Open Shortest Path First (OSPF) is a routing protocol for networks with Internet Protocol (IP) link status. It uses a routing algorithm connection status and falls into the group of interior routing protocols, operating within a single autonomous system (AS). Is defined as OSPF Version 2 in RFC 2328 (1998) for IPv4. The updates for IPv6 are specified as OSPF Version 3 in RFC 5340 (2008).
OSPF Configuration :
Sample configuration file
Router R1 :
Router 2 :
Router 3 :
Routing table of routers
Router 1:
Router 2 :
Router 3 :
OSPF(ospf cisco) is an interior gateway protocol that routes packets of Internet Protocol (IP) in a routing domain ( autonomous system ) . Gather link state information available routers and constructs a topology map of the network. Topology determines the routing table presented at the Internet layer that makes routing decisions based solely on the destination IP address found in the IP packet address. OSPF mask was designed to support the subnet mask length variable ( VLSM ) or Inter - Domain Routing ( CIDR ) addressing models classless routing ospf cisco.
OSPF detects topology changes such as link failures cisco ospf configuration, and converges on a new loop-free routing structure within seconds. Calculation of the shortest path tree for each channel using a method based on the Dijkstra algorithm cisco ospf configuration, an initial algorithm shortest path ospf cisco.
OSPF routing policies to build a routing table are governed by link cost factors ( external measurements ) associated with each routing interface . Cost factors are the distance of a router ( round trip time ) cisco ospf configuration, the network performance of a link ospf cisco, or the availability and reliability of the connection , expressed in simple numbers without units. This provides a dynamic load balancing of traffic between equal cost routes ospf cisco.
An OSPF network can be structured or divided into zones to simplify routing traffic management and optimization and resource utilization ospf cisco. Zones are identified by numbers that are 32 bits, expressed only in decimal notation or byte often based on the dot notation to decimal IPv4 address family ospf cisco.
By convention, area 0 (zero) or 0.0.0.0 represents the area of the core or backbone of an OSPF network. Identifying other areas can be selected will often administrators to select the IP address of the primary router in an area such as the identification of the area. Each additional area must have a direct link or virtual for the OSPF backbone area cisco ospf configuration. These connections are maintained by a router interface ospf cisco, called area border router (ABR ) . ABR maintains a database link status separately for each area it serves and maintains summarized all areas of network routes ospf cisco.
OSPF does not use a TCP / IP network transport protocol (UDP, TCP ), but in IP data grams directly encapsulated with protocol number 89 cisco ospf configuration. This is in contrast with other routing protocols such as Routing Information Protocol (RIP) or Border Gateway Protocol (BGP ) . OSPF is its own error correction and detection functions ospf cisco.
OSPF uses multicast to withstand the flooding of the road on a broadcast domain ospf cisco. For networks non - broadcast special provisions for configuration facilitate neighbor discovery . [1] IP OSPF multicast packets never reach the IP routers (never Areas of cross diffusion) , do not travel more than one hop. Reserve the OSPF multicast address 224.0.0.5 for IPv4 or IPv6 FF02 :: 5 ( all routers state SPF / Bond, also known as AllSPFRouters ) and 224.0.0.6 in IPv4 or IPv6 FF02 :: 6 ( all AllDRouters the designated routers ) as specified in RFC 2328 [3] and RFC 5340 [4] .
For traffic IP multicast routing , multicast support OSPF Open Shortest Path First protocol ( MOSPF ) as defined in RFC 1584 ospf cisco. [5 ] Neither Cisco nor Juniper Networks include MOSPF in their OSPF implementations cisco ospf configuration. PIM ( Protocol Independent Multicast ) with OSPF or another IGP (Interior Gateway Protocol ) is widely deployed ospf cisco.
OSPF , when run on IPv4 , can operate securely between routers ospf cisco, if necessary by using a variety of authentication methods to allow only trusted routers participate in routing. OSPFv3 , running on IPv6 , and does not support authentication protocol built cisco ospf configuration. Instead , it is based on the IPv6 protocol security (IPsec) ospf cisco.
OSPF Version 3 makes changes to the implementation of the IPv4 protocol. [2] With the exception of virtual links , all exchanges of neighbors using the link-local IPv6 only. IPv6 is performed for each link rather than based on the subnet cisco ospf configuration. All information of IP prefix was removed from link state advertisements and discovery by OSPFv3 Hello packet essentially independent . Despite the expansion of intellectual property against 128 bits for IPv6 , the area and the router ID is based on 32-bit values ospf cisco. |
|
Aucun commentaire:
Enregistrer un commentaire