Subject: Re: Multiple net interfaces
To: Greg S. Burd <>
From: Dirk Steinberg <>
List: current-users
Date: 03/02/1994 09:31:02
>>>>> "Greg" == Greg S Burd <> writes:
    > 	If you have multiple interfaces to the same network,
    > is there a way to load-level between them?  Eg: If I have
    > two ethernet interfaces to the Internet on one machine, will
    > it use both interfaces equally therefor effectively doubling
    > my throughput?

    Greg> Packets are routed over network interfaces, such as /dev/en0
    Greg> and /dev/ppp0, via a routing table.  The routing table
    Greg> specifies an IP address, or subnet and an network interface.
    Greg> When a packet is being routed, a netmask is applied to a
    Greg> packet's destination address.  If the packet is bound for a
    Greg> remote network, then the interface it is sent over is the
    Greg> first entry in the routing table which describes that
    Greg> address.  So unless your two ethernet cards are talking to
    Greg> different subnets, and you have a routing table which
    Greg> describes that situation, all packets will be routed over
    Greg> one of the two ethernet cards.  There will be no speed.

You are describing the static routing as implemented in the current
NetBSD kernel. Given that scheme, you are right. But this doesn't mean
that it cannot be done with TCP/IP in principle.