Chapter 13 Esrp Commands - Extreme Networks ExtremeWare XOS Command Reference Manual

13
ESRP Commands
This chapter describes the commands for:
• Enabling and disabling ESRP
• Performing ESRP configuration
• Enabling and disabling port restart and failure tracking for ESRP
• Displaying ESRP configuration information
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).
Extreme Networks switches that are not running ESRP but are connected on a network that has other
Extreme Networks switches running ESRP are ESRP-aware. This means that when Extreme Networks
switches are attached to the ESRP-enabled switches, the non-ESRP switches reliably perform failover
and failback scenarios in the prescribed recovery times. No configuration of this feature is necessary.
However, you can improve the performance of the ESRP-aware switch to forward packets and perform
failover operations if you configure an ESRP domain on an ESRP-aware switch. Use the
create esrp
command to create an ESRP domain. After you create the domain, do not enable it.
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 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.
• The IP address for the VLANs participating in an ESRP domain must be identical.
• All switches in the ESRP network must use the same election algorithm, otherwise loss of
connectivity, broadcast storms, or other unpredictable behavior may occur.
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