D-Link DSN-540 Software User's Guide for DSN-1100-10 - Page 108

Table 6-4. Advanced System Settings Advanced Setting Remote System Time NTP (Time Server) IP Address iSCSI Port Number TCP/IP - Time to Live TCP/IP - Maximum IP Segmentation TCP/IP - Window Scale TCP/IP - Timestamp TCP/IP - PMTU TCP/IP - Reset Upper Layer Counter iSNS Enabled iSNS Server IP Address iSNS Server Subnet Mask iSNS Server Port Default Block Size Description Date and time of the storage system, adjusted for its local time zone. Enter the IP address of the NTP Time Server to allow the storage system to synchronize its date and time with an external time server. The Default IP address is 0.0.0.0, which indicates that no time server synchronization will be performed. Specifies the TCP port number used for the iSCSI communication. The default value for the iSCSI protocol is 3260 and should not be changed. Specifies the Time To Live value set in the header of outgoing IP packets. This value determines the maximum number of seconds an IP packet can live in the network without reaching its destination. This limits the number of hops an IP packet can pass through before being discarded. The allowable range is 60 to 255 seconds. The default is 64 seconds. Specifies the largest amount of data, in bytes, that TCP is willing to send in a single segment. For best performance, this value should be set small enough to avoid IP fragmentation, which can lead to excessive retransmissions if there is packet loss. The allowable range is 512 to 65535 bytes. Default is 8960 bytes. For efficient use of high bandwidth networks, a larger TCP window size can be used. This option increases the maximum window size from 65,535 bytes to 1 Gigabyte. Scaling up to larger window sizes is a part of what is necessary for TCP Tuning. This option is used only during the TCP 3-way handshake. The window scale value represents the number of bits to left-shift the 16-bit window size field. The window scale value can be set from 0 (no shift) to 14. Default is 0. Causes the receiving computer to send a time-stamp reply back to the originating computer. Systems can use time-stamp requests and replies to measure the transmission speed of datagrams on a network. Choices are:  Enabled = TCP/IP timestamp is enabled.  Disabled = TCP/IP timestamp is disabled. (default) Determines whether the storage system automatically adapts its packet size. Choices are:  Enabled = automatically adapts its packet size. (default)  Disabled = keeps its default packet size (576 bytes), even if it receives an ICMP request to change its packet size. This can render some remote systems unreachable, because if intermediate systems on the path to the remote system cannot support the default packet size, the storage system ignores their requests to make the packets smaller. Determines whether the TCP/IP upper layer counters can be reset. Resetting the counters simplifies the ability to look at the counters for an accurate percentage of packets sent or received. Choices are:  Enabled = upper layer counters can be reset.  Disabled = upper layer counters cannot be reset. (default) Indicates whether iSNS is enabled. Choices are:  Enabled = iSNS is enabled and will register clients automatically  Disabled = iSNS is not enabled. (default) Enter the IP address of the iSNS server. Default is 0.0.0.0. Enter the subnet mask of the iSNS server. Default is 255.255.255.0. Enter the port of the iSNS server. Default is 0. Specifies the default block size that should be used for all newly created volumes. Choices are:  512 bytes (default)  4096 bytes (allows volume sizes up to 16TB with 32-bit operating systems) 98 Chapter 6 System Administration