
Operation Manual – IPv4 Routing
H3C S3610&S5510 Series Ethernet Switches
Chapter 4 IS-IS Configuration
4-28
Note:
z
On the broadcast link, you can specify different intervals for Level-1 and Level-2
hello packets; if no level is specified, the interval applies to both Level-1 and Level-2
hello packets, but only takes effect on the level of the current process; if a level is
specified, it applies to hello packets at this level. The point-to-point link does not
distinguish between Level-1 and Level-2 hello packets, so you need not specify a
level.
z
Hello packets are used to establish and maintain neighbor relationships. If no hello
packets are received from a neighbor within the time for receiving the specified hello
packets, the neighbor is considered dead.
z
CSNPs are sent by the DIS on a broadcast network for LSDB synchronization. If no
level is included, the specified CSNP interval applies to both Level-1 and Level-2 of
the current IS-IS process. If a level is specified, it applies to the level.
z
On a point-to-point link, if there is no response to a LSP sent by the local router
within the specified retransmission interval, the LSP is considered lost, and the
same LSP will be retransmitted. On broadcast links, responses to the sent LSPs are
not required.
z
The interval between hello packets sent by the DIS is 1/3 the hello interval set by the
isis timer hello
command.
4.5.4 Disabling an Interface from Sending/Receiving IS-IS Hello Packets
Follow these steps to disable an interface from sending hello packets:
To do…
Use the command…
Remarks
Enter system view
system-view
––
Enter interface view
interface
interface-type
interface-number
––
Disable the interface from
sending and receiving
hello packets
isis silent
Required
Not disabled by default
4.5.5 Configuring LSP Parameters
An IS-IS router periodically advertises all the local LSPs to maintain the LSP
synchronization in the entire area.
A LSP is given an aging time when generated by the router. When the LSP is received
by another router, its aging time begins to decrease. If the receiving router does not get
the update for the LSP within the aging time, the LSP will be deleted from the LSDB.