Operation Manual – IPv6 Routing
H3C S3610&S5510 Series Ethernet Switches
Chapter 3 IPv6 OSPFv3 Configuration
3-3
3.1.4 Timers of OSPFv3
Timers in OSPFv3 include:
z
OSPFv3 packet timer
z
LSA delay timer
z
SPF timer
I. OSPFv3 packet timer
Hello packets are sent periodically between neighboring routers for finding and
maintaining neighbor relationships, or for DR/BDR election. The hello interval must be
identical on neighboring interfaces. The smaller the hello interval, the faster the
network convergence speed and the bigger the network load.
If a router receives no hello packet from a neighbor after a period, it will declare the peer
is down. The period is called dead interval.
After sending an LSA to its adjacency, a router waits for an acknowledgment from the
adjacency. If no response is received after retransmission interval elapses, the router
will send again the LSA. The retransmission interval must be longer than the round-trip
time of the LSA in between.
II. LSA delay time
Each LSA has an age in the local LSDB (incremented by 1 per second), but an LSA is
not aged on transmission. You need to add an LSA delay time into the age time before
transmission, which is important for low speed networks.
III. SPF timer
Whenever LSDB changes, SPF recalculation happens. If recalculations become so
frequent, a large amount of resources will be occupied, reducing operation efficiency of
routers. You can adjust SPF calculation interval and delay time to protect networks from
being overloaded due to frequent changes.
3.1.5 OSPFv3 Features Supported
z
Basic features defined in RFC2740
z
OSPFv3 stub area
z
OSPFv3 multi-process, which enable a router to run multiple OSPFv3 processes
3.1.6 Related RFCs
z
RFC2740: OSPF for IPv6
z
RFC2328: OSPF Version 2
