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Re: [Xen-users] DomU Bridged vs. Routed Networking?

To: Andy Lee <andylee@xxxxxxxx>
Subject: Re: [Xen-users] DomU Bridged vs. Routed Networking?
From: Nivedita Singhvi <nsnix@xxxxxxxxxxx>
Date: Tue, 16 Aug 2005 23:54:24 -0700
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Andy Lee wrote:
Is there a performance difference between bridged and routed DomU networking?

Seems like most users opt for the bridged approach. Perhaps it's because it is easier to setup and it is the default setting. For route, I spent several days to learn that /proc/sys/net/ipv4/conf/eth0/proxy_arp needs to be set to 0. It is not (Debian Sarge). It should probably be added to /etc/xen/scripts/network-route.

I also modified scripts/vif-route (using iptables) to forward only packets belonging to each domU's IP address, thereby preventing domU's from using IP addresses not assigned to them. With bridge, I'd need to install etables - one extra program to install and learn.

There is one other factor which some people have noticed
and pointed out on this list: the interface is in promiscuous mode
in the bridging scenario, which deteriorates performance.
Your mileage may vary.

thanks,
Nivedita


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