Cisco DS-C9216I-K9, Руководство по настройке

Страница: 304 / 436

24-16
Cisco MDS 9000 Fabric Manager Switch Configuration Guide
OL-7753-01
Chapter 24 Configuring IP Storage
Configuring FCIP
Monitoring Window Congestion
The congestion window monitoring (CWM) option determines the maximum burst size allowed after an
idle period.
•
If the FC traffic burst is smaller than the configured CWM value, every packet is sent immediately,
provided that no TCP drops were detected in the previous RTT.
•
If FC traffic burst is larger than the configured CWM value, the excess packets will be sent during
succeeding RTTs.
By default the tcpcwm option is enabled and the default burst size is 10 KB.
Tip
We recommend that this feature remain enabled to realize optimal performance. Increasing the CWM
burst size can result in more packet drops in the IP network, impacting TCP performance. Only if the IP
network has sufficient buffering, try increasing the CWM burst size beyond the default to achieve lower
transmit latency.
Advanced FCIP Interface Configuration
You can establish connection to a peer by configuring one or more of the following options for the FCIP
interface. To do so, you must first create the interface and enter the config-if submode.
Configuring Peers
To establish a FCIP link with the peer, you can use one of two options:
•
—Used to configure both ends of the FCIP link. Optionally, you can also use the peer TCP port along
with the IP address.
• —Used to configure one end of the FCIP link when security gateways are present in the IP network.
Optionally, you can also use the port and profile ID along with the IP address.
Peer IP Address
The basic FCIP configuration uses the peer’s IP address to configure the peer information. You can also
specify the peer’s port number to configure the peer information. If you do not specify a port, the default
3225 port number is used to establish connection.
Special Frames
You can alternatively establish a FCIP link with a peer using an optional protocol called special frames.
You can enable or disable the
special-frame option. On the peer side, the special-frame option must be
enabled in order to establish the FCIP link. When the special-frame option is enabled, the peer IP
address (and optionally the port or the profile ID) only needs to be configured on one end of the link.
Once the connection is established, a special frame is exchanged to discover and authenticate the link.
By default, the special frame feature is disabled.
Refer to the Fibre Channel IP standards for further information on special frames.
Tip Special frame negotiation provides an additional authentication security mechanism because the link
validates the WWN of the peer switch.