Specifications

228 ExtremeWare XOS 11.0 Concepts Guide
Extreme Standby Router Protocol
Networks that contain switches running ExtremeWare with both ESRP and Extreme Loop Recovery
Protocol (ELRP) enabled and switches running ExtremeWare XOS 11.0 with ESRP enabled have been
extensively tested. ExtremeWare XOS does not implement ELRP but is compatible with the ELRP
mechanisms available in ExtremeWare.
Reasons to Use ESRP
You can use ESRP to achieve edge-level or aggregation-level redundancy. Deploying ESRP in this area
of the network allows you to simplify your network design, which is important in designing a stable
network. ESRP also works well in meshed networks where Layer 2 loop protection and Layer 3
redundancy are simultaneously required.
ESRP Terms
Table 42 describes terms associated with ESRP.
Table 42: ESRP terms
Term Description
election algorithm This is a user-defined criteria to determine how the master and the slave interact
with each other. The election algorithm also determines which device becomes the
master or the slave and how ESRP makes those decisions.
For more information about the election algorithms, see “ESRP Election Algorithms”
on page 237.
ESRP domains An ESRP domain allows multiple VLANs to be protected under a single logical entity.
Domains also increase the scalability of ESRP. An ESRP domain consists of one
domain-master VLAN and zero or more domain-member VLANs.
ESRP groups An ESRP group runs multiple instances of ESRP within the same VLAN or broadcast
domain. To provide redundancy at each tier, use a pair of ESRP switches on the
group.
ESRP instance You enable ESRP on a per domain basis. Each time you enable ESRP is an ESRP
instance.
ESRP VLAN A VLAN that is a part of an ESRP domain, with ESRP enabled, is an ESRP VLAN.
ESRP-aware An ESRP-aware device is an Extreme Networks switch that does not participate in
ESRP elections but is capable of listening to ESRP PDUs (which is what ESRP uses
to transmit information).
For more information see “ESRP-Aware Switches” on page 231.
ESRP-enabled An ESRP-enabled device is an Extreme Networks switch with an ESRP domain and
ESRP enabled. ESRP-enabled switches include the ESRP master and slave
switches.
extended mode ESRP extended mode supports and is compatible with switches running only
ExtremeWare XOS. By default, ESRP is in extended mode in ExtremeWare XOS.
Extended mode is not compatible with ExtremeWare; however, use extended mode if
your network contains switches running only ExtremeWare XOS.
To force a change in the mode of operation, use the configure esrp mode
[extended | standard] command. The mode of operation is also updated by
the type of protocol data unit (PDU) (ExtremeWare or ExtremeWare XOS) received
from the neighbor switch.
For more information, see “Standard and Extended ESRP” on page 231.