H3C Technologies H3C S12500-X Series Switches - Manual (Page 73)

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Static routes
Static routes are manually configured by the administrator. After you configure a static route, an FC frame
to the specified destination is forwarded along the path specified by the administrator.
In a simple network, static routes are enough for implementing network connectivity. By correctly setting
and using static routes, you can improve network performance and guarantee bandwidth for critical
network applications.
However, the static routes cannot automatically adapt to network topology changes. When the network
fails or the network topology changes, the routes might fail to be reachable, and the network is
interrupted. In this case, you must manually modify the static routes.
Static routes support equal-cost routes. When you configure multiple equal-cost static routes to the same
destination but with different outgoing interfaces, equal-cost routes are generated.
FSPF routes
As a route selection protocol based on link states, FSPF can automatically calculate the best path
between any two switches in a fabric.
FSPF has the following characteristics:
• Can be used for any topology.
• Supports equal-cost routes.
• Performs topology calculations on a per-VSAN basis.
• Runs only on E_Ports and provides a loop-free topology.
• Provides a topology database on each switch to track the state of all links.
• Uses the Dijkstra algorithm to calculate routes.
• Provides fast convergence in the event of topology changes.
Basic concepts
• LSDB
The link state database (LSDB) is used to store global topology information for switches and link
state information of all switches in link state records (LSRs).
• LSR
An LSR describes information about all link states between a switch and its directly connected
switches.
Each LSR generated by a switch is called an LSR instance. LSRs generated by all switches comprise
the LSDB. An LSR contains one or more pieces of link state information, including the following:
{
LSR hold time.
{
Domain ID of the switch advertising the LSR.
{
LSR instance number. Every time an LSR is updated, the instance number increments by 1.
{
Link ID, which identifies a link and includes the domain ID of the switch at the peer end of the
link.
{
Source interface and destination interface of the link.
{
Link type, for example, point-to-point connection.