McDATA StorageWorks 2/140 - Director Switch Planning Manual page 192

Implementing SAN Internetworking Solutions
4
McDATA Products in a SAN Environment - Planning Manual
4-50
To support greater Fibre Channel transmission rates (long-link ports),
the Intrepid 10000 Director provides a buffer pool that allocates
user-defined BB_Credits to each port. This buffer pool is increased if
the remote fabric PFE key is enabled (refer to
information). Each director line module (LIM) contains two scalable
packet processors, each supporting two optical paddles. A paddle
pair provides 16 ports (1.0625 or 2.1250 Gbps operation), four ports
(10.2000 Gbps operation), or ten ports (mixed data rate operation).
The buffer pool is allocated among all ports in a paddle pair subject to
the following constraints:
• Each paddle pair is allocated a maximum of 1,373 BB_Credits.
• Each short-link 1.0625 or 2.1250 Gbps port must be assigned a
minimum of 16 BB_Credits (default value).
• Each short-link 10.2000 Gbps port must be assigned a minimum
of 96 BB_Credits (default value).
Users assign BB_Credits to ports at the Element Manager application,
using entries in the RX BB Credit column of the Configure Ports dialog
box. Assuming four port paddle-pair combinations, the following
examples explain BB_Credit allocation to configure one port in a
paddle pair for extended distance (long-link) operation:
• 1.0625 or 2.1250 Gbps long link - A paddle pair with 1.0625 or
2.1250 Gbps ports provides 16 connections. 16 BB_Credits are
assigned to 15 short-link ports (240 BB_Credits total). The
remaining 1133 BB_Credits are assigned to the long-link port,
supporting a repeated transmission distance of 2,200 km (1.0625
Gbps) or 1,100 km (2.1250 Gbps).
• 10.2000 Gbps long link - A paddle pair with 10.2000 Gbps ports
provides four connections. 96 BB_Credits are assigned to three
short-link ports (288 BB_Credits total). The remaining 1085
BB_Credits are assigned to the long-link port, supporting a
repeated transmission distance of 180 km.
• 1.0625 or 2.1250 Gbps long link (mixed paddles) - A paddle pair
with one 1.0625 or 2.1250 Gbps paddle and one 10.2000 Gbps
paddle provides ten connections. 16 BB_Credits are assigned to
the slowest seven short-link ports, and 96 BB_Credits are
assigned to both 10.2000 Gbps short-link ports (304 BB_Credits
total). The remaining 1069 BB_Credits are assigned to the
long-link port, supporting a repeated transmission distance of
2,000 km (1.0625 Gbps) or 1,000 km (2.1250 Gbps).
Remote Fabric for