3.12.1 Maximum number of neighboring routers

The following table describes the maximum number of neighboring routers.

Table 3-69: Maximum number of neighboring routers
Routing protocol	Maximum number of neighboring routers
Routing protocol	The tracking functionality of policy-based routing is not used	The tracking functionality of policy-based routing is used
Static routing (total of IPv4 and IPv6)	1024^#	128^#
RIP	50	25
RIPng	50	25
OSPF	200	25
OSPFv3	50	25
BGP4	250	25
BGP4+	50	25
Sum of RIP, OSPF, BGP4, RIPng, OSPFv3, and BGP4+	250	25

#: The number of neighboring routers that can be monitored by the dynamic monitoring functionality is limited by the polling interval. For details, see the following table.

Table 3-70: Maximum number of neighboring routers that can use the static dynamic monitoring facility
Polling interval	Maximum number of neighboring routers that support the dynamic monitoring functionality
1 second	60
2 seconds	120
3 seconds	180
5 seconds	300
10 seconds	600
20 seconds	1024

The following table describes the maximum number of neighboring routers for each routing protocol.

Table 3-71: Definition of the maximum number of neighboring routers
Routing Protocol	Definition
Static Routing	Number of next hop addresses
RIP	How many RIP routers are on the network on which RIP runs
RIPng	How many RIPng routers are on the network on which RIPng runs
OSPF	Sum of routers on each interface on which OSPF operates If the interface is the designated router or designated backup router: The number of other OSPF routers connected to the interface If the interface is not the designated router or designated backup router: The number of designated routers and designated backup routers connected to the interface These two conditions effectively mean the number of neighboring routers in Full status displayed by the show ip ospf neighbor operation command.
OSPFv3	Sum of routers on each interface on which OSPFv3 operates If the interface is the designated router or designated backup router: The number of other OSPFv3 routers connected to the interface If the interface is not the designated router or designated backup router: The number of designated routers and designated backup routers connected to the interface These two conditions effectively mean the number of neighboring routers in Full status displayed by the show ipv6 ospf neighbor operation command.
BGP4	Number of BGP4 peers
BGP4+	Number of BGP4+ peers