Chapter 20: Esrp Commands - Extreme Networks ExtremeWare XOS Command Reference Manual

20 ESRP Commands
This chapter describes the commands for:
Enabling and disabling ESRP
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Performing ESRP configuration
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Enabling and disabling port restart and failure tracking for ESRP
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Displaying ESRP configuration information
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Enabling and disabling ELRP in an ESRP environment
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Extreme Standby Router Protocol
The Extreme Standby Router Protocol (ESRP) is a feature of ExtremeWare XOS 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. You can use these "layered"
redundancy features 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)
or Virtual Router Redundancy Protocol (VRRP).
You configure ESRP on a per domain basis on each switch. A maximum of two switches can participate
in providing redundant Layer 3 or Layer 2 services to a single virtual LAN (VLAN). If you configure
and use ESRP groups, more than two switches can provide redundant Layer 2 or Layer 3 services to a
single vlan. The switches exchange keep-alive packets for each VLAN independently. Only one switch
(the master) can actively provide Layer 3 routing and/or Layer 2 switching for each VLAN. This switch
handles the forwarding, address resolution protocol (ARP) requests, and forwarding for this particular
VLAN. Other participating switches for the VLAN are in slave mode waiting for an ESRP state change.
To participate in ESRP, the following must be true:
A VLAN can belong to only one ESRP domain.
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The IP address for the VLANs participating in an ESRP domain must be identical.
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All switches in the ESRP network must use the same election algorithm, otherwise loss of
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connectivity, broadcast storms, or other unpredictable behavior may occur.
If you have an untagged master VLAN, you must specify an ESRP domain ID. The domain ID must
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be identical on all switches participating in ESRP for that particular domain.
If you have a tagged master VLAN, ESRP uses the 802.1Q tag (VLANid) of the master VLAN for the
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ESRP domain ID. If you do not use the VLANid as the domain ID, you must specify a different
domain ID. As previously described, the domain ID must be identical on all switches participating in
ESRP for that particular domain.
Extreme Networks recommends that all switches participating in ESRP run the same version of
ExtremeWare XOS. Not all ESRP features are available in all ExtremeWare XOS software releases.
ExtremeWare XOS 11.3 Command Reference
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