RIP features:
hop-convergence, convergence is slow, long time Recovery
rumors routing update mechanism, the lack of understanding of the global network topology
of "hops" for the measure, there is a risk selecting suboptimal path of
how to solve the problem of RIP:
triggered update
router topology information, based on the route calculated independently
the routing link bandwidth as a reference value
OSPF
name: Open Shortest Path First protocol
developed by the IETF, the core algorithm SPF
classless routing protocol (carry mask), link state protocol, the IGP
the IP protocol number: 89 (work in the transport layer)
protocol priority: 10
Multicast update address: 224.0.0.5,224.0.0.6
The difference between 224.0.0.5 and 224.0.0.6
224.0.0.5 is just open the OSPF, OSPF and add interfaces to the device, it will listen to the multicast address
224.0.0.6 is the only DR and BDR will go to listen
If A has a routing update, how the whole network is sent?
A first this route will first send the information via 224.0.0.6, DR after learning the information in the notice to the other routers 224.0.0.5 through these routes.
Link state transfer (LSA) comprising:
the IP address and mask of the interface
bandwidth of the interface
neighboring to the interface connector
Each router will own a calculation to the LSDB (Link State Data Base),
and to generate a routing table database.
OSPF working process:
the first step, establishing a neighbor, and then after the neighbor is established, the second step is sent to a neighbor LSA, to synchronize the link state database by LSA have to understand the topology of the entire network, after the completion of synchronizing databases, a third step, the optimal route calculated by the SPF algorithm, added to the routing table.
OSPF zoning advantages, easy management, reduction in the size of the topology within the region, thereby reducing the pressure of the router, easy to manage.
You can not directly exchange data packets between regular areas of OSPF.
Only one region, the area is non-zero number configuration will be a problem? (no problem..)
AS: Autonomous System.
If an OSPF router to import external routing, then this router belongs ASBR.
Election of Router-ID:
1. Manually configured priority
2. If not specified manually using logical interface (port loopback) the
highest IP address as the Router-ID
3. If there is no logical interface, using the maximum active physical interface IP address as the Router-ID
What is the MA network: multiple access multiple access networks, multiple access means there are multiple access points on a link. (Neighbor relations and more complex management, duplicate LSA flooding, resulting in waste of resources)
The DR and BDR role:
to reduce adjacency.
Reduce the OSPF protocol traffic.
Dummy node is a virtual node device, its function needs a router to carry.
DR and BDR election: interface based on the DR and BDR election of
priority 1. interfaces, more preferably greater priority.
2. If the priority is the same, comparison RID, more preferably greater RID.
(First elected BDR, if at this time there is no DR, the BDR at this time will become DR, then see at this time there is no BDR, BDR election again from another DRother in).
How DR's single point of failure to solve? BDR
An interface is a router DR, another interface is BDR.
An interface bandwidth, cost = reference / actual bandwidth, the default reference bandwidth 100M.
