.Part 4 SAN Extension and Bridging HP SAN Design Reference Guide 785354-001

Table 145 Network requirements for long-distance IP gateways with XCS 11 x , XCS 10 x , or XCS
09 x
DescriptionSpecification
IP bandwidth
1
• Must be dedicated to the HP P6000 Continuous Access storage replication function.
• The minimum IP bandwidth required for HP P6000 Continuous Access with
P63xx/P65xx EVA, EVA4400/6400/8400, and EVA4400 (embedded switch)
with FCIP is 2 Mb/s per path, or 4 Mb/s for two paths when using one IP link.
• There is no support for dynamic pacing of the gateway.
For the maximum number of DR groups, see Table 114 (page 228).
Maximum number of DR
groups
For minimum supported bandwidth and resulting maximum number of DR groups based
on the average packet-loss ratio and one-way inter-site latencies, see Table 146 (page
298) and Table 147 (page 298).
1,500 bytesMTU of the IP network
100 ms IP network delay one-way or 200 ms round-tripMaximum latency
1
Low-loss network: 0.0012% average over 24 hours
Average packet-loss ratio
2
High-loss network: 0.2% average over 24 hours; must not exceed 0.5% for more than
5 minutes in a two-hour window
Must not exceed 10 ms over 24 hours
Latency jitter
3
1
Pre-existing restriction
2
A high packet-loss ratio indicates the need to retransmit data across the inter-site link. Each retransmission delays
transmissions queued behind the current packet, thus increasing the time to complete pending transactions. Unless noted
otherwise, gateways listed in Table 146 (page 298) and Table 147 (page 298) are supported in both low-loss and high-loss
networks.
3
Latency jitter is the difference between the minimum and maximum values, and indicates how stable or predictable the
network delay. The greater the jitter, the greater the variance in the delay, which lowers the performance predictability.
NOTE: Applications typically require more than the minimum bandwidth to meet throughput
requirements. To increase the maximum number of DR groups, you must increase the minimum
available IP bandwidth. For example, if the maximum number of DR groups required is 10, increase
the minimum available bandwidth to 10 Mb/s; for 15 DR groups, increase it to 15 Mb/s; and for
128 DR groups, increase it to 128 Mb/s.
Table 146 (page 298) describes the network bandwidth requirements and IP gateway support for
XCS 09x with B-series switches.
HP storage replication products 297