Nortel BayStack 5520-24T-PWR Specifications page 4

Figure 4. Distributed Multi-Link Trunking
(DMLT) across stack
DMLT across stack with
load-balancing and failover
protection for uninterrupted
access to servers or the
network center
BayStack 5520
stack
Server
Passport 8600
4
The BayStack 5520 Switches support the DHCP (Dynamic Host Configuration
Protocol) Relay feature that provides the system with the ability to relay DHCP
requests to the DHCP server and eliminates the need for a DHCP server on every
subnet. It forwards a request for an IP address from a client to a DHCP server
across subnets.
Software feature enhancements are planned to include support for routing protocols
such as Routing Information Protocol (RIP v1/v2)
Compact form factor
The BayStack 5520 Switches are offered in a compact one-rack unit high design. An
eight unit stack provides up to 384 10/100/1000 ports. This allows for significant
space and cost savings in the wiring closet.
Up to 32 built-in GBIC ports in a stack
BayStack 5520 Switches have four built-in SFP GBIC ports for dedicated uplink
connectivity to network core switches such as the Passport 8600. This increases the
uplink bandwidth as GBIC ports are not required for stacking purposes. Using the
proven Distributed Multi-Link Trunking (DMLT) resiliency feature, up to 32 GBIC
ports are available for pure uplink connectivity in a full stack—among the highest in
the market. BayStack 5000 Switches have also been architected to support future
technologies such as 10 Gigabit uplinks.
Plug-and-play stacking with built-in stacking ports
BayStack 5520 Switches have built-in stacking ports for faster, plug-and-play stack-
ing. This is more cost-effective as cascade modules are not required. This stacking
design frees up both of the uplink ports for dedicated connectivity to the backbone.
BayStack 5520 Switches include a cascade cable (1.5 feet). In addition, cascade cables
are available in different lengths—1.5 feet, 10 feet, and 5 meters (16.4 feet)—to cover
a variety of stacking needs.
Recessed stacking connectors for higher reliability
BayStack 5520 Switches are designed with recessed stacking connectors that save premium
closet space and protect the integrity of the stack from accidental contact (Figure 3).
BoSS (BayStack operating system Switching Software)
BoSS for BayStack 5000 Switches is a single software image that allows BayStack 5520-48T-
PWR, 5520-24T-PWR, 5510-48T, 5510-24T, and future BayStack 5000 models to stack
together. BoSS for BayStack 5000 Switches is specific to this next generation of stacking
switches, with a software image that supports this new architecture. Earlier BayStack
switches support a different version of BoSS—although all share the same core software.
Simplified network operations
BoSS simplifies network operations by reducing the number of steps required for switch
software updates. With BoSS, only a single image needs to be downloaded from Nortel
Networks support site for all BayStack 5000 Switch types. Loading the image to different
switches is also considerably simplified. The image is loaded only to the base unit of the stack
which automatically loads it to other switches in the stack.
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