Intel 480T, User Manual

Page: 158 / 367

156
C H A P T E R 9 Enterprise Standby Router Protocol
The failover time associated with the ESRP protocol is dependent
on the timer setting and the nature of the failure. The default timer
setting is 2 seconds; the range is 1 to 255 seconds. Default settings
usually result in a failover time of 5 to 8 seconds.
If routing is configured, the failover of the particular routing
protocol (such as RIP V1, RIP V2, or OSPF) is added to the failover
time associated with ESRP.
Configuring ESRP and Multinetting
When configuring ESRP and IP multinetting on the same switch,
the parameters that affect the determination of the ESRP master
must be configured identically for all the VLANs involved with IP
multinetting. For example, the number of links in your
configuration, the priority settings, and timer settings must be
identical for all affected VLANs.
ESRP and VLAN aggregation
ESRP can be used to provide redundant default router protection to
VLAN aggregation clients. ESRP is enabled on the super-VLAN
only (not the sub-VLANs). The procedure is to add ports to the
super-VLAN that is shared with the sub VLANs. To do so, the
super-VLAN should be configured with an 802.1Q tag, and added
as tagged with the sub-VLAN ports to avoid a protocol conflict.
Lastly, enable ESRP on the super-VLAN.
For more information on VLAN aggregation, see Chapter 10, IP
Unicast Routing.
The following example combines ESRP and VLAN aggregation for
the super-VLAN
vsuper and two sub-VLANs, v1sub and v2sub ,
that have ports 1 and 2 as members, respectively.
1 Create the VLANs and setup the super to sub-VLAN relation-
ship
create vlan v1sub
create vlan v2sub
create vlan vsuper
config vsuper ipaddress 10.1.2.3/24
enable ipforwarding
enable ospf