Voice-Class Availability
Modular Operating System
for High Availability Operation
True Preemptive Multitasking
and Protected Memory
Summit X250e switches allow each of
the many applications—such as Open
Shortest Path First (OSPF) and
Spanning Tree Protocol (STP)—to run
as separate Operating System (OS)
processes that are protected from each
other. This drives increased system
integrity and helps protect against
Denial of Service (DoS) attacks.
Process Monitoring and Restart
ExtremeXOS improves network
availability using process monitoring and
restart. Each independent OS process is
monitored in real time. If a process
becomes unresponsive or stops running,
it can be automatically restarted.
Loadable Software Modules
The modular design of the ExtremeXOS
OS allows the upgrading of individual
software modules, should this be
necessary, leading to higher availability
in the network (see Figure 1).
High Availability Network
Protocols
Ethernet Automatic Protection
Switching (EAPS)
EAPS allows the IP network to provide
the level of resiliency and uptime that
users expect from their traditional voice
network. EAPS differs from Spanning
Tree or Rapid Spanning Tree protocols
and offers sub-second (less than 50
milliseconds) recovery that helps deliver
consistent failover regardless of the number
of VLANs, network nodes or network
topology. Since EAPS allows the network
to recover almost transparently, VoIP calls
do not drop and digital video feeds do not
freeze or pixelize in most situations.
Spanning Tree/Rapid Spanning
Tree Protocols
Summit X250e switches support Spanning
Tree (802.1D), Per VLAN Spanning Tree
(PVST+), Rapid Spanning Tree (802.1w)
and Multiple Instances of Spanning Tree
(802.1s) protocols for Layer 2 resiliency.
Software-Enhanced Availability
Software-enhanced availability allows users
to remain connected to the network even
if part of the network infrastructure is down.
Summit X250e switches continuously check
for problems in the uplink connections
using advanced Layer 3 protocols such as
OSPF, VRRP and ESRP (ESRP supported
in Layer 2 or Layer 3), and dynamically
routes traffic around the problem.
Equal Cost Multipath Routing
Equal Cost Multipath (ECMP) routing allows
uplinks to be load balanced for performance
and cost savings while also supporting
redundant failover. If an uplink fails, traffic is
automatically routed to the remaining
uplinks and connectivity is maintained.
Link Aggregation (802.3ad)
Link aggregation allows trunking of up to
eight links on a single logical connection, for
up to 2 Gigabits per Second (Gbps) of
redundant bandwidth per logical connection.
Powered by the ExtremeXOS operating system, the Summit X250e switch supports process recovery and application
upgrades without the need for a system reboot. Summit X250e offers the high network availability required for converged
applications.
5154-01
PIM-SM
V4.6
PIM-DM
V4.4
SSG-2 +
SCP
Third
Party
Application
PIM-SM
V4.5
PIM-DM
V4.5
ExtremeXOS
Kernel
Kernel and
Kernel Loadable
Modules
Application
Modules
Kernel Loadable
Module
E
x
tr
e
m
e
X
O
S
Updated application
modules can be
upgraded during runtime
New Extreme Networks or
external application modules
can be added during runtime
1
2
Figure 1: ExtremeXOS Modular Design
Voice-Grade Stacking with
SummitStack
Summit X250e offers dual stacking interfaces
to provide high-speed 40 Gbps stacking
bandwidth. SummitStack architecture is
designed to support converged services by
its highly available, rapid failover capability
with n-1 master redundancy, distributed
Layer 2 and Layer 3 switching, link aggregation
across the stack and distributed uplinks.
SummitStack supports up to eight units in a
stack (mixture of the units can be
Summit X250e, Summit X450e,
Summit X450a and Summit X650 switches)
and provides sub-second failover for path
failure and hitless master/backup failover
along with hitless protocol support such as
OSPF graceful restart, PoE configuration
and Network Login user authentication.
Summit X250e provides chassis-like
management and availability with its
SummitStack stacking technology
(see Figure 2).
Figure 2: SummitStack Stacking
Architecture
© 2009 Extreme Networks, Inc. All rights reserved.
Summit X250e Series—Page 2
Extreme Networks Data Sheet
