HP-UX TCP/IP Performance White Paper, March 2008

in IPv6 for all non-local destinations to improve routing lookup. None of the routes from the netstat –rn

output will be deleted.

ip6_ire_hash:

Displays a report of all routing table entries, in the order

searched when resolving an IPv6 address.

The IPv6 Internet Routing Entry (IRE6) is the primary data structure that links IPv6 addresses with particular

interfaces, attached networks, gateways, and local and remote hosts. The corresponding data structure for

IPv4 is an IRE.

ip6_ire_pathmtu_interval:

Every "ip6_ire_pathmtu_interval milliseconds", IPv6 will scan

its routing table for entries that have an MTU less than the

MTU for the first hop interface. For each, it will increase

the value to the next highest value in its internal table of

common MTU sizes. In this way, if the path to a remote host

has changed, and a larger MTU is now usable, the new MTU

will be discovered. If this value is made too small, then

excessive lost packets can result. [5000, -]

Default: 600000 (10 minutes)

ip6_ire_redirect_interval:

All routing table entries resulting from ICMPv6 "Redirect"

messages are deleted after this much time has elapsed, whether

or not the entry has been recently used. An ICMPv6 "Redirect" is sent

to a host when it uses a gateway that believes there is a "better"

way for that host to send IPv6 datagrams to their final destination.

This can come about when one relies on default routes and there are

multiple routers on the local network, each going to different

destinations. [5000, - ] Default: 300000 (5 minutes)

ip6_ire_status:

Displays a report of all IPv6 routing table entries. Same

information as in ip_ire_hash, but format and ordering is

different.

ip6_reass_mem_limit:

Sets an upper bound on the number of bytes IPv6 will use for

packet reassembly. If the limit is reached, reassembly lists

are purged until the space required for the new fragments

becomes available.

It is rare that this value should need to be changed. Most of the

time, the successive fragments of an IP datagram will arrive fairly

close to one another, and will not sit very long in the reassembly

queue. However, if "netstat -p ipv6" shows a large number of IPv6