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5–Fibre Channel over IP
Configuring FCIP
5-10 ISR651101-00 G
Link Data Rate
The available link data rate is not typically the same as the connection speed at
the router’s GE port. The GE port is typically connected to a local IP switch with
ports running at 1 gigabit. The provider of the long-distance connection (WAN)
provides the link data rate. Table 5-2 lists some examples of data rates for
commonly used WANs.
In some configurations, the data rate (bandwidth) supported by the WAN may not
be dedicated to a single application such as FCIP. The ability to set the router's
FCIP bandwidth usage provides for such configurations (see “Bandwidth Limiting”
on page 5-14).
Link Quality
The link (WAN) quality can be difficult to determine; however, monitoring the
router's statistics should provide an indication of the overall link quality. Typically,
low link level errors are not seen at the router because they generally occur in the
WAN.
The following TCP statistics are a useful indicator of WAN congestion or packet
errors:
TCP Received Duplicate ACKs—Receiving a duplicate ACK indicates that
the receiver did not receive the packet following the ACK’d packet (packet
whose sequence number follows the ACK'd packet). This is typically the
result of the following:
Congestion: An IP switch or router somewhere in the WAN has
dropped the packet due to its inability to transmit or buffer the packet.
Error: The packet was dropped somewhere in the WAN as a result of
the detection of a data error (corruption).
Table 5-2. WAN Data Rates
Link Type Speed
T1 and DS-1 1.554Mbps
T3 and DS-3 45Mbps
OC-1 50Mbps
OC-3 150Mbps
DS-5 400Mbps
OC-12 621Mbps
OC-24 1.5Gbps