Extreme Networks ExtremeWare Command Reference Manual page 735

14
ESRP Commands
This chapter describes the following commands:
• Commands for enabling and disabling ESRP
• Commands for performing basic ESRP configuration
• Commands for enabling and disabling port restart and failure tracking for ESRP
ESRP is a feature of ExtremeWare that allows multiple switches to provide redundant layer 3 routing
services to users. In addition to providing layer 3 routing redundancy, ESRP also provides for layer 2
redundancy. These "layered" redundancy features can be used in combination or independently. The
layer 2 redundancy features of ESRP offer fast failure recovery and provide for dual-homed system
design. In some instances, depending on network system design, ESRP can provide better resiliency
than using the Spanning Tree Protocol (STP).
Extreme switches that are not running ESRP, but are connected on a network that has other Extreme
switches running ESRP are ESRP-aware. This means that when Extreme switches are attached to the
ESRP-enabled switches, the non-ESRP switches reliably perform fail-over and fail-back scenarios in the
prescribed recovery times. No configuration of this feature is necessary.
ESRP is configured on a per-VLAN basis on each switch. A maximum of four switches can participate
in providing redundant layer 3 or layer 2 services to a single VLAN. A maximum of 3000 VLANs can
run ESRP simultaneously on a single switch. The switches exchange keep-alive packets for each VLAN
independently. Only one switch can actively provide layer 3 routing and/or layer 2 switching for each
VLAN. The switch performing the forwarding for a particular VLAN is considered the "master" for that
VLAN. Other participating switches for the VLAN are in standby mode.
To have two or more switches participate in ESRP, the following must be true:
• For each VLAN to be made redundant, the switches must have the ability to exchange packets on
the same layer 2 broadcast domain for that VLAN. Multiple paths of exchange can be used.
• For a VLAN to be recognized as participating in ESRP, the assigned IP address or the IPX NETid for
the separate switches must be identical. Other aspects of the VLAN, including its name, are ignored.
• ESRP must be enabled on the desired VLANs for each switch. ESRP cannot be enabled on the VLAN
"default."
• Extreme Discovery Protocol (EDP) must be enabled on the ports that are members of the ESRP
VLANs. (The default setting is enabled.)
ESRP can also be enabled on super-VLANs. The super-VLAN must be configured with all the ports as
the sub-VLANs.
ExtremeWare Software 7.0.0 Command Reference Guide 735