area-type nssa
This command specifies the area to be a Not So Stubby Area. External routing information
is imported into an NSSA in Type-7 LSAs. Type-7 LSAs are similar to Type-5 AS-external
LSAs, except that they can only be flooded into the NSSA. In order to further propagate
the NSSA external information, the Type-7 LSA must be translated to a Type-5
AS-external-LSA by the NSSA ABR.
.. cfgcmd:: set protocols ospf area <number> area-type nssa no-summary
This command specifies the area to be a NSSA Totally Stub Area. ABRs for such an area do
not need to pass Network-Summary (type-3) LSAs (except the default summary route),
ASBR-Summary LSAs (type-4) and AS-External LSAs (type-5) into the area. But Type-7 LSAs
that convert to Type-5 at the NSSA ABR are allowed.
.. cfgcmd:: set protocols ospf area <number> area-type nssa default-cost <number>
This command sets the default cost of LSAs announced to NSSA areas.
The cost range is 0 to 16777215.
.. cfgcmd:: set protocols ospf area <number> area-type nssa translate <always|candidate|never>
Specifies whether this NSSA border router will unconditionally translate Type-7 LSAs into
Type-5 LSAs. When role is Always, Type-7 LSAs are translated into Type-5 LSAs regardless
of the translator state of other NSSA border routers. When role is Candidate, this router
participates in the translator election to determine if it will perform the translations
duties. When role is Never, this router will never translate Type-7 LSAs into Type-5 LSAs.
.. cfgcmd:: set protocols ospf area <number> authentication plaintext-password
This command specifies that simple password authentication should be used for the given
area. The password must also be configured on a per-interface basis.
.. cfgcmd:: set protocols ospf area <number> authentication md5
This command specify that OSPF packets must be authenticated with MD5 HMACs within the
given area. Keying material must also be configured on a per-interface basis.
.. cfgcmd:: set protocols ospf area <number> shortcut <default|disable|enable>
This parameter allows to "shortcut" routes (non-backbone) for inter-area routes. There
are three modes available for routes shortcutting:
"default" – this area will be used for shortcutting only if ABR does not have a link
to the backbone area or this link was lost.
"enable" – the area will be used for shortcutting every time the route that goes through
it is cheaper.
"disable" – this area is never used by ABR for routes shortcutting.
.. cfgcmd:: set protocols ospf area <number> virtual-link <A.B.C.D>
Provides a backbone area coherence by virtual link establishment.
In general, OSPF protocol requires a backbone area (area 0) to be coherent and fully
connected. I.e. any backbone area router must have a route to any other backbone area
router. Moreover, every ABR must have a link to backbone area. However, it is not always
possible to have a physical link to a backbone area. In this case between two ABR (one
of them has a link to the backbone area) in the area (not stub area) a virtual link is organized.
<number> – area identifier through which a virtual link goes.
<A.B.C.D> – ABR router-id with which a virtual link is established. Virtual link must be
configured on both routers.
Formally, a virtual link looks like a point-to-point network connecting two ABR from one
area one of which physically connected to a backbone area. This pseudo-network is considered
to belong to a backbone area.
Interfaces configuration
------------------------
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf authentication plaintext-password <text>
This command sets OSPF authentication key to a simple password. After setting, all OSPF
packets are authenticated. Key has length up to 8 chars.
Simple text password authentication is insecure and deprecated in favour of MD5 HMAC
authentication.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf authentication md5 key-id <id> md5-key <text>
This command specifys that MD5 HMAC authentication must be used on this interface. It sets
OSPF authentication key to a cryptographic password. Key-id identifies secret key used to
create the message digest. This ID is part of the protocol and must be consistent across
routers on a link. The key can be long up to 16 chars (larger strings will be truncated),
and is associated with the given key-id.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf bandwidth <number>
This command sets the interface bandwidth for cost calculations, where
bandwidth can be in range from 1 to 100000, specified in Mbits/s.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf cost <number>
This command sets link cost for the specified interface. The cost value is set to
router-LSA’s metric field and used for SPF calculation. The cost range is 1 to 65535.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf dead-interval <number>
Set number of seconds for router Dead Interval timer value used for Wait Timer and
Inactivity Timer. This value must be the same for all routers attached to a common
network. The default value is 40 seconds. The interval range is 1 to 65535.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf hello-interval <number>
Set number of seconds for Hello Interval timer value. Setting this value, Hello
packet will be sent every timer value seconds on the specified interface. This
value must be the same for all routers attached to a common network. The default
value is 10 seconds. The interval range is 1 to 65535.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf mtu-ignore
This command disables check of the MTU value in the OSPF DBD packets. Thus, use
of this command allows the OSPF adjacency to reach the FULL state even though
there is an interface MTU mismatch between two OSPF routers.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf network <type>
This command allows to specify the distribution type for the network connected
to this interface:
"broadcast" – broadcast IP addresses distribution.
"non-broadcast" – address distribution in NBMA networks topology.
"point-to-multipoint" – address distribution in point-to-multipoint networks.
"point-to-point" – address distribution in point-to-point networks.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf priority <number>
This command sets Router Priority integer value. The router with the highest
priority will be more eligible to become Designated Router. Setting the value
to 0, makes the router ineligible to become Designated Router. The default value
is 1. The interval range is 0 to 255.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf retransmit-interval <number>
This command sets number of seconds for RxmtInterval timer value. This value is used
when retransmitting Database Description and Link State Request packets if acknowledge
was not received. The default value is 5 seconds. The interval range is 3 to 65535.
.. cfgcmd:: set interfaces <inttype> <intname> ip ospf transmit-delay <number>
This command sets number of seconds for InfTransDelay value. It allows to set and adjust
for each interface the delay interval before starting the synchronizing process of the
router's database with all neighbors. The default value is 1 seconds. The interval range
is 3 to 65535.
Redistribution configuration
----------------------------
.. cfgcmd:: set protocols ospf redistribute bgp
Redistribute BGP routes to OSPF process.
.. cfgcmd:: set protocols ospf redistribute connected
Redistribute connected routes to OSPF process.
.. cfgcmd:: set protocols ospf redistribute kernel
Redistribute kernel routes to OSPF process.
.. cfgcmd:: set protocols ospf redistribute rip
Redistribute RIP routes to OSPF process.
.. cfgcmd:: set protocols ospf redistribute static
Redistribute static routes to OSPF process.
.. cfgcmd:: set protocols ospf default-metric <number>
This command specifies the default metric value of redistributed routes.
The metric range is 0 to 16777214.
.. cfgcmd:: set protocols ospf redistribute <route source> metric <number>
This command specifies metric for redistributed routes from given route source. There
are five modes available for route source: bgp, connected, kernel, rip, static. The
metric range is 1 to 16.
.. cfgcmd:: set protocols ospf redistribute <route source> metric-type <1|2>
This command specifies metric type for redistributed routes. Difference between two metric
types that metric type 1 is a metric which is "commensurable" with inner OSPF links. When
calculating a metric to the external destination, the full path metric is calculated as a
metric sum path of a router which had advertised this link plus the link metric. Thus, a
route with the least summary metric will be selected. If external link is advertised with
metric type 2 the path is selected which lies through the router which advertised this link
with the least metric despite of the fact that internal path to this router is longer (with
more cost). However, if two routers advertised an external link and with metric type 2 the
preference is given to the path which lies through the router with a shorter internal path.
If two different routers advertised two links to the same external destimation but with
different metric type, metric type 1 is preferred. If type of a metric left undefined the
router will consider these external links to have a default metric type 2.
.. cfgcmd:: set protocols ospf redistribute <route source> route-map <name>
This command allows to use route map to filter redistributed routes from given route source.
There are five modes available for route source: bgp, connected, kernel, rip, static.
Configuration example
---------------------
Below you can see a typical configuration using 2 nodes, redistribute loopback
address and the node 1 sending the default route:
**Node 1**
.. code-block:: none
set interfaces loopback lo address 10.1.1.1/32
set protocols ospf area 0 network 192.168.0.0/24
set protocols ospf default-information originate always
set protocols ospf default-information originate metric 10
set protocols ospf default-information originate metric-type 2
set protocols ospf log-adjacency-changes
set protocols ospf parameters router-id 10.1.1.1
set protocols ospf redistribute connected metric-type 2
set protocols ospf redistribute connected route-map CONNECT
set policy route-map CONNECT rule 10 action permit
set policy route-map CONNECT rule 10 match interface lo
**Node 2**
.. code-block:: none
set interfaces loopback lo address 10.2.2.2/32
set protocols ospf area 0 network 192.168.0.0/24
set protocols ospf log-adjacency-changes
set protocols ospf parameters router-id 10.2.2.2
set protocols ospf redistribute connected metric-type 2
set protocols ospf redistribute connected route-map CONNECT
set policy route-map CONNECT rule 10 action permit
set policy route-map CONNECT rule 10 match interface lo
OSPFv3 (IPv6)
#############
A typical configuration using 2 nodes.
**Node 1:**
.. code-block:: none
set protocols ospfv3 area 0.0.0.0 interface eth1
set protocols ospfv3 area 0.0.0.0 range 2001:db8:1::/64
set protocols ospfv3 parameters router-id 192.168.1.1
set protocols ospfv3 redistribute connected
**Node 2:**
.. code-block:: none
set protocols ospfv3 area 0.0.0.0 interface eth1
set protocols ospfv3 area 0.0.0.0 range 2001:db8:2::/64
set protocols ospfv3 parameters router-id 192.168.2.1
set protocols ospfv3 redistribute connected
**To see the redistributed routes:**
.. code-block:: none
show ipv6 ospfv3 redistribute
.. note:: You cannot easily redistribute IPv6 routes via OSPFv3 on a WireGuard
interface link. This requires you to configure link-local addresses manually
on the WireGuard interfaces, see :vytask:`T1483`.
Example configuration for WireGuard interfaces:
**Node 1**
.. code-block:: none
set interfaces wireguard wg01 address 'fe80::216:3eff:fe51:fd8c/64'
set interfaces wireguard wg01 address '192.168.0.1/24'
set interfaces wireguard wg01 peer ospf02 allowed-ips '::/0'
set interfaces wireguard wg01 peer ospf02 allowed-ips '0.0.0.0/0'
set interfaces wireguard wg01 peer ospf02 endpoint '10.1.1.101:12345'
set interfaces wireguard wg01 peer ospf02 pubkey 'ie3...='
set interfaces wireguard wg01 port '12345'
set protocols ospfv3 parameters router-id 192.168.1.1
set protocols ospfv3 area 0.0.0.0 interface 'wg01'
set protocols ospfv3 area 0.0.0.0 interface 'lo'
**Node 2**
.. code-block:: none
set interfaces wireguard wg01 address 'fe80::216:3eff:fe0a:7ada/64'
set interfaces wireguard wg01 address '192.168.0.2/24'
set interfaces wireguard wg01 peer ospf01 allowed-ips '::/0'
set interfaces wireguard wg01 peer ospf01 allowed-ips '0.0.0.0/0'
set interfaces wireguard wg01 peer ospf01 endpoint '10.1.1.100:12345'
set interfaces wireguard wg01 peer ospf01 pubkey 'NHI...='
set interfaces wireguard wg01 port '12345'
set protocols ospfv3 parameters router-id 192.168.1.2
set protocols ospfv3 area 0.0.0.0 interface 'wg01'
set protocols ospfv3 area 0.0.0.0 interface 'lo'
**Status**
.. code-block:: none
vyos@ospf01:~$ sh ipv6 ospfv3 neighbor
Neighbor ID Pri DeadTime State/IfState Duration I/F[State]
192.168.0.2 1 00:00:37 Full/PointToPoint 00:18:03 wg01[PointToPoint]
vyos@ospf02# run sh ipv6 ospfv3 neighbor
Neighbor ID Pri DeadTime State/IfState Duration I/F[State]
192.168.0.1 1 00:00:39 Full/PointToPoint 00:19:44 wg01[PointToPoint]
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