55 lines
2.3 KiB
HTML
55 lines
2.3 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
|
|
<!--Converted with LaTeX2HTML 96.1-c (Feb 29, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds -->
|
|
<HTML>
|
|
<HEAD>
|
|
<TITLE>The Future</TITLE>
|
|
</HEAD>
|
|
<BODY LANG="EN">
|
|
<A HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <BR>
|
|
<B> Next:</B> <A HREF="node80.html">Name Service and Resolver </A>
|
|
<B>Up:</B> <A HREF="node58.html">Configuring TCP/IP Networking</A>
|
|
<B> Previous:</B> <A HREF="node78.html">Checking the ARP Tables</A>
|
|
<BR> <P>
|
|
<H1><A NAME="SECTION0071100000">The Future</A></H1>
|
|
<P>
|
|
networking is still evolving. Major changes at the kernel
|
|
layer will bring a very flexible configuration scheme that will allow
|
|
you to configure the network devices at run time. For instance, the
|
|
ifconfig command will take arguments that set the IRQ line and
|
|
DMA channel.
|
|
<P>
|
|
<A NAME="3129"></A>
|
|
<A NAME="3195"></A>
|
|
Another change to come soon is the additional mtu flag to the
|
|
route command which will set the Maximum Transmission Unit for a
|
|
particular route. This route-specific MTU overrides the MTU specified
|
|
for the interface. You will typically use this option for routes
|
|
through a gateway, where the link between the gateway and the
|
|
destination host requires a very low MTU. For instance, assume
|
|
host wanderer is connected to vlager through a SLIP link.
|
|
When sending data from vstout to wanderer, the
|
|
networking layer on wanderer would would use packets of up to
|
|
1500 bytes, because packets are sent across the Ethernet. The SLIP
|
|
link, on the other hand, is operated with an MTU of 296, so the network
|
|
layer on vlager would have to break up the IP packets into
|
|
smaller fragments that fit into 296 bytes. If instead, you would have
|
|
configured the route on vstout to use a MTU of 296 right from
|
|
the start, this relatively expensive fragmentation could be avoided:
|
|
<pre>
|
|
# route add wanderer gw vlager mtu 296
|
|
</pre>
|
|
|
|
Note that the mtu option also allows you to selectively undo
|
|
the effects of the `Subnets Are Local' Policy (SNARL). This policy is
|
|
a kernel configuration option and is described in chapter-<A HREF="node41.html#hardware"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif"></A>.
|
|
<P>
|
|
|
|
|
|
<BR> <HR>
|
|
<P><ADDRESS>
|
|
<I>Andrew Anderson <BR>
|
|
Thu Mar 7 23:22:06 EST 1996</I>
|
|
</ADDRESS>
|
|
</BODY>
|
|
</HTML>
|