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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/configuration/protocols/ospf.rst | 259 |
1 files changed, 253 insertions, 6 deletions
diff --git a/docs/configuration/protocols/ospf.rst b/docs/configuration/protocols/ospf.rst index acb1bce8..77ed4a37 100644 --- a/docs/configuration/protocols/ospf.rst +++ b/docs/configuration/protocols/ospf.rst @@ -19,6 +19,9 @@ 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 @@ -49,11 +52,6 @@ OSPFv2 (IPv4) :cfgcmd:`route-map` specifies to advertise the default route if the route map is satisfied. -.. 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 distance global <distance> This command change distance value of OSPF. The distance range is 1 to 255. @@ -70,10 +68,27 @@ OSPFv2 (IPv4) .. 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. + 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) @@ -101,6 +116,238 @@ OSPFv2 (IPv4) 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 --------------------- |