451
generates a link-state advertisement according to its surrounding network topology
structure (router LSA), and sends the LSA to other layer3 switches through link-state
update (LSU) packages. Thus, each layer3 switches receives LSAs from other layer3
switches, and all LSAs combined to the link-state database.
2
）
Since a LSA is the description of the network topology structure around a layer3 switch,
the LS database is the description of the network topology structure of the whole network.
The layer3 switches can easily create a weighted vector map according to the LS
database. Obviously, all layer3 switches in the same autonomous system will have the
same network topology map.
3
）
Each layer3 switch uses the shortest path finding (SPF) algorithm to calculate a tree of
shortest path rooted by itself. The tree provides the route to all the nodes in the
autonomous system, leaf nodes consist of the exterior route information. The exterior
route can be marked by the layer3 switch broadcast it, so that additional information
about the autonomous system can be recorded. As a result, the route table of each
layer3 switch is different.
OSPFv3 protocol is developed by the IETF, the OSPF v3 used now is fulfilled
according to the content described in RFC2328 and RFC2740.
As a result of continuous development of IPv6 network, it has the network
environment of nonsupport IPv6 sometimes, so it needs to do the IPv6 operation by
tunnel. Therefore, our OSPFv3 supports configuration on configure tunnel, and passes
through nonsupport IPv6 network by unicast packet of IPv4 encapsulation.
13.7.2 OSPFv3 Configuration Task List
1.
Enable OSPFv3 (required)
（
1
）
Enable/disable OSPFv3(required)
（
2
）
Configure the router-id number of the layer3 switch running OSPFv3
(optional)
（
3
）
Configure the network scope for running OSPFv3 (optional)
（
4
）
enable OSPFv3 on the interface (required)
2.
Configure OSPFv3 auxiliary parameters (optional)
（
1
）
Configure OSPFv3 package sending mechanism parameters
1)
Set the OSPFv3 interface to receive only
2)
Configure the cost for sending packages from the interface
3)
Configure OSPF package sending timer parameter (timer of broadcast
interface sending HELLO package to poll, timer of neighboring layer3 switch
invalid timeout, timer of LSA transmission delay and timer of LSA
retransmission.
