ip_ire_pathmtu_interval
| Description | The interval in milliseconds
when IP flushes the path maximum transfer unit (PMTU) discovery information,
and tries to rediscover PMTU.
Refer to RFC 1191 on PMTU discovery.
| | Default | 10 minutes
| | Range | 5 seconds to 277 hours
| | Dynamic? | Yes
| | When to Change | Do not change this
value.
| | Commitment Level | Unstable
|
ip_icmp_return_data_bytes and ip6_icmp_return_data_bytes
| Description | When IPv4 or IPv6 sends
an ICMPv4 or ICMPv6 error message, it includes the IP header of the packet
that causes the error message. This parameter controls how many extra bytes
of the packet beyond the IPv4 or IPv6 header to be included in the ICMPv4
or ICMPv6 error message.
| | Default | 64 bytes
| | Range | 8 to 65,536 bytes
| | Dynamic? | Yes
| | When to Change | Do not change the
value. Including more information in an ICMP error message might help in diagnosing
network problems. If this feature is needed, increase the value.
| | Commitment Level | Unstable
|
TCP Tunable Parameters
tcp_deferred_ack_interval
| Description | The time-out value for
TCP delayed acknowledgment (ACK) timer in milliseconds for hosts that are
not directly connected.
Refer to RFC 1122, 4.2.3.2.
| | Default | 100 milliseconds
| | Range | 1 millisecond to 1 minute
| | Dynamic? | Yes
| | When to Change | Do not increase this
value to more than 500 milliseconds.
If in some circumstances, slow network links (less than 57.6 Kbps) with
greater than 512 bytes maximum segment size (MSS) when the interval is short
for receiving more than one TCP segment, increase the value.
| | Commitment Level | Unstable
|
tcp_local_dack_interval
| Description | The time-out value for
TCP delayed acknowledgment (ACK) timer in milliseconds for hosts that are
directly connected.
Refer to RFC 1122, 4.2.3.2.
| | Default | 50 milliseconds
| | Range | 1 millisecond to 1 minute
| | Dynamic? | Yes
| | When to Change | Do not increase this
value to more than 500 milliseconds.
If in some circumstances, slow network links (less than 57.6 Kbps) with
greater than 512 bytes maximum segment size (MSS) and the interval is short
for receiving more than one TCP segment, increase the value.
| | Commitment Level | Unstable
|
tcp_deferred_acks_max
| Description | The maximum number of
TCP segments (in units of maximum segment size MSS for individual connections)
received from remote destinations (not directly connected) before an acknowledgment
(ACK) is generated. If set to 0 or 1, it means no delayed ACKs, assuming all
segments are 1 MSS long. The actual number is dynamically calculated for each
connection. The value is the default maximum.
| | Default | 2
| | Range | 0 to 16
| | Dynamic? | Yes
| | When to Change | Do not change the
value. In some circumstances, when the network traffic becomes very bursty
because of the delayed ACK effect, decrease the value. Do not decrease this
value below 2.
| | Commitment Level | Unstable
|
tcp_local_dacks_max
| Description | The maximum number of
TCP segments (in units of maximum segment size MSS for individual connections)
received from directly connected destinations before an acknowledgment
(ACK) is generated. If set to 0 or 1, it means no delayed ACKs, assuming
all segments are 1 MSS long. The actual number is dynamically calculated for
each connection. The value is the default maximum.
| | Default | 8
| | Range | 0 to 16
| | Dynamic? | Yes
| | When to Change | Do not change the
value. In some circumstances, when the network traffic becomes very bursty
because of the delayed ACK effect, decrease the value. Do not decrease this
value below 2.
| | Commitment Level | Unstable
|
tcp_wscale_always
| Description | If set to 1, TCP always
sends SYN segment with the window scale option, even if the option value is
0. Note that if TCP receives a SYN segment with the window scale option, even
if the parameter is set to 0, TCP responds with a SYN segment with the window
scale option, and the option value is set according to the receive window
size.
Refer to RFC 1323 for the window scale option.
| | Default | 0 (disabled)
| | Range | 0 (disabled), 1 (enabled)
| | Dynamic? | Yes
| | When to Change | If you want the window
scale option in a high-speed network configuration, enable it.
| | Commitment Level | Unstable
|
|
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