Bookmark and Share

Director Local Switching

Architecture | Power and Cooling | Local Switching | Trunking | Oversubscription | IP Distance | Power Calculator

Why is local switching important?

Local switching allows neighboring ports to communicate without consuming valuable core / slot bandwidth. It also results in lower switching latency and higher full-speed port density.

How does Brocade compare?

Brocade is the only vendor that delivers local switching. In the 48000, in addition to 64 Gbit/sec of core switching bandwidth per slot,

  • the 4 Gbit/sec 32-port director blade provides 128 Gbit/sec of local switching -- if all 64 Gbit/sec of slot bandwidth is used, 64 Gbit/sec of local switching is still available on the blade.
  • the 4 Gbit/sec 48-port director blade has 192 Gbit/sec of local switching -- if all 64 Gbit/sec of slot bandwidth is used, 128 Gbit/sec of local switching is still available on the blade.
  • 8 Gbit/sec blades also support local switching in the 48000

In the DCX, in addition to 256 Gbit/sec of core switching bandwidth per slot,

  • the 8 Gbit/sec 48-port director blade has 384 Gbit/sec of local switching -- if all 256 Gbit/sec of slot bandwidth is used, 128 Gbit/sec of local switching is still available on the blade.
  • there is no oversubscription in slots when using either 16 or 32 8 Gbit/sec blades, but local switching bandwidth is still available.
  • there is no oversubscription in slots when using 4 Gbit/sec optics in the 48 port 8 Gbit/sec blades, and local switching bandwidth is still available.

As a result, Brocade has the industry's highest full-speed 4 Gbit/sec and 8 Gbit/sec port density.

Function Brocade DCX Brocade 48000 Brocade Mi10000 Brocade M6140 Cisco MDS 9513
Local Switching Yes
16 to 48 x 8 Gbit/sec ports 		Yes
16 to 48 x 4 or 8 Gbit/sec ports 		No No No
Local bandwidth per blade 128 to 384 Gbit/sec 64 to 192 Gbit/sec 0 0 0
Backplane bandwidth per slot 256 Gbit/sec
(32 x 8 Gbit/sec)
(32 x 4Gb + 16 x 8Gb) (&#lt; 48 x 4 Gbit/sec) 		64 Gbit/sec
(16 x 4 Gbit/sec) 		64 Gbit / sec
(16 x 4 Gbit/sec) 		8 Gbit/sec
(2 x 4 Gbit/sec) 		48 Gbit/sec
(12 x 4 Gbit/sec)

Cisco MDS directors cannot switch locally. Traffic between neighboring ports must use valuable backplane bandwidth that is already at a premium with only 51.2 Gbit/sec of bandwidth per linecard slot. As a result, no more than 12 ports per slot can simultaneously communicate at 4 Gbit/sec, even when the 24 and 48-port linecards are in place. While ports on the 24 and 48-port linecards no longer need to be turned off when the 12 ports are set at 4 Gbit/sec, they must share a meagre 3.2 Gbit/sec, or 0.8 Gbit/sec per port group.*.

 

Click here for references.