Date: Thu, 23 Jan 1997 19:19:35 +1100 From: Andrew McRae <amcrae@cisco.com> To: luigi@labinfo.iet.unipi.it Cc: hackers@freebsd.org, jdp@polstra.com Subject: Re: Fault-tolerant network with 2 ethernets Message-ID: <199701230819.TAA16703@metaplex-ss10.cisco.com>
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>A problem with BSD networking is that once a connection is opened, the >socket is bound to a specific interface and so it does not help to >have multiple paths starting from the same host. I forget the details, >but have been told that there is a very minor modification (a few >lines) that fixes this problem. > >Another trick (inefficient) you might use is to make all your >traffic through tun0 and then write your own forwarder for outgoing >traffic. Yes, an interesting idea, and one that I actually used in an embedded system that contained the BSD stack. The problem is pushed off into the forwarder, and it has to deal with all the routing issues. This can work, but I would have thought that any applications requiring 100BT bandwidth would not want the data to traverse across kernel/user space a couple of times :-) Presumably tun0 has its net interface on the application side, so what does it do with the pkts it reads? Look at the IP address inside the packet and then send it down a raw socket to one of a couple of interfaces? How does it receive the packets destined for the applications? Hmm, I guess it can be done, but I doubt whether it would be real easy (in my embedded environment, the forwarder could access the net devices directly). > Luigi >-----------------------------+-------------------------------------- >Luigi Rizzo | Dip. di Ingegneria dell'Informazione >email: luigi@iet.unipi.it | Universita' di Pisa >tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) >fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ >_____________________________|______________________________________ Cheers, Andrew McRae
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