Chapter 11. Advanced Copy Services 551
/SM590000IP partnerships between the two systems can be over IPv4 or IPv6 only, but not both.
/SM590000Virtual LAN (VLAN) tagging of the IP addresses that are configured for remote copy is 
supported starting with V7.4.
/SM590000Management IP and iSCSI IP on the same port can be in a different network starting with 
V7.4.
/SM590000An added layer of security is provided by using Challenge Handshake Authentication 
Protocol (CHAP) authentication.
/SM590000Transmission Control Protocol (TCP) ports 3260 and 3265 are used for IP partnership 
communications. Therefore, these ports must be open in firewalls between the systems. 
/SM590000Only a single Remote Copy (RC) data session per physical link can be established. It is 
intended that only one connection (for sending/receiving Remote Copy data) is made for 
each independent physical link between the systems. 
/SM590000The maximum throughput is restricted based on the use of 1 Gbps or 10 Gbps Ethernet 
ports. It varies based on distance (for example, round-trip latency) and quality of 
communication link (for example, packet loss):
– One 1 Gbps port can transfer up to 110 MBps unidirectional, 190 MBps bidirectional
– Two 1 Gbps ports can transfer up to 220 MBps unidirectional, 325 MBps bidirectional
– One 10 Gbps port can transfer up to 240 MBps unidirectional, 350 MBps bidirectional
– Two 10 Gbps port can transfer up to 440 MBps unidirectional, 600 MBps bidirectional
The minimum supported link bandwidth is 10 Mbps. However, this requirement scales up 
with the amount of host I/O that you choose to do. Figure 11-97shows the scaling of host 
I/O.
Figure 11-97   Scaling of host I/O
The equation that can describe the approximate minimum bandwidth that is required 
between two systems with < 5 ms round-trip time and errorless link follows:
Minimum intersite link bandwidth in Mbps > Required Background Copy in Mbps + 
Maximum Host I/O in Mbps + 1 Mbps heartbeat traffic
Increasing latency and errors results in a higher requirement for minimum bandwidth.
Note: A physical link is the physical IP link between the two sites: A (local) and B 
(remote). Multiple IP addresses on local system A could be connected (by Ethernet 
switches) to this physical link. Similarly, multiple IP addresses on remote system B 
could be connected (by Ethernet switches) to the same physical link. At any point in 
time, only a single IP address on cluster A can form an RC data session with an IP 
address on cluster B.