Ip performance tuning, Distance, Bandwidth per route – HP IP Distance Gateway User Manual
Page 25: Latency, Mtu/jumbo frames
IP performance tuning
The mpx110 supports Fibre Channel service at transmission rates of 1 Gb/s or 2 Gb/s with a
maximum frame size of 2,148 bytes. It supports Ethernet service at transmission rates of 1,000 or
100 Mb/s with an MTU size between 1,000 and 9,000 bytes (jumbo frames). Related performance
characteristics include the following:
•
•
•
•
•
•
TCP Window size/scaling performance tuning (page 26)
Distance
Consider the physical distance between the mpx110 gateways. This is usually measured in RTT.
The RTT can be anywhere from less than 1 millisecond to as great as 200 milliseconds.
Bandwidth per route
Bandwidth is a measure of the volume of data that can be transmitted at a given transmission rate.
WAN data rates range from 1.5 Mb/s (T1) to greater than 600 Mb/s (OC-12). The proper
mpx110 bandwidth setting is determined based on the bandwidth available for each FCIP route,
irrespective of the total bandwidth and physical speed of the link.
To determine the proper mpx110 bandwidth setting, start with the total bandwidth of the WAN
link. Adjust this number based on the guaranteed allocated FCIP bandwidth, then further adjust
this number if the number of FCIP routes configured is greater than one. For example, if the WAN
link is 45 Mb/s, and 15 Mb/s is allocated to network traffic, the remaining 30 Mb/s is available
for FCIP. If in this example the mpx110 is configured for two routes, based on the 30 Mb/s total
bandwidth available for FCIP, you would set the mpx110 bandwidth parameter to 15, the available
bandwidth for each FCIP route.
HP P9000 and P6000 Continuous Access replication solutions require dedicated bandwidth for
the intersite link. If other applications share the intersite link, some method of QoS must be used
to ensure that the replication application has uncontested access to the allocated bandwidth.
NOTE:
Setting the bandwidth per route parameter higher than the actual bandwidth available
for each route results in a decrease in performance; the optimal setting matches the bandwidth
per route setting to the actual bandwidth available to each FCIP route.
Latency
Latency is the amount of time a packet takes to traverse the network from source to destination.
MTU/Jumbo frames
For MTU size there are 3 settings, Normal (1500 bytes), Jumbo (9000 bytes) and Other, where
you are then prompted for a value between 1000 and 9000.
•
Normal: Typically MTU should be set to the default of 1500; rarely do WAN networks support
MTU sizes greater than 1500.
•
Jumbo - Jumbo frames can enhance the IP performance of the mpx110. Before enabling jumbo
frames, ensure that all switches in the IP path are configured for jumbo frames.
IP performance tuning
25