Routing Preference; Load Sharing - HP 3600 v2 series Configuration Manual

Criterion
Routing algorithm
Destination address
type
IP version
NOTE:
An AS refers to a group of routers sharing the same routing policy and working under the same
•
administration.
This chapter focuses on unicast routing protocols. For more information about multicast routing
•
protocols, see

Routing preference

Different routing protocols can find different routes to the same destination. However, not all of those
routes are optimal. For route selection, routing protocols, direct routes, and static routes are assigned
different preferences. The route with the highest preference is preferred.
The preference of a direct route is always 0 and cannot be changed. You can manually configure
preferences for any other route type. Each static route can be configured with a different preference. The
following table lists the types of routes and the default preferences. The smaller the preference value, the
higher the preference.
Routing approach
Direct route
OSPF
IS-IS
Static route
RIP
OSPF ASE
OSPF NSSA
iBGP
eBGP
Unknown (route from an untrusted source)

Load sharing

A routing protocol can be configured with multiple equal-cost routes to the same destination. These routes
have the same preference and will all be used to accomplish load sharing if there is no route with a
higher preference available.
Categories
•
Distance-vector protocols—RIP and BGP. BGP is also considered a path-vector
protocol.
•
Link-state protocols—OSPF and IS-IS
•
Unicast routing protocols—RIP, OSPF, BGP, and IS-IS
•
Multicast routing protocols—PIM-SM and PIM-DM
•
IPv4 routing protocols—RIP, OSPF, BGP, and IS-IS
•
IPv6 routing protocols—RIPng, OSPFv3, IPv6 BGP, and IPv6 IS-IS
IP Multicast Configuration Guide
.
Preference
0
10
15
60
100
150
150
255
255
256
3